GPS World

Tag: The System

  • The System: British Patent Filings Threaten GPS III and Galileo Progress

    Two British technologists backed by the U.K. Ministry of Defense have filed patents on the future interoperable GPS and Galileo signal designs that severely disrupt modernization plans for both systems and suddenly, unexpectedly place receiver manufacturers in a highly uncertain and unfavorable situation. Some of the patents have been granted in the U.K. and in Europe, and applications are pending in U.S. patent court, with a ruling expected at any time.

    Companies in the United States and outside the country are being approached and asked to pay royalties, on the basis of the patent filings, for use of the European E1 Open Service signal and the modernized GPS L1C signal. Should such initiatives prevail, costs would presumably be passed along to end users of GPS and Galileo — the same taxpayers who have already paid once for the systems.

    The purveyor of the royalty solicitations is Jim Ashe, vice president for sales and intellectual property at Ploughshare Innovations Ltd., Hampshire, UK. The patents, if successfully used to collect fees from satellite manufacturers or receiver manufacturers, would have a chilling effect on the use of the new interoperable signals that all parties have labored so hard, for so long, to design. They could quite possibly lead to a return to a BOC(1,1) structure for these signals, losing the benefits of MBOC.

    “There’s quite an argument going on,” said one person familiar with the controversy. “Some of the methods of arguing have not been too kind.”

    The Background. A great deal of work was accomplished cooperatively between the United States and the European Union (EU) to develop the landmark 2004 signal agreement that emerged from the Galileo Signal Task Force, formalizing cooperation on satellite navigation between the United States and more than two dozen European countries, including the U.K. Part of that agreement concerned a common signal structure (spectrum) for the civilian signals for both the E1 Open Service (OS) signal — the Galileo equivalent of GPS L1 — and the new U.S. GPS L1C signal to be implemented on the GPS III satellites, coming as early as 2015.

    The EU said during that process, in effect, “Even though we have agreed on this, Europe wants to be able to optimize the E1 OS signal beyond the agreement on that civilian signal being a binary offset carrier BOC(1,1) signal.” Both international entities had agreed that would be the waveform or the spectrum of the new signal.

    The Europeans began to evaluate methods of optimizing their signal. They had some designs called composite binary coded symbols (CBCS), a mechanism of putting a higher frequency componenent into the signal structure, and also a version called CBCS*, meaning that they found there was a bias generated by that extra signal, and so they had to invert every other one of its repetitions.

    The signal structure that they were playing with was centered on a plus and a minus 5-MHz component. (Actually five times 1.023, because of the inherent clock of GPS, you can think of it as 1.023 MHz. Everyone in doing compatible or interoperable signals agreed upon that; when reference is made to 5 or 10 MHz, or an even 5 or an even 10, it means that number multiplied by 1.023).

    The Europeans were were putting an additional BOC signal on top of the BOC 1,1, and it would have plus or minus 5 MHz as the centers of those two BOC peaks, and then some kind of waveform to modulate that.

    The United States pushed back against that to some degree, and proposed adoption of the so-called MBOC waveform, in which case the U.S. signal was equally optimized with a concept called time-multiplexed BOC (TMBOC). The Europeans used the CBOC approach. So, very different ways of doing this. In the European way, they transmitted a continuous but very low-power BOC(6,1) term. The U.S approach transmits four BOC(6,1) chips out of every 33 chips of code (see “Future Wave” sidebar).

    A chip in this case means a part of the spreading code, so each signal has its spreading codes, just like the C/A code is a spreading code, meaning a pseudorandom code modulating the carrier. L1C and E1 OS have a pseudorandom spreading code.

    The U.S. approach does not put BOC(6,1) components onto the data; that’s what is commonly called MBOC. The U.S. approach is TMBOC, on the pilot carrier only, not on the data component. The European system is like two separate signals, the BOC(1,1) signal having both pilot and data, and a BOC(6,1) signal having both pilot and data. They’ve put the (6,1) into both data and pilot components.

    Cue the Antagonists. Part of the task force from Europe and the United States considering the future signals’ make-up were Tony Pratt and John Owen, who works for the U.K. Ministry of Defense and whose office sponsored Pratt’s work. The two participated heavily in all these signal discussions. They stated in early meetings they planned to file patents in some areas.

    “Frankly,” states one source, “people should have paid more attention when they said that, and asked ‘What do you mean, and how’s it going to work, etcetera?’ And secondly, there probably should have been a written agreement between parties that nobody will take advantage or patent any of these ideas that we are developing.”

    Pratt and Owen filed a number of patents domestically, in the U.K., and and in the European Union, in 2003 and in 2006, and in other places around the world, such as Japan, Canada, and in the United States as well. Some of the U.K. and European patents have been granted. The first of some of those U.S. patents may be issued in the near future.

    The original patent filings were later amended to include new claims. The new claims were much more specifically oriented toward TMBOC and CBOC, whereas the original claims were more generally oriented toward modulated methods. The claims have been modified over the years; this is fairly standard patent practice.

    As a result, the original 2003 patent doesn’t necessarily read on a particular signal, but its early filing date has precedence. The claims have been updated and modified, and if the patent office issues those, as a true patent, then the new claims apply. Plenty of big patent battles have been fought over just such issues.

    Once the patent is issued, a satellite or receiver  manufacturer must assume that it is valid, and has only two responses to make, other than acquiescing to royalty claims. The manufacturer can either say, if building a product, “No, my product does not infringe, and I will prove that it doesn’t.’” The other choice for manufacturers is to go back into the patent office and sue the patent filer (and grantee) in the patent courts and prove that the patent was invalid in the first place that the patentee should not have been granted it.

    The United States and others were taken off-guard when the U.K. company Ploughshare, which is owned and controlled by a part of the British MoD called Defense Science and Technology Laboratory (DSTL), started making claims on manufacturers. The DSTL is similar to the U.S. Defense Advance Research Products Agency (DARPA), which is credited with inventing the Internet. If taxpayer money goes into something new and interesting, it is considered in some circles legitimate to file patents on those and attempt to recover taxpayer money through royalties on that taxpayer investment. That concept is not being challenged. Questions as to whether the patents are legitimate are very much in discussion.

    Ploughshare has contacted companies, saying, “If you use these signals coming from either the European satellites or the U.S. satellites, we will go after companies using these signals.” There are different patents issued, one by the European Patent Office, applying to most of the EU countries, that applies directly to the TMBOC signal, the E1 OS signal, and possibly also to Europe’s E5 signal, which is E5a and E5b; and there is also a patent for GPS III, the L1C signal.

    The Devil. For details on the various patents, see Application 10594128 and Application 12305401. See also European patent specification EP 1 664 827 B1, and International Application WO2007/148081. These are examples; there are other applications as well. It is to be argued in some future court as to how those patents are to be interpreted.

    “If you take the patent that hits TMBOC, and you take the broadest possible interpretation of that patent against receiver companies, it says: if you bring into your antenna and process that signal, whether you use all parts of it or not, for instance if you use the BOC(1,1) and not the BOC(6,1) part — then you infringe the patent. Others argue that if you don’t use both components, you don’t infringe.

    “But the claim is written broadly enough that it would apply to any receiver receiving and processing the signal. Nobody says what processing means. The patent says if you receive and process the TMBOC signal, as defined in the prior claim, you infringe the patent.

    “There is confusion as to whether that will apply or not apply — some people expect that it doesn’t and some people think that it might. That’s up in the air.”

    George Is Getting Upset. Various factions in the United States are upset by and trying to figure out what to do about the impasse. From a government point of view, there are three paths that the U.S. government can follow:

    • Put pressure on the U.K. diplomatically. That would be up to the State Department to put pressure on the EU or the U.K. in particular. The EU and the continental Europeans are equally furious at the British for doing this, as far as parties in the U.S. understand. This can’t be stated as a fact but is widely understood and thought to be the case. The diplomatic approach has its limits, obviously.
    • Go into Europe and fight the patents in European patent court and try to prove them invalid, to invalidate the patents. Companies could do the same thing, go into various courts, whether they be U.S. or European or Japanese, and say: “Our receivers don’t infringe,” and then have to prove that to the court; or say “The whole patent should not have been allowed, and I’ll fight the legitimacy of the patent.”
    • Some believe — and there is controversy and anger on this point — that, just as Galileo’s IOV satellites have the capability to transmit without the BOC(6,1) component, the United States should be able to do that with the GPS III satellites as well. Because if the signal is not there, and if the receivers are therefore not designed to process the signals that are not there, then the patent no longer has any relevance.

    “If we are to turn off the BOC(6,1) term for a period of time until the legal or diplomatic or other approaches worked, then we would be able to turn the BOC(6,10) term back on again, and return to the original agreed MBOC and TMBOC signals. That requires some coordination between the United States and Europe, and it requires some work to make that possible in the GPS III satellites, putting a switch in the GPS III satellites to permit the operators to turn that (6,1)BOC on and off. This is being hotly debated.”

    Some parties object, stating that L1C is too important a signal to mess with, and this proposal runs the risk of slowing down the program, and/or making it more expensive. They believe strongly that the off/on switch is not the best or most far-sighted option: why should the United States be forced to change its signal design due to an illegitimate patent, and in the end wind up with a less capable system?

    It is not publicly known whether the Air Force is or is not looking into that option.

    During the week of June 25 there was Working Group-A meeting in Washington D.C. followed by a plenary meeting between the EU and United States. The patent controversy was presumably discussed in some fashion, but whether formally addressed or lurking in the background is unknown at this time.

    “There is some naivete around this,” said the magazine’s soure. “It’s a serious threat. People think maybe they’ll only go after the high-end receivers, and maybe the royalties won’t be so bad. Ploughshare is trying to lull people into a false sense of security. The impact of this will be great unless it is defeated.”

