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  • Galileo from the Top: Interview with the EC’s Paul Verhoef

    Paul Verhoef
    Paul Verhoef

    Paul Verhoef, the European Commission’s program manager for European Union (EU) satellite navigation programs — namely Galileo — discussed current issues at some length with GPS World, in a conversation on November 10. He addressed aspects of interoperability with GPS and prospects for further development in that area, the need for an ongoing political commitment by the EU to Galileo, the challenges of financing, the prospects for an 18-satellite constellation (which he dismisses as unrealistic), military considerations for both Galileo and GPS, and the recent uncertainty around Galileo’s Public Regulated Service.

    Alan Cameron (AC): All four GNSS operators are or have been in discussions about interoperability, to varying levels. In my perception, the U.S.-E.U. agreement on GPS/Galileo interoperability appears to be the strongest, most defined, and most committed result of all these talks.  Do you agree?

    Paul Verhoef: I think that’s correct. We have I think seen in the process with the U.S. that first of all there has been a quite clear political commitment on both sides, at the highest levels, that interoperability was wanted. Secondly, in the implementation we’ve had a very good working relation with our U.S. colleagues in order to establish that. The advantage that I see is that we have been able at a very early stage to deliver on such an interoperability agreement, that this is clear to industry, it provides for predictability. It allows industry to monitor clearly how the two systems are evolving, and when this interoperability is actually going to be available in the marketplace, and it allows them to time their investments, their R&D, their production, and all the rest.

    I’m extremely happy with that. We have moved on with U.S. colleagues to look at a whole range of other issues between the two systems, be it safety-of-life service, be it all sorts of other issues, and I think also because we jointly tie in our industries, we are transparent about the results, we provide papers, as we have recently done on SOL, we provide clarity to users worldwide. I think it is an excellent example of how this work can be done, and I’m extremely happy with it.

    There is possibly still quite a lot of work ahead of us. I would say there is work forever. There are evolutions in the thinking on GPS, there are evolutions in the thinking on Galileo, we need to adapt to new situations jointly, but there is a clear endeavor between the two sides to progress with that. There are suggestions every now and then, also some of the areas we haven’t been looking into, we should look into more closely, particularly referring to our PRS service, and whether we should have some closer contacts with the U.S. on how we would, on what we do jointly on PRS and GPS use, etc. But comments made, there is quite a lot of work underway.

    This doesn’t mean we aren’t doing anything with the other systems. We have with most of them very good relationships. Sometimes, like with the Russians, interoperability is a bit more complex because of the different technologies used, but the interest is there. We are with Japan pretty well advanced with the number of discussions; it is of course in a bit more limited context in relation to what the result would be for the services over Japan and the Asian region. With India, we are moving forward. As you know, with our Chinese colleagues the situation is a bit more complex. Although we have good discussions, I think there is still a bit of length to go before . . . . We come first of all with clear notions of compatibility, and interoperability is yet beyond that. So we need to take that in the order of priority, and the first priority is obviously compatibility.

    AC:     How does this commitment to interoperability balance with the lagging arrival of Galileo satellites, relative to the speed with which Compass is establishing a constellation?  For market acceptance and worldwide use, is a well-defined and interoperative signal structure more important than a fully operating constellation?

    Verhoef: That’s a good question. It’s not easy for me to predict how the markets will see that. If I judge by the way that our interoperability agreement with the U.S. has been received, one would tend to think that the market would be in favor of some predictability and some transparency in terms of the plans of the deployment schedule, and the standing, the solidity of the program in having a visibility, the capabilities of the technology, in having a timely interface specifications available, and all that sort of thing. We have done that, obviously there are currently a number of delays. My sense from what I hear from the marketplace is they are not too worried about that. They are really interested in being able to follow that.

    Whether the strategy of playing for speed is going to work, I guess is still an open issue. In my view it is rather a dangerous and rather tricky situation, because there is not too much visibility on the Chinese program. It is only recently that they have started lifting a bit of the veil on it. I’m not sure from what I hear from the marketplace, whether they think they know what the system is going to do, they don’t know the specifications, they don’t know what the exact planning is. And obviously there is a bit of an issue hanging in the air there: that if compatibility and interoperability with that particular system is not in place, what is going to be the consequence?

    Those agreements from China are not in place with us. It is not in place with the U.S., it is not in place with Russia, it is not in place as far as I can see it with Japan or with India. So the Chinese give a bit of an impression that they’re quite willing to go at this alone. Now I must say that over the last two years they have come into the fold of the international community a bit more, we have managed to convince them to discuss these issues with us not only bilaterally but also multi-laterally, at the providers’ forum which is taking place in the context of the International Committee on GNSS of the U.N. I think that they see that this is a good place to be. They have now offered to host a meeting of that committee in 2012, so the first indications are there that they are ready to be more of a world citizen, so to speak. But I think in order to find acceptance not only at the level of governments, but also at the level of markets, they’re going to really come forward with clarity on their intentions on compatibility and interoperability.  As long as there is uncertainty about that, my sense is that the marketplace will be holding back and will want to see how this develops before they move on anything at all.

    So it could be a rather risky strategy for the Chinese if they don’t seek to come to rather clear agreements with the other providers.  And not only the first time, like now, but on a continuous basis. We all have evolving systems, we all want to come with the possibility of new ideas. I don’t think there is anybody really trying to stop the others, but we are going to have to work very hard to make sure our respective plans all can be granted without undue impacts on the others. This is a continuous process which is going to last, I guess, forever. We’re going to have to really work at that. We are continuing everything we can in order to progress with the colleagues in China. I’ve recently had meetings with them, a couple of weeks ago, in August, to try and really understand what their concerns are and be able to address those. We still have hope to be able to
    come to a satisfactory conclusion.

    AC: Other than financing, what are the most significant challenges for the Galileo programme today?

    Verhoef: My sense, Alan, is that the most significant challenge for the programme is that we need to be able to give from the EU levels, at a political level, a political commitment to the system, which is solid. Meaning investments in receivers, in applications are done on the basis of a belief that the political commitment to the system, to supply the necessary minimum technical performance, that commitment is sufficiently solid, and sufficiently underpinned in order to have users worldwide say, Yes, we believe in this, and we think our own investment in this, even if it is sometimes a few thousand euros or sometimes hundreds of thousands or millions of euros is really warranted.

    Of course this commitment is currently in place in the U.S., the U.S. government has been able over the years to provide a very credible goal commitment as to its performance with GPS. There are sometimes discussions on it, but by and large people do accept that the commitment of U.S. government is very credible. Obviously, we seek to establish a very similar level of credibility of commitment, because otherwise there would always be doubt as to, well, there is a problem now and what would you do in the future, and would they continue doing this, and would I finance that, and all the rest, and you would have continuous discussions, and it brings a large measure of uncertainty in the marketplace. Given the rather difficult financial times everybody goes through around the world, this is not a good way to proceed. We are really working very hard with all the political levels in Europe to try and get such a commitment to the table, and with it of course the underpinning for it.

    The other challenge is, I think it is time that Galileo delivers something concrete. We’ve had many years of discussion behind us on whether the system will come, and if it will come, and how it will come, and what it will look like, and all the rest. I think that for my part, I’m very happy to see that in 2011, we plan to launch. The first four satellites are on the way; they are almost ready. About half the ground infrastructure is currently under implementation, we have every couple of months the opening of another ground station around the world. We had recently Kourou, New Caledonia, we will have next month the opening of the new ground station in Kiruna in northern Sweden. We have Oberpfafenhoffen in Germany open, we have Fucino in Italy open. With this, the system becomes a reality, and I think once the satellite launches will go across television screens in the whole world, people will see that the system is becoming a reality. And I think that is desperately needed in order to give it a sense that things are moving forward. I’m really looking forward to that. That is a piece of good progress we have achieved over the last couple of years.

    AC: And now, would you like to say anything about financing?

    Verhoef: Financing of any big programs, be it in the U.S. or Europe or any other part of the world, is always a challenge. Whether it is for civil programs, for military programs, for space programs, for terrestrial programs, no matter what, these sort of programs always have an issue with financing. Obviously, what we are trying to do at the moment is come to a financial engineering of the program, if you wish, in such a way that we can, from the program management point of view, take a commitment that we are normally not going over certain levels of financing, of budget use. I think this is possible to do. Obviously, then we will need our political levels, as I just said, to come to the commitment for this financing. We have at the moment in the world, but also in Europe, a particularly harsh financial crisis which means that many programs, be it in infrastructure provision, or in space, or in other areas, are under pressure.

    We think that the situation with Galileo is rather solid, not only have we already invested a lot, but I think the return on investment is important. The fact that we need an independent system is clear to everybody. Just to give you some figures on that, at the moment, 6 to 7 percent of the European Union GDP is directly dependent on the availability of GPS. This is a GDP value of around 800 billion euros, this is more than 1,000 billion dollars. This is a figure where you say, well, you know, is it acceptable that we have this all dependent on a single system, and I think that the view of most is, No, this is silly, this is a risk we shouldn’t take. Therefore our own system is well worth putting in space. I think the cause for Galileo is fully accepted, and on that basis I don’t feel too concerned.

    What is important is that we get a good grip on the cost of such a program. We’ve had to struggle with that a bit because we have found out — and this is known — we have found out that a number of our estimates a couple of years have been underestimated, particularly in the area of launches, which is much more expensive that we had anticipated. It is always difficult to do a good estimation for a program like this, because basically what you are buying is a machine that has not been made, at least in Europe, ever been made before. And because it is completely custom-made, it is not entirely clear during the estimates what are the costs that would be associated with it. But we are slowly coming to grips with that.

    We now have a much better view of where our cost envelopes would be going, and I think this is important for the European ministries of finance. I think they are not necessarily too worried about the actual costs, as long as those costs have some form of stability in them. As soon as there is any uncertainty, of course, ministries of finance become very nervous, because then they are heading for very uncertain futures, and they don’t know how to handle any possible program reserves, and all the rest of it.  That is of course a very difficult situation for them. But I think these times are now almost over, we now know, after we have the majority of the initial procurements behind us, we know pretty well what the system is going to cost, and that is a good basis to proceed.

    AC: Regarding the launches in particular, I’ve seen a proposal recently to move the launches away from Ariane and to Russia. Is this politically feasible?

    Verhoef: This is obviously politically very complex, in the sense that there are a couple of elements. The number one element, we have in Europe an access to space policy with a clear strategy to make sure we have our own abilities to launch. This access to space policy is built on a philosophy that we need to have our own capacity, meaning that Ariane Espace is also used for commercial purposes, but it is particularly used for governmental launches. There is obviously a price tag attached to that, and I think that is then to be seen how we handle that.

    The second thing is maybe a very formal issue, but in the end I think is very important. We have taken in the WTO a commitment that others could launch governmental satellites for us, but only the basis of reciprocity, meaning that we are willing to open our markets of governmental launches for launch providers from other regions of the world, but only if they open up their own governmental markets. This until now has not happened. So, if we would give access to either Russian or U.S. launchers, to take two of a number of theoretical possibilities, it would be difficult to see that we would see competition to our own launch system, without our own launch system having access to the governmental markets in the U.S. and in Russia. I think this is a basic political fact of life, and I don’t see quite easily that this position is going to be changed.

    I know there has been an expressed interest, both from a couple of Russian quarters, also from U.S. quarters, and I have been very clear to them. At the moment that the two respective governments that I mentioned open up their governmental launch market for the European launch systems to compete in, then I can accept offers from them in any bidding phases that we have. This is an issue, one can say, well you are running over cost, maybe you should go out nevertheless.  This is an easy way out, but on the one hand, it would completely undermine our WTO commitment and our policy in this, so I cannot see at the political level that there is going to be a change in this. We’re going to have to see how this proceeds. There is obviously a discussion on it, because one can now see what some of the price implications possibly would be, but this is where we are. I’m not too worried about that.

    It is true that we receive the launch providers, they have their ideas, they have their suggestions they offer to us. I have been careful in making sure to them they understood the context in which they do this, and I think they know what the situation is. Obviously they still try because maybe they would be able to provoke a change at the political level, but for the moment I very much doubt that that would be the case.
    AC: Going back to the figures of GDP percentage dependent on GNSS, if these could be published, and if the U.S. could supply the corresponding figures for the U.S. economy, and even Russia and China, this would be of mutual benefit, to furthering all GNSSs everywhere.

    Verhoef: These are indeed as you mentioned very important notions and they need to be well understood. This is where I see that the cooperation with us and the U.S. government is so good, because we have realized, on both sides, exactly that. We are very happy that there is a GPS system in certain ways complementary to ours, and in other ways a backup to us, and vice versa. You see it in the recent statement of the Obama administration, where they say they would want to extend their discussions with third countries to look at how these systems work together. My sense from what I hear is that this goes well beyond compatibility and interoperability. If we together provide a real important piece of infrastructure to the world, we need to be aware of the responsibility we carry with that.
    AC: When you say it goes beyond compatibility and interoperability, what would you call it?

    Verhoef:     There have been certain very informal suggestions already over the last couple of years from the U.S. as to whether we think it would be possible at some moment in the future to optimize operations between the two systems. For example, look at maintenance and outages jointly, so there is the least impact on the user community. To see whether certain optimizations would be possible between the two systems which would help that.  Maybe to even go so far as looking into what sort of backup we could play to each other, etc., etc. I can well see for example that we have a need to have access to a large amount of territories around the world for our ground segment. So does the U.S., and I hear that this discussion is coming to the fore once more. Well, we can help each other with that.  The European countries have access to quite a bit of territories around the world, the U.S. has as well, and there are other territories. Maybe we can co-locate a number of facilities with some joint security and all the rest of it.

    One can imagine a whole lot of things where we say, well, you know, we are helping each other to make sure that in terms of operations and overall service provision, that we have a common strategy. This doesn’t mean we are going to be fully dependent on each other. It is more the reverse. Use the respective independencies to the maximum, but by having the common strategy, optimize the full use of those infrastructures so there are the least impact on users if there are issues.

    AC: I’ve heard that kind of suggestion of optimization between the two systems from Brad Parkinson. Have you heard them from some kind of official entity, a negotiating body of the U.S. government?

    Verhoef: I have personally been approached at a very high level in the U.S. government about this, but very, very, very informally.  As to whether we would think that, not immediately but in the future, and these would be possibilities, and would we be interested to discuss that, and all the rest. Now, for the moment, it hasn’t come to much, because we have so much else to look at which is much more urgent. But the notion that this is maybe useful in the longer term is clear. Let’s face it, the current work that we are currently doing with the U.S. colleagues on defining safety of life service, which has a single standard across the two systems and which is then respectively implemented and supported, and being a future backbone for the aviation sector, is one of these things.

