GPS World

Author: Eric Gakstatter

  • What’s Going to Happen When High-Accuracy GPS is Cheap?

    Last week, as you may have heard given the multiple launch delays, the United Launch Alliance (a Lockheed and Boeing joint venture), under contract with the U.S. Air Force, successfully rocketed a new GPS satellite into orbit.

    The GPS satellite launched into orbit last week wasn’t just any other GPS satellite. It was the first of a new generation of GPS satellites that are going to change the way surveying, engineering and construction data is collected and processed in the future. Its new features are going to profoundly transform surveying, engineering and construction. I’m not exaggerating.

    Before you stop reading because you think you’ve read this already in my other newsletter, Geospatial Solutions Weekly released earlier this week, hang in there because although some of it is the same, I’ve added some surveying-specific comments.

    First of all, it’s important to understand that this is going to happen. It’s not a matter of if, but rather when. What I mean is the price of high-accuracy GPS is going to be very inexpensive, both horizontal and vertical, and it’s going to dramatically affect your business.

    Here’s why.

    The new L5 signal will eventually (when it’s being broadcast from enough satellites – more on that later) significantly transform GPS receivers in two ways:

    1. It will result in high-accuracy GPS receivers being much cheaper and smaller.
    2. It will make collecting high-accuracy GPS data much more convenient for the average person.

    Let’s examine in more detail.

    Why will high-accuracy GPS receivers be cheaper and smaller?

    Today’s GPS dual-frequency receivers (L1/L2) can achieve a high level of accuracy (1 cm) in a short period of time, as little as a few seconds. But, they are expensive. An entry-level GPS dual-frequency receiver is a few thousand U.S. dollars. The primary reason is because there is a limited number of companies that design GPS dual-frequency receivers for surveying, maybe a dozen or so. Why is there a limited number of manufacturers? The answer is because the original L2 was not an open signal. In the 1980s, some very smart engineers figured out how to utilize L2 (designed for military use only) in commercial receivers. When they developed those techniques, the companies were smart enough to patent them. There are so many patents in place that it makes it very difficult for a new designer to enter the traditional GPS dual-frequency market, whether it’s surveying, machine control, GIS, or whatever.

    Unlike the original L2, L5 is an open signal. Its specification is published for anyone to use. No license fee. No receiver tax. Nothing.

    Without any patent blocks, any company in the world is free to develop a GPS dual-frequency (L1/L5) receiver that would be just as accurate, and arguably more accurate, than today’s L1/L2 GPS dual-frequency receivers.

    Looking back on the history of electronics, within and outside the GPS industry, we know that increased competition usually results in lower prices to the consumer and improved product quality.

    Take, for example, GPS L1 receiver chips used in personal navigation devices and mobile phones. Those chips are available today for less than $3 each. Fifteen years ago, much less powerful GPS L1 receivers were $200 each and 10 times larger.

    Mark my words: you will see a similar trend with high accuracy GPS dual-frequency receivers. GPS dual-frequency receivers will be sold at prices you can’t imagine today, allowing surveyors, engineers, contractors, GIS folks, biologists, ecologists, etc. (and an educated general public) to collect high-accuracy data (horizontal and vertical) very inexpensively.

    The only thing holding this trend back is the availability of L5. It needs to be broadcast by  about 24 GPS satellites. That’s going to happen somewhere between 2018 and 2020. Of course, GPS designers will be working on their receivers long before that.

    Why will collecting high-accuracy GPS data be much more convenient for the average person?

    First of all, the cost of high-accuracy GPS dual-frequency receivers will plummet significantly due to the open L5 signal. This will spur a fantastic amount of innovation and competition among a large number of receiver designers, especially in the consumer electronics market. Surveyors, engineer, contractors, GIS folks, etc. will benefit greatly from the consumer electronics industry because the high volumes in the consumer market will further spur innovation and cost reduction.

    Oddly enough, at that time, the most expensive part of a high-accuracy GPS receiver may be the antenna. The consumer electronics market won’t accept the type of high-accuracy GPS antenna we need (too big/bulky), so the limited number of antennas means you’ll pay a higher price, maybe a $100, maybe $200.

    If you have a minute, you might want to browse this article by Dr. Frank van Diggelen. Essentially, he says that consumer GPS receivers in your mobile phone, PND, etc. can be as accurate as a GPS receivers built for high-accuracy surveying. The reason they aren’t, he says, is due largely to the inferior antenna being used in mobile phones, PNDs, etc. Now, I’m not saying I buy everything he’s writing, but he’s a lot smarter than I am with regards to GPS, and I do have enough experience to know that antennas can make a big difference in receiver performance.

    What you’ll see, eventually, is GPS dual-frequency (L1/L5) receiver technology in consumer electronics, which means high-accuracy positioning at consumer prices. Take it a step further and one can make the statement that high-accuracy positioning will be in the hands of the consumer. A knowledgeable consumer will be able to take a  low-cost, high-accuracy GPS dual-frequency receiver and collect (or have others collect) an amazing amount of valuable data (think high-accuracy vertical) that would otherwise be too expensive to collect using today’s technology.

    That is where we are headed, guaranteed.

    Wildcards

    Other GNSS

    The time-frame estimation I made above (2018-2020) for a full (24-satellite) constellation of GPS satellites broadcasting L5 is based solely on the activities of the U.S. government. Keep in mind that the U.S. government can’t exceed the 2020 deadline because December 31, 2020, is when the U.S. Air Force says it will stop supporting legacy GPS L1/L2 dual-frequency receivers. So, the end of 2020 is the worst-case scenario.

    Of course, the U.S. isn’t the only country working on GNSS. Europe’s Galileo system also utilizes L1 and L5. It’s possible that in the 2014 timeframe, the U.S. could have a dozen GPS satellites broadcasting L1/L5 and Galileo could have a dozen Galileo satellites broadcasting L1/L5. Because the U.S. and Europe have been working so closely together to ensure GPS and Galileo work together seamlessly, having 12 Galileo satellites broadcasting L1/L5 is the same as GPS broadcasting L1/L5.

    China is also working on a GNSS called Compass/BeiDou. Although China is very tight-lipped with its intentions, it’s possible China could launch some satellites in orbit that may contribute to an L1/L5 solution, but China is a serious wildcard.

    L2C

    Some of you may be wondering why I haven’t included GPS L2C in the discussion. L2C is an open GPS signal much like L5. There are currently seven GPS satellites broadcasting L2
    C. Not including Galileo, there will be 24 GPS satellites broadcasting L2C before there are 24 GPS satellites broadcasting L5. In fact, some designers may decide to develop L1/L2C receivers. However, Galileo isn’t supporting L2 so while there will probably be triple-frequency receivers (L1/L2C/L5), my guess is that the standard will be L1/L5, because the third frequency isn’t going to buy you much.

    Conclusion

    No other conclusion can be drawn but that in the future, as soon as 2014 and as late as 2020, high-accuracy GPS receivers (cm-level in both horizontal and vertical) will be in the hands of anyone with a few hundred dollars to spend. This will be consumers as well as surveyors, engineers, contractors, GIS folks, and many other folks who see value in spatial data. They will have easy access to a fantastic new tool that will allow them to collect high-accuracy, horizontal and vertical data, at a very low cost and very conveniently. I keep referring to vertical accuracy because accurate vertical data is much more expensive to acquire with the technology that exists today, GPS and otherwise. Not so in the future. When one really thinks about the value of accurate low-cost vertical data, the numbers of applications are mind-boggling and will certainly send all disciplines that use spatial data in a new direction.

    Perhaps no discipline will be more affected by this technology advancement than surveying. If you’re retiring in five years, you can probably get away with not thinking about this. But, if you’ve got more than that left in your career, you really need to consider what direction you want to go.

    The bad news is that you have to change. Change is stressful, especially at mid-career, but you don’t have a choice if you want to enjoy a career in surveying. Technology is transforming surveying. You know it because you’ve been feeling the squeeze. You’ve seen that engineers and contractors have acquired technology tools to bring some activities in-house. Machine control is an obvious one. In just a few years, you likely won’t be doing the same sorts of tasks you’re doing today. There will be much more emphasis on data management and data analysis than on data collection (less field time, more office time). Of course, there will still be a need for people in the field, but that’s not where the professional wage is going to be earned. Those in the field will only have jobs, not careers. The well-paying careers will be in the office (either home office or business office or mobile office).

    The good news is that there’s more opportunity than ever before. I can’t count the number of times I’ve had people from different organizations (public and private) ask me if I knew someone who could help solve their geospatial problem. Sometimes, it’s a problem combining data sets. Sometimes, it’s a problem interpreting the data they have as well as finding or collecting new data. Guess what? They aren’t looking in the telephone book (yellow pages) to find someone to help solve their problem. In fact, in some cases they don’t even care if you live in the same country as they do. True, you may have to travel to their office, but they don’t care as long as you solve their problems. I realize this may be a strange concept to many of you, but the Internet has made the world a lot smaller than it used to be. Your clients don’t have to be located within 200 miles of your office. You can have clients in different counties, states, provinces, and even countries! When you start letting go of the idea that your clients need to be geographically close to you, suddenly your business prospects start to look bright. When you limit your ten-person company to clients located within 100 miles in rural Alabama in this economy, you’re going to starve. When you release that limit and start thinking and acting regionally, statewide, nationwide, or worldwide, all of the sudden there’s a lot more opportunity to keep your employees working.

    One important note

    In order to take advantage of the opportunities I mentioned above, you have to expand your knowledgebase. There’s no choice. It’s either that or you’re bagging groceries at Walmart. Technology is changing and its forcing changes in your business, so you must adapt to those changes. Recently, I wrote about a technical session at the ACSM/GITA conference I attended called the Surveying Body of Knowledge (SBoK). Although I may have some differences with some of the SBoK committee member’s intentions, the concept is right. SBoK does a good job of defining the different disciplines in which surveyors can diversify. Briefly, the five areas are:

    1. Positioning (field data collection)
    2. Imaging (photogrammetry/remote sensing/3D scanners/LiDAR/)
    3. GIS (mapping/cartography)
    4. Law (boundary/real property/business law)
    5. Land development (construction/planning/development)

    The idea is that if one discipline is weak, such as positioning, in the current economy, then you could shift your business in another direction where you are qualified, such as GIS or imaging. You certainly don’t need to be qualified in all five disciplines, but having three or four in your pocket gives you a lot of flexibility when the economy is as weak as it is now.

     

    Thanks, and see you next time.