    Future Wave

    Excerpted from the “Future Wave” article on L1C, GPS World, April 2011:

    “The L1C waveform originally was to have been a pure BOC(1,1) (a 1.023 MHz square wave modulated by a 1.023 MHz spreading code). Negotiations between the U.S. and the European Union (EU) at that time resulted in an agreement that both GPS and Galileo would use a baseline BOC(1,1) signal. However, the EU reserved the right to further optimize their signal within certain bounds. Some of the optimization proposals were known as CBCS and CBCS*. However, in further EU/US discussions it was decided that L1C and the Galileo E1 open service signal should have identically the same spectrum. This was a significant challenge because of different baseline signal structures and existing designs.

    “The breakthrough came when [U.S. representative] John Betz proposed what is called MBOC. The MBOC waveform has 10/11th of its power in BOC(1,1) and 1/11th in BOC(6,1). However, L1C and E1 OS achieve this result in very different ways. The Galileo technique is called CBOC. The GPS technique is called TMBOC. Whereas Galileo has a 50/50 power split between pilot and data and includes the BOC(6,1) component in each, GPS includes the BOC(6,1) waveform only in the pilot component by modulating four of every 33 spreading code chips with a 6 MHz square wave and 31 chips with a 1 MHz square wave. With 75 percent of the power in the pilot, the result is 3/4 x 4/33 or 1/11, as required. It is likely the BOC(6,1) signal component will be ignored by consumer-grade GNSS receivers where a narrow RF bandwidth is preferred. Fortunately that is a loss of only 12 percent (0.56 dB) of the L1C pilot power. However, for commercial and professional grade receivers, the extra waveform transitions (wider Gabor bandwidth) can be used to improve code tracking signal-to-noise ratio, and with certain advanced techniques it should be possible to improve multipath mitigation. This final point depends on careful control or calibration of the transmitted code timing and symmetry.”

    EGNOS and Galileo IOV Satellites Shift Right

    The next EGNOS satellite, originally scheduled for a June 18 launch, now has a rise date of July 7 from Baikonur Cosmodrome in Kazakhstan. The launch was delayed by a problem with a first-stage subsystem on the Proton rocket. SES-5 is also known as Sirius 5, stemming from the development of the Sirius satellite constellation by Nordic Satellite AB, now owned by Luxembourg’s SES.

    The satellite carries a transponder for the European Geostationary Navigation Overlay Service (EGNOS). The transponder is intended to eventually replace or one of those on the currently used EGNOS satellites (Inmarsat 3-F2 at 15.5 degrees west using PRN 120, Artemis at 21.5 degrees east using PRN124, and Inmarsat-4-F2 at 25 degrees east using PRN 126 and designated for industry tests).

    Unlike the present L1-only EGNOS satellites, SES-5 will have transponders on both L1 and E5 frequencies similar to the Wide Area Augmentation System satellites, which broadcast on L1 and L5.

    SES-5 is to be stationed at 5 degrees east longtiude.

    A second SES satellite with EGNOS transponders is under construction. The SES Astra 5B satellite is scheduled for launch in the second quarter of 2013 and will be positioned at SES Astra’s 31.5 degrees east orbital position.

    Role Switch. On March 22 and 23, Inmarsat-4-F2 at 25 degrees east using PRN126 and Artemis at 21.5 degrees east using PRN124 switched roles. PRN126 became an EGNOS operational signal-in-space satellite, while PRN124 became the test satellite, transmitting message type 0. PRN120 and PRN126 returned to service around 17:00 UTC on Tuesday, June 26.

    According to an EGNOS service announcement dated April 3, the switch was due to the aging state of the Artemis satellite.

    Galileo October Birds. According to a usually reliable source, the launch date for the second set of Galileo IOV satellites, previously announced as September 28, has been pushed back a couple of weeks to October 12.

  • The System: Commercial GPS in Combat

    Partnership Council Affords Insight, Drama

    By Alan Cameron

    This year’s GPS Partnership Council provided among other highlights a discussion of the tensions between commercial off-the-shelf (COTS) receiver systems used in tactical combat operations versus official military GPS user equipment (MGUE), and an enthralling warfighters’ panel that revealed much of those COTS/MGUE dilemmas. The event, held May 1–2 in El Segundo, California, drew an enthusiastic and involved audience, including many GPS veterans. I was struck by the graying of the clan as well as the practiced and confident presentations of current civilian and military program staffs.

    Keynote speaker Brig. Gen. Martin Whelan, Director of Requirements, Headquarters Air Force Space Command, emphasized that ideas for improvement of the system would be hard sells under current budget realities, but good ideas for lower cost would be welcome. Referring to the three segments — space, ground, and user — he recommended that the segments should talk with each other and challenge requirements. In effect, he implied that the separate segments could reduce overall costs, rationalize requirements, and cooperate better in optimizing the resilience and flexibility of the system, including — this is my interpretation — taking advantage of the “competitive” GNSSs to effect user satisfaction.

    According to Whelan, resiliency of the space segment is a top priority; smaller satellites, hosted payloads, and net-centric designs were highlighted. He commented that multiple GNSSs should be employed in such a way that the user does not know the difference.

    Regarding the upcoming budget, he told us that Department of Defense will be cut by 22 percent, the Air Force will drop 9 percent — but the AF space budget only 1.5 percent. A notable exception to the generally favorable overview was his comment that the MGUE segment, from a distance, looked uncoordinated. Much more along this line came up later during both days of the Council.

    Widespread COTS. There was an air of defensiveness about the user segment, and many comments on both the success and the risks associated with the widespread use of COTS user equipment. We heard further commentary on the very infrequent use of SAASM keys, due to the difficulty of procedures to obtain and employ them, and due to the perception of very low risk of jamming and spoofing threats in current combat deployments.

    A session on “The Future Military Receiver” enlisted two panels of government experts and contractors from Deere-NavCom, Garmin, IEC, Johns Hopkins Applied Physics Labs, Raytheon, and Rockwell-Collins. Although the unclassified nature of the presentations limited the level of detail, it clearly emerged that many tactical, in-combat deployments of COTS GPS receiver systems had occurred and continue to occur.

    A video compared the jamming resistance of a Garmin receiver with that of approved GPS User equipment receivers. It showed a screen of the Garmin receiver losing satellites at greater distances from the jammer and losing lock at closer distances. Directorate employees and officers made several references to the risks from dependence upon COTS receivers, and related with considerable candor the difficulties with large, expensive, power-hungry MGUE, both mobile and platform-mounted, models of which were held up during the presentations — often to laughter from some in the audience.

    More on this followed in Day Two’s dramatic warfighters’ panel, which many people felt was by itself worth the price of admission. These experienced users of GPS under fire — from Coast Guard search and rescue to Air Force forward controllers calling in air strikes within range of small-arms fire — related direct personal experience in a broad array of critical applications. They clearly knew how to use COTS equipment to good advantage and described the operational protocols developed from hard and sometimes painful experience.

    Manipulation of multiple screens in a heavy device, which requires initialization or synchronization before dismounting, was often simply not an option. Translation of such experience into qualified requirements is a major challenge for the Air Force and Army. Overdependence on the anecdotal but very valid combat experiences would weaken a design against an enemy with even rudimentary jamming and spoofing capability.

    An astute questioner asked “Have you seen any evidence that the enemy (in Afghanistan) has changed tactics because of our technology?”

    The answer came “Not yet,” with a comment that the enemy’s early warning systems are very sophisticated and the target of a mission to capture a high-value individual (HVI) frequently knows that such a mission is underway; his support network spirits him away and attacks the mission with the advantage of surprise denied to our forces, abetted by the advantage of favorable terrain and numbers accruing to the enemy.

    The Puck. The Army-led MGUE program status was described as being at technology readiness level (TRL) 6.0; the request for proposals was released on April 16. The key to the success across platforms of this “system of systems” was said to be the Common GPS Module (CGM), also referred to as the Puck. This module is M, P, and C/A code-capable and SAASM-capable but has flexible interfaces and “emulates commercial.” The module itself is a system-on-chip (SoC) that can be integrated across many platforms. Depending upon the level of integration employed, it can be as small as chips found in smartphones or somewhat larger.

    The program schedule was defended as having only been funded two years ago and having very complex security and platform interfaces. This program presentation drew a large number of questions and commentary from the audience, much of it politely skeptical and showing impatience with the bureaucratic aspects of the program. Well-informed former military field-grade officers in the audience questioned its real availability. The answer that it would be available in quantity sometime in 2017 did not please the questioners.

    In short, procurement regulations appeared to be the highest barrier to a rapid, flexible program for a net-centric, open-architecture system development.

    Currently, the circuit boards for the MGUE are classified secret, but it is hoped to have these at a confidential or unclassified level for deployment by handling the encryption exclusively in software. The leader of this presentation indicated that software receivers were the ideal but were not available, so reduction in size, power consumption, and complexity in hardware was the goal.

    Trumping Military. One almost nostalgic comment hearkened back to the time when military systems were regarded as the height of technological excellence, whereas it is now generally perceived that commercial systems trump the military in sophistication. Garmin claimed to have developed SAASM receivers in the lab but found little interest from business leaders at that time.

    The CEO of Mayflower Communications, which makes and sells miniaturized SAASM receivers, pointed out that anybody could make a SAASM receiver employing a Sandia crypto-chip approved by the U.S. National Security Agency (NSA) but pointed out, as did several others, that the availability of certifications and authorizations was very limited, and that volume drove cost. Implicitly, NSA’s requirements and protocols got blamed for the limited distribution and use of SAASM receivers.

    Day Two

    The second day of the GPS Partnership Council comprised The Nation and The Warfighter. In the latter group came an outline of the Army’s COTS vision and — the hit of the entire conference — the Warfighter panel with a keynote introduction by a USAF colonel warrior now at the GPS Directorate.