    If one goes further, there have been indeed also by people more on the ground, there have been suggestions, maybe we could learn from each other. I recall a visit to the GPS Wing where the colleagues there were enthusiastic, saying we have learned all sorts of good things, and maybe you want to profit from that: you get certain experiences in the future from which we would like to learn. We should keep an open mind to see that we on both sides have some channels on that, etc., etc.

    This is not to say — on the contrary — that we have received formal letters with requests for all this to be put on paper and negotiated. That is not the point.  I think on both sides there is awareness that these are potentials that one moment we may want to develop.

    AC: You mentioned earlier the words “commitment to a minimum necessary technical performance.” Is that 18 satellites, is that 24?

    Verhoef: There are a number of factors in that. The first is, I think we need to be looking at where the users are going. The users are clearly asking for high figures in terms of availability, and in terms of accuracy. Those sort of demands, which I would only expect to increase over time, I would hardly expect to see that in this particular technological world, users are going to say, no, no, we can do with less availability and less accuracy — I just don’t believe it, I don’t think that is the normal trend where you go with technology. My sense is there is always going to be pressure from users for those, which translates certainly into more satellites. At the very simplest level, it militates in favor of more satellites. This is the first element.

    The second element is I see, the discussion in the U.S. where there is a commitment of the U.S. government to provide 24 satellites, and as we saw at the ION conference once more serious discussions as to whether, with over 30 satellites in orbit, how comfortable the U.S. is positioned in providing that minimum technical performance. I think one has to come to the conclusion that this is to be looked at with some care. The question is, indeed, is 24 enough, or should we go to a higher minimum in order to look at that. Or should we adjust the spare strategy in order to have a much larger margin on that. Which effectively means that you also have more satellites in orbit, presumably.

    There are obviously, there is a discussion in Europe, because the 30-satellite constellation that we had defined was in part dictated by a very high-performance safety-of-life service that we had foreseen. Now that we have come to the conclusion that that  particular safety-of-life service, whic
    h at that time was foreseen to be much more proprietary, to give a PPP consortium a chance of better revenues — now that we have come to the conclusion that that is no longer necessary, and no longer desired by the marketplace, because the marketplace is very clearly saying, sorry guys, we are much more interested in you having an agreed standard with GPS and implementing that. There is obviously a review needed to see whether the 30-satellite constellation we had foreseen is what we’re going to do.

    There is another element. If I look for the moment at the performance charts and statistics which are put in front of me by the European Space Agency and a few other space agencies in Europe, it is clear that it is probably more satellites that are necessary rather than less. There is a bit of a discussion for some reason in Europe, for some reason some people seem to think that we could do a way with 18 satellites. Well, from me you will hear a solid No.

    The availability figures for an 18-satellite constellation are around 90 percent on average, which means that for an aggregate total of some six weeks a year you would not receive sufficient views, not have sufficient satellites in sight to actually determine a position. There are going to be sectors like aviation where this is completely unacceptable, and they would never invest in anything if that is what we’re going to do. So my sense is that we will always have a lot of upward pressure in terms of constellation size. Of course it needs to be offset against costs and other considerations, but I think the pressure is always going to be there. It is very premature for people to be trying to take a shortcut, to think, well, maybe we could do with less.  Because in the end you would have a constellation with a technical performance which the marketplace is not interested in, and then you would have a real problem.

    AC: What about factors other than the marketplace? European governments and European militaries, what is their thinking about the PRS, and about having to work with an 18-satellite constellation, either for incomplete, as you say 90 percent availability, or perhaps a reconfigured constellation that gives continuous coverage over Europe but not over the rest of the world?

    Paul Verhoef: The latter, I have not heard of. Presumably if Europe, there is an interest in using satellite navigation for strategic defense capabilities as you mention, my impression is that that is only in part an interest in Europe, but that is particularly of interest outside Europe, so I think you would still look at a sort of near-worldwide requirement.

    Let me say it in different words. Everything that I have heard is that our governments are interested in a fully fledged PRS service which is accessible from around the world, which is uninterrupted, and which has the highest grades of security. All of that means 18 satellites is just not going to do it, and we need more. There is then a question, coming back to the discussion on interoperability, what is it GPS and Galileo could do together? I think that it’s early days, the discussion is not really fully on the table yet. There are a number who show an interest in possibly discussing this. We will see whether this comes to a discussion and how we would do that.

    My presumption is, nevertheless, even if this would be done there is on both sides of the Atlantic an interest in having a basic level of autonomy and independence, even if there is a possible combined use, and it means that under the basic conditions of autonomy and independence, that you are fully capable of using that services for governmental purposes. From that perspective, we’re going to need a fully-fledged constellation.

    So I think the discussion on the constellation size is particularly introduced by those who consider that the system is maybe expensive, and one can cut costs and thereby reducing the size of the constellation is an element of cutting costs. Which obviously, in theory is true. But I think that no matter what the size of the constellation, you’ll always have a basic level of costs, of operations which is linked to manpower and basic ground installations which is going to be necessary. The procurement of a number of satellites more or less, I don’t think is going to be making that much of a difference in the overall picture.

     AC: In all European discussions, the military seems to take a very quiet and very backrow seat, if even perceived to be in the room at all.  This is very different in the U.S., where the GPS is financed, largely, out of the military budget and obviously administered by the military. What influence on your activities and the Galileo program does the military in Europe play, and secondly, if there was a budget shortfall, can military funds be accessed to help get Galileo going?

    Verhoef: It’s a bit of a theoretical question. You know, the EU budget is made available by our 27 member states, and we get money from them. There is no tag on that money which says, “this part is coming from agriculture and this part is coming from military and this part is coming from transport, and therefore it has to be used for that.” We get a certain sum of money and on the basis of that, on the total, there is then a discussion on for what purposes it is used. So the question in Europe is not so much where it comes from, but what it is being used for.

    On the national level, of course, it is a bit different, because there you have a defense ministry or a transport ministry, buying with its budget a certain thing. Well in this case, it is the European Commission buying, on behalf of the EU, on the basis of a general budget which is made available.

    But let’s come back to the military. There is at the moment, number one, there is a discussion ongoing in the Council, on the basis of a proposal which we have recently made in the Parliament on the access rules to the PRS service. That means, what are the agreed rules that the member states would like to establish, who is having access, under what conditions, to PRS? It is a fully controlled service with only government-authorized users. It is clear there is an enormous amount of use foreseen , including in the defense area. I think there is a very broad level of agreement in the EU, that the normal use in terms of logistics etc. etc. of the defense establishment should be completely possible. There seems to be an increasing majority of member states that is keen to see that the PRS is made available for certain peacekeeping missions and other things. You know this is defense/military use, but in the particular context.

    What is still not being discussed is would Galileo be used for purely military purposes? Let’s put a word to it, for missile delivery, or not? This is where I think the discussion is not there. There are no doubt member states that have a view on that. I think everybody is aware of the sensitivity of that particular discussion. It is not something that the Commission gets involved in, because this is an issue would need to be decided by the member states and the European Parliament. Everybody knows that there are differences of views on this.

    But with that sector excluded for the moment, this means that there is a large sector of agreement for civil protection purposes, for overall logistics purposes, for peacekeeping purposes, and all sorts of other purposes — PRS should be used. There are as a result in many of our member states, very advanced works taking place on shaping this up, on finance preparations at the national level, to put authorities in place at the national level who control this use. They will in turn interact with the system in order to organize the distribution of encryption keys and all the rest. There are going to be common minimum standards which are going to be developed. In a whole lot of ministries there are groups looking at how this technology is going to be used, under what circumstances industry can be licensed to build the receivers necessary for it, how they would use it in their respective operations, etc., etc.

    So what you see in addition to the expenditure at the EU level for the system itself, and for the security of the system itself, there is quite a large investment in member states to prepare themselves for the use of PRS. It is true that in some countries, the military se this as an opportunity to have much more direct involvement in advanced satellite navigation technology, which with GPS is always under license form the U.S. DoD, which has a lot of strings attached. In this case too there will be strings attached, but they will be strings which we attach ourselves to it.

    One also has to say that the use of GPS for military purposes in Europe, between member states is not equal. Not all our member states have access to military GPS, which means that for example if we would have joint peacekeeping missions from EU member states, and we would do that on the basis of GPS, that a number of member states would not be able to involve themselves in that, if that is a core technology which needs to be used, because they don’t have access to it. So this is another reason why there is an increased interest to see what we would do with the situation and how it would evolve.

    My sense is that this is an area where there is a lot of discussion. There is a lot of effort being put into it. PRS service is clearly one of the key services that the system is going to deliver. Our governments are by and large very upbeat about using it, they are preparing for it, and this is a good issue.

    AC: In September, you participated in GPS World’s Grand Game of GNSS, playing for the purpose of the game the role of a member of the U.S. Industry group.  Any lessons learned, perspectives gained?

    Verhoef: First of all, Alan, it was a fantastic game. I want to congratulate you personally for having put this into the very enjoyable evening, it was certainly part of a lot of fun. It was fun to play U.S. industry, and my colleague from the State Department playing a European operator, a funny situation.

    What I learned from this, if you slip into these roles, basically everybody has similar roles across the world, industry, governments, same roles. One can easily understand — whether I did learn anything particular from it, I did learn that one can have a lot of fun together.

  • GSA Releases First GNSS Market Monitoring Report

    The European GNSS Agency (GSA) has published a 2010 GNSS Market Monitoring report, providing key information in support of entrepreneurship in the satellite navigation sector.

    GNSS market forecasting is of great interest to private and public GNSS stakeholders, for business and strategic planning and policymaking, said the GSA. According to the new report, the market for GNSS will grow significantly over the next decade, at a compound annual growth rate (CAGR) of 11 percent, reaching €165 billion for the core GNSS market in 2020. Delivery of GNSS devices will exceed one billion per year by 2020.

    “This Report confirms that the market potential of GNSS is significant,” said Gian Gherardo Calini, head of the GSA Market Development Department. “The information should be useful to researchers, market players and decision makers who want to grasp the GNSS market opportunities today and tomorrow.”

    Report Highlights

    Road leads the way: The report shows that the road transport sector is still the leading GNSS segment, accounting for more than 50% of market share. The penetration of receivers in road vehicles, today at 30%, will exceed 80% over the next decade. However, after a period of fast growth, market saturation and competition in the form of ‘smartphones’, often equipped with free navigation capabilities, have resulted in a slowdown in the car-based navigation market.

    Price erosion has been high, driven by declining costs and strong competition. Vendors are using innovation as a differentiator resulting in ‘converged’ products with both communication and multimedia functionalities. Some Personal Navigation Device (PND) vendors are also tapping into new distribution channels, including car dealerships and smartphone application stores.

    GNSS for road transport: The road transport sector is facing major challenges, such as the demand for increasing safety and for reduced congestion and pollution. These problems are particularly acute in highly populated zones, including big cities and suburban areas. GNSS represents a powerful tool for improving road transport. Not only does it help get drivers where they want to go more quickly and efficiently, but it also promises fairer road-pricing schemes, for example, to automatically charge drivers for the use of road infrastructure.

    GNSS in your hands. Mobile location-based services (LBS) are taking off as progress is being made in different areas. More and more mobile phones now have GNSS capabilities, the result of both increasing consumer and developer awareness and an improvement in navigation services and performance.

    All major mobile phone operating system vendors now provide application programming interfaces (API) with location functions. In 2009, in the UK, France and Germany, 5 out of the 10 best-selling iPhone applications were related to navigation or location-based applications. Also, 30% of Android developers’ contest winners used location capabilities in their applications.

    A promising future for location-based services.     The integration of accurate hand-held positioning signal receivers, within mobile telephones, personal digital assistants (PDAs), mp3 players, portable computers, even digital cameras and video devices, brings GNSS services directly to individuals, making possible a fundamental transformation of the way we work and play. The penetration of GNSS in mobile phones is therefore expected to increase very quickly, from some 20% today to above 50% within the next five years.

    The GSA says Galileo in the future and EGNOS today open up new and exciting prospects for economic growth, benefiting citizens, businesses and governments throughout the EU and beyond.

    Just the beginning. The GSA underlines that the GNSS Market Monitoring process is ongoing and future reports are planned to update information presented in this first report and to cover other sectors. The Agency welcomes stakeholder contributions.

    The 2010 GSA Market Monitoring Report can be downloaded free.

     

  • GEOINT 2010

    By Art Kalinski, GISP

    It’s not what you look at, it’s what you see. (Thoreau)

    GEOINT is “the” conference of the year for geospatial intelligence professionals. This year’s attendance was even stronger than last year, with more than 3,3000 attendees and 225 exhibitors.

    Originally scheduled for Nashville, the significant flooding of May third caused severe damage to the Gaylord Opryland Conference Center. The damage was so extensive that the facility will not reopen until late November, too late for the originally scheduled GEOINT 2010. The nimble USGIF staff did a rapid about-face and rebooked GEOINT at the Earnest N. Morial Convention Center in New Orleans. The conference and all related activities went off without a hitch, a testament to the hard work of the folks at USGIF.

    GEOINT Awards Ceremony.
    GEOINT Awards Ceremony.

    There is no way to cover the entire conference in this column, but there is extensive coverage available online from USGIF.  One of the useful features of GEOINT was the publication of a timely and professional-looking show daily that was authored by KMI and USGIF during the day/evening, printed overnight, and slipped under hotel room doors of attendees each morning. The daily laid out the schedule and highlights for the day as well as summaries of key speakers the day before. Reading the show daily publication online is a good way to review the conference for those of you that weren’t able to attend. Following are links to the show daily.

    GEOINT – Show Daily Day One

    GEOINT – Show Daily Day Two

    GEOINT – Show Daily Day Three

    GEOINT – Show Daily Day Four

    GEOINT – Show Daily Wrap Up

    USGIF also produced a daily video show that played on hotel room TVs. This was yet another way to view topics that may have been missed due to conflicting schedules. I always found it frustrating to attend large conferences with competing exhibits and multiple-track break-out sessions. The combination of video shows, daily news, and online information helped mitigate this frustration. You can view the GEOINT TV presentations by clicking here.

    USGIF videographer.
    USGIF videographer.

    Describing the conference title, GEOINT 3.0 in the opening session, K. Stuart Shea, CEO of USGIF paraphrased a definition of geography that I first heard from Dr. Jerry Ingalls of UNCC. He stated that old geography merely focused on locating features, but with analytic tools such as statistics and GIS, new geography had evolved into a broad definition simply stated as “why what is where.” And knowing that, one could then perhaps predict “where the next what would be.”

    That summed up my general take on the conference. GEOINT is rapidly evolving to meet the needs of warfighters. Without going into detail, you could “smell” the difference in just one year. There was a greater emphasis on integrating GIS, imagery, multispectral, FMV (full motion video), SIGINT (signals intelligence), HUMINT (human intelligence), human terrain, and crowd-sourced and open-source information into a cohesive temporal picture that could be quickly and easily visualized and understood by troops in the field.