    Free Webinar on June 24th

    On June 24 (was originally scheduled for June 22), I will be conducting a free 60-minute webinar on “GIS Mapping for Forestry, Agriculture, and Other Natural Resource Professionals.” I will discuss GIS mapping software tools/concepts/techniques as well as GIS mapping hardware such as GPS receivers, digital cameras, and laser rangefinders. Although focused on natural resources, it will be relevant for all people interested in GIS mapping, which could be utility companies, municipalities, transportation organizations, etc.  Sign up now by clicking here and submit questions in advance.

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    https://twitter.com/GPSGIS_Eric

  • GPS, GLONASS, and SBAS Webinar Follow-up

    Normally, my column following a webinar is dedicated to Q&A follow-up from the webinar. However, immediately following the April 22 webinar, I traveled to Phoenix, Arizona, to attend the ACSM/GITA conference, which I wrote about earlier this month.

    This column is dedicated to answering questions I didn’t address during the webinar. Also, I always find the results from the polls I conduct during the webinar very interesting.

    Poll #1: Have you or your work crews had to stop or alter your work pattern due to the lack of GPS satellites?

    Total votes: 128, Yes: 73%, No: 27%

    Gakstatter comment: This is consistent with other polls I’ve conducted regarding GPS satellite availability. The new GPS 24+3 configuration will help mitigate this problem. Read more about the new GPS 24+3 configuration in a three-part series I wrote earlier this year.

     

    Poll #2: How often do you upgrade your GPS equipment?

    Total votes: 113

    Gakstatter comment: There’s no clear pattern here except to say that 46% of the users wait until at least 3 years before they consider upgrading their GPS equipment. That makes sense to me.

     

    Poll #3: Does any of your GNSS equipment utilize GLONASS?

    Total votes: 115, Yes: 39%, No: 61%

    Gakstatter comment: When considering the result of this poll, keep in mind that there are very few “mapping-grade” receivers that are designed to utilize GLONASS. For example, there are very few, if any, sub-meter receivers that utilize GLONASS, primarily due to the lack of correction sources. SBAS doesn’t support GLONASS, DGPS (radiobeacon) doesn’t support GLONASS, and most CORS do not support GLONASS. Only recently did OmniSTAR begin supporting GLONASS. I think this trend will continue, although I doubt that SBAS or DGPS (radiobeacon) will support GLONASS in the foreseeable future.

    Poll #4: Does any of your GNSS equipment utilize SBAS (WAAS/EGNOS/MSAS) as a primary source of corrections?

    Total votes: 111, Yes: 60.5%, No: 39.5%

    Gakstatter comment: This poll result doesn’t surprise me. Given that SBAS corrections are widely available, free of charge, reasonably accurate, and require no action by the user, it makes a lot of sense they are being used.

    Following are some of the questions that were posed by the audience during the webinar:

    Question #1: I am not sure, but when you say you’re “pushing” something out to us, it sounds like your trying to “push” something on us. Just a comment.

    Gakstatter: I’m sorry about the webinar-speak. When I say “pushing the next slide,” that means I’m changing slides. I may change the way I say this. Thanks for your comment.

    Question #2: Can you correct GLONASS signals with WAAS or other real-time technologies?

    Gakstatter: WAAS (or any SBAS) doesn’t support GLONASS. Neither does DGPS (radiobeacon). This doesn’t mean that GLONASS measurement can’t be used, but you’ll be using uncorrected measurements to augment SBAS-corrected measurements. A case where it may be useful is when you’re mapping in an environment where there are a lot of trees. You might only have four GPS satellites visible that are being corrected via SBAS. In that scenario, there might be value in utilizing measurements from GLONASS satellites just to improve the PDOP, even though the GLONASS measurements are uncorrected.

    Question #3: Do you feel manufacturers will begin to release lower-end mapping-grade GPS receivers with L2C and L5 functionality in the future?

    Gakstatter: Yes, I do, but it will be a few years before there are enough satellites broadcasting an L5 signal. I think what you’ll end up seeing are inexpensive L1/L5 receivers (Galileo doesn’t support L2). They will not only be able to provide mapping-grade sub-meter, decimeter) but also RTK accuracies (cm-level). Since L2C and L5 are open civil signals, you won’t see the patent blocks that restrict competition for L1/L2 receivers like you do today.

    I’m not saying L2C will not be supported at all. I think there will be L1/L2C/L5 receivers, but I think you’ll see L1/L5 on lower-end receivers.

    Question #4: There is apparently some degradation of accuracy when using GPS and GLONASS for RTK. Have there been any rigorous studies quantifying this that you are aware of?

    Gakstatter: I’m not sure I’d say I believe there is degradation in accuracy, but I wouldn’t count on GLONASS to improve accuracy. The value of GLONASS is improving productivity. Since it adds several satellite signals to the solution, it effectively eliminates GPS “brown-out” periods so RTK can be used 24/7. There was a rigorous study released by The Survey Association in the UK. The report focused on network RTK. They tested both GPS and GPS+GLONASS. You can download a copy of the report here.

    Question #5: Does using GLONASS-capable receivers shorten the observation time required for fast-static points?

    Gakstatter: My first thought is yes since generally more observables equates to shorter occupation time, but I would check with the manufacturer and follow their recommendations. Honestly, I’ve only used fast-static with GPS-only receivers so I don’t have any personal experience with your scenario.

    Question #6: When is GLONASS-K launch scheduled? When can we receiver a valid CDMA signal?

    Gakstatter: The first GLONASS-K satellite is scheduled for launch later this year. I haven’t seen a launch schedule beyond that. A representative from the Russian Space Agency is scheduled to present at the Institute of Navigation (ION) GNSS conference in September, so I’ll probably learn more at that point. However, it’s a lengthy process. It’s not just a matter of launching satellites. There are many other variables and unknowns such as the control segment and user equipment compatibility. I think it’s safe to say that we are a few years away from having a minimal GLONASS satellite constellation broadcasting CDMA.

    Question #7: The visibility plots show one extra satellite in the “after” plots. Was that intentional? I would have expected there to be an improved number of satellites visible when one more was added to the plotted constellation.

    Gakstatter: Good catch. In the “after” scenario, I set SVN-49 healthy, which it is currently not. The reason I did this was because SVN-49 is in an important slot in the 24+3 configuration. The status of SVN-49 is still undecided, but if they decide to not set it healthy they will move another satellite to take its place in the 24+3 configuration. If I would have kept it unhealthy in the “after” scenario, it would have only s
    hown a 24+2 configuration. Clear as mud?

    Question #8: Is 24+3 the solution to the blackout problem from now to 2014 stated by the GAO Report from last year?

    Gakstatter: The definition of the 24+3 configuration had been around before the GAO Report. Personally, I don’t think the GAO Report had anything to do with 24+3. The 24+3 configuration just helps optimize the current satellites in orbit, whereas the GAO Report addresses the attrition of GPS satellites outpacing the addition of GPS satellites.

    Question #9: Cellphone question: Is the move to 24+3 likely to degrade indoor GPS coverage – fewer peak sats => lower probability of seeing 4+ sats indoors?

    Gakstatter: Interesting question. My first thought is probably so, although I think it would be a temporary problem. Assuming Galileo keeps pushing forward, that would be a big help for cellphone users, both indoors and outdoors.

    Question #10: GPS Satellites are getting beyond the design life…is the USA behind schedule in satellite updates?

    Gakstatter: GPS satellites have been unbelievably reliable. PRN-24, the oldest operational satellite, has been in operation since August 30, 1991. Since they have been so reliable, there hasn’t been as much pressure to launch GPS satellites. Prior to the 24+3 initiative, the minimum guaranteed constellation was 24 satellites. It costs $50-60 million to build each GPS satellite and another $150-200 million to launch it. With the GPS constellation hovering around 30 satellites these past few years, and government budgets tightening, I think it’s clear that the pressure to save money has resulted in a more relaxed launch schedule.

    The delay in the Block IIF satellite (the first one being launched this week) was not a result of the above, but rather technical and program management mis-steps. The GAO Report was particularly critical of the IIF development.

    Question #11: Do you see any future for ground-based free systems such as those broadcasting corrections in LF/MF radio, like the Coast Guard broadcasts?

    Gakstatter:     There is an interesting debate between DGPS (what you mention) and SBAS. The DGPS infrastructure has been in place and working reliably for mariners for better than a decade. Funding for DGPS seems solid for marine navigation, but less stable for inland-based applications (like the U.S. NDGPS system). I think the future of DGPS for mariners is solid for the next 10 years. Once there is a full constellation of satellites broadcasting GPS L5, the value of DGPS will be questioned.

    Question #12: Will WAAS, EGNOS, etc. be needed after L1/L5 receivers can measure the iono effects themselves?

    Gakstatter: I think it comes down to integrity. If the L1/L5 combo can deliver integrity that safety-of-life applications require (such as aviation), then one has to question the value of SBAS. My gut feeling is that the L1/L5 combo can’t and that some sort of augmentation will be needed to attain the integrity level required.

    Question #13: What are your thoughts concerning Compass? Do you feel this will eventually be applicable for public use as part of a functioning GNSS?

    Gakstatter: Compass is the GNSS wildcard. Since the Chinese aren’t particularly forthcoming with their plans, it’s hard to say. But I’m not sure that matters. With a full constellation of GPS, GLONASS (CDMA), and Galileo satellites in the future, that’s around an average of 25+ satellites in view at any one time during the day. If China doesn’t play well with others in a timely fashion, the user community won’t care what Compass brings to the table.

    Question #14: If my current GPS receiver is not ready for L2C and L5, do I have to buy a new GPS or I can upgrade software/firmware later so that I can still use it?

    Gakstatter: You’ll have to trade-in. Some might be upgradable to L2C, but L5 is a different story. It’s a completely different frequency. That affects the receiver as well as the antenna.

    I wasn’t able to address all of the questions here, so look for more in the next newsletter. Particularly I’ll cover some discussion about reference frames, SBAS and L5.

    Look for announcements in the next day or so about the Block IIF GPS satellite launch. It’s scheduled for Friday, May 21. It’s a new era with the first GPS satellite to broadcast an operational L5 signal.

    Thanks, and see you next time.

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

  • ACSM/GITA Conference Coverage

    The annual ACSM (American Congress on Surveying and Mapping) isn’t what it used to be. Attendance was way down and the number of exhibitors is way down. The technical content, however, was still pretty good. In fact, I’ve included links to several videos I recorded at the ACSM/GITA conference.

    This year, the ACSM conference was co-located with the GITA (Geospatial Infrastructure & Technology Association) annual conference. This made the trip worthwhile. By themselves, both conferences are becoming too small for most attendees (and therefore, exhibitors) to attend.