    The Nation. Tony Russo, director of the National Coordination Office for Space-Based Positioning, Navigation, and Timing, disabused those who thought that the apparent demise of the LightSquared threat had eliminated that subject from his agendas; he still deals with it often. He provided entertaining and informative examples of non-obvious and valuable applications of GPS, from assessing rugby players’ game performance through detection of clandestine underground nuclear tests to a social application of matching available part-time and temporary workers with jobs when labor demand surges and a roster shows where the closest qualified candidates are.

    John Merrill of the Department of Homeland Security (DHS) identified 18 critical infrastructures that depend upon GPS integrity and showed the cascading effect of taking out sites like SCADA (Supervisory Control and Data Acquisition) systems. He related a threat-illustrative story of a DHS agent who required constant contact via his agency smart phone but who could not get reception while attending mass in church. The pastor later and very proudly showed him the mobile phone jammer in the sacristy; he had given up on asking parishioners to turn off their cell phones off during services.

    James Miller of the National Aeronautics and Space administration noted that only 5 percent of space missions lie outside the GPS coverage envelope (3,000 kilometers to geostationary altitude of 35,800 kilometers is the space service volume). Reducing the burden on spacecraft tracking networks is a highly profitable application for GPS.

    Warfighters Panel. These real-life experiences from combat and other vital operations could easily justify an entire article of their own. The following examples will illustrate the life-saving force multiplication of GPS, particularly the ubiquitous civil GPS technology in the current combat environment.

    •  An Air Force Special Operations Major described a mission to snatch an HVI, giving great detail on battlefield terrain, combat conditions, and how he worked between a COTS GPS receiver and a COTS handheld computer with Google Earth-like facilities to bring JDAMs (GPS-equipped smart munitions) onto an ambush mounted by defenders of the HVI, who were alerted to the raid by their extensive and sophisticated early-warning network consisting of sympathizers with cell phones. His description of the heroics of individual forward controllers, their injuries and fatalities, and the symbiosis of man and machine in a relatively benign electromagnetic interference but relatively malign electromagnetic propagation environment, and overtly and covertly hostile indigenous population, was dramatic and compelling.

    Clearly, unsophisticated  and easily-available  high-power jammers rapidly alter such situations to reduce our technological advantages. Also clear was the need to design user equipment, not just to reject interference but to minimize time and the inevitable ambiguities in actual combat situations.

    •  A Coast Guard lieutenant described the search-and-rescue missions he flies out of local airports to Pacific Ocean sites. Again, COTS equipment, aided by the near-ubiquity of commercial GPS equipment, along with VHF marine radio on boats and ships, enhances these mission results over those flown with standard USCG-issued navigation equipment.

    •  An Air Force tanker pilot major now attached to the GPS Directorate described three personal experiences. He once had to ask his boom operator to retrieve the Garmin receiver issued in the survival kit in order to navigate the tanker for rendezvous with tactical aircraft needing fuel when the tanker’s standard equipment failed.

    When tasked to fly into an airport in Afghanistan with unreliable navaids, under suddenly occurring zero-zero conditions, the onboard GPS enabled him to land safely.

    In a third instance in Iraq, he observed a downed airman being approached by gunmen. The gunmen with AK-47s were being targeted by drone operators. The major was able to discern that these gunmen were friendly forces moving to rescue the downed airman and avert a friendly-fire disaster. The downed airman’s ability to send his exact coordinates were key to the ability of the observer to get close enough to direct rescue efforts and to avoid a fatal error.

    • A Navy surface warfare lieutenant commander and a CWO Riverine or small boat skipper cited instances in which GPS was essential to missions and ways in which user equipment design could improve their operations — for example, by making it float.

    All the veterans repeated, during or after their accounts of ways in which GPS saved lives or enabled missions, “thank you for what you do,” addressed to the audience, the presenters, and their leaders. Going into denied territory places a high premium on user friendliness, battery life, robustness, size, and weight. In the future, inevitably, jam and spoof resistance will be an object of gratitude, as well.

    Final Review. We all know these things, intuitively and by doctrine, but hearing reports from people in harm’s way or retrieving comrades from harm’s way was a great addition to the usual program and technology descriptions by the development teams.

    I was particularly impressed with the very articulate, sophisticated, and focused presentations of these combat veterans. It is highly incumbent on the industry and the government GNSS leaders to translate these experiences into design requirements quickly, so that future systems are less dependent on individual ingenuity and on commercial gap-fillers.

    Much of this progress depends on truly incorporating the applications focus of commercial product development and on use of other GNSS systems for robustness, flexibility, and affordability — often quoted as mission goals by the leaders of this enterprise.

    MBOC Signal Furor

    A subsidiary of the UK Ministry of Defence has taken a UK patent on the new Galileo/GPS III MBOC signal design, the product of lengthy and cooperative negotiations between U.S. and European scientists. The patent, in the names of two UK engineers who participated in the project, is being used by a legal firm to demand royalty fees from receiver manufacturers, causing considerable controversy.

    LightSquared Bankrupt

    LightSquared, the company that mounted a powerful threat to GPS signals from November 2010 through February 2012, filed for bankruptcy protection on May 14 after losing a protracted battle in the court of the Federal Communications Commission. The war is not over, however. Exploding sprectrum demand for mobile data use makes it likely that future challenges to GPS and GNSS spectrum will emerge.

    Compass Muscling Up

    Two mid-Earth orbit (MEO) Beidou/Compass satellites were launched April 29. Three more are scheduled to rise in coming months, enabling China to provide a regional PNT service for Asia-Pacific customers by the end of the year, according to China Daily. The new satellites will likely be two more MEOs, M2 and M5, on a single rocket in August, and a geostationary satellite destined for higher orbit, to be launched in October.

  • The System: GPS III Endures Bad Press, IIAs an OCX Concern

    GPS III Endures Bad Press, IIAs an OCX Concern

    Reports in daily news media such as the Washington Post and Denver Post that “Lockheed Martin will lose its entire fee of about $70 million to defray an 18 percent cost overrun” on GPS III satellites misconstrue the facts.

    Don Jewell, contributing editor for GPS World, said after informal talks with key Lockheed executives, “This is a good story, but it has been sensationalized.”

    Lockheed Martin’s fee is 5 percent of the target cost, which includes one-time engineering tasks, test equipment, and satellite assembly, according to the Air Force.

    The first GPS III satellite remains on schedule to be available for launch in 2014, Lockheed Martin spokesman Michael Friedman said via email.

    “While we have encountered challenges associated with higher standards for parts testing and first-time technical issues, the program is on firm footing and our cost estimate remains within the original Air Force budget,” Friedman stated, adding that the company doesn’t discuss specifics of fees.

    “In their defense,” Jewell reports, “the program was initially identified as stable with no government change request allowed, to keep it on schedule and budget. The recent budget furor has introduced chaos into the requirements process and contributed significantly to the increased costs.”

    Lockheed Martin is using a full-sized prototype to identify and solve many assembly issues “that would have cost more and presented more risk if they had been discovered later in production,” Lockheed’s Friedman said.

    “We have identified tens of millions of dollars in cost savings for the production satellites and in some cases we are seeing 50 to 80 percent reductions in labor costs,” he added.

    Ground Control to Aged Birds

    By Don Jewell

    One of the long-standing issues for support of IIA vehicles after the future GPS Operational Ground Control Segment’s (OCX’s) ready-to-operate (RTO) date, which should fall in December 2016 at the latest, is what ground command-and-control (C2)system will steer GPS IIA satellites, do navigation uploads, and so on. The issue is that AEP, the current C2 system, will no longer be available once the transition to OCX takes place, and OCX has no requirement to control IIA satellites.

    The OCX program, which struggled early, is now under new program leadership within Raytheon Space Systems, and while Ray Kolibaba, the new OCX program manager, is making great progress, OCX does not need to be burdened with additional requirements at this stage of the program.

    Just how big an issue is GPS IIA C2? Initially the Aerospace projections were that there would only be one or two GPS IIAs left on orbit in 2017, and it was not worth the costs to include the C2 software for the legacy system in the new software code. However, I have long maintained that Aerospace and Space Missile Systems Command (SMC) neglected to count the residual satellites, maintained by Launch, Anomaly, and Disposal Operations (LADO), which might very well actually amount to 3–4 additional IIAs. Added to the two IIAs on orbit, this could amount to six IIA SVs that need to be maintained.

    The solution announced during the week at the National Space Symposium (NSS, April 16–19) by General William Shelton, the four-star chief of Air Force Space Command, is to fund the current LADO operator, Braxton Technologies, to build in this support for the IIAs. This is significant for several reasons: One, of course, is that it solves the IIA C2 issues, it does it now, and at a relatively modest cost, and it utilizes more of the capabilities of the Braxton Technologies’ LADO software. Additionally it provides a true backup capability for assets on orbit that become increasingly valuable as the number of available launch slots for GPS decreases.

    Braxton Technologies initially demonstrated this capability years ago in a lifeboat drill during the transition to AEP, but the navigation upload capability was never maintained for LADO after the successful transition. This is certainly a step in the right direction and provides a simple solution to a vexing problem that has plagued the GPS program for the last several years.

    Dual Launch. I asked General Shelton if he would support an approach that would allow the United States to go to dual launch of GPS III on vehicles 5–6 instead of waiting until 8–9 as planned today. He said the Air Force would certainly support that, and is looking at making it possible with vehicle 7 currently. That will come even sooner if the program advances with glitches.

    I also asked him about the gap between GPS III launch and OCX RTO. The gap seems to be getting wider, not narrower, and he agreed that OCX could probably not move to the left, and GPS III has moved significantly to the left, so this is still an issue that needs to be addressed. There are plans in place, but the recent budget activity has caused some uncertainty.

    Sequestration. On the subject of sequestration — a highly charged Congressional effort to force another $500 billion-plus in additional defense cuts — General Shelton said it would come on top of the approximately $487 billion already cut from programs, and that many space programs might be unsustainable in their current mode if that occurs.