    There was a sense of urgency, as explained by General Koziol who heads up the ISR Task Force. He spoke of the rapid evolution of enemy tactics driving the need for faster response to ISR requirements. He detailed needs for software with deliveries in less than 30 days and hardware deliveries in less than one year. Any longer means that the solutions will be obsolete by the time they get implemented.

    One example that demonstrated the rapid intel environment was explained in a FMV breakout session. One of the indicators of a potential suicide bomber was the observation that frequently two vehicles were involved, a lead vehicle carrying the explosives with a suicide bomber and a trailing vehicle with a remote detonator. Seems like many of the suicide bombers are not volunteers that will self detonate, so the trail vehicle makes sure the act is carried out. If the driver “chickens out,” the vehicle is detonated anyway, and the driver’s family receives no reward money, just shame. You can easily see how time-critical identifying a similar event and acting on it can be.

    There was a general consensus among the speakers that sharing data rapidly with our coalition partners was critical to success. Our tendency to over-classify and restrict our data makes the perishable data less useful. However, that opinion was tempered at this conference with the yellow flags sent up by WikiLeaks.

    General Clapper, the director of National Intelligence, was the opening keynote speaker. Having held every key position in the intelligence community including NIMA director during 9/11, he showed a keen understanding of geospatial technology. He indicated that GEOINT was the most integrative environment to visualize and understand the complex data sources we have. He also felt that GEOINT would be equally valuable in the emerging cyber threat arena by mapping the virtual environment coincident with real physical locations and acting as a visualization tool to understand and combat the threat.

    General Clapper seems to have a wry sense of humor with little patience for games. During his interview with the president, he stated that with “one foot in assisted living” he didn’t have the time nor desire for a lot of “Oval Office carpet time.” This must have been quite off-putting for most politicos within earshot. General Clapper also indicated that the SECDEF efficiency review was going to affect all defense communities with the possibility of seeing similar cuts that we saw in the early 90’s, in the range of 20%. He further elaborated that “What I’d look to do is profit from what happened to us in the 1990s, and lay out a strategy for this and absorb the pain smartly.”

    The new National Geospatial-Intelligence Agency director, Letitia A. Long, shared her vision for NGA. She stated that “I want to put the power of GEOINT directly in the hands of our users.” She wants to change the user experience by providing online, on-demand access to GEOINT data. She also wants to expand the analytic capabilities by providing contextual analysis of geographic features and imagery enhanced with temporal and human terrain geography.

    The expo was quite extensive, with elaborate booths by all the major players. The show daily did a good job highlighting new products and capabilities of the majors firms. One thing I like to do at conferences is look at the small booths on the fringes of the exhibit hall. There is always a gem or two to be found with these small emerging companies. One example at GEOINT 2010 was GCS research with TerraEchos. This company was demonstrating a simple underground sensor that was covert, sensitive, and could accurately detect sounds, foot, or vehicle traffic while mapping the location on a GIS. The device, based on early U.S. Navy passive sonar work, consists of a ¼-inch rubber cable housing a thin fiber-optic line fed with a laser. The cable is buried 6 to 18 inches below ground, could be thousands of feet long, and displays the vibrations though micro distortion of the laser-illuminated fiber optic line.

    GCS Research Display.
    GCS Research Display.
    TerraEcho2
    GCS Research Display.

    USGIF also announced and presented a well-deserved Lifetime Achievement Award to Esri’s Jack Dangermond. The only surprise was that it didn’t happen sooner.

    In several years of attending GEOINT, the environment is clearly getting more complex and “squishy” with the integration of many different intel sources in a rapidly changing world and a greater need for speed. Intelligence and the need to understand and act rapidly is paramount. A quote by Henry David Thoreau used by one speaker was spot on describing what the GEOINT community is tasked with accomplishing: “It’s not what you look at that matters, it’s what you see.”

  • J911: Fast Jammer Detection and Location Using Cell-Phone Crowd-Sourcings

    By Logan Scott

    Inexpensive, readily available GPS jammers constitute a threat to safety, national infrastructure, and industry revenue streams. Cell phones could incorporate GPS jam-to-noise (J/N) ratio detectors to provide timely interference detection and effective localization, with a flexible and updateable system since the crowd processing function resides in software.

    Events in early 2010 at Newark Liberty International Airport demonstrate the vulnerability of civil GPS infrastructure to interference. Over a period of several weeks, sporadic outages of the GPS Ground Based Augmentation System (GBAS) located at the airport to provide precision approach services occurred, due to radio-frequency (RF) interference from unknown sources. Analysis showed that certain vehicles on a nearby freeway were the likely culprit(s), and an interdiction effort was launched to catch an offender. Using advanced interference detection equipment and multiple surveillance cameras, an offender — a truck driver — was caught and arrested. In his possession: a widely available $33 GPS jammer.

    For sale over the Internet, the jammer emits 200 mW and plugs directly into a vehicle’s cigarette lighter (see photo). To prevent future incidents, the FAA is relocating the airport’s GBAS system to a more protected location away from the freeway.

    Such an approach to jammer detection, localization, and enforcement, while successful in this instance, ultimately serves only as a stopgap. It took tremendous resources and several weeks to find one offender.

    Increasing use of GPS jamming and spoofing to cover both licit and illicit activities is likely, given the general public’s desire for privacy and the general lack of awareness of how devastating GPS jamming can be. The $33 jammer in this instance could have affected critical flight operations 10 miles away. Currently, most jammers are not even detected; we simply have an unidentified GPS outage. It was only because of the technical sophistication of the FAA’s GBAS that the outage’s underlying cause was identified as jamming.

    GPS Jammer. A $33, 200mW jammer for sale over the Internet.
    GPS Jammer. A $33, 200mW jammer for sale over the Internet.

    At the ION-GNSS 2010 plenary session, Phil Ward advanced the notion that cell phones could incorporate GPS jam-to-noise (J/N) ratio detectors to provide timely interference detection. Having an extensive background in cellular communications as well as GPS, I found the idea intriguing. In this article, I explore the viability of this concept, whether jammer location can be determined, and what it would take to implement such a system.

    In urban and suburban areas, it appears feasible to provide warning of jamming in less than 10 seconds while providing real-time jammer location to better than 40 meters. Such a capability would aid immensely in mitigating jamming events by enabling effective law-enforcement action. Potential jammers will know they are likely to be caught and that the penalties are severe. They won’t do it after a few well publicized interdictions. The cost for this nationwide system can be relatively modest. It won’t take billions of dollars and decades to implement; it will take an act of national will similar to the phase II wireless E911 effort. IOC could happen as early as 2015, with full national coverage by 2017.

    J911 System Architecture

    Figure 1 depicts the automatic gain control (AGC, the process by which RF front-end gain is controlled so as to present the analog-to-digital (A/D) converter with appropriate signal levels) loop found in some form in virtually all GPS receivers. The core objective is to set the gain GA so a set percentage of 2-bit A/D converter outputs correspond to large values of 3 and -3. Typically, VT percentage is set to 35 percent in a Gaussian noise environment to hold A/D conversion losses to ~0.5 dB. In another popular variation, the 1.5 bit A/D converter, the zero threshold is not implemented and three possible values are output (-1, 0, and -1). Such a converter has about 0.9 dB of conversion loss if VT percentage is set to 40 percent, and considerably simplifies correlator processing.

    J-1
    Figure 1. Adaptive A/D converter with jamming-to-noise (J/N) meter output. Knowing you are jammed is the first step.
    J-2
    Figure 2. J/N as a function of position relative to a 200 mW jammer. phones located closer to the jamming source will see higher J/N than those further away.

    Of particular interest for interference detection purposes, the control voltage to the AGC amplifier can also be used to measure jammer-to-noise power (J/N). Under unjammed onditions, the nominal input power to an L1 C/A receiver is about -110 dBm, most of this due to naturally occurring thermal and amplifier noise. The C/A code signal at -130 dBm is a factor of 100 weaker and does not influence AGC operation. If, however, interference starts rising above the thermal noise floor, the AGC will respond by decreasing gain GA so as to maintain the correct percentage in large outputs. Response times to a change in input power level are very fast, typically less than 1 millisecond, and so pulse jamming characteristics can be determined as well.

    If the receiver knows the control characteristics of the AGC amplifier (β,α) then the receiver can determine the change in J/N given V1. Additionally, if the receiver knows the quiescent V1 associated with a thermal noise-only input, it can obtain J/N on an absolute scale. To obtain the quiescent value, the receiver can short the antenna on power-up as part of built-in test prior to operation. Alternatively, it can maintain and refine a historical value during normal operations, the caution being that spoofers and jammers may try to manipulate history-based values.

    Even with relatively small jammers, front-end saturation can be a problem when the jammer is nearby. The thermal noise floor in a 1.7 MHz bandwidth is about -110 dBm, and so a J/N of 60 dB corresponds to jamming signal strength of -50 dBm. Accurate J/N measurements are possible at this level, but likely require adding a switchable input step attenuator in the down-conversion chain. Measuring J/N above this level gets problematic for a low-cost GPS front-end.

    In a further refinement, receivers can include additional comparators set at -1.2 VB and + 1.2 VB. If a constant envelope (CE) jammer (CW, swept CW, or Gold code jammer types) is present, this threshold will be crossed 16 percent of the time given CE jamming, versus 32 percent of the time for Gaussian distributed jamming if VT percentage is set to 40 percent, as is typical for a 1.5 A/D converter. With the jammer type identified, the receiver can adapt V<su
    b>T percentage if it is seeing CE jamming to obtain several dB of additional jamming resistance. The TI-420 L1 C/A receiver developed by my team at Texas Instruments in 1986 routinely outperformed P-code receivers against CE jammers using this technique. The takeaway from this discussion is that with very simple hardware, an L1 C/A receiver can measure J/N and also determine the approximate type of jamming that it sees: pulse, constant envelope, and Gaussian.

    Can this information be used to detect and locate jammers? In Figure 2, a 200 mW jammer is located at the origin [0,0] and J/N (dB) is plotted as a function of relative location. Conceptually, phones located closer to the jamming source will see higher J/N than those further away. The aggregate of phones, each reporting J/N and own position, provides a basis for locating the jammer. Some phones may also report the type of jammer they are seeing. Information about phone type and its physical orientation would also be of use in interpreting and correcting raw J/N information with regards to antenna gain and accuracy.

    Structurally, the J911 system would be very similar to the E911 system and would heavily leverage existing infrastructure and standards already in place. When a wireless E911 call is placed, the serving base-station(s) routes the call through a mobile switching center (MSC) where the call is identified as a 911 call. The MSC then connects the call to a local exchange carrier (LEC) who then connects the call to a public safety answering point (PSAP).

    In the United States, 6,149 PSAPs are distributed around the country.Wireless E911 calls are connected to a specific PSAP usually based on the location of the caller as determined by the cellular carrier. Under Phase II requirements, E911 call takers receive both the caller’s wireless phone number and their location information. Currently, 95 percent of PSAPs have some Phase II E911 capability.

    Using the E911 system as a basis, creating a federal J911 PSAP to process J/N measurements into jammer location estimates would not be all that problematic. Software upgrades to phones, base stations, MSCs, and so on, are routine and often include new or modified message provisions and capabilities. Adding a Jamming Report message type would use existing message transport and routing facilities already part of the infrastructure. The main infrastructure addition would be a facility to process jamming reports, either at the federal level or as an adjunct to existing PSAPs.

    Adding a J/N measurement capability to phones is a straightforward hardware issue, but modifying extant phones is not feasible. Fortunately, cell phones typically have a two-year lifecycle before being replaced. Adding a jammer reporting capability can be accommodated through the normal replacement cycle.

    J911 System Performance

    Given the location and J/N measurements obtained by a crowd of randomly located cell phones, one approach to determining the jammer’s location is to perform a series of curve fits for a grid of hypothetical jammer locations and see which location provides the best fit. Figure 3 illustrates this process; for the moment, the cell phones (observers) are assumed to provide exact J/N and location measurements.

    Here, a 200 mWatt jammer is located at xy = [0,0]. 1,000 cell phones are uniformly distributed over a surrounding 1-square-kilometer area. A hypothetical jammer location grid of points 5 meters apart is created over a span of ±150 meters in x and y. At each hypothetical point, the 250 highest non-saturated J/N reports are used in a least-squares curve fitting process that assumes jamming strength falls off as 1/Rα. (In the ground mobile environment, α is usually in the range of 2 to 4. α = 2 is consistent with a free space propagation model.)

    Specifically, J/N (dB) is presumed to be a linear function of log10 (R) where R is the range from reported observer position to hypothetical jammer location. At each hypothetical jammer location point, the norm of the residuals is collected as a metric of how closely the jamming reports (J/N + location) matched the least squares curve fit. The smaller the norm of the residuals, the better the curve fit. This metric is plotted in Figure 3 and shows that the best fit is obtained at the true jammer location.

    ▲ Figure 3. Location metric as a function position relative to true jammer position (no observer errors).
    Figure 3. Location metric as a function position relative to true jammer position (no observer errors).

    In practice, knowledge of cell-phone locations is imperfect, and for those phones near to the jammer, GPS will be unavailable. There are several alternatives for determining location. Cellular carriers use a plethora of location determination techniques based on round-trip timing between the cell phone and observing base stations. Another very good option is to use Wi-Fi-derived location based on visible access points (AP). Companies such as Skyhook and Google have commercialized this technology, and it is available now in most areas. Positioning accuracies of 30 meters are typical, absent GPS. Looking down the road a bit, many phones now have integral accelerometers and could in the future propagate position with good accuracy even when GPS is unavailable.

    Another very important factor is that J/N observations are going to be highly variable.

    Three major effects to consider:

    • Cell phone errors in measuring J/N due to quiescent V1 errors, imperfect AGC amplifier characterization, and uncompensated receive antenna gain directionality.
    • Variability in J/N due to large-scale shadowing due to buildings, hills, bridges, etc.
    • Variability in J/N due to small-scale multipath effects. Jamming signals may follow multiple paths to the cell phone and add up constructively or destructively. Moving the cell phone a few inches may yield a very different J/N.

    To model these effects, a log normal model of J/N measurement deviation from ideal free-space propagation is used. In this model, free-space propagation represents median signal strength and σ log normal, expressed in dB, describes Gaussian random deviation from the median signal strength. Such models are widely used in predicting statistical cellular coverage and have a strong correlation with real-world observations.

    Figure 4 shows a jammer location metric manifold computed using the same process as in Figure 3, except now with observer location errors of
    σx = σy = 30 meters and σ log normal = 6dB. Basically this says that the cell phones have Wi-Fi-based locations, and that the measured J/N is within ±6 dB of the free space value 68 percent of the time, and, within ±12 dB of the free-space value 95 percent of the time. These are relatively modest performance goals for the cell phones.