    GITA is a GIS conference targeted at the global geospatial community, but in reality it attracts infrastructure geospatial users such as electric/gas/water utilities and local government.

    This mix of ACSM and GITA is interesting and was a great opportunity for surveyors. While the economy is starving surveyors who are in the typical boundary and land development markets, the GITA crowd, in my estimation, are in dire need of a GIS-versed land surveyor.

    There are many topics that were interesting and I thoroughly enjoyed most of the ones I attended, but there are two points I want to address about this conference:

    1. Surveying/GIS collaboration discussion
    2. Surveying Body of Knowledge discussion

    If I can write fast enough, there is a third I’d like to tackle regarding the Driven By Data discussion. If not in this column, I’m sure I will touch on it in a future column or maybe in my Geospatial Solutions Weekly column.

    Surveying/GIS Collaboration

    One of the major benefits of co-locating the ACSM and GITA conferences is that it gives attendees a chance to mix it up with the “other side.” History has consistently demonstrated that it’s always easier to view the “other side” with a certain level of antipathy from afar. However, when one learns more intimately about the adversary’s intentions and struggles, that antipathy eventually turns towards empathy and appreciation. I recall listening to a US Veteran of World War II talking about fighting the enemy. I’m paraphrasing, but it went something like this:

    “I believed in what we were doing and fighting the enemy was just doing my job. In those circumstances, we were enemies. Under peaceful circumstances, however, we may have been neighbors and we may have even been good friends.”

    Land surveyors and GIS folks should be good friends. They both have a lot to gain from a positive relationship and a lot to lose with an adversarial relationship, with the former standing to lose the most.

    Rudy Stricklin presented a very good session entitled “Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona.” In the presentation, he describes the process surveyors and GIS folks went through in Arizona to collaborate and find a common ground to work from. I’m not saying I necessarily agree with everything that was presented or enacted in Arizona, but Rudy’s consistent and often used terms like “collaboration” and “inclusive” certainly conveyed the team-building spirit and positive attitude needed to build a long-term relationship. The bridge-building process presented by Rudy is a model that would be difficult to go wrong with in a similar endeavor by another state, province or local/regional government.

    I recorded the presentation in its entirety. It’s in five parts with each being about 10 minutes in length. I suggest listening to the first segment as he paints the broad picture. However, the entire presentation is well worth your time.

    Part 1 – Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona (9:10 minutes)

    Part 2 – Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona (9:23 minutes)

    Part 3 – Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona (9:39 minutes)

    Part 4 – Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona (9:12 minutes)

    Part 5 – Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona (9:59 minutes)

    There was also a discussion panel entitled “GIS/Surveying Geospatial Collaboration.” On the panel was Gene Trobia, Arizona State Cartographer, Jack Avis, PLS, and Bill Coleman, PLS. Jack and Bill are both land surveyors who offer GIS services.

    Gene has some great stories about the early ESRI years and GIS challenges. He recalled there were 37 people at the first ESRI User Conference he attended.

    Watch this 85 second description by Gene of the challenge faced by GIS managers explaining why some are myopic.

    I posed a couple of questions to the panel.

    The first was the subject of a National Parcel Database with references to the First American parcel database.

    Part 1 – National Parcel Database discussion (2:26 minutes)

    Part 2 – National Parcel Database discussion (8:36 minutes)

    The second question I posed was how can a small surveying firm that is focused on boundary and mortgage surveys (and is starving) can transition to offering GIS services.

    How Can a Small Surveying Firm Transition to Offering GIS Services (9:55 minutes)

     

    Surveying Body of Knowledge (BoK) discussion

    • Josh Greenfeld, Ph.D., PLS
    • Earl Burkholder, PLS, PE (New Mexico State Univ)
    • Wendy Lathrop, PLS (Private practice)
    • Joe Paiva, Ph.D., PLS (Geomatics consultant)

    The focus of this presentation/discussion was to define the role (Body of Knowledge) of professional surveyors in the 21st century.

    Why develop a Surveying Body of Knowledge (BoK)?

    According to the committee (the folks above plus Bob Burton, PLS, PE and Bob Dahn, PLS), the Surveying BoK was developed to:

    1. Formulate a scope of the surveying profession.
    2. Promote recognition for the need for college education.
    3. To help surveyors in business development.
    4. To develop a surveying scholarship
    5. To help promote the surveying profession.
    6. To define the distinctiveness of the surveying profession.

    The Surveying BoK Committee has defined the surveying profession to encompass the following disciplines:

    • Positioning
    • Imaging
    • GIS
    • Law
    • Land development

    The discussion was led by Josh Greenfeld with Earl and Joe presenting on Positioning, Josh presenting for Robert Burtch on Imaging, Wendy presenting on Law, Josh presenting on GIS, and Wendy presenting on Land Development.

    Often referred to as the world’s second-oldest profession, it’s ironic that land surveyors are trying to redefine themselves after thousands of years. But, technology has forced them to face reality. I can’t say I wouldn’t do the same thing. I would say, however, that it’s late in the game for this. Of course, hindsight is 20-20, but this effort really should have begun 10 years ago. Someone dropped the ball.

    Regardless, I think they’ve got the right idea. The BoK committee consists of pe
    ople who are highly respected in the surveying profession. The BoK document is not perfect (and they recognize that and are looking for input), but it’s a step in defining the future of the surveying professional.
    I think expanding the horizons of the land surveyor to include the five disciplines (positioning, imaging, GIS, law and land development) is a great idea. This would expand the profession significantly as it would paint a much more current and accurate picture of the knowledge and skillset a student could strive to achieve if they chose surveying as a profession to pursue. A Surveying Body of Knowledge (BoK) doesn’t exist today so it’s difficult to paint a picture and describe the knowledge and skillset much beyond that of boundary surveyor.

    Kudos to the committee for devoting the time and energy to assemble the BoK document. Although I don’t have a link to the detailed Surveying BoK that was handed out at the presentation, click here to view a Surveying BoK paper that Dr. Greenfeld presented at the FIG (International Federation of Surveyors) conference about one month ago.

    However, I want to make what I feel is a very important point

    I mentioned this during the discussion and I’ll write it here. If one of the purposes of this document is to take it and run to the state legislature to have it legally define the land surveyor’s domain (and therefore eliminate others from operating in that space), I would vehemently oppose it. Honestly, I got that weird feeling when Dr. Greenfeld made a comment early in his presentation that one of the Surveying BoK purposes was to be used “to define the distinctiveness of the profession against those who are trying to encroach on our profession [because] there are a lot of cases like this.” In other words, he’d like positioning, imaging, GIS, law (as related to surveying) and land development to be the exclusive domain of the land surveyor. That would be a mistake, a HUGE mistake. After the discussion group, I asked Dr. Greenfeld about this remark. He dismissed the premise with the thought that laws can be changed and that a larger group with more resources could overturn such a law if there was enough dissent.

    The reason I think it would be a huge mistake is because it limits competition. It’s common knowledge that competition breeds innovation. Henry Ford said “you can have any color (automobile) you want, as long as it’s black.” Without competition, you may still be driving a black automobile without air conditioning. Of course, all-out competition is not the answer either. Just like in politics, the right answer is not at either extreme, but somewhere in the middle.

    As a side note, here is a short clip from the audience regarding the importance of communication skills in the education of land surveyors.

    The importance of land surveyor communication skills (4:36 minutes)

     

    To give you a flavor of the rest of the conference content, following is a partial list of technical presentations at both conferences.

    ACSM:

    • The Surveyor’s Role in the FEMA Flood Insurance Program
    • Hydrographic Surveying
    • Understanding the Statistics Used in GPS Surveying
    • Development, Implementation, and Future of the National Spatial Reference System
    • The Surveying Body of Knowledge
    • The Surveyor’s Role in Boundary Conflict Resolution
    • Introduction to GIS for Surveyors
    • GIS, Geodesy, and the Ghost in the Machine: A Workshop for Surveyors and GIS Professionals
    • Professional Land Surveyors and Geospatial Professionals Building Bridges in Arizona
    • Panel Discussion: Driven by Data: Who Pays? Who Plays?
    • GNSS Technology Update (presented by Yours Truly)
    • The Truth about an RTK Localization/Calibration

    GITA:

    • How the Evolution of GPS is Transforming Surveying and Mapping (presented by Yours Truly along with Pam Fromhertz of NGS)
    • Geospatial Solutions to Address Aging Infrastructure
    • GIS/Surveying Geospatial Collaboration
    • Geospatial Solutions for Preparing and Responding to Natural Disasters
    • Spatial Analysis in a CAD-driven GIS
    • Geodata Creation and Sharing
    • Location, OGC, and the Smart Grid
    • Spatial Law and Policy
    • Building a Facilities Information Infrastructure to Support Public Safety
    • Offshore Wind Energy GIS Development for the Gulf of Maine
    • Haiti, Open Source Mapping, and the Collaborative Environment
    • Phoenix Sky Harbor Airport Enterprise GIS – Managing Signage Infrastructure and Content
    • Streamlined Methods to Collect and Maintain GPS and Attribute Information for Utility Assets

     

    Lastly, if you’re interested, here’s a link to my “GNSS Technology Update” presentation I made at the ACSM Technical Session.

    GNSS Technology Update

    Thanks and see you next time.

     

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

     

  • SBAS Crashing

    It’s been a tough couple of weeks for SBAS (Satellite-Based Augmentation System), namely the USA’s WAAS program and India’s GAGAN program. WAAS and GAGAN have taken big hits recently that threaten the integrity of the programs. Both events were totally unexpected and are causing disruptions of GPS correction services.

     

    Let’s Start with WAAS

    First of all, consider the following infrastructure graphic describing WAAS.

    WAAS Infrastructure (note: GEO satellites positioning not geographically correct in graphic)

    At the moment, WAAS uses two geostationary satellites (referred to as GEOs) to broadcast GPS corrections throughout the WAAS service area, which covers the U.S., Mexico, and most of Canada. The user’s GPS receiver must be able to “see” at least one of the WAAS GEOs in order to receive the GPS corrections. Currently, one WAAS GEO (PRN 135) is located at 133°W longitude and one (PRN 138) is located at 107°W longitude. They are positioned, for the most part, to provide “dual coverage” in case one fails as the following graphic illustrates. The solid line represents the visibility above the horizon of PRN 138 (107°W). The dashed line represents the visibility above the horizon of PRN 135 (133°W). In New York, for example, PRN 138 is visible at 30°+ above the horizon while PRN 135 is visible at ~15° above the horizon.