    However, the U.S. Armed Services have been informed by the White House Office of Management and Budget not to make plans for sequestration. So right now, the services and other agencies of the U.S. government have been forbidden to make programmatic decisions based on a possible sequestration. Interesting.

    By the way, attendance at NSS this year surpassed 9,000.

    Galileo Launches Accelerated, First Payload Shipped

    Javier Benedicto, head of the Galileo Project Office for the European Space Agency (ESA), set an aggressive schedule for launching some Galileo satellites as many as four at a time in 2014 and 2015, to meet a target provision date of Galileo initial services in 2014 and full services in 2015. The announcement came at the Munich Summit, March 14.

    The hurry-up to carry 22 satellites into orbit proceeds with dual-satellite launches aboard Russian Soyuz rockets, as was the case for the most recent in-orbit validation (IOV) launch in October 2011. There will be three Soyuz launches in 2013, for a total of six new satellites in orbit, and two Soyuz launches in 2014, adding four more. Then the burden will shift to European rockets from Arianespace, according to a contract signed in February of this year. One Ariane 5 rocket is slated to carry four Galileo satellites aloft in 2014, bringing the projected total of IOV and eventually operational Galileo satellites in space to 16 by the end of 2014. ESA had ealier aired plans for further Soyuz IOV launches in 2012, but the Munich statement did not mention these.

    In 2015, two more Ariane 5 launches will add eight satellites, for a total on orbit of 24, estimated to be sufficient for Galileo full operational capability (FOC).

    In subsequent talks with European satellite manufacturers OHB Systems and Astrium, GPS World contributing editor Don Jewell was told that the future launch schedule is “subject to change.”

    ESA headquarters has made no official announcement of a detailed launch schedule; inquiries regarding the Benedicto remarks were referred to the February contract statement, cited above.

    Payloads. Meanwhile, Surrey Satellite Technology Ltd. (SSTL) delivered the first of 14 FOC satellite payloads to prime contractor OHB System AG, for mechanical integration of the payload with the satellite platform and the beginning of overall vehicle assembly, integration, and testing for what will eventually become the fifth satellite in the Galileo constellation.

    Compass on the Grow

    Discussions in Internet forums indicate that the next BeiDou-2/Compass launch will take place on or about April 28, after this magazine goes to press. The launch purportedly will place two mid-Earth orbit satellites into space: BeiDou M3 and BeiDou M4. Sometime in June, plans call for BeiDou M2 and BeiDou M5 to be launched.

  • The System: eLoran Gets Trials, Possibly a New Life

    eLoran Gets Trials, Possibly a New Life

    As result of a Cooperative Research and Development Agreement (CRADA) between the U.S. Coast Guard and UrsaNav, Inc., on-air tests are being conducted from the former Loran Support Unit site in New Jersey.

    One of the CRADA’s goals is to research, evaluate, and document a wireless technical approach as an alternative to GPS for providing precise time. The ability to obtain precise time to at least one microsecond is necessary for the proper operation and functioning of many critical industries and systems. Examples include telecommunications networks, banking and finance, energy and power delivery, emergency services, transportation systems, and military and homeland security systems.

    Additional on-air tests are planned at various sites throughout the United States. Broadcasts will test several different frequencies, waveforms, and modulation techniques using evolutionary, state-of-the-art technology. Reception of these broadcasts are planned at both on-shore and off-shore locations, and will include advanced LF data delivery techniques. The results of these trials will be presented at national and international conferences. Parties interested in any part of the trial, or interested in doing their own measurements, are invited to contact UrsaNav.

    The company has partnered with precise-time synchronization company Symmetricom and Nautel, supplier of high-power RF transmitters. According to UrsaNav, this “alliance of expertise” provides the foundation technology for a wide-area, terrestrial-based alternative to satellite systems such as GPS, GLONASS, and Galileo.

    For further background and commentary, see Don Jewell’s Defense e-newsletter for April.

    “Global government, industry, and academic experts recognize that advanced LF signals, of which eLoran is just one example, can provide alternative timing — either as a stand-alone service, or as a component of an existing positioning, navigation, and timing (PNT) service. The high-power, virtually jam-proof and spoof-proof LF signals operate independently of GPS and GNSS, and provide a Universal Coordinated Time (UTC) time reference in the order of tens of nanoseconds. The recognition of the criticality of time to many aspects of our national critical infrastructure has led to establishment of the CRADA to evaluate the benefits of an LF wide-area timing system.”

    The LF signals can also be used as pseudoranges mixed in with GPS, or if enough transmitters are available, as a fully independent PNT network. In other words, a true backup PNT capability for safety-of-life navigation, for dispatching first responders, and for supporting critical national infrastructures.

    First Galileo PRS Signal Received

    Septentrio and QinetiQ, in close partnership with the European Space Agency (ESA) and their industrial partners, achieved the first successful reception of the encrypted Galileo Public Regulated Service (PRS) signal from the first Galileo satellites, launched in November 2011.

    The signal was received on the Galileo PRS Test User Receiver (PRS-TUR) jointly developed by Septentrio (Leuven, Belgium) and QinetiQ (Malvern, United Kingdom) under an ESA contract. For the reception test, the receiver was installed in the Galileo Control Centre in Fucino, Italy, and operated by technical experts from ESA.

    Septentrio and QinetiQ are long-term contributors to the Galileo Programme, working closely with ESA, the European GNSS Agency (GSA), and European industrial partners since 2003.

    Count Five Compass IGSOs

    The BeiDou-2/Compass G5 satellite launched on February 24 has achieved an initial approximately geostationary orbit.

    The current sub-satellite east longitude is 57.23 degrees. The intended final orbital slot may be 58.75 degrees, one of the previously announced orbital locations and one used by the BeiDou-1 demonstration system.

    GPS Use in FAA’s NextGen 2012 Plan

    An overview of NextGen benefits and accomplishments is available in the 2012 update to the NextGen Implementation Plan, published by the Federal Aviation Administration (FAA). 

    The 2012 NextGen Plan specifically mentions GPS/GNSS as follows:

    Performance Based Navigation (PBN). The current aircraft fleet is well equipped with PBN capability. In the air carrier community, the heart of the PBN capability is the Flight Management System, which uses input from multiple distance measuring equipment (DME), or from the GNSS using a GPS sensor or a GPS with Wide Area Augmentation System (WAAS) sensor.

    Ground Based Augmentation System Landing System (GLS) Enabler. This program researches use of differential GPS corrections to support Category III (Cat III) approaches. This capability will be the same as Cat III instrument landing system (ILS), without the need to restrict taxiing aircraft near antennas and at reduced cost to the FAA.

    Automatic Dependent Surveillance–Broadcast (ADS-B). Aircraft position (long-lat, altitude, and time) is determined using GPS, an internal inertial navigational reference system or other navigation aids. ADS-B Out involves transmission of a GPS position (or of comparably performing navigation equipment meeting integrity and accuracy requirements) from an aircraft to display its location to controllers on the ground or to pilots in other aircraft equipped with ADS-B In.

    Low-Visibility/Ceiling Approach. Localizer Performance (LP) with Vertical Guidance (LPV) Approaches. These are more cost-effective to implement compared to additional ground-based navigation aids (NAVAIDs) and their approach procedures. Increasing the number of LPV/LP approaches will provide further incentives for users to equip with GPS/WAAS. This will provide increased utility to the more than 40,000 general aviation aircraft that are already WAAS-capable. The FAA will also deliver LP approaches to runways that do not qualify for LPVs due to obstacles.

    Ground Based Augmentation System (GBAS) Precision Approaches. GPS/GBAS support precision approaches to Cat I and eventually Cat II/III minima for properly equipped runways and aircraft. GBAS can support approach minima at airports with fewer restrictions to surface movement and offers potential for curved precision approaches. GBAS may also support high-integrity surface movement requirements.

    — Bill Thompson, GPS World aviation editor

    LightSquared-Sprint Contract Terminated

    Business Case for GPS Threat Gone Away

    The principal business prop under the LightSquared plan for ancillary terrestrial component (ATC) broadcast of a powerful signal that would have disrupted GPS operations dropped out from under the company on March 16, as wireless carrier Sprint terminated its $9 billion agreement with LightSquared. LightSquared had several such partnership agreements, but the Sprint deal was the largest, and in many eyes the driver of the aggressive plan. With it gone, LightSquared’s other deals will likely dissipate — and the current threat, at least, to GPS industry and users should effectively go away.

    Sprint has apparently concluded that LightSquared has no prospect of reversing the revocation of its conditional waiver last month by the Federal Communications Commission, as a result of extensive testing conducted by the company, various government agencies, and the GPS industry. Earlier, Sprint had twice extended its tentative agreement with LightSquared as the tests took place over the last year, but reached the end of its road March 16 — which is also the last day the FCC is accepting public comments on its decision to revoke the waiver.

    An official LightSquared statement said termination of the Sprint agreement was “in the best business interests of both companies, and was not unexpected given the regulatory delays.” Sprint will return $65 million in prepayments that LightSquared made to Sprint.

    Some analysts have predicted that LightSquared may be forced to sell off its assets by the end of the year. Among these assets are the spectrum licenses for the lower LightSquared band (1526–1536 MHz), the so-called Low 10, and the higher band (1545-1555 MHz), known as the Upper 10, adjacent to GPS L1. These bands have a history of trading hands as their owners go into bankruptcy or otherwise out of business.

    The next touchpoint of concern for the GPS community is the outcome or perhaps various outcomes of the FCC workshop on spectrum efficiency and receivers that took place March 12–13. The workshop was convened to discuss the characteristics of receivers and how their performance can affect the efficient use of spectrum and opportunities for the creation of new services, according to the FCC.