    ▲ Figure 4. Location metric as a function position relative to true jammer position (observer errors: 30 meter 1 /6 dB 1 J/N).
    Figure 4. Location metric as a function position relative to true jammer position (observer errors: 30 meter 1 /6 dB 1 J/N).

    In this particular run, the hypothetical jammer position yielding smallest residual norm is at xyjammer = [10,45] meters. Even though the individual measurements are of poor quality, the crowd consensus yields a fairly accurate estimate of the jammer’s position.

    Before continuing, a few words on crowd size and cell phone densities. Assuming a cellular penetration rate of 70 percent, Table 1 shows approximate cell-phone densities for select suburban and urban municipalities. No doubt there is considerable variation in cell phone densities even within a municipality, but as a rough order of magnitude, 1,000 cell phones per square kilometer is not an unreasonable number.

    Table1
    Table 1. Density of 1,000 phones/square kilometer Is common in urban areas.

    Figure 5 shows statistics of jammer location accuracies, presuming a uniformly distributed cell phone density of 1,000 cell phones per square kilometer. Based on a simulation of 500 independent runs, this figure plots jammer location radial error statistics assuming 25, 100, 500, or 1,000 measurements are processed in the curve-fitting process where radial error is given by:

    J-EQ.

    Processing the full crowd yields 14-meter or better radial errors in 50 percent of the trials and better than 27 meters in 90 percent of the trials. So why process less than the full set of measurements obtained by the cell phones? In practice, if all cell phones observing a jamming event were to report everything they see, the cellular infrastructure could be overwhelmed. To limit traffic surges and to limit false alarms, a jamming event is likely to be processed in two distinct phases; the detection phase and the locating phase.

    J-5A
    Figure 5. Radial error statistics with 1,000 phones/sq km crowd density.

    Jammer Detection

    In the detection phase, cell phones would report relatively infrequently based on which page group they are in. In current practice, to minimize cell-phone power consumption while in standby, each cell phone belongs to a particular page group based on its supposedly unique International Mobile Equipment Identity or IMEI. (As a bit of trivia, most cell phones display their IMSE if you dial *#06#). In GSM there may be 50 distinct page groups. Depending on which page group the phone belongs to, the phone knows when to wake up to listen to the paging channel (PCH) and see if there is an incoming call for it. By limiting jammer reporting based on which page group the phone is a member of (or IMEI), the size of the initial traffic surge can be limited.

    During the detection phase, the system will also need to determine the type of interference event being seen. A solar event may trigger large numbers of phones, but the flat J/N versus location response can be used to rule out a localized jamming event. A real jamming event will tend to have a geographic center with many high J/N values over a fairly restricted area. Also, if CE interference is reported as opposed to Gaussian interference, there is good confidence the event is human originated, and the source can be located.

    Jammer Localization

    If jamming is determined to be the cause of interference, then the system transitions to a jammer localization phase. Tentatively, the jammer location process would seem to be better served by using phones near the jammer, but not those phones with saturated J/N meters. The non-saturated phones provide good RSSI (received signal strength indicator) information that is correlatable with distance, and those cell phones closest to the jamming source (high J/N) tend to experience fewer propagation anomalies. To control traffic loads during a jamming event, the J911 PSAP may restrict which phones report by requesting that only phones seeing a J/N value of greater than J/Nmin report.

    Returning to Figure 5, processing the full set of data yields better snapshot jammer location accuracy as opposed to results obtained using a trimmed subset. Processing the full crowd yields 14 meter or better radial errors in 50 percent of the trials and better than 27 meters in 90 percent of the trials. Relying on only the subset of the 250 strongest J/N values adversely affects jammer snapshot location accuracy; yielding 47 meter or better radial errors in 50 percent of the trials and better than 110 meters in 90 percent of the trials.

    The upside is that the traffic generated on the cellular network is one quarter as much. Stated another way, for a given traffic handling capacity, we could update jammer location at four times the rate. Using page group membership, general location, or IMEI as an additional reporting criteria, we can sample different cell-phone populations at each snapshot interval.

    If a Kalman filtering approach is used to track/smooth jammer location estimates, the reduced set of observations may ultimately yield better performance, especially considering that individual phones can move around considerably over time. Also, geographical centroiding using phones with saturated or very high J/N indications may be another viable jammer locating technique, and perhaps combining approaches would be good. If the jammer is determined to be in a vehicle, substantial accuracy improvements in location accuracy may also be obtained by limiting the hypothetical jammer location grid to include only roads based on map input. These are all open issues for further study.

    Figure 6 repeats the analysis of figure 5 except now, cases of much reduced cell-phone density are considered. In all cases, the full set of data is reported and processed. Not surprisingly, with more observers, the jammer locating accuracy is better, but even with low cell-phone densities, the performance is not bad: 50 meters 50 percent of the time, and 100 meters 90 percent of the time with 100 phones per square kilometer. Jamming detection and location is feasible in modestly populated areas.

    J-6
    Figure 6. Radial error statistics with crowd densities of 50, 100, 250 and 1,000 phones per square kilometer

    Figure 7 shows radial accuracy statistics for σlognormal = 4, 6, 8 and 10 dB. As expected, as J/N measurement reliability deteriorates due to increased propagation variability and/or cell phone measurement errors, the accuracy of jammer location estimates also deteriorates but not catastrophically so.

    J-5
    Figure 7. Radial error statistics with σlog_normal =[4,6, 8, 10] dB crowd densities of 1,000 phones per square kilometer.

    Similarly, simulation runs with larger cell-phone location errors showed modest performance losses in jammer location accuracy. In aggregate, Figures 5 through 7 point towards crowd size and crowd selection algorithm, not the accuracies of individual measurements, as the main driving factors in jammer-location accuracy.

    Putting J911 in Place

    Initially, wireless operators had little enthusiasm for implementing wireless E911 as it introduced substantial hardware requirements for mobile station (MS) position reporting (a cell phone is an MS). Now, E911 provides the technical underpinning for numerous revenue streams, most notably the location-based services (LBS) industry. GPS jamming is a direct threat to this revenue stream.

    As GPS becomes integrated with vehicle navigation systems and intelligent highway systems, cellular carriers will play an important role in provisioning needed communications facilities. GPS jamming is a direct threat to this future revenue stream.

    Cellular signal jamming is also a threat to national infrastructure (and carrier revenue). The approaches described above are readily adaptable to detecting and locating cellular frequency band interference sources in a timely manner. By emphasizing the potential benefits of a J911 system to the cellular carriers, there is better potential for buy-in by industry.

    Using the wireless E911 experience as a model, J911 could be made a reality using a three-step process:

    Rulemaking. After validating the requirement, the FCC would issue a Notice of Proposed Rulemaking (NPRM) stating the system functional requirements. Industry would comment, and through an iterative process the J911 requirements regarding performance and mandated deployment schedules would be established. This process would take about two years.

    Standards Setting. Well established wireless, LEC, and PSAP standard-setting bodies would create detailed standards for implementing J911. The bulk of the work would be done by collaborating representatives from industry. Standards would be issued for various system portions — for example, MS standards, BSS standards, and so on — to permit manufacturers to build interoperable equipment. The standards setting process would take one to two years.

    Rollout. With the exception of the MS portions, J911 does not require hardware modifications to the cellular infrastructure. J911 would be implemented and deployed as part of the normal update and release cycle. Under the mandate, new mobile stations would have to meet the requirements of the FCC rulemaking and standards setting processes. Over a two-year period, mobiles would transition to J911 capable models and the J911 system would be in place.

    Crowdsourcing

    In the March 7, 1907, issue of Nature, Francis Galton reports on an experiment where, at a county fair, he had 787 people guess the dressed weight of a fatted ox, charging them six-penny a guess. Individual estimates varied wildly, as did the expertise of the guessers. However, the median estimate of the crowd was within 0.8 percent of the correct value.

    Conclusions

    Creating a national infrastructure for detecting and locating GPS and cellular jammers is needed. Such a capability would provide the underpinnings for rapid and effective enforcement actions. Crowdsourcing approaches using a multitude of opportunistic cell phone based observers appears a plausible solution providing timely and location specific alerts. Even though the individual measurements are of poor accuracy, the crowd consensus yields good accuracy. While this system would not reliably detect purpose-built precision power-controlled spoofers, it could detect coarser cell-phone apps-style spoofers that might, for example, be seen in road-use tax avoidance.

    Numerous open issues remain. Jammer antenna gain patterns can adversely affect locating accuracy. To what extent can this be mitigated by mapping out antenna gain contours? How can multiple simultaneous jammers be resolved? Can map and propagation modeling based aiding algorithms improve jammer location accuracy?

    Significant research is needed, but the proposed system is open for continual improvement, even after it is fielded, since the crowd processing function resides in software.

    Logan Scott is a consultant specializing in radio frequency signal processing and waveform design for communications, navigation, radar, and emitter location. He has more than 32 years of military and civil GPS systems engineering experience. As a senior member of the technical staff at Texas Instruments, he pioneered approaches for building high-performance, jamming-resistant digital receivers. He is currently active in location-based encryption and authentication, high performance/low bias adaptive array technologies, and RFID applications. He teaches Navtech Seminars’ New Signals course and holds 32 U.S. patents.

     

  • 2010 Leadership Dinner: Recognizing GPS Heroes, Grand Game

    GPS World’s seventh annual Leadership Dinner, which took place during the ION-GNSS conference in Portland, Oregon, and was sponsored by Rockwell Collins, this year honored some of the surviving GPS Heroes (see May and June 2010 issues). PLUS: We invited 120 dinner guests to find out by walking a mile in someone else’s shoes, in the Grand Game of GNSS, a role-playing and negotiation exercise. Learn who won!

    Recognition for the GPS Heroes

    Leadership Dinner Speech by Brad Parkinson

    Good evening. It is good to see you all. Particularly it is wonderful to see some of the surviving heroes of the Phase One Brotherhood who helped make GPS possible against desperate odds. We came together in 1972, and by 1978 had proven the dream. We could not fail. It is now hard to believe that it started 38 years ago.

    Would the Phase One Heroes please stand and be recognized?

    Engineers are usually destined to be forgotten. I wrote the two articles that many of you have seen in an attempt to remember the wonderful officers, aerospace engineers, and supporting contractors who made GPS a reality. All of you were needed.

    I want to acknowledge my co-author, Steve Powers, my roommate as a midshipman back at the the Naval Academy and now a professional historian, for his help.

    Unfortunately, both memory and space limited the numbers of early contributors to whom I could give credit. Alan Cameron has been extremely
    helpful in publishing those articles and helping compile a list of the heroes. I would urge you to scratch your heads and add to the list of names.
    And thanks to GPS World for this great dinner and gathering.

    We could foresee many of the early uses of GPS. But we could not foresee hundreds of other uses. Perhaps most astonishing, the best GPS receivers now routinely resolve position in real time with accuracies better than a centimeter. This has opened up a whole new world of robotic control and tracking. It is a credit to the engineers who succeeded us and invented the techniques of real-time kinematic positioning.

    The burden for maintaining and improving GPS has now been passed to yet another generation of leadership. I am particularly pleased that the JPO Director, or GPS Wing Commander, Colonel Bernie Gruber is here this evening. He is a worthy successor to the many fine program directors that GPS has had since I retired in 1978. He will have his hands full with keeping the torch lit, in particular with maintaining the size of the GPS constellation to ensure its availability for all users.

    Bernie, we are very pleased to see you back with the GPS brotherhood. For those who are not aware of it, Bernie served in the user equipment area of GPS about 18 years ago. He certainly qualifies as a veteran of this program.

    I propose three toasts:

    • To those who are now carrying the burden of GPS: the Joint Program Office, Aerospace, and the supporting contractors.
    • To those still alive who could not be here but who were the brotherhood of heroes who started it all, from 1972 to 1978.
    • Last, to those who are now dead, and gave so much to make GPS possible. The names of those that I know who are no longer with us: Mel Birnbaum, Val Denninger, Ivan Getting, Don Henderson, Gary Hahn, Ernst Jechart, Ken Schultz, Werner Weidemann, and Jack Barry.

    If you know of others who have passed away, please tell me or e-mail me.

    I would like to close with a paraphrase from Shakespeare: Henry V’s speech just prior to the Battle of Agincourt.

    And a New Year shall ne’er go by,
    From this day to the ending of the world,
    When we in it, we engineers shall be
    forgotten;
    But we few, we band of brothers,
    We shall remember that brotherhood and the sacrifices we all made.
    For he that stood with me,
    He that labored with us in the desperate early days of the GPS,
    Shall be our brother.

    Thank you all.

    GPS World magazine and dinner sponsor Rockwell Collins, represented by Gary McGraw, then joined Dr. Parkinson to present small mementoes to these attending GPS Heroes:

    • Hugo Fruehauf, chief engineer at Rockwell International for design and development of the first GPS satellites, whose oversight was essential to producing the first GPS atomic clocks;
    • Gaylord Green, the first officer then-Colonel Parkinson brought onboard the new Joint Program Office, and who succeeded him as a JPO director several years later;
    • Ed Lassiter, who had extensive space-flight experience and led the early Aerospace contingent of engineers working on the system;
    • Ed Martin, who made significant contributions, collaborating on the early, important decision that the carrier, code, and data of the GPS signal would all be phase-coherent;
    • Brad Parkinson, first GPS JPO director;
    • Tom Stansell, a Transit expert who helped design the first GPS civil receivers at Magnavox;
    • Joe Strada, a key leader in the extensive test program, developing test environment and analysis setup;
    • AJ Van Dierendonck, who helped define GPS time and developed a modified Kalman filter for near-real-time orbital prediction;
    • Chuck Wheatley of Rockwell’s Autonetics Division, part of a team that built a space-qualified clock for the first GPS launch, February 1978.
    • Phil Ward, developer of Texas Instruments’ TI-140, an early commercial high-precision receiver;
    • Paul Weber, GPS JPO deputy program manager from the U.S. Army.
    Gaylord Green, Joe Strada, and Paul Weber were among those honored for getting GPS off the ground, 1972–1978.
    Gaylord Green, Joe Strada, and Paul Weber were among those honored for getting GPS off the ground, 1972–1978.

    H-2
    Brad Parkinson proposes three toasts: to those now administering GPS, to those still living who launched the program but could not attend the dinner, and to those from that heroic group who have passed away.
    H-3
    GPS pioneers Hugo Fruehauf, Brad Parkinson, and Ed Lassiter.
    H-4
    (From left) Ed Martin, AJ Van Dierendonck, Chuck Wheatley, and Phil Ward.
    Tom Stansell, and the GPS Heroes glass memento.
    Tom Stansell, and the GPS Heroes glass memento.