    WAAS GEO Footprint Coverage (Dashed = PRN 135, Solid = PRN 138)

    The Federal Aviation Administration (FAA) is the WAAS steward. WAAS (and SBAS) was designed for aviation use and paid for by the FAA. The fact that surveying and mapping users benefit from WAAS is a by-product. The FAA owns and controls most of the WAAS infrastructure, such as the 38 WAAS reference stations located throughout the U.S., Canada, and Mexico. About the only thing they don’t own are the WAAS GEO satellites, and this has been the source of most of the problems with WAAS in the past few years.

    Lease vs. Buy

    It would be prohibitively expensive for the FAA to own GEO satellites that were exclusively used by WAAS. Instead, the agency leases bandwidth from owners of commercial satellites. These are the same commercial satellite owners who lease bandwidth to media (e.g., television) customers. It’s not unlike a utility pole you see along the road with many different wires and devices attached to the pole from different companies who pay to lease space on the pole, except it’s a very expensive pole orbiting in space.

    If you’ve been using WAAS for a number of years, you’ll remember back in 2006 there was a hiccup with the WAAS GEOs at that time. The FAA was leasing space on two Inmarsat satellites (AOR-W and POR). They began transitioning to the current WAAS GEOs but before the transition was complete, Inmarsat began moving AOR-W. This was a headache for some WAAS users and really showed the vulnerability of WAAS.

    Losing Control

    The vulnerability reared its ugly head again last week when one of the commercial satellite operators (Intelsat) that the FAA leases space from announced it had lost contact with its Galaxy 15 (G-15) satellite, which is the GEO that WAAS PRN 135 is broadcast from. Intelsat reported it had lost the ability to send commands to G-15. Without the ability to control the satellite, it will slowly drift out of orbit until it becomes unusable. The FAA estimates this will occur in one to three weeks.

    Solutions?

    Intelsat’s answer was to bring in an older generation backup satellite (G-12), which was in a backup orbit at 122°W. It arrived at 133°W around April 14. Intelsat said that G-12 has virtually an identical C-band package as the G-15 and they could transfer C-band customers to the G-12. The problem is that there is no L-band package (which WAAS needs) on the G-12, so the FAA was out of luck.

    Since Intelsat’s G-12 backup won’t help WAAS, the FAA is looking at other alternatives:

    1. Contract with Inmarsat to bring back POR (178°E). The FAA says that will take 12-18 months. Personally, I don’t think it’s a good solution. It’s too far to the east to help much at all. Its coverage footprint barely covers the western U.S.
    2. Speed up the testing on the new PRN 133 (98°W) and bring it into service more quickly than the original December 2010 schedule. The FAA says it can accelerate testing by one to two months. This is good and I see the benefit, but it still doesn’t help Alaskan users.
    3. The replacement backup satellite being moved to 122°W to backup G-12 may be a solution. It will be a few weeks before it is known what is possible. That would be the best scenario from a coverage footprint standpoint. The question is how long it would take to bring it into service.

    On another note, the FAA stated that with the money they are saving with G-15 going out of service, they will be able to accelerate the acquisition of another WAAS GEO. I have no doubt that this has put a new level of fear into the FAA folks, and they have to realize that they can’t be running thin on WAAS GEOs. If you weren’t aware, the future of aviation navigation is based on GPS, WAAS, LAAS, etc. These sorts of hiccups would be an absolute nightmare if the National Airspace System (NAS) was already dependent on GPS.

    GAGAN

    GAGAN (GPS-Aided Geo Augmentation Navigation) is India’s SBAS. It has been under development for many years and is quite far along in development. It is funded through implementation by the Airport Authority of India with the Indian Space Research Organization. In 2008, GAGAN was broadcasting a test signal from an Inmarsat GEO with reasonable results.

    India’s intent was to launch its new GSAT-4 communication satellite with part of its purpose being a GAGAN GEO satellite. GSAT-4 was to be India’s first rocket with an Indian-designed and built cryogenic-fueled third stage. Apparently it is a very difficult technology to master as it reportedly took India 16 years to develop.

    Last week, after much anticipation, the rocket with GSAT-4 onboard was brought to the launch pad. Liftoff was reportedly flawless. At 8:25 minutes into flight, the rocket failed and the entire rocket, GSAT-4 and all, ended up splashing into the Bay of Bengal. It’s a crushing blow to India’s GAGAN SBAS program, which has suffered a number of delays.

    P.S. Veeraraghavan, director of the Vikram Sarabhai Space Centre in Thiruvananthapuram, said “Our target is to fly a GSLV with our indigenous cryogenic engine within one year. But it will be tough.”

    Following is a video report from an India news organization describing the event:

     

     

     

     

     

     

     

     

     

     

    Webinar Tomorrow

    If you don’t receive this too late (or you can access the archive if you do miss it), you might want to catch my 60-minute webinar “GPS, GLONASS and SBAS Constellation Updates.” It’s free and full of the latest information. I’ll also be answering a number of questions from people who registered. I hope to see you there!

     

    GITA and ACSM Conferences Next Week

    Next week, I’ll be blogging and such from the Geospatial Infrastructure Technology Association (GITA) annual conference and American Congress on Surveying and Mapping (ACSM) annual conference in Phoenix, Arizona. In addition to presenting at both conferences, I’ve got a number of interviews scheduled with interesting people. Follow my blog on the Geospatial Solution’s website Live Event Blog area.

     

    Thanks, and see you next week.

    Follow me on Twitter at

    http://twitter.com/GPSGIS_Eric

  • Solar Activity and RFID Technology

    Updated: Friday, April 9 11:00am US Pacific. I added more specific information regarding signing up for Space Weather Prediction Center email alerts. See below.

     

    It’s time to touch on the solar activity subject again, as there was an event earlier this week and rumors began to fly. The mainstream press jumped on a story back in January when the first solar flare of Solar Cycle 24 occurred. Of course, journalists were writing about worst-case scenarios in the event of extreme solar events that could cause power grids to fail, GPS to stop working, etc.

    While that is true, it’s a real stretch and the typical “sky is falling” reporting. In reality, the solar flare back in January had no effect on GPS operations. In fact, it would take an event 10-20 times stronger than last January’s to begin to notice any effect on GPS operations. Earlier this week (Monday 0800 GMT), the first geomagnetic storm of Solar Cycle 24 occurred.

    Geomagnetic storms are the ones that will give GPS users problems, although this one didn’t because it was relatively minor. The last geomagnetic storm strong enough to noticeably affect GPS users occurred in December 2006. During such an event, it might interrupt your GPS receiver for 10-15 minutes. Most users would not notice or they might attribute it to a local system malfunction. By the time they investigate and reset the system, the event would have passed and the user is back in operation. It would be barely noticeable, if at all.

    According to Joe Kunches of the NOAA Space Weather Prediction Center, a geomagnetic storm is a global event (as opposed to a regional event) that is caused by a highly energized solar wind that is fast and embedded with a strong magnetic field. In the following chart, you can see how this week’s event illustrates this.

    Source: NOAA Space Weather Prediction Center

    In the above chart, the top panel illustrates how the magnetic field becomes much more turbulent starting at 0700 GMT. The fourth panel on the chart denotes the solar wind speed, which ramped up to approximately 2,000,000 mph (3,218,688 kph) at its peak.

     

    Extreme geomagnetic storms = Dynamic TEC = GPS interruptions

    There needs to be very turbulent solar wind that disturbs the Earth’s geomagnetic field in order for GPS operations to be affected. For those of you who are familiar with the Total Electron Count (TEC), a dynamic TEC density in the ionosphere is what really messes up GPS operations. If the TEC is stable, the ionospheric models work fine and we get really good GPS performance like we’ve seen in the past few years in between solar cycles.

    GPS L1 users are affected most by a dynamic TEC density in the ionosphere. These are users of WAAS, DGPS, and commercial L1 correction services like OmniSTAR VBS (not their XP or HP service). During the extreme geomagnetic event in October 2003, published simulations (Yousuf, Skone, Coster, University of Calgary, ION NTM 2005) that illustrated the WAAS maximum horizontal error (95th percentile) blew out to 25 meters while single baseline DGPS maximum horizontal error (95th percentile) blew out to 18 meters. This extreme event lasted for several days.

    This doesn’t mean you’re going to have major problems in the future if you are using WAAS (or another SBAS) or DGPS, but just that high-performance GPS L1 receivers are the most susceptible to extreme solar events. In the case of the December 2006 event, SBAS and DGPS users might have experienced 10-15 minutes of unusual behavior depending on their locations. According to Kunches, high latitude geographic regions (60+ degrees latitude) and the region within 10 degrees of the geomagnetic equator (as opposed to the geographic equator) are affected the most by geomagnetic storms.

    GPS L1/L2 receivers are less susceptible to extreme solar events because they can actively model the affects of the ionosphere, but they are not immune. Extreme events such as in October 2003 can cause a loss of phase lock, especially on L2 with GPS receivers that utilize codeless/semicodeless techniques, which are virtually all of the dual-frequency GPS receivers on the market today. The L2 signal-to-noise (SNR) ratio on L2 is quite a bit lower due to the codeless/semicodeless technique so it is more susceptible.

    GPS L1/L2 receivers using L2C will be less affected (assuming a sufficient number of GPS satellites are broadcasting L2C) due to a stronger SNR.

     

    Not the time to panic

    The reason I wrote this article is to share what I’ve learned about the effects of solar storms on GPS operations from speaking with a number of different scientists. This isn’t meant to be a warning of impending doom for GPS users or anything or that sort. Extreme events typically occur near the solar peak and then again during the decline of the cycle. The peak is estimated to occur around May 2013, so the typical extreme events affecting GPS would likely occur in 2013, 2014, and 2015. It’s too early to start worrying much about it now.

    However, as Solar Cycle 24 ramps up, we’ll see more and more geomagnetic storm activity. If you’re a high-performance GPS user (meter or sub-meter level GPS L1 and GPS L1/L2), I think it’s a good idea to monitor space weather now. Fortunately, the NOAA Space Weather Prediction Center (where Kunches works) provides a service that will notify you of unusual space weather by e-mail. You can sign up to receive e-mail alerts at http://www.swpc.noaa.gov

    Following are detailed instructions for signing up for alerts:

    -Goto the Space Weather Prediction Center website.

    -Click on Email products (under the Support Services menu on the left)

    -Create an account if you don’t have one already (it’s free).