  • The System: NTIA, FCC Waiver No More on LS

    “We conclude that LightSquared’s proposed mobile broadband network will impact GPS services and that there is no practical way to mitigate the potential interference at this time.” These words from Lawrence Strickling, U.S. assistant secretary for communications and information and head of the National Telecommunications and Information Administration (NTIA), appear to signal the end of LightSquared’s run.

    Strickling’s letter to Federal Communications Commission (FCC) chairman Julius Genachowski appeared in public on February 14. Later that same day, FCC spokesperson Tammy Sun released a statement from that agency that “the Commission will not lift the prohibition on LightSquared,” and that it plans to “vacate the Conditional Waiver Order, and suspend indefinitely LightSquared’s Ancillary Terrestrial Component authority.”

    The NTIA and the FCC share responsibility for controlling U.S. radio spectrum use. The FCC supposedly has final authority in these matters, although the NTIA, representing government interests, may swing the bigger cat in the room. LightSquared’s inability to satisfy the requirements of the Federal Aviation Administration (FAA), coupled with unremitting frowning and glowering from the Department of Defense, may have been the deciding factors — more so than the uproar among most GPS manufacturers. The FAA and the U.S. military, two key government entities with widely fielded GPS equipment and applications, constituted the backbone that the NTIA finally showed, although the military has been, with one notable exception, silent on the issue, and indeed is not mentioned in the NTIA letter.

    Strickling’s eight-page letter recaps the history, with a July 6, 2011, early climax: “Test results demonstrated that LightSquared’s then-planned deployment of terrestrial operations posed a significant potential for harmful interference to GPS services.” He relates further NTIA testing of cellular GPS receivers, joint continued analysis by FAA and LightSquared of impact on aviation receivers, and testing of general/personal navigation GPS receivers by the Executive Steering Group of the Interagency National Executive Committee for Space-Based Positioning, Navigation, and Timing (EXCOM).

    Strickling quotes a January 13 letter from Ashton Carter, deputy secretary for defense, and John Porcari, deputy secretary for transportation: “It is the unanimous conclusion of the test findings by the EXCOM agencies that both LightSquared’s original and modified plans for its proposed mobile network would cause harmful interference to many GPS receivers. Additionally, an analysis by the FAA has concluded that the LightSquared proposals are not compatible with several GPS-dependent aircraft safety-of-flight systems. . . There appear to be no practical solutions or mitigations that would permit the LightSquared broadband service, as prosposed, to operate in the next few months or years without significantly interfering with GPS. As a result, no additional testing is warranted at this time.”

    But Wait. We’re not done yet. Strickling calls for GPS receiver standards to be developed, citing the EXCOM’s decision that “federal agencies will move forward this year to develop and establish new GPS spectrum interference standards that will help inform future proposals for non-space commercial uses in the bands adjacent to the GPS signals.”

    NTIA and PNT EXCOM will devise “standards for the development and procurement of GPS receivers to support their various mission requirements.” NTIA recognized “the importance that receiver standards could play as part of a forward-looking model for spectrum management even beyond the immediate issue of GPS.”

    The FCC, in its concurrence statement to the NTIA letter, begins by reciting the mantras of “economic growth, job creation, and to promote competition . . . freeing up spectrum for mobile broadband,” and gradually works its way around to its decision on the waiver. This signals an ongoing commitment to make further efforts towards broadband implementation.

    In-Car Nav Under Safety Scrutiny

    The U.S. National Highway Traffic Safety Administration (NHTSA) proposed voluntary guidelines for car manufacturers on February 16, including a recommendation to design dashboards so that distracting devices are automatically disabled unless the vehicle is stopped and the transmission is in park. The agency is concerned about proliferation of text messages, GPS images, phone calls, and web surfing, and wants carmakers to curb those distractions when vehicles are moving.

    Technological advances, among them GPS-enabled navigation, have raised concerns that drivers’ attention is being diverted too much from the road.

    “We recognize that vehicle manufacturers want to build vehicles that include the tools and conveniences expected by today’s American drivers,” said NHTSA Administrator David Strickland. “The guidelines would offer real-world guidance to automakers to help them develop electronic devices that provide features consumers want without disrupting a driver’s attention or sacrificing safety.”

    Under the guidelines, GPS and other navigation devices that provide directions would be permitted while driving, but NHTSA asks that they be designed so that drivers can’t manually enter a destination unless the car is in park. A spokesperson for the Alliance of Automobile Manufacturers cautioned against this. “There are often passengers in the car who can enter addresses, so we need to consider that when looking at requiring these technologies to only be used in park,” she said. “And if the GPS is disabled when moving, consumers can always bring their own Garmin into the vehicle. It’s complicated.”

    Other dashboard technologies recommended for automatic disabling include text-messaging, Internet browsing, social media browsing, phone dialing and computer screen messages of 30 characters or more that are unrelated to driving.

    Manufacturers are also urged to revise in-car designs to reduce to two seconds or less the amount of time drivers must divert their eyes from the road to use a device. Devices should also be designed so that drivers don’t have to use more than one hand or glance through extraneous information.

    A spokesperson for state highway safety offices said that “the safest thing is for drivers not to use these systems at all — both hands on the wheel and the mind focused solely on driving.”

    The process for writing actual federal rules often takes years to complete. The guidelines represent a way “ to continue the drumbeat” that distracted driving is a serious safety issue that costs lives.

    NHTSA is also considering guidelines to address portable electronic devices drivers carry with them into cars, including GPS navigation systems.

    SSTL-OHB to Build Eight More Galileo Satellites

    European Commission Vice President Antonio Tajani announced in London that the consortium led by OHB System AG and Surrey Satellite Technology Ltd. (SSTL) will build a further eight satellites for the European Union’s Galileo satellite navigation program under the supervision of the European Space Agency.

    The new contract will see SSTL, builder of the GIOVE-A satellite, continuing its role as payload prime, assembling, integrating, and testing the navigation payloads in the UK, while OHB System, as the prime contractor, builds the eight satellite platforms and executes final integration of all the satellites in Germany. The SSTL-OHB partnership is already building 14 satellites for the Galileo program and will draw on its heritage and experience to produce the additional satellites to demanding schedules.

    SSTL is assembling the Galileo program payloads at its recently opened purpose-built Kepler technical facility in Guildford, UK. SSTL will manufacture the electrical harnesses and the electronics to interface the navigation payload with the satellite platform.

    The remaining payload equipment will be externally procured by SSTL from European and other suppliers. SSTL’s payload solution is based on European-sourced atomic clocks, navigation signal generators, high-power traveling-wave tube amplifiers, and antennas, and will provide all of Galileo’s services.

    Compass Poised

    As this magazine goes to press, a new GNSS satellite may simultaneously be rising. The Chinese government issued a Notice to Airmen (NOTAM) for a satellite launch on, February 24,  at about 16:20 UTC. According to web reports, the launch from the Xichang Satellite Launch Center will orbit the fifth geostationary satellite in the BeiDou-2/Compass constellation.

    Funding Affirms NextGen; Unmanned Flight Advances Also

    For the last five years, the Federal Aviation Adminstration (FAA) has made do with 23 short-term funding appropriations from Congress, but on January 30, congressional leaders agreed on a four-year, $63 billion funding bill. The funding will accelerate the creation of the NextGen (Next Generation Air Transportation System) air traffic control system. A new post will be created — the Chief NextGen Officer — to oversee the effort, and a schedule for progress will be set.

    A key piece of NextGen includes GPS-enabled Required Navigation Performance (RNP), which allows an aircraft to fly a specific path between two 3-dimensionally defined points in space.

    The bill also assures funding subsidies for rural airports at $190 million a year. New labor rules will make it harder for airline employees to unionize, requiring half the workers in a bargaining unit to petition for a vote to certify a union, an increase from the current 35 percent.

    “All of us at this table made compromises,” Sen. Jay Rockefeller, D-W.Va., chair of the Senate’s transportation committee, told USA Today. “The outcome is that we have a bill that will take steps to modernize our air traffic control system, make the air transportation system safer than ever, and make certain small communities have access to critical air service.”

    Unmanned Aircraft. Congress also passed legislation starting the clock on a number of deadlines the FAA must meet to safely integrate unmanned aircraft systems (UAS) into the national airspace system. Chief among them is a deadline for full integration by September 2015.

    Using GPS to underlie the whole concept, the UAS industry has made significant technological advancements during the last decade, and the legislation recognizes the important role UAS will play in the future air transportation system.

    Michael Toscano, president of the Association for Unmanned Vehicle Systems International (AUVSI) said, “UAS are truly a revolutionary-type technology, and I’m confident that once people can fly UAS in the national airspace for civil and commercial purposes, such as oil and pipeline monitoring, crop dusting, and search and rescue, a whole new industry will emerge, inventing products and accomplishing tasks we haven’t even thought of yet.”

    Other major provisions of the bill include:

    • Requiring six UAS test sites within six months (similar to the language in the already-passed Defense Authorization bill);
    • Requiring small UAS (under 55 pounds) be allowed to fly in the U.S. Arctic, 24-hours-a-day, beyond line-of-sight, at an altitude of at least 2,000 feet, within one year;
    • Requiring expedited access for public users, such as law enforcement, firefighters, emergency responders;
    • Allowing first responders to fly very small UAS (4.4 pounds or less) within 90 days if they meet certain requirements.

    The goal is to grant law enforcement and firefighters immediate access to start flying small systems to save lives and increase public safety.

    Spectrum Swamp

    On January 30, the same day that a LightSquared VP told an Institute of Navigation audience that moving to a different spectrum posed formidable difficulties, a company working on behalf of LightSquared contacted a Department of Defense official to discuss just such a spectrum swap.