    The Grand Game of GNSS

    How difficult can it be to build a satellite system, sustain an industry, or equip users? We invited 120 dinner guests to find out by walking a mile in someone else’s shoes, in the Grand Game of GNSS, a role-playing and negotiation exercise. Twelve teams represented system operators, industries, and user groups from the United States, Russia, Europe, and China. Operators and Users had money. Industries had satellites and receivers. Each wanted what the other had. For rules and results see env-gpsworld-integration.kinsta.cloud/wideawake.

    GLONASS operators Chaminda Basnayake (General Motors) and Di Qiu (Sigtem Technology) pay a call on Russian Industry captain John Betz (MITRE). European Industry captain Sam Pullen (Stanford) checks inventory, as Sergey Karutin (Russian Institute of Space Device Engineering), Neil Gerein (NovAtel), Mike Shaw (Lockheed Martin), and Colin Beatty (Royal Institute of Navigation) mull strategy. Scott Feairheller (U.S. Air Force) tries on another hat for size. GLONASS operators Chaminda Basnayake (General Motors) and Di Qiu (Sigtem Technology) pay a call on Russian Industry captain John Betz (MITRE).
    • GLONASS operators Chaminda Basnayake (General Motors) and Di Qiu (Sigtem Technology) pay a call on Russian Industry captain John Betz (MITRE). • European Industry captain Sam Pullen (Stanford) checks inventory, as Sergey Karutin (Russian Institute of Space Device Engineering), Neil Gerein (NovAtel), Mike Shaw (Lockheed Martin), and Colin Beatty (Royal Institute of Navigation) mull strategy. • Scott Feairheller (U.S. Air Force) tries on another hat for size. • GLONASS operators Chaminda Basnayake (General Motors) and Di Qiu (Sigtem Technology) pay a call on Russian Industry captain John Betz (MITRE).
    G-2
    Compass operator Anthea Coster (MIT) looks on as Galileo captain Dorota Grejner-Brzezinska (Ohio State University) and Jane Wilde (DW International) drive a hard bargain on European Industry.
    • (Clockwise from top left) China User Grace Gao (Stanford) puts on her business face. Captain Frank van Diggelen (Broadcom) recalls, “Grace, assisted by Sherman Lo, leapt into the fray, and was soon taking care of all the business 10 times more effectively than the rest of us together. We were left to tally the numbers, count money, and drink the wine — activities we found hard to keep up with, the speed with which Grace made things happen.” • Compass Operator Mike Whitehead (Hemisphere GPS) flashes a wad of several hundred million dollars at Russian industrialists John Lavrakas (Advanced Research) and Art Gower (Lockheed Martin), as U.S. Industry captain Matt Harris (Boeing) kibbitzes. • China Industry rep Frank Czopek (Boeing) negotiates with Russian industrialists Vince Massimi (MITRE) and Antje Tucci (University FAF Munich). • GPS Wing Commander Bernie Gruber finds a quiet moment to get the real story from (Mrs.) Ginny Parkinson.
    • (Clockwise from top left) China User Grace Gao (Stanford) puts on her business face. Captain Frank van Diggelen (Broadcom) recalls, “Grace, assisted by Sherman Lo, leapt into the fray, and was soon taking care of all the business 10 times more effectively than the rest of us together. We were left to tally the numbers, count money, and drink the wine — activities we found hard to keep up with, the speed with which Grace made things happen.” • Compass Operator Mike Whitehead (Hemisphere GPS) flashes a wad of several hundred million dollars at Russian industrialists John Lavrakas (Advanced Research) and Art Gower (Lockheed Martin), as U.S. Industry captain Matt Harris (Boeing) kibbitzes. • China Industry rep Frank Czopek (Boeing) negotiates with Russian industrialists Vince Massimi (MITRE) and Antje Tucci (University FAF Munich). • GPS Wing Commander Bernie Gruber finds a quiet moment to get the real story from (Mrs.) Ginny Parkinson.

    G-4
    The Galileo team thinks they have won.
    G-5
    The End of the Game. Ian Mallett (Australia Civil Aviation Safety Authority), Nunzio Gambale (Locata Corp.)

  • Out in Front: An Open or Shut Case

    Engineers are an eager lot, by and large. They like talking about their work, openly showing information and results, testing their work against data and alternate hypotheses, getting feedback and even critique from colleagues near and far. They value an iterative, elaborative, collaborative process.

    Politicians and business managers, on the other hand, tend to the dour. They would rather not show their hand, nor do they care to hear what you think of their organization’s work, citing intellectual property or national security reasons.

    This is not just about last month’s abrupt withdrawal of a session’s worth of Galileo papers from the showcase rank of the European Navigation Conference (see story, page 14). It extends across governance of all GNSS, and ultimately affects the frontiers of knowledge everywhere. GLONASS has never been particularly forthcoming with technical details, while Compass has taken reticence to new heights. Or depths.

    The socialist countries have not taken much heat for this practice, perhaps because it is assumed to be part of their political culture. Europe, on the other hand, surprises us a bit. It may be a sign of the changing of the times, the tightening of the GNSS space race. Once Galileo held unquestioned second place as the GNSS of choice to combine with GPS. No longer. GLONASS revives itself on practically a daily basis, and Compass goes about launching satellites with quiet regularity — 
although without much useful information on signal structure.

    The GPS Wing of the U.S. Air Force deserves commendation for the frankness with which it has discussed recent problems. Even the Europeans admitted, “ION was a little better this year. The Americans talked about the failures they had, the problems with their ground stations and satellites.” At least one prominent U.S. government  contractor, however, has moved in the opposite direction.

    European system managers have grown cautious, and stress the importance of protecting intellectual property. “We were too open before.” The case of the behavior of atomic clocks, for example, comes up in discussion. “You take sx months to find a solution, and then give it away in one session. Knowledge, what you find out by trial and error, or even by accident, this is the most critical thing.”

    From another quarter came this opinion: “Detailed information on tests is a clear transfer of technology. It’s not a matter of security, it’s business.”

    Ironically, the Europeans have run into a stone wall of their own, after granting the level playing field that U.S. industry agitated for, in terms of access by foreign companies to Galileo contracts. A European satellite builder visited a U.S. company, on U.S. soil, prepared to solicit a bid. But the U.S. company’s compliance officer — charged with keeping all operations in line with government rules and regulations — repeatedly stood up in the meetings and told colleagues, “Stop talking about how you are doing it and just talk about what it does.”

    Unable to obtain sufficient technical context to prepare a request for proposal, the European company walked away, thinking “They don’t want our business.”

    Opportunity lost.

  • Expert Advice: Block IIR Lifetimes and GPS Sustainment

    Willard Marquis (left) and J. David Riggs
    Willard Marquis (left) and J. David Riggs

    In 2009, a Government Accountability Office (GAO) report claimed that the GPS constellation was extremely vulnerable to failure, and a recent September 2010 GAO follow-up continues to make that assertion. In this article, we present the technical data to contradict some of the GAO report conclusions.

    Fifty-nine GPS space vehicles (SVs) have been put into orbit since 1978. From 1997 to 2009, 13 IIR and eight IIR-M SVs were launched to replenish the GPS constellation, and eight Block II SVs and four Block IIA SVs were deactivated. Three other SVs were put into spare status, meaning that the navigation signal is not currently in use, it has no pseudo-random number (PRN) assigned, but some future capability may still remain if that SV is required. This has led to a robustly populated, but increasingly old, GPS constellation.

    A robust constellation is important in many ways. An increased number of SVs provides higher likelihood of an available signal for the user. The greater the number of available satellites visible in the sky at a particular time reduces the measure called dilution of precision (DOP). DOP feeds directly into the accuracy equation such that accuracy improves (reduces) as DOP is reduced with better SV availability and sky geometry. Since Full Operational Capability (FOC) in 1995, the constellation size has grown from the minimum required 24 SVs to a very full constellation of 31 SVs plus a few spares.

    GAO Report

    The April 2009 GAO report focused on the most conservative (that is, pessimistic) predictions, including the so-called cliff of multiple, nearly simultaneous SV failures. Figure 1 shows the most pessimistic curve of likelihood of GPS constellation outages, 2010–2013. The report states “[I]n 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to.” The analysis in the body of the report clarifies that this refers to fiscal year 2010, ending in September 2010. In fact, as this magazine goes to press, there is virtually no likelihood of a sudden collapse of GPS service. There will not be an end-of-the-world loss of 10 SVs in a single year.

    ▲ Figure 1. GAO failure analysis: “Probability of Maintaining a constellation of at least 24 GPS satellites” — an overly pessimistic view.
    Figure 1. GAO failure analysis: “Probability of Maintaining a constellation of at least 24 GPS satellites” — an overly pessimistic view.

    The warnings of the GAO report are not new to the United States Air Force. The USAF, in particular, Air Force Space Command (AFSPC), has been concerned with constellation sustainment and has managed this issue for many years. AFSPC acknowledged the potential for an availability gap years ago. This was part of the reason for changing Block IIR SVs from launch-on-schedule to launch-on-demand back when they were first being launched. This led to a 13-year launch span for IIR instead of just five years.

    Causes of Satellite Failure

    The primary reasons for final failure of GPS satellites have varied widely. An early cause on a few Block Is was failure of the last of three atomic frequency standards (AFS). Indeed, the older designs of the rubidium AFS on GPS Block I, Block II, and Block IIA SVs have had a noticeably shorter life span (1–4 years) compared to the cesium AFS added to later Block I SVs, which became the clocks of choice on Block II and IIA.

    The myth persists today that GPS SVs, regardless of block number, ultimately fail due to the on-board clock. The facts show that only nine of 24 older SVs experienced final failure due to AFS failure. It may be the most common single cause of final failure to date, but it applies to less than half of the SVs. It is not likely that clock failure will be so prominent for newer SV blocks.

    Thus, a culture change was required once Lockheed Martin and its navigation payload subcontractor, ITT, were unable to find a space-qualified cesium AFS for Block IIR and chose to have just three next-generation Rubidium Atomic Frequency Standards (RAFS) on each SV. It was feared that the IIR SVs would only operate for a few years, but it turns out that many on-orbit IIR RAFS will remain unused, as they evidence an extremely long and accurate life.

    Solar array failure was the final failure mode on only three Block I SVs and no other GPS SVs to date. Solar arrays in medium-Earth orbit degrade in a substantially different manner than those placed in low orbit or geosynchronous altitudes. This may be from contamination, or from the severe radiation environment. Several degradation models have been developed for the GPS orbit. This has led to strengthened specifications to assure adequate power on later-model GPS satellites. In fact, both IIR and IIR-M show no SV life limitations to date due to solar array degradation. Power limitations due to degraded solar array performance have forced a change in SV operations for a few older Block II and IIA SVs, but they have maintained the navigation mission.

    Thus, the GAO report states the issue incorrectly: “[E]xcluding random failures, the operational life of a GPS satellite tends to be limited by the amount of power that its solar arrays can produce.” The evidence concludes just the opposite.

    Reaction wheels (used to gently control SV pointing attitude) have been the cause of eight of 24 final failures. Early reaction-wheel designs on older GPS SVs contained inadequate lubricant for the pre-launch storage and on-orbit life of the SV. This led to premature failure of one or more of the four wheels. Several SVs had to be monitored closely for several years in three-wheel or even two-wheel mode. Two Block I and six Block II SVs were deactivated due to wheel failure. Again, newer SVs have applied lessons learned to ensure robust wheel life.

    “One component [away] from total failure,” a commonly cited cause for concern, primarily indicates that the designed redundancy on the SV is being employed. Many SVs operate for many years on the redundant component. It does not signify the navigation mission will fail tomorrow. See Table 1.

    Table 1. Years on primary versus redundant component.
    Table 1. Years on primary versus redundant component.

    The list is not comprehensive, but shows a few examples of primary component and redundant component life at the time of final failure of that redundant component. Sometimes the redundant components show significant life when taking over for the primary components, sometimes they do not. In fact, SVN-24 has been single-string for more than 10 years. It has been on the watch list for replacement for almost that long. Though no longer in a primary slot, it continues to provide a valued navigation signal to the users.

    Mean Mission Duration

    Mean mission duration (MMD) specifies and measures the longevity of an SV in on-orbit operation. The strict definition of MMD is the area under the probability of success curve (the reliability curve), integrating from time zero (launch) up to the contractual design life (also called mission durat
    ion). It is the initial pre-launch estimate of how long the SV is expected to survive, given that it fails completely at its design life. MMD is usually imposed as a requirement on the SV design, guiding parts selection, systems design, SV assembly, and pre-launch test to ensure that the SV is robust and will provide service for many years.

    Once the SVs for that build are all launched, MMD has less value. Over time, the MMD requirement must be shown to have been met on-orbit, but it is not a good number to estimate how long a specific SV will actually last. Several years ago, Aerospace realized that the MMD was too conservative to use as an on-orbit lifetime estimate. In recent years, another measure called the Mean Life Estimate (MLE) has attempted to better define the SV longevity that can be expected.

    Mean Life Estimate. MLE attempts to incorporate the actual projected end-of-life into the reliability calculations, where end-of-life is based on consumables and/or component wearout, such as solar array power degradation. On GPS III, assemblies that potentially have a life limit must be life tested to 2X design life. This almost guarantees that they will live beyond design life. MLE was proposed as a method of improving the estimate of how long the SV will survive. These calculations typically use a normal (Gaussian) distribution with a mean and sigma to predict when individual assemblies wear out. A Monte Carlo simulation then calculates the life of each assembly and the probabilistic loss of the same component due to random failure. The shortest of these times represents the failure time for the assembly for that specific simulated mission. The average of all these runs produces the composite curve for the vehicle that considers real wearout limits for each assembly.

    Thus, MMD estimates should be limited to prelaunch estimates that are based on the contractual design life. After launch, any adjustments to lifetime limits or wearout life should employ MLE. Table 2 lists the MMD requirement, design life, and current life estimate (MLE, when available) for all GPS versions to date.

    Table 2. GPS SV life requirements and prediction.
    Table 2. GPS SV life requirements and prediction.

    II and IIR Lifetime

    GPS Block II SVs have exceeded all MMD and lifetime requirements with one exception. With several SVs still on-orbit, GPS Block IIA SVs have already exceeded all MMD and lifetime requirements, with one exception.

    All 13 Block IIR SVs have been launched. To date, no on-orbit IIR SVs have been disposed due to final failure. The oldest Block IIR SV, SVN-43, is now more than 13 years old. The youngest, SVN61, is almost six years old.

    The lifetime prediction of the IIR SVs has been examined, incorporating component failures into the reliability prediction. The original MMD requirement was specified at six years, with a design life of 7.5 years and an expendables life of 10 years. Analysis suggests that the GPS Block IIR SVs will exceed all MMD and lifetime requirements.

    When analyzed for an expected 15-year lifetime, the current IIR MLE exceeds 14 years. This incorporates all the on-orbit failures experienced to date. As of this writing, there have only been a few failures resulting in components being reconfigured to the redundant sides. Only one of these has been for a RAFS. Thus, 35 RAFS clocks remain on 12 IIR SVs. This bodes well for IIR lifetime: clocks will not be a life-limiting item.