    -Click on Subscribe

    You don’t want to subscribe to everything. Here are the ones specific for GPS operations:

    -Advisories/Space Weather Bulletin

    -Geomagnetic Storm Products/(sign up for both Alerts and Warnings for K6, K7, K8, K9 events.

    -For high latitude (55 degrees and higher) users, also sign up for Alerts and Warnings for K4 and K5 events.

     

    Following are some good reference links regarding the Solar Cycle and TEC:

    GPS World article in January 2010 (scroll to end of article)

    GPS World article in October 2009 (follow-up to other October 2009 article)

    GPS World article in October 2009

    GPS World article in May 2003

    Latest NOAA prediction on Solar Cycle 24

    Solar Cycle 24 page

    Real-time TEC plot from the Jet Propulsion Lab

    Wikipedia description of the Ionosphere

    Wikipedia description of the Total Electron Content (TEC)

     

    RF ID (Radio frequency Identification) in Survey Monuments

    If you haven’t been followi
    ng my Geospatial Solutions Weekly newsletter (sign up here for free), you might want to sign up and read the article I wrote on how RF ID is going to be a technology very much used by surveyors in the future. You can read the article by clicking here.

     

    Webinar later this month (April 22, 10 a.m. Pacific time, 6 p.m. GMT): GPS, GLONASS, and SBAS Constellation Updates

    There’s been a lot of infrastructure changes with GPS, GLONASS, and SBAS in the past six months. We’ve already got several hundred people registered for this webinar. It’s going to be a good one. Here are some of the questions I’ve received already and will be addressing:

    1. When and where will the new FAA WAAS GPS Satellite cover?
    2. Will the accuracy of hand-held units be increased with these latest changes?
    3. What developments will make GPS & GLONASS work better together? In terms of RTK accuracy.

    There have been some questions as to whether you can receive continuing education credit (PDH, CEUs, etc.) by attending the webinar. Please e-mail me directly with these requests and I will do my best to accomodate.

     

    See you next time.

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

     

     

     

     

  • GIS at its Finest: Storm Surge Analysis

    Earlier this week, First American Spatial Solutions (FASS) released a report detailing the risk of 13 coastal cities in the United States to storm surge. It’s a fantastic example of how GIS analysis can be used in a very practical way and on a very broad scale. Did you know that there is a difference (in the insurance company’s eyes) whether an insured residential structure is destroyed by hurricane-force winds or by a storm surge (flooding) caused by the hurricane? The first is covered, while the second might not be.

    I had the opportunity to speak with author Dr. Howard Botts about his report this morning; a link to the 10-minute conversation comes at the end of this article. Dr. Botts is executive vice president and director of database development at First American.

    First of all, from a GIS perspective, FASS has a database of approximately 124 million U.S. parcels. That equates to about 87 percent of the parcels in the United States. FASS estimates there are somewhere around 144.3 million total parcels. Dr. Botts said the biggest challenge for FASS, from a GIS perspective, is automating the management of this massive dataset.

    “There is no national mandate for cadastral or parcel data. So you have about 4,000 different collection units, primarily cities and counties, each of which has their own projection, data standards, different attributes,” said Dr. Botts. “So the first couple of challenges are normalizing the data in terms of projection and coverage and then georectifying it. Some stuff is survey-quality, some stuff is so bad we just put it on the shelf because we can’t use it. Then we also normalize the attributes.”

    “We are using ArcInfo to do the processing and rectification along with some various air photos and other kinds of information and then we manage the entire dataset in Oracle Spatial,” he said. “Literally on a daily basis, we are getting cities and counties feeding us new parcels that have been created. We are constantly refreshing that data and so we do all of that data management within Oracle.”

    The source of the land-elevation and bathymetric data, the heart of the data needed to run analyses such as this, was developed using techniques proprietary to FASS. Dr. Botts wouldn’t go into further detail about the source of the data, but he did say that developing and maintaining that data is more complex than people would think. For example, the bathymetric properties of the sea floor and coast line can change substantially after a storm event, to the point that FASS’s models need to be updated, which they do on an annual basis at the end of April.

     

    Storm Surge Graphic Courtesy of First American Spatial Solutions

    On to the FASS report

    “Retired insurance agent Norman Broussard and his wife Genevieve lived at 154 Brady Drive in Biloxi, Mississippi. Their home, which they built in the 1960s, was just a short stroll from the picturesque Mississippi Sound. When Hurricane Katrina hit, they sought refuge with their daughter. But when they returned, there was nothing left but the concrete slab — the slab the home used to sit upon. The Broussards filed a claim with State Farm. They argued that their home and its contents were destroyed by the hurricane-force winds. State Farm, Mississippi’s largest insurer, denied the claim. The company asserted that the house had been destroyed by the storm surge, or flood, for which coverage was excluded. The Broussards sued. Theirs was the first of the so-called “slab suits” to go to trial. The court’s decision, rendered on January 17, 2007, was a warning to all carriers handling coastal property. In a directed verdict, Judge L.T. Senter found in favor of the Broussards, reasoning that the insurer could not prove what portion of the loss was due to flooding and what portion to wind. The judge then sent the question of punitive damages to the jury, which promptly awarded the plaintiffs $2.5M (later reduced to $1M).”

    After reading the above, you can understand that this is a serious issue involving billions of dollars in residential real estate value — more precisely $234 billion in 13 high-risk U.S. cities, according to FASS. Furthermore, the $234 billion value only includes “current structure value” and does not consider replacement costs, contents, vehicle loss, loss of life or business interruption.

    The 13 cities were determined, using GIS, to be the highest-risk cities to storm surge. The only properties included in the report were those that would be “wet” in a storm-surge event. FASS storm-surge polygons assume the worst-case scenario for each category of hurricane based on the following factors, according to FASS:

    1. Maximum wind speed for each category at time of landfall.

    2. Right-front quadrant of the storm at landfall.

    3. Peak high tide at time of landfall.

    As mentioned previously, FASS has a database of ~124 millions parcels. FASS then identified every property contained within each category of the storm-surge polygon and matched the structure valuation for each residential structure identified.

    The FASS report states that storm surge can damage in several ways:

    1. Water depth. The higher the water level, the greater the damage.

    2. Storm surge velocity. A cubic yard of sea water weighs nearly a ton (1,728 lbs)! Wind-driven water moving at 10-15 mph can cause a tremendous amount of damage.

    3. Transportation of debris. Storm surge can move large objects such as trees, vehicles, boats, and other large objects, and sweep them up against other structures.

    4. Standing period. After the storm surge event, standing water can turn into a toxic lake of debris. Generally, the longer it stands, the more damage is caused.

    Several factors were considered when determining which geographic areas to study:

    1. Hurricane probability.

    2. Vulnerability. Storm surge is most pervasive in coastal areas where there is shallow offshore bathymetry, low-lying coastlines or river estuaries.

    3. Residential density. Most of the nation’s population density is located along the coast.

    Based on the above criteria, FASS selected the following 13 geographic areas:

    *Brownsville, TX
    *Corpus Christi, TX
    *Myrtle Beach, SC
    *Wilmington, NC
    *Long Island, NY
    *Jacksonville, FL
    *New Orleans, LA
    *Charleston, SC
    *Houston-Galveston, TX
    *Tampa, FL
    *Virginia Beach, VA
    *Miami-Dade, FL

     

    The report provides substantial detail on each geographic area such as storm history, number of properties affected, and value of properties affected. For each geographic area, three different maps    illustrate the affected area. Following is an example that shows some of the summary data. Further details of the Gulf-Shores area and the rest of the geographic areas are provided in the full report.

    Gulf-Shores, AL

    Category 5 Exposure: $1,154,467,296.00
    Hurricane Probability: High
    Storm-surge Vulnerability: High
    Residential Density: Medium

    Overhead View of Categories 1-5 Storm Surge Impacting Gulf-Shores and Mobile, AL

     

    The full 18-page FASS report can be downloaded from the FASS website by clicking here. Note that the report is free of charge, but you’ll have to re
    gister before downloading.

    Listen to my 10-minute conversation with Dr. Botts by clicking here. It’s about a 2.5mb audio file.

     

    See you next week.

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

  • Augmented Reality and Podcast Interview with Accela

    I recently viewed a TED presentation on augmented reality that was quite impressive. Honestly, I hadn’t heard much about augmented reality by name, I really have been thinking about it for some time. An example is when I’ve been in the field mapping existing features such as irrigation piping or drainage that is eventually filled in and covered by material (e.g., soil, concrete). I’ve often thought how cool it would be if I could wear some sort of high-tech goggles, while GPS mapping, that would allow me to “see” the underground infrastructure as I looked around a city park. In other words, have the existing as-built map in a head-up display in the goggles that is spatially correct.

    I think you’ll see what I mean if you watch the following TED video on Augmented Reality. I guarantee if you watch it, you’ll be glad you spent the eight minutes or so.

    After you view the TED talk, can you imagine how this could be applied to mobile mapping?

    Also, within the last few days, GM made an announcement about its experimentations with head-up displays in automobiles. Essentially, these display (and augment) information on the windshield of the vehicle. I suggest viewing the short two-minute video on Youtube below.

    These are both fascinating looks at how 3D geospatial data is going to be utilized in our everyday lives.

     

    Podcast Interview with Accela

    I spent a few minutes with Brian Weinke, product manager at Accela, about that company’slatest Accela Automation 7.0 and Accela Mobile Office release. Version 7.0 is a “web-based, enterprise application that boosts the ability of governments to automate critical tasks such as permitting; licensing; code enforcement; community planning and development; asset management; and emergency response.”

    You can listen to the ~10 minute podcast here.

    Thanks, and see you next week.

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

  • LSAW Conference RTK Network Discussion Roundtable

    A couple of weeks ago, I participated in a roundtable discussion at the Land Surveyors Association of Washington (LSAW) annual conference on the subject of RTK Networks (RTN). Gavin Schrock, administrator of the Washington State Reference Network (WSRN), did a good job of selecting a number of industry folks who’ve got personal experience with RTN to be on the panel.

    I always enjoy listening to heavy RTK users about their thoughts, their procedures and how they arrived at them. We danced around a number of subjects with one being the “RTN’s biggest flaw.” My first thought was the communications link. That always seems to me to be the biggest problem with RTK in general. When it’s not working, the first thing I check is the communications link.

    “Wrong,” said the panel members.

    According to them, the biggest weakness of RTK/RTN is the vertical accuracy. They want vertical accuracy to be equal to horizontal. Duh, why didn’t I think of that? My only excuse is that I’m so used to expecting vertical to be 2x-2.5x worst than horizontal that I already have my expectation set and don’t see it improving until we have a lot more satellites in orbit that will bring very low VDOP values. But I guess if I really think about it, vertical accuracy is the Achilles heel (well, maybe behind the line-of-sight limitation).