    The McChrystal Group, led by retired four-star general Stanley McChrystal, contacted the Department of Defense’s Mid-Atlantic Area Frequency Coordinator at Pawtuxet River, Maryland, to discuss “a spectrum swap.”  The McChrystal representatives indicated interest in the upper 10 MHz (1515–1525 MHz) of the Aeronautical Mobile Telemetry band (1435–1525 MHz). This spectrum is vital to the development and test of aircraft and weapon systems, for both government agencies and industry, is heavily scheduled and utilized, and is also used for safety of life services (see “Letters to the Editor” in this issue, page 8).

    Moving LightSquared’s license to a different radio frequency spectrum has been suggested by some as a possible exit strategy from the LightSquared/GPS interference conflict. At least one wireless industry analyst has surmised that this  constituted a part of LightSquared’s strategic plan all along.

    A source familiar with the situation contacted GPS World after this story appeared online to say that “a swap would be complicated but never ‘insurmountable.’  The bottom line is that [LightSquared’s VP] did not talk about swaps of any specific spectrum. He talked about the difficulty to get a wireless company up and running, and if you’ve got something that has spectrum, technology, and a successful business model, then that’s very rare, and you can’t necessarily duplicate it. But he said nothing about whether a swap of some specific kind of spectrum could be done. If the parties are willing, it’s actually not that hard.”

    Nevada OKs Unmanned Driving

    Nevada became the first state in the nation to authorize the use of autonomous vehicles on its roadways.

    Manufacturers are developing vehicles that could allow a motorist to plug in a destination and let the vehicle drive there automatically. Google has several prototypes, logging more than 160,000 test miles.

    The Nevada Department of Motor Vehicles will formalize licensing procedures for companies that want to test their vehicles in the state.

    General Motors has run several tests, some in conjunction with Carnegie-Mellon University on a self-driving Chevrolet Tahoe, The Boss. BMW has several test vehicles in operation, as does Audi in collaboration with Stanford University. Many of these cars, or their predecessors, have participated in DARPA Grand Challenges, reported in this magazine.

    SVN-49 Broadcasting on L-Band

    GPS satellite SVN-49 began transmitting an L-band signal on or about February 2. SVN-49 is currently being used as a vehicle of opportunity for satellite subsystem testing. However, SVN-49 is declared unusable until further notice, and will not be included in the broadcast almanac.

  • The System: U.S. DoD, DoT Tell FCC No LightSquared

    Ashton Carter, U.S. deputy secretary for Defense, and John Porcari, deputy secretary for Transportation, have written an official letter to the assistant secretary of Commerce stating that “there appear to be no practical solutions or mitigations that would permit the LightSquared broadband service.” Carter and Porcari are co-chairs of the National Executive Committee for Space-Based Positioning, Navigation, and Timing. This represents the strongest intra-government statement to date on the issue.

    Their letter further states that “both LightSquared’s original and modified plans for its proposed mobile network would cause harmul interference to many GPS receivers. Additionally, an analysis by the Federal Aviation Administration has concluded that the LightSquared proposals are not compatible with several GPS-dependent aircraft safety-of-flight systems.”

    “No additional testing is warranted at this time,” the authors conclude.

    They further propose to “draft new GPS spectrum interference standards that will help inform future proposals for non-space, commercial uses in the bands adjacent to the GPS signals.”

    No response has emerged from either the Federal Communications Commission or the National Telecommunications and Information Administration, the two bodies charged with making a determination on the issue. But the letter appears to signal a coming end to a conflict that has occupied many, and tied up many resources and consumed many millions of dollars, for the past year.

    One source commented off the record that “Our hope is this will be the end of the matter, and the FCC will withdrawal its initial approval and inform LSQ they must seek the 500 MHz in a different portion of the spectrum.”

    Second Galileo IOV Satellite Transmits

    On January 17, the E1 signal of the Galileo Flight Model 2 satellite (FM2, also known as GSAT0102) was successfully acquired and tracked by the researchers of the Navigation, Signal Analysis and Simulation (NavSAS) group at Politecnico di Torino / Istituto Superiore Mario Boella. The signal was received with a non-directive GNSS antenna, a commercial narrowband E1 RF front-end, and the N-GENE software receiver developed by the NavSAS lab.

    Other research facilities and advanced GNSS companies around the world have also reported reception of a signal from this, the second in-orbit validation Galileo satellite, launched on October 21, 2011. The first IOV satellite, Galileo-ProtoFlight Model (PFM) began broadcasting in December.

    FM2 currently transmits a Galileo Open Service signal on the E1 band using the Code Number 12 of the Galileo Interface Control Document (ICD). Acquisition and tracking results are reported in Figures 1, 2, and 3. The signal was received with a C/N0 of approximately 46.4 dBHz and a Doppler frequency shift equal to –2595 Hz.

    Both Galileo craft were in view on January 17. Figure 4 shows both the estimated Doppler and C/N0 profiles obtained from multiple measurements performed on the same time interval.

    As a final step, the demodulation of the E1b data channel has also been performed, checking the navigation messages for both the satellites. It has been noticed that, at the moment, the navigation messages present only two types of page: reserved (word type field with value 63) and type 0 (spare). Type 0 words have valid Week Number and Time Of Week fields. On the other hand, both the satellites broadcast a valid secondary code on their E1c pilot channels, compliant with the Galileo ICD.

    — Fabio Dovis


    FIGURE 1. Search space of the successful acquisition of the Galileo FM2 satellite (PRN 12).


    FIGURE 2. Peak obtained acquiring the Galileo FM2 satellite.


    FIGURE 3. Estimated C/N0 and correlation values obtained tracking the PRN 12.


    FIGURE 4. Estimated Doppler and C/N0 profiles along multiple measurements performed on January 17.

     

    More GPS III Birds, Launch, Checkout Awarded

    The U.S. Air Force awarded Lockheed Martin a $238 million contract for production of the third and fourth satellites in the next-generation GPS III constellation.

    In May 2008, the Air Force awarded Lockheed Martin an initial contract to design, develop and build the first two GPS III satellites. The contract also includes options for up to 10 additional spacecraft. With the most recent award, the GPS III team is now on contract to deliver four GPS III space vehicles, with the first launch scheduled in 2014. The Air Force has plans to build up to 32 GPS III satellites.

    The Air Force also signed a $21.5 million contract with Lockheed Martin to provide a launch and checkout capability (LCC) to command and control all GPS III satellites from launch through early on-orbit testing.

    The LCC will be integrated into the Raytheon-developed Next Generation Operational Control System (OCX). It includes trained satellite operators and engineering solutions in partnership with OCX to support launch, early orbit operations, and checkout of all GPS III satellites before the spacecraft are turned over to Air Force Space Command for operations.

    “Achieving initial launch capability in 2014 is critical to introducing new GPS capabilities on time and will enable the GPS III program to continue its production pace, maximize efficiencies and reduce long term costs for the GPS enterprise as a whole,” said Col. Bernard Gruber, director of the GPS Directorate. “LCC will ensure we can launch in 2014, effectively closing the time gap between GPS III and the Next Generation Operational Control System.”
    Lockheed Martin is the GPS III prime contractor with teammates ITT Exelis, General Dynamics, Infinity Systems Engineering, Honeywell, ATK, and other subcontractors.

    Increase Proposed for GLONASS

    A December 27 meeting in Moscow heard a proposal to expand the GLONASS constellation to 30 satellites and six orbital planes, among five other modernization options. The Presidium of the TsNIImash Council (Central Research Institute of Machine Building) is the arm of Roscosmos, the Russian federal space agency, responsibale for civil aspects of GLONASS.

    The other options include adding one more satellite to each of the existing three planes, but that would involve rephasing almost all of the operating satellites, which could cause problems. Adding three new planes to the constellation, each with two satellites, is the leading option, and will be considered in detail over the next few months.

    It is not clear how the present GLONASS frequency-division multiple-access (FDMA) channel spectrum could handle 30 satellites. It appears that the current arrangement can only handle a maximum of 28 satellites. The concept would need support from the Russian Defense Ministry among others to go ahead.

    Incomplete Compass ICD Released

    China announced the official start of Compass operational positioning, navigation, and timing services to China and surrounding areas and released a test version of an interface control document (ICD) on December 27. The ICD is available in both Chinese and English in PDF format from the system’s website, www.beidou.gov.cn.

    The nine-page test ICD is incomplete. It only describes the basics of the coordinate and time systems and the basic characteristics of the open service B1 signal transmitted as the in-phase component on the 1561.098 MHz carrier frequency, including the ranging codes assigned to different satellites. There is no discussion of the details of the navigation message or associated algorithms.

    A spokesperson stated that the test version is being released to stimulate research and development work and promote applications as soon as possible, and that some aspects of the transmitted signals are not yet finalized or “cured” and that is why they are not discussed in the test ICD.

    Leap Second

    The International Earth Rotation and Reference Systems Service (IERS) announced that a positive leap second will be introduced into Coordinated Universal Time (UTC) at the end of June 2012. UTC will be retarded by 1.0 second so that the sequence of dates of the UTC markers will be:

    2012 June 30 23h 59m 59s
    2012 June 30 23h 59m 60s
    2012 July 01 0h 0m 0s

    UTC and all time scales based on UTC will be affected by this adjustment. However, GPS will not be adjusted physically. For GPS, the leap second correction contained within the UTC data of subframe 4, page 18 of the navigation message transmitted by satellites will change.

    Before the leap second: GPS-UTC = +15s (that is, GPS is ahead of UTC by 15 seconds).

    After the leap second: GPS-UTC = +16s (GPS will be ahead by 16 seconds).

    Meanwhile, the International Telecommunication Union postponed until 2015 a vote on a proposal to do away with leap seconds completely.

  • The System: Galileo in Its Glory

     


    GALILEO PROTOFLIGHTMODEL satellite began transmitting E1 and E5 signals in early December. ESA reports them well within power and shape specifications, and suited for interoperability with GPS.