    So far, only two IIR SVs have experienced reaction-wheel assembly (RWA) problems. These issues were of an electrical nature as opposed to the lubrication issues on earlier vehicles. The wheels stuck when transitioning through null regions while reversing spin direction. Subsequently, these wheels have been revived through a software modification. A patch to the bus computer software enabled recovery of the stuck RWAs. Thus, there was no loss of reaction wheel redundancy on these SVs.

    For IIR, excluding random failures, current evidence suggests the most likely life-limiting item will be battery capacity, or the combination of battery capacity and solar-array output power. This limitation of IIR SV life will not occur any time soon. During eclipse seasons — twice per year with the GPS orbit — solar arrays must support normal vehicle power requirements, in addition to fully recharging the batteries prior to entering the next eclipse. Though estimating future battery performance is difficult, recent studies conclude an expected battery life of up to 18.5 years for IIR and 12 years for IIR-M.

    The IIR robust lifetime comes from following military standards, employing tight limits on parts selection, and executing a thorough testing program.

    IIR-M Lifetime

    All eight Block IIR-M SVs have been launched. To date, no IIR-M SVs have been disposed due to final failure. The oldest is SVN-53 at just over five years of age; the youngest is the recently launched SVN-50 at just over one year. SVN-49, on orbit, awaits being set healthy to users. Optimism remains that it will eventually have a long successful life serving the user community.

    IIR-M MMD, design life, and expendables requirements are the same as for IIR SVs. However, the life longevity is expected to be shorter than IIR due to the higher transmitter power requirements on IIR-M for the new modernized signals and the associated higher electrical power demands and thermal profile. Analysis (summarized in the next section) suggests that the GPS Block IIR-M SVs will exceed all MMD and lifetime requirements. The IIR-M expected life (MLE) exceeds nine years when analyzed for a 10-year lifetime.

    IIR Special Study Results

    Three recent studies have shown increased lifetime prediction for Block IIR: the Limited Life Components Analysis (LLCA) study, conducted with the Aerospace Corporation, the Power Consumption study, and the updated IIR Reliability analysis.

    The 2007–2008 LLCA sought to determine possible areas that might limit the maximum life of the vehicle. It analyzed solar array degradation, battery charging capacity degradation, orbital environment degradation of certain transistors in the RAFS units, and the general reliability analysis of the IIR and IIR-M as expressed in the MLE. Table 3 summarizes study results.

    Table 3. LLCA study results.
    Table 3. LLCA study results.

    There was no issue with environmental radiation due to the shielding on select transistors within the RAFS. The solar-array degradation model tracks well, with the trend showing adequate power supply for 15–20 years, and battery capacity still exceeds the expected SV reliability.

    Enhanced Low-Dose Radiation Sensitivity (ELDRS) is a concern for the degradation of certain types of transistors when held in an unpowered state on-orbit. This situation has been suspected for GPS Block IIA AFS units when they are not powered on for many years in the severe radiation of the MEO environment. Redundant AFS (2–3 per GPS SV) are kept in an unpowered condition until required to replace the primary unit. The ELDRS analysis performed in this study showed no vulnerability of the IIR RAFS to this degradation due to the presence
    of adequate radiation shielding in the unit.

    Another limiting factor examined during the LLCA study focused on battery degradation. The study developed a degradation model showing adequate battery performance margin for the SV life. But it is acknowledged that the IIR low-level trickle charge rate employed during the non-eclipse portion of the year may heat the battery cells somewhat more than optimal. It would be preferred to cut the trickle charge rate in half. The battery degradation model, developed by the Aerospace Corporation, suggests that this reduction in charge rate would add two years of life to each IIR and IIR-M SV, except the few oldest. A study is currently underway to demonstrate the feasibility of this change.

    The updated solar array degradation model developed during the study suggests that the power production will be more than adequate over the predicted lifetime of both the IIR and IIR-M SVs. On-orbit solar array capability tests on several SVs has begun, with results confirming the predictive analysis. It is expected that this on-orbit capability test will eventually be expanded to all IIR SVs as part of normal on-orbit monitoring. See Figure 2 for a plot of the solar array power capacity trend for SVN-43 over 13 years. The power capacity degradation per year decreases as the arrays age.

    Figure 2. IIR solar array power capacity trend.
    Figure 2. IIR solar array power capacity trend.

    The Power Consumption Study tracked actual on-orbit box-level power use on several SVs, in order to advance from the designed power consumption predictions to actual on-orbit values. This was compared with the solar-array degradation seen on-orbit to update the possible life limitation due to solar array capacity.

    Finally, the on-board fuel budget shows more than adequate margin to fully meet mission needs for all SVs, including station-keeping maintenance and disposal operations. Thus, component failure — failure of a final redundant box — is still the primary concern for IIR and IIR-M final failure. Random component failures represent the most likely cause of IIR and IIR-M SV loss.

    IIF Lifetime Requirement

    The first IIF SV was launched in May 2010. Eleven others will be launched in the next four years. The Block IIF will primarily replace well-used and over-age IIA SVs. For each new IIF launched, a PRN must be taken away from an on-orbit asset. The old SV may be disposed due to final failure, or it may be maintained in its GPS orbit as a spare, should it have capability remaining.

    The IIF SV has MMD and design life requirements of 9.9 and 12 years, respectively. This is several years beyond that required of all earlier GPS SVs. Obviously, the new IIF SV has no track record yet, but analysis by the contractor and USAF suggests that the GPS Block IIF SVs will exceed all MMD and lifetime requirements.

    IIIA Lifetime Requirement

    The GPS IIIA contract was awarded in May 2008, and the Critical Design Review was completed in August 2010, two months ahead of schedule. Long lead part acquisition and subsystem build have started. The first launch is still targeted for May 2014. Analysis presented at the GPS IIIA SV CDR currently predicts that the GPS IIIA SVs will exceed all MMD and design life requirements of 12 and 15 years.

    The GPS IIIA System Design Review occurred in March 2007, just prior to the expected release of the final RFP. The delay of the final RFP release until July and contract award decision postponement until May 2008 were two final delays which directly affect the tight schedule for first launch. The IIIA schedule suffered from these delays on top of the extended proposal activity from 2002–2008.

    Despite these delays, IIIA benefits now from the numerous risk reduction and systems engineering efforts performed in the interim. Also, the IIIA design leverages significant design maturity from the A2100 satellite bus, the IIR-M SV heritage, and the fact that Lockheed Martin’s navigation payload subcontractor, ITT, has provided navigation payload components on every GPS SV to date.

    Since the GPS III production looks to be on schedule, the worst thing that could happen would be an acquisition delay or reduction of the SVs necessary to keep the constellation robust. This could well bring the GAO report’s worst-case predictions to pass in a few years.

    Another primary GAO conclusion was that “[the GPS IIIA development] schedule is optimistic, given the program’s late start, past trends in space acquisitions, and challenges facing the new contractor.” But Lockheed Martin and ITT built 21 IIR and IIR-M SVs and bring significant GPS experience to the GPS III design and development — a major benefit to keeping the program on schedule.

    Constellation Sustainment

    The 20 IIR SVs will form the backbone of the constellation for many years to come. But GPS constellation sustainment will depend on all GPS SV types operating together. The 12 IIF SVs will generally replace the older IIA SVs, and the new GPS IIIA SVs will begin launching in 2014 to initially replace older IIR SVs and eventually supplement the constellation beyond 32 SVs. GPS IIIA SVs will be able to broadcast on PRNs as high as 63, though there may be some delay before the Control Segment (CS) can monitor these modernized capabilities and before users are equipped to use them.

    Figure 3 shows a projection of GPS constellation size over the next decade as Block IIR provides the foundation, while IIF and IIIA replace older SVs or add to the size. This figure gives a prediction of constellation health over the next 10 years, considering IIA failures, IIF life, IIR failures, and III life. It suggests a busy operations tempo of disposing of at least one old SV to free up a PRN in time for the launch of a new SV, to maintain constellation strength while reducing the number of extremely old SVs. Moving an SV to spare status slightly relaxes this tempo. Should GPS III SVs be unavailable or significantly delayed (for example, due to boosters), the constellation health will definitely suffer.

    Figure 3. GPS constellation size projection.
    Figure 3. GPS constellation size projection.
     

    In addition to the general long-life predictions, on-orbit SVs can have their operational life extended through employment of various options. Power management is available to extend SV useful life for the navigation and timing community. On Block IIA and Block IIR SVs, this is limited to turning off non-navigation boxes. This is always an option if the available solar array power or battery capacity threatens limiting the legacy signal capabilities. This has been employed on Block IIA SVs with the benefit of extending the SV life by several years. It is expected that this technique will be used periodically on all SV versions in the future.

    On Block IIR-M SVs, reducing the L-band broadcast power (that is, turning off the modernized signals) is an option. Analysis in a recent MMD report shows that this would add several years (2–4) to IIR-M SV life. This would probably be the first step of several available to extended IIR-M life.

    Current Operations

    Regular IIR and IIR-M operati
    ons start with the normal daily navigation data uploads, routine telemetry collection, and memory dumps as for all GPS SVs. Other on-orbit support for IIR and IIR-M SVs consists of a variety of periodic operations from orbital repositioning and minor hardware reconfiguring, to data and computer program updates of the on-board processors. When necessary, anomaly investigation support is provided for any issue or event with causes or could potentially cause an SV outage.

    To maintain proper constellation coverage and proper relative spacing of the SVs, orbital repositioning maneuvers are performed regularly on almost all SVs to counteract the effects of the normal orbital perturbations and natural in-plane acceleration. Occasionally, rephasing maneuvers are performed to move an SV to a new orbital location. Approximately 15 orbital maneuvers are performed per year for the 20-SV IIR/IIR-M subconstellation.

    The SV communication mode for command and telemetry is occasionally modified temporarily to avoid communication conflicts with nearby SVs. Also, certain heaters must be enabled during a portion of the year to avoid excessive cooling.

    The bus and the navigation processors on the IIR/IIR-M SVs are both reprogrammable on-orbit. This includes program updates and data changes. Flight computer maintenance has required an update every year or so. The bus computer has seen eight sets of patch updates to date. The navigation computer has been reprogrammed approximately every two years (patches are not used here). These updates have provided adjustments to current capability, including accommodating degraded hardware component performance, allowing them to perform nominally. Other updates have enabled enhanced capabilities on the SVs.

    The navigation computer program was updated for a number of items including time-keeping system (TKS) loop stability and data collection for offline performance analysis. This has avoided numerous outages due to clock jumps. RAFS frequency drift adjustments must be performed occasionally. All clocks are monitored and uploaded as required.

    Data parameter updates to the bus computer occur occasionally to accommodate Earth/lunar eclipse pair issues and other purposes. Backup ephemeris data uploads are performed on every IIR/IIR-M SV every 10 months. Occasional events caused by the space weather environment must be tracked and addressed using data provided by on-board data monitors. Memory dumps and buffer dumps are performed daily on every SV.

    The bus computer processing was enhanced by adding a rolling buffer for telemetry data collection when out of contact with the CS. This high-fidelity data collection recently has been used to collect battery performance information during an investigation into battery performance degradation.

    The IIR-M SV provides legacy signals just like a IIR SV, and many of the operations are similar, but modernized signals require unique operations for
    IIR-M. To date, these capabilities have been accomplished on the non-modernized CS by using work-arounds. Full modernized capability and signal monitoring will come online with the GPS Advanced Control Segment (OCX).

    The new M-code signal has only been used to date for MUE development and test, but L2C-capable civilian receivers have been sold on the market since before the first IIR-M SV launch in 2005. Users equipped with such recievers now have seven IIR-M and one IIF SV to provide half of the ionospheric correction from tracking the new signal. The remainder of the correction may not be available until the OCX deployment, when regular inter-signal correction (ISC) data gets modulated on the L2C signal.

    Users generally do not think much about GPS SV operations unless it affects the performance they experience. Block IIR and IIR-M SVs have shown significant performance improvement to users in accuracy and availability over the years, indicating that longer IIR life will benefit users by providing good-performing SVs which will last a long time.

    Figure 4 shows GPS accuracy over 13 years, tracking the daily peak estimated range deviation (ERD) trend. The trend has improved partly due to system improvements (both CS and Space Segment), partly due to more IIR RAFS and fewer older AFS, and partly due to RAFS maturation (the guess is that this is due to physics package stabilization within the RAFS). The full constellation accuracy has also improved from using additional National Geospatial-Intelligence Agency (NGA) monitor stations, and other Accuracy Improvement Initiative (AII) improvements to the CS.

    Figure 4. IIR, IIA, and full constellation average ERD trend.
    Figure 4. IIR, IIA, and full constellation average ERD trend.

    Concerning SV availability, General Kehler, commander, AFSPC, stated at the congressional hearing on the GAO report, “[S]ince we declared Full Operational Capability in 1995, the Air Force has maintained the constellation above the required 24 GPS satellites on orbit at 95 percent.” Figure 5, a plot of the number of SVs from 1995 FOC to present day, shows this claim is accurate.

    Figure 5. GPS constellation availability, 1995 to present.
    Figure 5. GPS constellation availability, 1995 to present.

    There have been no occasions when the constellation size dipped below 24 SVs, and there were only a few times in the mid-1990s with a few SVs briefly set unhealthy due to maintenance or anomalies when there were fewer than 24 available SVs. Very rarely has it been as low as 25 SVs. Only once since late 2006 has the number of available SVs dropped as low as 27. This doesn’t take into account the spare SVs that may still have some life left, if required.

    Future Operations

    Consideration of options for future operations include assistance for aging IIR SVs and any CS changes that could help the older SVs. Ideas have been explored, such as crosslinking clock timing data from other SVs if all clocks fail on a particular SV.

    It is expected that the past flight software update pace will need to continue into the future, both for the bus computer and for the navigation computer. This will likely be necessary to address SV hardware issues, CS updates (Architecture Evolution Plan [AEP] and the OCX), as well as compatibility with other future SVs (IIF and III). The OCX will bring to the IIR-M SVs command of the full modernized capabilities. This includes modulation of modernized data on the new signals, full employment of the new signal structure, and signal monitoring of the new signals at the USAF monitor stations. It is expected that most IIR-M SVs will be around for this.

    As has been seen with earlier SV blocks, future IIR and IIR-M availability may degrade somewhat as the SVs age, but the quality support from the Second Space Operations Squadron (2SOPS) and the flexibility of the SVs should minimize any significant outage periods.

    Having Block IIR SVs last longer will potentially allow for more SVs on-orbit providing greater coverage. More SVs will also allow for additional lower elevation SVs to be masked by the user equipment and thus avoid local obstructions.