    It was great to hear thoughts from real-life RTK users. Two panel members in particular espoused the value of RTK/RTN in their operations.

    Douglas Casement, PLS, a solo land surveyor using a Leica receiver on the Leica Spider Network, talked about the efficiency of RTK/RTN and doing projects in a half-day that would have taken a couple of days using conventional surveying equipment with a two-man crew.

    Mike McEvilly, PLS, works for a surveying/engineering firm in Washington State. He uses the WSRN for RTK corrections. He talked about using RTK on most of their projects in one way or another with the limitation being the vertical accuracy on some projects. I asked him if he had any problems with “brownouts” (lack of satellites), he said he didn’t, but then I found out he is using GPS+GLONASS receivers.

    Larry Signani, PLS, is responsible for the geodetic framework behind three RTNs in Washington State. He talked about how he constrains the networks and ties them into the National Spatial Reference System (NSRS). This is the behind-the-scenes grunt work that really makes an RTN perform. It really makes me wonder how other RTNs handle this.

    Gavin spoke a bit about procedures and the testing they’ve done, with RTN rovers, on NGS Calibrated Baselines (CBL) during the life of the WSRN. They’ve got a myriad of data that they’ve collected and used to develop their RTK operating procedures. It’s fascinating to look at the data they’ve collected…that’s another article altogether, but I will share with you a slide that summarizes their RTK field practice.

     

    There’s always been a lot of discussion about RTK procedures and occupation times. Last year, I wrote an article called “What’s Your Occupation Time?” that garnered quite a few e-mail responses. I want to address that subject again in the next couple of months.

    In the meantime, for those who haven’t read it, an extensive report was published by the UK Survey Association regarding RTK performance and procedures. I highly suggest downloading and reading the report. You can download it by clicking here. I would also suggest downloading and reading the National Geodetic Survey’s User Guidelines for Single Base Real Time GNSS Positioning. Although it doesn’t agree with the UK Survey Association on the time splits (the NGS suggests four-hour time splits) for setting project control, it is the most complete “RTK User’s Guide” I’ve run across. I think it’s a must-read for any RTK beginner as well as a refresher for veteran users.

    I could write a lot more about this, and will over the coming months. I’d love to hear about your RTK field procedures and how you arrived at them. E-mail me at [email protected] and let me know your procedures for setting control and topo surveying.

    Thanks, and see you next time.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric
    Edit: Link updated to User Guidelines for Single Base Real Time GNSS Positioning. Previous link was to a draft version of the document.

  • The Consumerization of GIS: Golf Carts on a Roll

    I had an interesting experience last month that opened my eyes and had me thinking about how consumer electronics has transformed GIS over the last several years. Google Earth was cool when it first came out, but nothing earth-shattering. We’ve been doing the same thing (albeit on a smaller scale) for many years. Although you can debate how much technology it brought to the table, it would be hard to argue that it didn’t bring a new level of digital mapping to the consumer.

    The advancement in GIS technology sort of sneaks up on you in a Moore’s Law sort of way. Every year, the performance of desktop computer and workstation technology improves and sometimes is actually less expensive than the year before. I’ve recently written about this phenomenon when discussing the Apple iPad and the potential impact it (and similar technology) might have on the GIS industry.

    My experience last month has to do with the golf industry. I’ve been involved in the golf industry for about 10 years. There are several uses for GIS and GPS in golf course construction management and operations so I keep my finger on the pulse of that industry.

    You’ve probably seen (and maybe have used) some of the GPS/GIS-based products in golf. Probably the most visible are the handheld GPS receivers targeted for golf and the GPS golf carts that provide a moving map as the golfer drives around the golf course.

     

     

    A quick look at what’s needed with a GPS golf cart system:

    • A detailed map of the golf course is required, typically by GPS mapping all of the features (tees, fairways, bunkers, cart paths, etc.). From the GPS data, a graphical 3D (or 2D) map of the golf course is created.
    • On the golf cart is a touch-screen computer with GPS built in, as well as some sort of communication link (either spread spectrum, Wi-Fi, or GPRS) to facilitate communications from each cart back to the clubhouse. GPS is used to position the location of the golf cart on the map as well as its distance to the green and other features such as ponds and sand bunkers.
    • In the office, a computer with management software is used to view the status/location of each cart and manage the flow of carts on the golf course.
    • A host of other features such as food/beverage ordering, 911, text messaging, etc. are available.

    I was moderately involved with GPS golf cart systems five or six years ago as I had several active golf course projects ongoing.

     

    Part of my deliverable was to provide the GIS vector data that would serve as the base map for the GPS golf cart system. In working with the golf cart systems, there were two weak areas that I could see: hardware reliability and cost.

     

    Hardware reliability: Yesteryear

    The computer hardware used several years ago in GPS golf cart systems to display the map and provide the user interface were essentially early-generation tablet computers. Reliability was an issue largely because these systems were highly customized (e.g., not mass-produced). During that time, notebook computers and LCD displays were still relatively high-end items.

    GPS golf cart systems are subjected to a lot of vibration and shock, and therefore it wasn’t uncommon for three or four carts (out of ~80) to be out of order at any one time.

     

    Hardware reliability: Today

    The sales of notebook computers over the past five years has exploded. More and more, notebook computers are being used in place of desktop computers. This huge boost in production has resulted in widespread mass-production of all types of components used in notebook computers. Consumers are a hard bunch to please, and that is why the major market leaders like Dell, HP, ASUS, Toshiba, etc. have to make their products super reliable. The GPS golf cart systems have benefited tremendously from this growth. Not only are off-the-shelf systems more available and reliable today, but also less expensive than before due to economies of scale.

     

    Yesteryear‘s return on investment

    Years ago, the cost to outfit a fleet of golf carts at the typical golf club was between US$225,000 and $275,000. That is a healthy chunk of change, considering that the entire annual maintenance budget of a typical golf course is only $350,000-$450,000. Mind you, the GPS golf cart generates revenue from rental fees, increased speed of play, etc., but the return on investment (ROI) for a typical golf club was hard to justify since the golf club was left to figure out its financing.

    After factoring in that the useful life of a golf cart is only about five years, you can see that convincing a golf club to invest such a large sum of money would be a difficult task…and it was. Worldwide, only several hundred (maybe a thousand at most) invested in GPS golf cart systems.

     

    Today’s ROI

    In years past, there were only a handful of startup companies designing, manufacturing, and selling GPS golf cart systems. Several of them raised venture capital money (one investor was popular Pro Golfer Greg Norman) and most of them burned through the cash without ever turning a profit.

    As with most emerging markets, industry consolidation is bound to happen. With each GPS golf cart company struggling to survive on its own, the GPS golf cart business was no different. The top three industry leaders (ParView, ProLink, GPS Industries) eventually merged to form GPS Industries LLC.

    GPS Industries then teamed up with Club Car, a leading golf cart manufacturer, and established the Visage GPS Golf Cart System. Last month, they introduced Visage, and I had a chance to go through the system (albeit on a tradeshow floor) with a Club Car product manager.

    With Visage, the cost to the club is a nominal $40/month per cart. For an 80-cart fleet, that’s under $40,000 per year. Visage asks the golf club for a
    five-year commitment, but the golf club has the choice of opting out of the agreement after a year and each year after that with no penalty.

     

     

     

     

    A Perfect Storm

    It was interesting for me when I looked at the Visage after not having much hands-on with GPS golf cart systems in the past several years. It was orders of magnitude better than the previous systems I had encountered. The hardware was cleaner and the software was better from a graphics/functionality perspective.

    The product manager talked about the hardware being customized very little. You’ve seen the improvement in notebook computer screens over the past few years, so you can imagine the display quality of the Visage system. Of course, the computer onboard the golf cart is orders of magnitude more powerful than in previous years.

    I thought to myself, this is the perfect storm of the maturation of computer technology, GPS technology, GIS technology, GPRS/Wi-Fi technology, and 3D graphics technology coming together at the right time to create a fine experience for the golfer with an affordable price tag.

    Each of these technologies has matured considerably over the past few years:

    • Computer technology largely follows Moore’s Law.
    • GPS technology (the systems use a u-blox GPS receiver) using SBAS for GPS corrections instead of setting up/maintaining a GPS reference station and communications infrastructure for broadcasting GPS corrections.
    • GIS technology using publicly available data (e.g., orthophotos and vector data) and leveraging off of the development of 3D GIS tools.
    • GPRS technology (mobile phone networks) has experience tremendous growth in the past few years with very affordable data plans. I neglected to mention that the $40/month per cart cost includes the GPRS data plan. Previous generations of GPS golf cart systems used spread-spectrum or early Wi-Fi technology and required repeaters throughout the golf course to propagate the communications signal.

     

     

    Visage’s GPS golf cart system is only one example of how GIS applications are leveraging of off the rapid developments occuring in consumer electronics. As I’ve written in recent columns, the Apple iPad might be a significant consumer electronic milestone that the GIS industry will leverage off of this year.

    Thanks, and see you next week.

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

  • GPS for GIS Data Collection – 101: Webinar Follow-up

    Thank you for making “GPS for GIS Data Collection – 101” one of the most well-attended webinars we’ve done. It’s the first that was co-hosted by GPS World magazine and Geospatial Solutions online. If you don’t subscribe to my Geospatial Solutions Weekly newsletter, you might want to consider it as I venture into GIS and broader issues that I don’t have the space to cover in this newsletter. Also, the webinar had a record number of sponsors. Thanks to Hemisphere GPS, Laser Technology, and First American. Those folks make it possible for us to bring these webinars to you free of charge.

    As customary, the newsletter after the webinar is dedicated to addressing some of the questions and posting the results from the polls I took during the webinar.

    Poll Results

    I conducted three polls during the webinar. I received some feedback that we aren’t giving folks enough time to respond to the polls. We’ll pay more attention to that in future webinars and allow more time. Following are the results:

    Poll #1: Do you currently use GPS for collecting GIS data?

    Yes:     68.5%
    No:     31.5%

    Total votes: 165

    Poll #2: What accuracy do you require in a GPS mapping system?

    cm-level:     28.4%
    One foot:     10.8%
    Sub-meter:    33.1%
    1-3 meters:    22.3%
    3-5 meters:    4.1%
    5+ meters:     1.4%

    Total votes: 148

    Poll #3: Select the three most important items to you in a GPS mapping system.