    The Galileo ProtoFlightModel (PFM) in-orbit validation (IOV) satellite GSAT0101 began transmitting E1 signals on December 10 using the E11 ranging code, and E5 signals early on December 14. Launched at the same time, Flight Model 2 (FM2), GSAT0102, has not yet started transmitting navigation signals. Several companies and laboratories around the world immediately began processing the PFM signals. This story briefly aggregates their reports.

    The European Space Agency (ESA) proudly released a statement: “Europe’s Galileo system has passed its latest milestone, transmitting its very first test navigation signal back to Earth. [. . . . ] The turn of Galileo’s main L-band (1200-1600 MHz) antenna came on the early morning of Saturday 10 December. A test signal was transmitted by the first Galileo satellite in the E1 band, which will be used for Galileo’s Open Service once the system begins operating in 2014.  [. . . . ]

    “The signal power and shape was well within specifications. The shape is especially important because its modulation is carefully designed to enable interoperability with the L1 band of U.S. GPS navigation satellites: Galileo and GPS can indeed work together as planned.

    “The test campaign is concentrating on the first satellite for the reminder of the year, with the focus moving to the second Galileo satellite from the start of 2012. The plan is to complete In-Orbit Testing by next spring.

    “The next pair of Galileo In-Orbit Validation satellites will also be launched next year, to form the operational nucleus of the full Galileo constellation. Meanwhile the next batch of Galileo satellites are currently being manufactured for launch in 2014.”

    Thales Avionics. Thales Avionics has developed a Galileo receiver capable of processing the Open Service, Commercial Service, and Safety of Life service of the Galileo constellation.

    Figure 1 shows a screenshot of the Thales Avionics receiver interface program, highlighting the L1 signal energy (top right) and the pilot secondary code (bottom). The satellite Doppler and C/N0 values have been recorded and are provided in Figure 2.


    Figure 1. Screen of Thales Avionics receiver interface highlighting L1 signal energy (top right) and the pilot secondary code (bottom). (Click to enlarge).


    Figure 2. Satellite doppler and C/N0 values from the Thales Avionics receiver.

    Thales has developed a coherent processing of the Galileo E5 AltBOC(15,10) signal compatible with hardware architecture designed for independent processing of both E5a and E5b. This processing is fully compatible with the mismatch between the two RF channels on E5a and E5b, thanks to real-time calibration based on satellite signals. This processing only requires software implementation, without additional recurrent costs. The technique is relevant for future receivers operating in the E5 band, in order to significantly enhance the accuracy, with respect to thermal noise and multi-path, and to improve the cycle slip probability.

    CONGO. Several COoperative Network for GIOVE Observation (CONGO) stations, including one at the University of New Brunswick, are tracking both the E1 and E5 signals. Figure 3 shows C/N0 values collected at UNB.


    Figure 3. C/N0 values in dB-Hz of PFM 1-Hz data collected at the University of New Brunswick, on December 10. Time axis runs for 24 hours starting at 01:00 UTC. Receiver is a Javad Delta-G2T.
    JAVAD GNSS. On December 12, JAVAD GNSS announced that it has tracked the Galileo in-orbit validation satellite, temporarily designated PRN-11.

    “An important point is that we tracked it with our units that are already in the market,” said Javad Ashjaee, CEO. “This is not a lab tests. Our customers can track it too.”

    Figure 4 shows the company’s tracking results of PRN-11: plots of pseudorange (in chips), doppler (in Hz), and SNR (relative number).


    Figure 4. JAVAD GNSS tracking results of Galileo PRN-11 for now, plots of pseudorange (in chips), doppler (in Hz), and SNR (relative number).

    Calgary PLAN Group. The University of Calgary sent a detailed report. (See Figure 5 and next item.)

    Figure 5. Raw correlator values for the E1 B/C, E5aI/Q and E5bI/Q signals. The bit periods can be clearly seen on E1B, E5aI and E5bI. The secondary code can be observed on E1C while the pilot signal can be seen on singals E5aQ and E5bQ. (From the Calgary Report.)

    Galileo E1 and E5: the Calgary Report

    By James T. Curran and Aiden Morrison

    Researchers in the Position, Location and Navigation (PLAN) Group at the University of Calgary recorded E1 and E5 data using a single dual-channel front-end and subsequently acquired and tracked E1 B/C, E5a and E5b signals in the early morning of December 15.

    Using a dual channel front-end designed in-house, a Novatel GPS-703-GGG antenna and a laptop computer, IF data was collected to examine these new signals. This data was processed by GSNRx, a reconfigurable a multi-system, multi-frequency software receiver developed by the PLAN Group.

    At approximately 03:20 MST (UTC – 7:00) more than 20 GNSS satellites were visible from a rooftop mounted antenna. Having reconfigured the front-end to accommodate the E5 band, IF data was collected which included Galileo E1 B/C and E5 A/B, GIOVE-B E1 B/C and E5a, GPS L1 C/A and L5, and GLONASS L1 C/A. Following some last-minute modifications to GSNRx to include the Galileo E5b signals, the samples were processed, simultaneously tracking GPS and Galileo on both the L1/E1 and L5/E5 frequencies and GLONASS on L1.

    A subset of the raw correlator values for the E1 B, E1 C, E5a I and E5a Q signals are shown in Figure 5 above. Note that the E1 C values have been offset by -2.0×105 for clarity. A data-rate of 250 symbol/s is clearly visible on the E1 B and E5b signals while a 50 symbol/s stream can be observed on the E5a I signal. The 25 chip secondary code is also evident on E1 C at a rate of 250 chip/s.

    All six components of the Galileo-PFM signals shown above (transmitted on PRN 11) were tracked independently and their signal modulations were found to agree with the Galileo Open Service ICD. A trace of the measured carrier-to-noise floor ratios for the Galileo signals is shown in Figure 6. As indicated by the ICD, the E5b signals were observed at 2 dB lower power than the E1 B and C signals. The E5a signals, however, were expected to be received at the same power as E5b and yet were observed at approximately 4 dB lower power. This is believed to be a combination of the antenna and IF filtering within the front-end as the E5a center frequency is located relatively near the pass-band edge of both.  This front-end was initially designed for 40 MHz bandwidth, but used in this experiment at 50 MHz, as will be discussed later.

    Figure 6. C/N0 for Galileo-PFM signals.

    The software receiver was once again reconfigured, this time to produce signal correlator values spaced along a delay of approximately 700 m and 70 m for the E1 A/B and E5 A/B signals, respectively, such that the cross-correlation of the received and local-replica PRN sequences could be examined. The signals were tracked for 10 seconds and the 1 ms correlator values averaged, to produce estimates of the code cross-correlation function. The characteristic ripple of the CBOC modulation on E1 B/C can be seen in Figure 7 (left), particularly on the right-most ascending feature of the envelope. Likewise, the alt-BOC cross-correlation of E5a Q in Figure 7 (right) is as expected. It is noted that the E5a I signal has suffered some distortion due to the filtering effects mentioned above.

    Figure 7. Measured cross-correlation functions for the Galileo PFM E1 B and C signals (left) and E5a I and E5b I signals (right).

    For details of the PLAN group’s front-end, a flexible GNSS signal capture tool, and other specifics on the process employed, see the full-length article.

    GPS III Testbed Sat Delivered

    Lockheed Martin delivered the the GPS III Non-Flight Satellite Testbed (GNST), the program’s pathfinder spacecraft, to its Denver-area facility. The pathfinder will now undergo final assembly, integration, and test activities.

    The GNST is a full-sized, flight equivalent prototype of a GPS III satellite used to identify and solve development issues prior to integration and test of the first space vehicle. According to the company, the approach reduces risk, improves production predictability, increases mission assurance and lowers overall program costs. In Denver, the GNST will be mated with its core structure, navigation payload, and antenna elements before completing pathfinding activities and checkout of environmental test facilities. The GNST will then be shipped to Cape Canaveral Air Force Station, Fla., for pathfinding activities at the launch site.

    GPS III satellites, when launched as scheduled to being in 2014, will replace aging on-orbit GPS satellites to deliver better accuracy and improved anti-jamming power, while enhancing spacecraft design life and adding a new civil signal designed to be interoperable with international global navigation satellite systems.

    In parallel with the GNST, progress on the first space vehicle is progressing on schedule. Lockheed Martin received the core structure for the first GPS III satellite in Stennis, Mississippi, on August 4, and is now integrating the space vehicle’s flight propulsion subsystem. The integrated core propulsion module will be shipped to the GPF in the summer of 2012 and will then undergo final assembly, integration and test in order to meet its planned 2014 launch.

    The GPS III team is led by the GPS Directorate at the U.S. Air Force Space and Missile Systems Center. Lockheed Martin is the GPS III prime contractor with teammates ITT, General Dynamics, Infinity Systems Engineering, Honeywell, ATK and other subcontractors.

    Drone Downed

    Press reports speculate that GPS spoofing was used to get the RQ-170 Sentinel Drone to land in Iran. According to an Iranian engineer quoted in a Christian Science Monitor story, “By putting noise [jamming] on the communications, you force the bird into autopilot. This is where the bird loses its brain.” At that point, the drone relies on GPS signals to get home. By spoofing GPS, Iranian engineers were able to get the drone to “land on its own where we wanted it to, without having to crack the remote-control signals and communications.”

    “The GPS navigation is the weakest point,” the Iranian engineer told the Monitor, giving a detailed description of Iran’s electronic ambush of the highly classified pilotless aircraft.

    In 2011, the U.S. Air Force awarded two $47 million contracts to BAE Systems and Northrop Grumman for development of a navigation warfare sensor to replace military GPS receivers on aircraft and missiles, and designed to maintain freedom of action under extreme GPS countermeasures.

    GLONASS Fully Operational

    For the first time in more than 15 years, GLONASS is fully operational, with 24 satellites in their designated orbital slots, set healthy, and providing world coverage.