    Conclusion

    The data and analysis presented here show no single point of vulnerability for the existing IIR and IIR-M on-orbit SVs. Lessons learned from older SVs have been applied to make later
    blocks more robust. IIR SVs have been studied thoroughly with no obvious life-limiting mode identified at this point. Robust and flexible SV design suggests long life for these SVs.

    Based on this analysis and performance, it is expected that IIR and IIR-M SVs will meet and exceed MMD and design life requirements, with some SVs lasting more than 20 years. This will form the backbone of the constellation well into the next decade and mesh well with GPS III.

    While the dire forecast of the GAO report will not come to pass, it is important to follow the guidance of the new National Space Policy of June 2010 to maintain U.S. preeminence in space: “The United States must maintain its leadership in the service, provision, and use of global navigation satellite systems (GNSS).” This can be accomplished by maintaining the steady course which has proven so fruitful to date. If more SVs are wanted, then there might be the option to build the simplified GPS III, the “IIIS,” as recommended by Brad Parkinson.

    Acknowledgments

    The authors thank Pete Barrell, Jim Martens, Joe Trench, Don Edsall, Kim Kruis, Amanda Keith, Wayne Rasmussen, Mark Merwin, Sam Bryant, Jeff Holt, and Chris Krier all of Lockheed Martin, Jeff Harvey of ITT, and Mike O’Brine of Aerospace for their contributions and comments on this work. A longer version of this article was presented at the ION-GNSS 2010 conference.

    WILLARD MARQUIS is a senior staff systems engineer with Lockheed Martin’s GPS IIR and GPS III Flight Operations Group. He has a masters degree in aeronautics and astronautics from the Massachusetts Institute of Technology.

    J. DAVID RIGGS is a staff systems engineer with Lockheed Martin Space Systems GPS IIR Flight Operations Group. He has an M. S. in electrical engineering from Colorado Technical University.

  • Where Time and Space Meet

    Where Time and Space Meet

    Sensor Modeling and Sensitivity Analysis for a Next-Generation Time-Space Position Information System

    By Mark Smearcheck and Michael Veth, Air Force Institute of Technology

    Increasing availability and performance of state-of-the-art navigation sensors motivates the need for a highly accurate reference system commonly referred to as a time-space position information (TSPI) device. The Advanced Navigation Center at the Air Force Institute of Technology is working with the Air Force Flight Test Center to develop a next generation time-space position information (TSPI) system to be used for test and evaluation of modern navigation devices.

    TSPI systems such as the GPS Aided Inertial Navigation Reference (GAINR) or Advanced Range Data System (ARDS) accompany navigation sensors during flight testing to collect the precise position, velocity, and attitude. Current GAINR TSPI performance levels include 1.0 m of position uncertainty, 0.1 m/s of velocity uncertainty, and 1.75 mrad of attitude uncertainty. Goal performance levels for next-generation TSPI call for an order of magnitude improvement over current systems.

    A more accurate test and evaluation device will likely require fusion of multiple sensors of varying modalities such as GPS, inertial, electro-optical and infrared cameras, laser range sensors, barometric altimeters, ground-based theodolites, and ground-based tracking radar. This research aims to identify an integrated sensing package and the sensing techniques required to achieve the next generation TSPI accuracy.

    In order to accomplish this task, a sensitivity analysis is performed that predicts the quality of the navigation solution attainable using various external sensor combinations. The sensitivity analysis requires sensor characterization and modeling in addition to development of a software simulated world (the flight test range) that the sensors are able to observe. Issues also investigated in this research include vision-aiding techniques, optical feature deployment, and testing in GPS-denied scenarios.

    PHOTODEVICE
    The GPS Aided Inertial Navigation Reference (GAINR) system consists of a Honeywell 764-G embedded GPS/INS with a custom control and recording unit. The data are post-processed using an optimal smoother and differential GPS measurements.

    Sensors and Simulated World

    The Air Force Flight Test Center currently obtains TSPI using the GAINR, which includes a navigation grade inertial measurement unit (IMU) and dual-frequency code-based differential GPS (DGPS). Carrier-phase GPS, if available, could be implemented to increase position accuracy.

    When integrated into a highly dynamic platform, such as tactical fighter, a kinematic solution may not always be obtainable due to difficulty resolving integer ambiguities and cycle slips experienced in the receiver’s tracking loops. The sensitivity of both code and carrier-phase differential GPS is included in this research due to the uncertain availability of a kinematic solution.

    Scenarios of GPS denial are always an area of concern for the warfighter, and thus GPS-independent test-platforms must be examined. Other positioning sensors, useful in GPS-denied testing, include ground-based theodolites and radars. These devices are installed at surveyed locations on the test range and are used to track the test aircraft. Theodolites are pivoting platforms that may contain various sensors and provide range, azimuth angle, and elevation angle measurements. Radars are also used to provide the same type of measurements, along with an additional velocity measurement (Figure 1).

    overview
    Figure 1. Overview of possible TSPI sensors. The sensors consist of both aircraft-based and ground-based devices.

    Onboard optical sensors including high-resolution digital cameras and laser range finders have also been investigated for TSPI use. This research proposes to install surveyed targets on the test range that are easily identifiable through feature extraction and tracking methods such as the scale-invariant feature transform (SIFT).

    Cameras are able to observe position and attitude through homogenous pixel location measurements of image features (FIGURE 2).

    FIG2
    Figure 2. Simulated test range at Edwards AFB that includes optical targets, ground sensors, and a flight test profile. Optical landmarks are randomly spread within the field of view of the optical sensor over the trajectory.

    An objective of this sensitivity analysis is to show the attitude performance achievable through feature tracking of surveyed targets. When image-aiding of an IMU is implemented in a navigation filter, such as the extended Kalman filter (EKF), next generation TSPI level attitude accuracy should be reached.

    The other optical sensor investigated, the laser range finder, is used to augment the navigation solution by measuring distance to the surveyed targets detected by the camera.

    For the sensitivity analysis a simulated world is generated for the sensors to make observations. The world simulation includes GPS ephemeris, a digital terrain elevation database (DTED), gravity models, natural terrain landmarks/targets, manmade targets, a ground sensor deployment map, simulated flight test profile, and vehicle sensor installation lever-arms.

    Sensitivity Analysis

    The goal of the sensitivity analysis is to determine the minimal set of sensors that will meet next generation TSPI performance requirements. Sensor models and world characteristics are used to calculate expected position, velocity, and attitude uncertainty given a particular trajectory, sensor package, and feature set. The aircraft’s state vector, x, as a function of the measurement, z, and uncertainty matrix, R, is represented as

    EQ1

    where H is the observation matrix. The observation matrix is a Jacobian made up of partial derivates of each sensor’s measurements with respect to position, velocity, and attitude. Example H matrix elements include the partial derivates describing the camera measurements with respect to position and attitude. The partial deviate of the pixel coordinate, zi, of an image feature with respect to position, pn, is

    EQ-2

    where Tcpix is the camera frame to pixel frame transformation matrix made up of calibration parameters, sc is the line of sight vector from the camera to the target expressed in the camera frame, Cnb and Cbc are direction cosine matrices, and the subscript z denotes the z dimension of the indicated navigation frame. The partial derivative of the pixel coordinate of an image feature with respect to attitude, α, is calculated as

    eq3

    The H matrix’s partial derivatives describing observations from other navigation sensors are derived in our previous
    work, “Sensor Modeling and Sensitivity Analysis for a Next Generation Time-Space Position Information (TSPI) System,” Proceedings of the ION International Technical Meeting, 2010. The a posteriori uncertainty of the state or sensitivity, P, at time k is calculated as

    eq4

    where P0 is the initial uncertainty.

    Results

    Results show the three sigma median uncertainty of position and attitude for various sensor combinations over a common flight profile through the test range (Figure 3).

    Smearcheck-Fig3
    Figure 3. Sensitivity analysis results of position and attitude with various sensor combinations. Scenarios of unobservable attitude are designed by the infinity symbol.

    Conclusions

    The sensitivity analysis indicates that the most practical sensor package that meets next-generation TSPI performance is the combination of carrier-phase GPS and a high-resolution camera tracking ten SIFT features per image.

    In this example, tracking only two SIFT features per image does not provide the necessary level attitude accuracy, although incorporating inertial measurements is expected to reduce the overall number of features required per image.

    In the absence of GPS, theodolites when coupled with a camera can function as a reasonable alternative. It should be noted that since the sensitivity analysis relies on a simulated world the feature tracking performance and target surveying accuracy may change during operational testing.

    The next phase of this research is to integrate the sensors with an IMU using an extended Kalman filter. Fusion with a navigation-grade INS is expected to improve position, velocity, and attitude accuracy.

    If simulated results are promising, the next phase of the effort will focus on collecting flight test data to validate the simulation and further increase the fidelity of the simulation.

    Acknowledgment

    The authors would like to thank the Air Force Flight Test Center for supporting this research.

    MARK SMEARCHECK is a research engineer with the Advanced Navigation Technology Center at the Air Force Institute of Technology (AFIT) at Wright Patterson Air Force Base in Dayton, Ohio. He received his B.S. in electrical engineering in 2006 and his M.S. in electrical engineering in 2008, both from Ohio University. His research topics include micro-air vehicles, indoor navigation, image-aided navigation, pseudolites, and test range instrumentation.

    LT. COl. MICHAEL VETH is an assistant professor of electrical engineering at AFIT and deputy director of the Advanced Navigation Technology Center. He received his Ph.D. and M.S. in electrical engineering from AFIT and his B.S. in electrical engineering from Purdue University. He is a graduate of Air Force Test Pilot School.

  • The System: Galileo PRS Delivery in Question

    Once envisioned to orbit 30 satellites, Galileo’s constellation has over time been reduced to a planned, though still not space-borne, four initial satellites plus 14 operational satellites for a total of 18. The European Space Agency (ESA), under direction of the European Commission (EC), confirmed at the October 19–21 European Navigation Conference (ENC) in Germany that it plans to declare an Initial Operating Capability (IOC), or FOC-1 (Full Operating Capability, Phase One) — the terminology varies — once a constellation of 18 is achieved, in the 2014–2015 timeframe.

    Such a reduced system will not enable global delivery of the Public Regulated Service (PRS), planned as a Galileo-only (that is, not in interoperation with or dependent upon any other GNSS) application. The PRS will use encrypted signals, and access will be limited to authorized governmental agencies. Much sought by the EC, its member states and militaries, and in some views the original and most compelling motivation for Galileo in the first place — to wit, independence from GPS — PRS now appears to recede from view. Quite simply, more satellites are necessary.

    The same geometry-in-space and radio-frequency factors apply to some of the high-precision services once envisioned for intelligent transport systems (ITS) within Europe: tools to relieve traffic congestion and decrease environmental pollution, to enable more and denser high-speed rail links and freight, and similarly for marine (in-harbor and along-canal) operations.

    Galileo finds itself face to face with the potential absence of its own raison d’être. It may need to collaborate with GPS to achieve what were Galileo-only goals. A possible alternative would be to reconfigure the reduced constellation somehow so that it can provide continuous service over the European continent only. This option would not satisfy the needs of European peace-keeping missions around the world, however.

    Doubts from the Floor. An audience member at the E1NC posed the question of the hour to Edgar Thielman, Head of Unit, EU Satellite Navigation Programmes, in charge of Applications, International Relations and Security Issues:

    “We are going to have Galileo-only applications like the Public Regulated Service (PRS) for governments. This cannot work with 18 satellites, unless maybe — this has to be investigated — the 18 satellites are configured in a constellation that will give optimum coverage of Europe. Has this been thought about yet?”

    Thielman replied that European governing agencies are “in discussions about what to do.”

    The EC’s problem is that there is no money available after 2014 — at least not until the next formal round of funding allocations is made.

    A high-level representative of DLR, the German aerospace agency, spoke from the audience about simulations his agency had undertaken using a hypothetical constellation of 24 satellites. This seemed to hint that Germany might know where additional funding could be found for more satellites, but separate news developments (see following story) contra-indicated this possibility.

    Proposal. Earlier in October, the EC released a proposal for better management of critical transport and emergency services, better law enforcement, improved internal security (border control), and safer peace missions — all through the PRS.

    “The safety and security of each and every European citizen lies at the heart of this proposal,” said Antonio Tajani, EC vice president in charge of industry and entrepreneurship. “Given our increasing reliance on satellite navigation infrastructures, there is an urgent need to ensure that key services, such as our police forces and rescue and emergency services, continue to function in moments of crisis, terrorist threat, or disaster. Furthermore, the market for PRS applications offers an important opportunity for Europe’s entrepreneurs.”

    Thielman Speaks. In a private conversation with GPS World, Edgar Thielman stressed that “PRS will be one of the first services of Galileo, as soon as it is functional. We envision that in the 2014/2015 timeframe, with 18 satellites enabling the IOC. We know that development of receivers and technical hardware is still to be done. Thus we put forward the proposal, to be on safe ground, to have a common understanding for industry and participants.

    “The IOC constellation will provide in the beginning the Open Signal (OS), the Safety-of-Life (SOL), and the PRS. The interests are of these three services are different from one another. The PRS follows a completely different logic. But the Member States are interested in getting this specific service, and also the European Commission and the European Council.”

    Thielman explained that these three collective entities anticipate PRS capabilities to deal with “crisis situations — 
where the Open Signal is jammed. Government services must be able to function in very difficult circumstances, for instance, peace-keeping missions.”

    He added, “We want to open this service to other international organizations and states, subject to agreement.” Such discussion on cooperation with third countries, as well as discussions within the EC and among Member States on optimization — that is, ways to overcome the deficiencies of a constellation limited to 18 satellites — are ongoing.

    “We have a lot of talks. The starting point is to have a system that satisfies the needs of the EU and EC with the means we have.”

    It was not stated, but seems implicit to many observers, that such means to enable the PRS may require more cooperation with and use of GPS than Galileo proponents may have originally wished.

    Space, Ground Work Package Signed

    The EC signed the fourth of six procurement contracts for Galileo, this one for €194 million for operations of the space and ground infrastructure, with Space-Opal GmbH, a joint venture created by DLR GfR (Germany) and Telespazio S.p.A (Italy). EC VP Antonio Tajani maintained that “Galileo is becoming a reality. Europe will have its own independent satellite navigation system capable of high precision and reliability. We are fully committed to the roll-out of the system. Given the increased reliance of companies and citizens on satellite navigation, Galileo will play an important role in our daily lives.”

    Procurement for Galileo’s full operational capability is divided into six contracts. In January 2010, three contracts were awarded to ensure system engineering support, satellites, and launchers. The two remaining procurement contracts, for the completion of the ground mission infrastructure and the ground control infrastructure, will be awarded in early 2011.