    Collect attribute data:    88.1%
    Cost:                71.4%
    Ergonomics:            7.9%
    Photo-geotagging:        19.8%
    Accuracy:            87.3%
    Laser offset points:        22.2%

    Total votes: 126

    Question #1: How many satellites are transmitting and how many are just for replacement purposes?

    Gakstatter: There are 30 operational GPS satellites. Currently, they are configured in a 24-satellite configuration so six of them are orbiting as “back-ups.” There are also three satellites, I believe, that are in inactive reserve that could be brought back into service if required.

    However, as covered in my last three newsletters, the DoD is transitioning the GPS constellation to a 27-satellite configuration to improve satellite visibility to users. The process of transitioning started in January will take up to two years to complete. Please see the following articles for details on the 24+3 configuration:

    The New GPS 24+3 Constellation: What Does it Mean to the Surveying and GIS User?

    GPS 24+3 Configuration: A Closer Look

    The Best and Final Look at the GPS 24+3 Configuration

     

    Question #2: I do have a question, but it will take too long right now. How do I contact you later?

    Gakstatter: Please feel free to e-mail me with questions any time…[email protected]. I learn a lot from your questions.

     

    Question #3: What about use of iPhones or Blackberries with GPS embedded in the device?

    Gakstatter: As smartphones become more powerful and prevalent, I think the use of them for GIS data collection will increase. I have two comments on this:

     

    • To this point, the ability to run GIS data collection software is hit or miss. Some smartphones just don’t have the resources (memory, processing speed) to handle running the more powerful data-collection software on the market. Of course, with technology advancing that may not be as much of an issue in the future, and it’s possible that GIS software manufacturers will write streamlined software specifically for smartphones.
    • The accuracy of GPS receivers built into smartphones will always be pretty rough. I’d put it in the 5+ meter category and I don’t think it will get much better, so adjust your expectation accordingly. However, using Bluetooth you might be able to “tether” the smartphone to a higher performance external GPS receiver.

     

    Question #4: Is there a place for consumer-grade receivers in GIS data collection?

    Gakstatter: Yes, I wrote an article on this last year. You can read it here…

    Consumer-Grade GPS Receivers for GIS Data Collection

    Please don’t hesitate to e-mail me more questions about this that may not be answered in the referenced article. I’ve been thinking about a follow-up article on this subject.
    Question #5: What accuracy would you expect to record from a GPS handheld unit?

    Gakstatter: There are high-performance handheld GPS receivers that can deliver centimeter-level positions and there are consumer-type handheld GPS receivers that delivery 5+ meter accuracy. This is typically a direct relationship between accuracy and cost (you’re not going to get sub-meter accuracy from a $200 receiver).

    The best way to approach this is to decide what accuracy you require (cm-level, one foot, sub-meter, 1-3 meters, 3-5 meters, 5+ meters) and look at the budget you have available. You might want to take a look at the webinar I conducted last year titled “A Buyer’s Guide to GPS/GIS Mapping Equipment” and a newsletter article I wrote around the same time titled GPS Receivers for GIS Data Collection.

     

     

    Question #6: We have a Topcon GMS-2 unit using an exteral antenna on a range pole similiar to one of the pictures you had in the presentation. How does the height of the range pole with the external antenna affect the X-Y position? Or does it? Thanks.

    Gakstatter: The value of the range pole is that it gives the GPS antenna a clear view of the sky (above your head and other local obstructions). It can only improve your X-Y position. I don’t know how many times I’ve seen users hold a handheld GPS receiver up against their chest, effectively eliminating the use (and degrading accuracy) of GPS satellites behind them.

     

    Question #7: For area determination which is preferred: static or dynamic?

    Gakstatter: Personally, I would use dynamic unless you’re talking about a very small parcel of land (less than an acre). I’ve seen a number of reports on this and I believe all of them used dynamic data collec
    tion with pretty reasonable results. In other words, I don’t think static buys you much in terms of acreage precision. However, I’ve been in circumstances where I used a combination of both such as when I know there’s a reasonably straight line between two vertices, but it would be very difficult to walk a direct line between them. In that case, I might use static for that leg of the traverse.

     

    Question #8: I thought that PDOP was Positional Dilution of Precision.

    Gakstatter: Several of you busted me on this. I mis-typed the presentation slide. I wrote Precision Dilution of Precision, which doesn’t make any sense. It should have been Position Dilution of Precision (PDOP). The horizontal component of PDOP is HDOP (Horizontal Dilution of Precision). The vertical component of PDOP is VDOP (Vertical Dilution of Precision).

    Click here for a Wikipedia link that provides a little more information on GPS DOPs.

     

    Question #9: Explain limitations of what type of project you cannot do if not a licensed surveyor.

    Gakstatter: Because local laws vary widely, it really depends on where you are working. Even within a country like the U.S., each state has its own statutes that define the roles of the land surveyor.

    In some areas, activities as simple as GIS data collection must be supervised by a licensed surveyor. In other areas, high-liability activities such as construction staking can be done by virtually anyone.

     

     

    Question #10: Could the steel plate in my head cause multipath or obstruct signals when I use the integrated antenna?

    Gakstatter: I can safely say (tongue in cheek) that in 20 years of GPS product development, conducting workshops/seminars, attending conferences, and performing GPS fieldwork, I’ve never heard this question. I’m speechless.  :-)

     

    Question #11: A presumption that we should avoid is that by default “GIS data collection” implies low accuracy. This is simply not true. Position accuracy is independent of GIS. GIS can handle any level of accuracy the user desires. There is no such thing as a “GIS-grade” or “GIS-accuracy” survey. What relationship does GIS have with accuracy?

    Gakstatter: I think Guest Commentator Craig Greenwald and I covered this well in the webinar, but it’s good to reinforce the point. I cringe when I hear someone say GIS stands for Get It Surveyed because it implies that the quality of a GIS is dependent on accuracy. It’s not. In some cases, +/- 500 feet. accuracy is perfectly fine for analysis in a GIS. The accuracy required by a GIS totally depends on the type of analysis you are conducting. Many surveyors typically think of GIS in terms of a land record (parcel) mapping system, but GIS is used for so much more than that. You don’t need cm-level accuracy to find the optimal location for the next McDonald’s restaurant within a city.

     

    Question #12: Do you plan on conducting a webinar that will discuss strictly GPS, i.e., RTK vs. static, data reduction, post processing, etc.

    Gakstatter: Yes, if you’re not subscribed to the Survey Scene newsletter, please sign up for that here as well as the Geospatial Solutions Weekly newsletter on the same sign-up page. The price is right…free. You can also look at the webinar archives where I have covered some of these subjects before. I’m also scheduled to conduct at least three more webinars this year (next one in May/June – topic not yet determined).

     

    There were many other questions and I’ll continue including answers to them in the mid-March Survey Scene newsletter. Also, I suggest you sign up for my Geospatial Solutions Weekly newsletter (GSS Weekly) as mentioned above as I tackle GPS/GIS-related issues there, too. Next week, in the GSS Weekly, I’ll continue my discussion on the roles of the surveyor and GIS professional.

     

    Thanks, and see you next time.

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

     

     

     

  • The Ugly LBS Word: Privacy

    As usual with an emerging personal, digital communications technology on the brink of mass appeal (think e-mail, mobile phones), privacy is a major concern and a serious topic of discussion with regard to location-based services (LBS). With the GPS component, LBS worries users and regulators even more. So much so that there was a House Congressional hearing this week on Capitol Hill regarding this very subject. It’s not the first hearing on location privacy and certainly won’t be the last. Following are the people who testified:

    Lorrie Cranor, Associate Professor, Computer Science and Engineering and Public Policy, Carnegie Mellon University

    Mike Altschul, Senior Vice President and General Counsel, CTIA – The Wireless Association

    John B. Morris, Jr., General Counsel, Center for Democracy and Technology

    Anne Collier, Co-Director, ConnectSafely.org

    Jerry King, Chief Operating Officer, uLocate Communications, Inc.

    Tony Bernard, Vice President and General Manager, Useful Networks

    If you’d like to read the testimony from each of these folks, you can do so here.

    I guess as geospatial-knowledgeable people, most are either on one side of the spectrum or the other. One side being the folks who understand the power of location and are willing to gamble that our privacy will remain within our control while enjoying the benefits of LBS applications. The other side being the folks who understand the power of location and are scared to death that Big Brother will have some amazing new tools to trace our every step and record our every decision.

    As you may surmise, I’m on the gambling side of the spectrum. While I don’t typically live on the bleeding edge of technology (I don’t own an iPhone or Blackberry), I do own a lot of technology and have a fairly powerful smartphone with GPS capability. I don’t currently subscribe to any LBS apps on my phone besides the navigation feature. However, I’m seriously excited about the future of LBS applications. Personally, I’m excited about LBS technology because it will help make my life run more efficiently. That’s what I’m in it for. GPS navigation has done that for me and I think some other LBS apps will do that for me too.

    I realize (and appreciate) that not everyone is like me. I’ve got four kids (ages 12-18), an active spouse, and a fair number of extended family members in the Portland, Oregon, metro area. I’m a family-oriented person so I’m active in my kids’ lives and also try to keep in regular touch with family members who are local. I also am involved in some community activities that require meetings, etc. All of this is on top of my work schedule, which can be hectic. To manage my schedule, I enter my commitments (business as well as personal) in my smartphone calendar. In turn, it tells me where I need to be and when I need to be there. Without it, I’d be in trouble. There’s no way I could commit to memory where I need to be and when.

    My smartphone takes care of helping me manage my schedule and how to get where I need to be (via GPS). I’m happy with it. It’s very good when I set up all my appointments and addresses in advance.

    However, I know I’m missing a lot of opportunities to meet up with my family and friends…if I only knew where they were (or they know where I am) at a particular point in time. For example, maybe I’m on the other side of town watching my kid’s basketball game. My sister could be in the same high school watching her kid, but on a different court. If I knew that at the time, I would certainly make the effort to go sit with her, even if it was just for a few minutes. Yes, I could call her and ask her where she is at, but she’s not the only one. There’s probably 25-30 people like her I stay in touch with and it is not practical to call each one. That number would grow substantially if I include business contacts who I’d be interested in meeting up with if the opportunity arose (think airports and conferences).

    This sort of dynamic people-connecting is what LBS can bring to the table. Of course, LBS can offer many other services (coupons at nearby restaurants, etc.) but the people-connecting opportunity, for me, is the big one.

    What does people-connecting entail?

    Essentially, you’ll need three items:

    • your current location.
    • some way to communicate with people.
    • software to make it all work.

    A mobile phone w/GPS fits that bill. It doesn’t necessarily need to be a smartphone, but a more powerful phone will offer more powerful features. Also, you’ll need some kind of data plan and possibly text messaging. Lastly, you’ll need some sort of software on the phone to make it all work together.

    Following is a sample phone screen of a people-connecting software application.

     

     

    Back to the original topic of this column: Privacy

    Of course, a major concern by regulators and potential users is how personal location information will be used by the LBS application software. Will this be just another way that your personal information will be collected and sold to spammers? In addition to spammers, do you really want your family/friends knowing where you are 24/7? These are not unreasonable concerns.

    I don’t worry about privacy with LBS applications and I’ll tell you why.

    There is a lot of hyper-sensitivity about privacy with LBS applications (House Congressional Hearing this week on the subject) so I think LBS software vendors are well aware that a line has been drawn in the sand and a sort of zero-tolerance policy has been established. Secondly, leading LBS companies were involved with CTIA (The Wireless Association) in developing a document titled “Best Practices and Guidelines for Location-Based Services” so they are intimately aware of the privacy issue.

    There are two guiding principles in the Best Practices guidelines mentioned above:

    1. LBS providers must inform users about how their location information will be used, disclosed, and protected so that a user can make an informed decision whether or not to use the LBS or authorize disclosure.
    2. Once a user has chosen to use an LBS, or authorized the disclosure of location information, he or she should have choices as to when or whether location information will be disclosed to third parties and should have the ability to revoke any such authorization.

    Read the entire CTIA Best Practices guideline here.

     

    The Final Analysis

    One consideration I will give when subscribing to a LBS app in the future is to make sure I subscribe either through my wireless service provider (Sprint, AT&T, Verizon, etc.) or by an established, reputable LBS app provider. This kind of due diligence is no different from when you consider purchasing an application for your personal computer. Common sense tells you not to download an app from Nigeria. You’ll need to practice the same diligence when selecting an LBS application.

    I also wouldn’t consider an LBS application where I don’t have the opportunity to control my personal network of people who are granted access to my current whereabouts. In fact, I’d want the ability to shut off broadcasting my location altogether. Again, I don’t think that any mainstream LBS application is not going to have these features due to the h
    igh-profile sensitivity to privacy.

    I know the LBS applications are already available to accomplish the people-connecting that I want. But, like I wrote earlier, I don’t live on the bleeding edge of technology. I live a step back from the edge. I wasn’t the first to join Facebook (although I’m glad I eventually did) and I won’t be the first to run a people-connecting LBS application, but there’s no doubt in my find that it will eventually be an important tool for me and, most likely, you too. The upside is just too big to ignore.

     

    Thanks, and see you next week.

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

    If you’d like to learn more about LBS, GPS World is hosting a free webinar entitled “What’s Next for LBS” on March 18, 2010.

  • The Best and Final Look at the GPS 24+3 Configuration

    I didn’t plan it this way, but my coverage of GPS 24+3 turned out to be a three-part series, with this column being part three. One reason it turned into a three-part series is because I’m learning more about it along the way, but its mostly because details weren’t released all at once.

    The good news is that I (along with help from others….thank you) was able to generate an almanac that simulates 24+3 reasonably well. The idea behind doing this is that I could compare the satellite visibility plots in satellite visibility software using both the original almanac (I chose January 1, 2010) and a GPS 24+3 modified version of the same almanac. For those plots, I could present to you what you can realistically expect the improvement to be with the 24+3 satellite configuration.

    A quick note before diving into the 24+3 configuration. At the end of this column is a brief discussion about solar activity and GNSS/GPS. Last week, there was a solar event and some users have voiced concerns about that. I’ve addressed those in a section at the end of this article.

     

    24+3

    You can view my first two columns relating to the 24+3 configuration by following these links:

    The New GPS 24+3 Constellation: What Does it Mean to the Surveying and GIS User?

    GPS 24+3 Configuration: A Closer Look

    Plus a news article: New Details of 24+3 GPS Configuration Released

     

    I’d like to update you on some bits of information that I’ve learned about 24+3 since my last column. I asked the HQ Air Force Space Command some questions about 24+3 and they kindly responded.

     

    EG: Will the satellites (SVN24, SVN26) remain healthy during their repositioning journey?

    HQ AFSC: Yes. The satellites will be set unhealthy for the initial Delta-V, but will return to healthy status approximately 24 hours after initiation of the Delta-V. Initial Delta-V for SVN24 was accomplished on 13 Jan 10 and returned healthy on 14 Jan 10. SVN 24 will take up to a year to reach its final destination. Initial Delta-V for SVN 49 was accomplished on 21 Jan 10 and will arrive at its expanded position in Jun 10.  Initial Delta-V for SVN26 will begin early Feb 10.

     

    EG: Why the two-year timeframe to realize the benefits when all repositioning will be complete in 12 months?

    HQ AFSC: The two-year timeframe is a conservative estimate which takes into account potential operational necessities which could extend the time required for completion. We must take a disciplined approach to cover possible failures and ensure continuity of coverage during the transition.

    We will be adding GPS IIF vehicles to the constellation and older vehicles may fail during the transition timeframe. As vehicles are added and removed, the current plan is subject to change in order to provide the best service to all civil and military users. Some of these decisions could require additional time to complete the expanded constellation. However, benefits will likely be realized well in advance of 24 months.

     

    EG: What is the reasoning behind using SVN49 as a key component of the 24+3 configuration since it won’t benefit a significant portion of the civilian user community, namely aviation and marine navigation as well as other SBAS (WAAS) and DGPS users? In my understanding, the FAA’s and the Coast Guard’s user bases are primarily single-frequency pseudo-range, users who won’t be able to use SVN49.

    HQ AFSC:  SVN49 was selected because it is a brand-new satellite with four good clocks. Although issues with SVN49’s navigation signals may make it unusable for all civil use, it could still put out a valid set of signals for military use. The Air Force team is continuing to work “open book” with civil and industry GPS experts to determine the possible outcome of SVN49. Although SVN49 is not currently healthy, GPSW and 50th SW are actively working a mitigation that may allow setting the vehicle healthy in the future. As a mitigation in case we are unable to set SVN49 healthy, SVN30 will be rephased to the same slot following a successful launch and on-orbit checkout of IIF-1. We expect to have either SVN30 or SVN49 healthy and broadcasting from the expanded slot within a 24-month timeframe. At this time, no decisions have been made and no options have been ruled out regarding SVN49.

    Satellite Visibility Plots

    As promised, I’ve (with help) been working on creating an almanac that simulates the 24+3 constellation. My goal was to be able to show you what the benefit to you will be with the new GPS 24+3 satellite configuration.

    The method I used was to modify an almanac from January 1, 2010. The reason I chose that day is because it was before the satellite repositioning began. The first satellite began its repositioning journey on January 13, 2010.

    Within the almanac, I adjusted the position of three of the satellites in the almanac to reflect the new orbit locations they are going to assume.

    • SVN 24 is moving from slot D5 to slot D2F
    • SVN 26 is moving from slot F5 to slot F2F
    • SVN 49 is moving from slot B5 to slot B1F

    Following is a graphic I’ve published before that illustrates the satellite repositioning:

    Using the original January 1, 2010, almanac to plot a satellite visibility chart and then using the 24+3 modified almanac to plot another chart for the same location, I was able to generate the following comparisons between the current GPS satellite configuration and the 24+3 satellite configuration. Please note the following:

    • A 15-degree elevation cutoff was used to account for obstructions (terrain, buildings, trees).
    • The modified almanac does not take into account the other three satellites that are being slightly repositioned (SVN46, SVN55, SVN56) so the modified almanac represents a worst-case scenario.
    • The original almanac is the first plot. The modified 24+3 plot is directly below it.

     

    Portland, OR USA (N45 41, W122 11) Original Almanac:

     

    Portland, OR USA (N45 41, W122 11) 24+3 Almanac:

     

    Miami, FL USA (N25 46, W80 11) Original Almanac:

     

    Miami, FL USA (N25 46, W80 11) 24+3 Almanac:

     

    Tokyo, Japan (N35 42, E138 30) Original Almanac:

     

    Tokyo, Japan (N35 42, E138 30) 24+3 Almanac:

     

    London, England (N51 30, W000 07) Original Almanac:

     

    London, England (N51 30, W000 07) 24+3 Almanac:

    src=”/files/gpsworld/nodes/2010/9563/LondonModified.jpg” />

     

    Moscow, Russia (N55 45, E37 37) Original Almanac:

     

    Moscow, Russia (N55 45, E37 37) 24+3 Almanac:

     

    New Dehli, India (N28 54, E77 13) Original Almanac:

     

    New Dehli, India (N28 54, E77 13) 24+3 Almanac:

     

    Rio De Janeiro, Brazil (S22 27, W42 43) Original Almanac:

     

    Rio De Janeiro, Brazil (S22 27, W42 43) 24+3 Almanac:

     

    Bangkok, Thailand (N13 49, E100 28) Original Almanac:

     

    Bangkok, Thailand (N13 49, E100 28) 24+3 Almanac:

     

    Perth, Australia (S31 49, E116 10) Original Almanac:

     

    Perth, Australia (S31 49, E116 10) 24+3 Almanac:

     

     

    A Quick Note about Solar Activity and GNSS/GPS

    I’ve read media reports and I’ve been asked about a solar event that occurred last week (Thursday, February 12) and what possible effect it had on GPS operations.

    I consulted with Joe Kunches of the NOAA Space Weather Prediction Center to understand how significant of an event it was.

    “There was some activity but I would not think it would have an impact on GPS,” stated Kunches.

    I asked him at what point would GPS operations be affected.

    “As for flares (Radio Blackouts on the NOAA Scales), I’d say 10 to 20 times stronger than last week (R3 to R4 and above) would be sufficient to affect GPS on the dayside, but not for long,” said Kunches.

    So, although there were media reports about the solar event last Thursday, if you had trouble with your GPS it wasn’t due to solar activity.

    However, solar activity is a serious issue for GPS users, especially those using high-performance L1 receivers (sub-meter). You can be sure that I’ll will be covering this subject in-depth as we move further into the current solar cycle.

     

    Thanks, and see you next time.

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

    If you haven’t seen the announcement regarding my Webinar this Thursday (February18, 10 a.m. Pacific Time, 1800 hrs GMT), you might be interested. The title is “GPS for GIS – 101.” It’s a beginner’s (and refresher’s) guide to using GPS for GIS data collection. I’ve invited Craig Greenwald as Guest Commentator.