    Money Trouble

    The global financial crisis has European finance ministers trying to back away from current Galileo funding, let alone any projected future increases. The German government asked the EC to propose ways to cut current Galileo cost projections, said that country’s Transport Ministry. According to reports, one suggestion to realize savings calls for a switch from the planned Ariane 5 launcher (operated by a largely French company) to the Russian Soyuz launcher to place Galileo satellites in orbit.

    Financial Times Deutschland cited an EC report forecasting extra costs of €1.5–1.7 billion ($2.1–2.4 billion), beyond the current €3.4 billion budget. FTD said the report labels Galileo as unprofitable in the long term, at an annual loss of €750 million.

    In 2007, the European Parliament withstood such running tides and devised an unusual financing scheme to keep the program going, by raiding a massive surplus agricultural support fund. Such a maneuver may not be repeatable, as farmers have long memories; EC officials, still feeling the heat from that move, profess that, barring an unforeseen occurrence, Galileo cannot get any more money.

    Notwithstanding, Edit Herczog, member of the European Parliament’s committee on industry, research, and energy, stated that “If it is too big to fail, then it can’t. This is something we can build on.”

    Antonio Tajani, an EC VP, rejected the German press figures as “exorbitant” and “unimagineable.” He maintained that Galileo’s costs remain at €3.4 billion ($4.7 billion). “I don’t know where these figures come from,” he stated at a news conference.

    Space Agency Acts on Security, IP Concerns

    ESA abruptly withdrew six technical presentations on new Galileo developments from the European Navigation Conference (ENC) without immediate explanation. Probing by GPS World elicited a reply that “the papers were withdrawn by ESA because they contained too detailed information that could have led to knowledge transfer.” A further hypothetical, and emphatically unofficial, possible reason was posited later by one knowledgeable attendee, having to do with security issues.

    Most of the presentations were due to be given during a session on “Galileo Development and Test Results” on Tuesday afternoon, October 19. The withdrawal created some consternation among the several hundred conference attendees, as the session would have been the technical highlight of the conference and was much anticipated, and further because no official explanation for the action was offered. A somewhat dated presentation was offered in place of the first paper, and the rest of the session was simply dismissed.

    Later during the conference, GPS World heard speculation from a conference participant, who did not have any official knowledge or clearance, that one or more of the papers may have contained information about the Galileo ground control system that, if made public, might have created vulnerabilities to Internet hacking attacks.

    The withdrawn papers covered the Galileo Orbit and Synchronisation Processing Facility, results from the first user receiver-autonomous integrity monitoring and interference mitigation tests at the Galileo Test Range (GATE) — although the GATE manager stated to GPS World that this particular paper was not withdrawn by ESA for any official reason, but by the GATE itself, because it had received the special test receiver necessary from ESA too late to perform the tests in question — the Galileo ground mission segment operability chain, cumulative distribution function overbounding, the Galileo constellation system verification processes and methods, and, from a later session on GNSS software and algorithms, a paper on coherent E5 ALTBOC processing with the Galileo TUS receiver.

    In the closing session, David Broughton, secretary-general of the International Association of Institutes of Navigation, summarized,”Content of the conference generally was excellent, with the exception of coverage of Galileo, with many papers withdrawn by ESA.  Understandably, this caused much annoyance from the delegates. It was disappointing to see the conference treated with such disdain — if the European Navigation Conference cannot be given a true account of Galileo’s progress, then who can?” This drew applause from the delegates.

    The authors of three of the papers are staffers from ESA itself; the authors of the other three come from companies under contract to the agency.

    SatNav Briefs

    China’s next BeiDou-2 Compass-G4 satellite rose into orbit on October 31 from the Xi Chang Satellite Launch Center in Sichuan Province, 10 years to the day from the launch of the first BeiDou-1A.

    Japan’s new QZSS vehicle Michibiki has reached its final quasi-zenith orbit.JAXA, the Japanese aerospace agency, stated “we started transmission of one of the positioning signals, namely the L1-SAIF signal from the L1-SAIF antenna of the Michibiki on October 19, after we turned on its onboard positioning mission devices.

    “We will make sure that the L1-SAIF signal has compatibility with the existing positioning services, and then begin transmitting signals from the L-band helical antenna, namely the L1-C/A, L2C, L5, L1C, and LEX signals.”

    SBAS for Latin America. A new satellite-based augmentation system signal covering the Caribbean, Central and South America was broadcast by GMV and Inmarsat. The demonstration of an SBAS in test mode took place in front of representatives from the International Civil Aviation Organisation (ICAO).

  • On the Edge: Tracking, Testing

    On the Edge: Tracking, Testing

    By Lukasz Bonenberg and Craig Hancock

    One-hundred-twenty meters of test track, designed for repeatable dynamic position testing, run along the roof of the new Nottingham Geospatial Building at the University of Nottingham, UK. The figure-eight track provides an optimal controlled environment with test equipment aboard a remote-controlled, multi-sensor 7¼-inch gauge locomotive platform with a top speed of 7 kilometers per hour, a dedicated power supply, and five antenna mounts. Simulation of the track using Spirent GSS8000 hardware (GPS and Galileo) provides additional planning and testing capacity.

    The combination of these tools creates the ideal environment for our new project: augmentation of GNSS systems with ground-based Locata positioning technology. This pseudolite-like system, described in the March issue of GPS World, works in a GNSS-like fashion, using code and carrier phase. The major advantage, apart from utilization of the licensee-free 2.4 GHz frequency band, is the precise time synchronization of the network to the nanosecond level.

    The proposed integration addresses Locata’s weak vertical coordinates (due to relative coplanarity of transceivers) and GNSS’s requirement for a clear view of the sky and location-specific weak geometric distribution of the satellites. Prior research and analysis suggests considerable improvement in 3D positioning accuracy when combining ground-based positioning devices (pseudolites) with GNSS, but the current project pushes the research forward by attempting to create on-the-fly ambiguity resolution.

    track-2

    Combination of hardware and software simulation has provided an initial assessment of the proposed integration, optimization of equipment location, and test of the mathematical model to be used. Practical tests, using the roof lab on top of the NGB, will further verify the method and allow comparisons between the predicted and real-life results. This will aid the assessment of noise, multipath, and in-bound interference. The test design minimizes the tropospheric effect, while track flexibility and repeatability offer the possibility of implementing and simulating obstructions and areas of GNSS outage. This will provide a full assessment of the mathematical model and the integrated system’s capacity.

    This project offers new opportunities in civil engineering, specifically monitoring and machine control. GPS is currently widely used for those applications, with Locata also proven successful. The integrated solution can provide not only enhanced positioning capacity but lower the required number of visible GNSS satellites, and offer improved integrity and quality control, ultimately increasing the safety of life.

    The intended utilization is for positioning in dense urban areas and essential structures (airports, seaports, factory sites, bridges) where sky visibility or correct satellite distribution cannot be guaranteed.

    The track is available for other projects. Funded by East Midlands Development Agency, hosted by the Institute of Engineering Surveying and Space Geodesy, the Centre for Geospatial Science, and the GNSS Research and Applications Centre of Excellence (GRACE).

    track-3

  • SBAS (WAAS) and NDGPS Accuracy and Statistics

    There’s something I’ve been wanting to write about since the ION-GNSS conference a few weeks ago. However, a nasty cold, a 10-day trip to Europe (INTERGEO conference), and some jet lag have kept me from it until now.

    Here goes.

    First of all, most of the presentations from the CGSIC meeting are available on the USCG Navigation Center website. You can view them by clicking here. There’s some very good reading and most of it is pretty light-weight and in PDF format.

    One of the presentations at the CGSIC (Civil GPS Service Interface Committee) meeting during the ION-GNSS conference was “Integrating NDGPS and SBAS —
    An Optimal Real-time GPS Mapping Solution,” presented by Jean-Yves Lauture of Geneq, Inc.

    I’m publishing two of the slides from his presentation in order to:

    1. Show the accuracy potential of WAAS and NDGPS given a high performance L1 receiver.
    2. Discuss the statistical names/values used to express GPS accuracy.

    First of all, each of the slides below are at the same scale. Each ellipse is 20 cm with the outside limit (radius) being one meter.

    I’ve known for quite sometime that SBAS (WAAS in this case) is capable of sub-meter precision with a single-frequency GPS receiver. These results are a bit better than what I’ve seen personally, and keep in mind it’s a limited data set of 1,800 continuous epochs, but impressive none the less. Also, keep in mind that the WAAS Performance Analysis Report published quarterly by the FAA’s National Satellite Test Bed shows the 95% horizontal accuracy value for Denver, Colorado, (near where this data was collected) being .547 meters for the quarter ending June 30, 2010 (7,856,354 samples collected over three months).

     

    30 minutes of WAAS-corrected data (each ellipse represents 20cm)

     

    The results I didn’t expect were the slide below, which shows NDGPS-corrected results using the same receiver/antenna. Keep in mind this is a GPS L1 receiver using phase-smoothed pseudorange measurements, not a GPS L1/L2 receiver using a carrier-phase float solution. If you look closely, you’ll see it states the baseline distance is 200 km. Granted, this is a limited data set, and I’ll be interested in seeing further results. If this was a dataset presented by a manufacturer or other party with some sort of interest, I wouldn’t publish it, but this is data collected by an objective entity (a credible U.S. government agency) so that earns, in my mind, a level of credibility.

    The results are pretty impressive. All data points fall within ~20 cm.

    30 minutes of NDGPS-corrected data (each ellipse represents 20cm)

    Keep in mind that this data was collected recently, and we are currently in a period of low ionospheric activity. In other words, data was collected under near-ideal conditions. At the end of the day, my point is that GPS L1 accuracy using SBAS and NDGPS has gotten pretty darned good.

    Accuracy Statistics

    The second reason I’m publishing the slides is to discuss accuracy statistics.

    Look at the small box inside each slide showing 99%, 95%, 68%, and 50% accuracies.

    If you look at the data points, it might not be immediately apparent how those values were arrived at. For example, how could a group of data points all within ~20 cm have a 95% confidence of 37 cm?

    To explain this, there was a good article published in GPS World in 2007 titled “GNSS Accuracy: Lies, Damn Lies, and Statistics” by Frank van Diggelen. It does a good job explaining statistical expressions (RMS, 2DRMS, etc.).

    Keep in mind that most manufacturers express horizontal GPS accuracy specifications based on 68% confidence. When the specification sheet states “sub-meter” HRMS (horizontal RMS) precision, that means 68% of the time; the horizontal accuracy will be less than a meter. In reality, that “sub-meter” receiver won’t consistently deliver sub-meter precision. If you convert the 68% HRMS value and express it with 95% confidence (2D HRMS), the actual horizontal precision for that same receiver will be well over one meter. That’s the precision you can expect from the receiver, not the 68% confidence value.

    Thanks, and see you next time.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric

  • Tradeshow’s the Appeal at INTERGEO 2010 Conference in Cologne

    This week, I’ve been attending the INTERGEO 2010 conference in Cologne, Germany. It’s a gathering of ~16,500 people interested in geodesy, geoinformation, and land management. It’s the largest event of its kind in the world.

    Although there’s a lot of GIS activity, it’s just as much a surveying/geodesy trade show. I borrowed a little of the following from my Geospatial Weekly newsletter because I think it’s relevant in this newsletter, too. Let me just say that if you’re a land surveyor/engineer/construction contractor/GIS’r, you won’t find a trade show anywhere in the world like this one. To me, two things differentiate it from all other conferences I’ve attended that are related to surveying, engineering, construction, or GIS.

    • The sheer size. 16,500 people buzzing around attracting 504 exhibitors. You can find a solution to any sort of challenge you have regarding surveying, geodesy, construction or GIS. The major GNSS manufacturers (such as Trimble/Spectra, Topcon/Sokkia, Leica, Javad) have enormous exhibit booths that rival the Consumer Electronics Show (CES) held every year in Las Vegas. You don’t see these companies spending this much money to exhibit at conferences in North America.
    • Unlike many of the conferences I attend, the focus at INTERGEO is on the trade show exhibit area. The technical sessions are few and most are in German, so that leaves the vast majority of the attendees to flock to the exhibit area. We’re currently in Day Two of the three-day conference, and the exhibit area attendance seems just as strong as the first day, which is not typical. On top of focusing on the trade show area, INTERGEO makes it inexpensive to attend. A one-day pass to the exhibit area is only EUR 20 (~US$26) and a three-day pass to the same is EUR 48.50 (~US$63). It’s even cheaper if you buy it online in advance.

    The few technical sessions held were presented by University Professors and various Ph.D.s, so although I submitted an abstract to present a paper, I knew there was no chance I’d be presenting in the formal technical sessions. The closest I am to a Ph.D. is my father’s, which he earned 40+ years ago. Anyway, INTERGEO has a stage in the exhibit area called the Trend and Media Forum. It’s sort of an infomercial stage for companies to show their products and services. They scheduled me to present on that stage, which I did earlier today (Wednesday). The title of my presentation was “GNSS is Changing a Lot — the Future of GNSS Mapping and Surveying.” The audience was sparse, but the good thing is that INTERGEO records the presentations and later posts them on their www.intergeo-tv.de site. My presentation is not on the TV site yet, but should be by Thursday. Please don’t laugh when I nearly fall down after stepping off the stage while I’m talking :-). Click on the following image to view my presentation.

     

    Following are some pictures I took of the conference exhibit area, with captions:

       

    Altus Positioning                                     Ashtech                                    Javad GNSS

     

       

    Carlson Software                    CHC Navigation (China)                                   FOIF (China)

     

         

    GeoMax GNSS (Leica)                           Leica Geosystems                                   Geneq   

     

       

    NavCom (John Deere)                  Pacific Crest (Trimble)                                  Sokkia (Topcon)

     

       

    Spectra Precision (Trimble)                                    Topcon                                         Trimble

     

    I’ll post some more photos on our live coverage website tomorrow.

    There were many new product announcements in the past day. I saw one that caught my particular interest. I’ve written before that for years I relied on stand-alone satellite mission planning software. The problem that most folks have is maintaining the software as they change computers or update operating systems. There’s also the pain of having to update the almanac every month or so.

    I’ve become a fan of online satellite mission planning. I’ve mentioned the NavCom Technology website a few times in this column. However, it has a few shortfalls, namely no control over the elevation mask used and no support for GLONASS or SBAS.

    I’m happy to report that today at INTERGEO, Ashtech released an online satellite mission planning tool, and it seems to fit the bill. Among other things, it allows you to adjust the elevation mask, and choose to include GLONASS and SBAS satellites. Of course, since it’s an online tool, you don’t have to worry ab
    out updating the almanac.

    Following are a couple of screenshots from the program.

    Select GPS and/or GLONASS and/or SBAS satellite

     

     

    Give it a try for yourself by clicking here. There’s a really cool plot that’s generated as a 3D visualization in Google Earth, showing each satellite (green = GPS, red= GLONASS and blue = SBAS).

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