    GLONASS 744, an M-class satellite and one of three launched from Baikonur on 4 November, was set healthy December 8, bringing the number of healthy operating satellites to the full complement of 24.

    GLONASS briefly achieved a 24-satellite constellation in early 1996 but it degraded rapidly due to Russia’s economic difficulties following the break-up of the Soviet Union coupled with the short lifetime of the GLONASS satellites. Since 2002, the GLONASS constellation has slowly but surely been rebuilt with the Russian government’s commitment to provide a global positioning and navigation system comparable to that of GPS.

    Luch SBAS. Roscosmos also launched the Luch-5A geostationary relay satellite on December 11.

    Luch-5A is the first in a series of new data relay satellites designed to rebuild the Luch Multifunctional Space Relay System, which had ceased operating by 1998. Among other functions, 5A hosts a wideband satellite-based augmentation system (SBAS) transponder.

    The SBAS transponder will transmit correction and integrity data for GLONASS and GPS on the GPS L1 frequency with a C/A pseudorandom noise code to be assigned by the GPS Directorate. The data will be provided by the System for Differential Correction and Monitoring or SDCM, which uses a ground network of monitoring stations on Russian territory as well as some overseas stations.

    As the SDCM primary service area is Russian territory, the main lobe of the SBAS antenna beam will be directed to the north with an angle of 7 degrees relative to the direction to the equator. Transmitted power of 60 watts will give a signal power level at Earth’s surface roughly equal to that of GLONASS and GPS signals, about –158 dBW.

    The current international SBAS data format has a limited capability for broadcasting corrections for both GLONASS and GPS satellites combined. There is space for only 51 satellites, insufficient for the current number of satellites on orbit. As a result, studies are being carried out in an attempt to resolve this problem. One option is to use a dynamic satellite mask, where an SDCM satellite would only broadcast corrections and integrity data for those GLONASS and GPS satellites in view of users in the territory of the Russian Federation.

    Luch-5A is the first of three MSRS/SDCM satellites. Luch-5B will be launched in 2012 into a slot at 95 degrees east longitude and Luch-4, in 2014, into a slot at 167 degrees east longitude.

    Beidou Launch Fills Regional Nav System

    The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit) satellite was launched on December. According to a Chinese government announcement, this launch completes the construction of the basic regional navigation system for service to China and will be operational by the end of the year. However, completion of the Phase II development, to provide service to the Asia/Pacific region, will require further satellite launches in 2012. Phase III global coverage, with a 30-satellite system, will be achieved by 2020 according to the Beidou website.

    The GNSS community outside China still awaits a Compass interface control document (ICD), which has been promised by the end of 2012.

    LightSquared Incompatibility Declared

    U.S. government tests conducted in November showed that 75 percent of GPS receivers examined were interfered with at a distance of 100 meters from a LightSquared (LS)base station.  The report states that “No additional testing is required to confirm harmful interference exists,” and “Immediate use of satellite service spectrum for terrestrial service not viable because of system engineering and integration challenges.”

    The tests showed interference by the LS Low 10 terrestrial signal with an overwhelming majority of general-purpose GPS receivers. Data from LS handsets was collected, analysis is underway, but no results were given. Wideband and military receivers were tested, but neither specifications nor results were presented; a classified session was convened for that purpose.

    Of the 92 receivers for which full data sets were compiled, 75 percent of them failed a 1db test, showing harmful interference at 100 meters from a LS base station. These 69 receivers failed at a broadcast level of around -15dBm from the LS transmitter.

    In a December 7 filing with the FCC, LightSquared further revised its public plans to say that it would “limit its power on the ground when transmitting in the lower 10 MHz from 1526-1536 MHz to no more than –30 dBm until January 1, 2015, –27 dBm until January 1, 2017, and –24 dBm thereafter.” According to test data, at –30 dBm, approximately 17 percent of GPS receivers would be disrupted; at –27 dBm, 25 percent; at –24 dBm, 36 percent. Proceeding with this scenario would require the assumption that the FCC, or indeed anyone, believes anything that LightSquared says at any given instant, for any given duration.

  • The System: EGNOS Toolkits Enhance GPS Accuracy

    EGNOS Toolkits Enhance GPS Accuracy

    Free downloadable software Toolkits at www.egnos-portal.eu can help cell-phone and handheld receiver developers enhance location and timing applications with GPS corrrection data from the European Geostationary Navigation Overlay Service (EGNOS) satellite-based augmentation system.

    The Toolkits include software packages, demo applications, and supporting materials, enabling application developers, researchers, university students, and others to create, use, and maintain EGNOS-capable positioning applications.

    For handheld receiver manufacturers and mobile-phone developers, the Toolkit contains free source code for easy integration of EGNOS capabilities into a smartphone, and all the necessary files for the demonstration application, for use as a basis for a new application, as well as core libraries, to integrate enhanced EGNOS positioning capability into an existing application.

    For the simply curious, an EGNOS Toolkit provides a means of exploring and understanding the entire chain from the raw GNSS satellite signal to enhanced EGNOS positioning data.

    The development kit provides an easy way incorporate all EGNOS corrections and integrity capabilities, allowing developers to perform real EGNOS integration directly into a smartphone. It works with different operating systems, including Android, Apple, and RIM.

    Static and kinematic tests show that EGNOS performs well in both cases: “The EGNOS SDK provides an average increase of 30 percent in position accuracy over GPS alone,“ according to developer DKE Aerospace.


    EGNOS Software Development Kit provides a software receiver to enhance GPS positions, displaying position accuracy increases on average of 30 percent.

     

    DOT Blank Stare on LightSquared

    The U.S. Department of Transportation (DoT) responded to a Freedom of Information Act (FOIA) request by GPS World for its recommendations to the National Telecommunications and Information Administration (NTIA) regarding LightSquared interference with GPS. The DoT wrote, “We are withholding two pages [of thirteen relevant pages] in part and eleven pages in their entirety,” and enclosed two completely blacked-out pages.
    Kathy Ray, DoT FOIA officer, added,  “We have determined that the release of the redacted and withheld portions would foreseeably cause harm to the government’s deliberative process.”

    The blacked-out DOT letter is dated August 25, 2011. How it differs from the agency’s July 21 “LightSquared Impact Assessment,” publicly available courtesy of the U.S. House of Representatives Committee on Science, Space, and Technology, cannot, of course, be known.

    The Department of Homeland Security wrote in response to GPS World’s FOIA request, “We conducted a comprehensive search of files with the Science and Technology Directorate’s Homeland Security Enterprise and First Responders Group, and Cyber Security Division for records that would be responsive to your request. Unfortunately, we were unable to locate or identify any responsive records.”

    The National Institute of Standards and Technology of the Department of Commerce replied, “NIST has no documents that are responsive to your request.”

    The Department of the Interior provided the same documents that were previously made public by the House committee.

    The National Aeronautics and Space Administration made a similar determination, but did not send a document, referring instead directly to the committee’s public website.

    PNT Board Hears Proposal for LightSquared Solution

    The  November 9 meeting of the National Space-Based Position Navigation and Timing (PNT) Advisory Board in Alexandria, Virginia got several earfulls regarding the LightSquared/GPS controversy. One of seven speakers on a two-hour panel, Javad Ashjaee, president and CEO of JAVAD GNSS, demonstrated his company’s newly developed filter technology that he said could protect GPS receivers from LightSquared broadband network interference.

    As Ashjaee stated, the proposed solution does not protect against interference from the so-called high-10 signals, one of two bands (the other is known as the low-10) for which LightSquared has received a conditional waiver. Unless and until a solution for the terrestrial high-10 signals is found, LightSquared transmissions in that band will still interfere with the GPS signal. The technical solution proposed by JAVAD GNSS addressed only the low-10 band.

     


    Proposed filter to “harden” high-precision GPS receivers against Lightsquared Lower 10 (click to enlarge.)
    The JAVAD GNSS proposed fix consists, in simplified form, of a ceramic filter followed by a series of surface acoustic wave (SAW) filters.
    A PDF of Ashjaee’s 76-slide Powerpoint demonstration, without his verbal explanations and commentary, along with other presentations from the board meeting, are available at www.pnt.gov/advisory/2011/11/. A December 8 GPS World webinar reprised the same presentation, and the download at env-gpsworld-integration.kinsta.cloud/webinar includes audio of Ashjaee’s remarks.

    Ashjaee said that his company’s testing of its own filter methodology found no GPS signal loss due to a low-10 (10L) signal power of –10 dBm. An “Ultimate Test: Special Zero Baseline” put receivers on a Moscow skyscraper with multipath from both above and below. One antenna fed two receivers (zero baseline). One receiver used standard filtering and the other the new filters. He said that over 15 hours of testing the average carrier-phase error between the two receivers was 0.2 millimeters, and the average code difference was about 5 centimeters.

    JAVAD GNSS has started production of what Ashjaee calls “LightSquared-compatible” Triumph GNSS receivers. He brought 40 units to the PNT Board meeting. The company will begin manufacturing “LightSquared-integrated” receivers in May 2012, for RTK positioning using the proposed LightSquared broadband network for high-speed communication, if and when it is deployed.

    Fellow presenter Jim Kirkland, vice president and general counsel for Trimble Navigation, pointed out that such filters represented a potential solution only for one class of high-precision receivers. Whether it would work for other classes of high-precision receivers had yet to be verified. Kirkland said that even if further independent testing shows that the filter solution is viable at the lower 10 MHz of the spectrum, retrofits would be costly and time consuming.

    Questions regarding cost and responsibility of retrofit, should the solution prove practical, were not discussed at length at the meeting, nor was any solution proposed.

    LightSquared executive vice president Martin Harriman did not directly answer a question as to whether his company intends to develop the upper 10 MHz for which it has been given a conditional waiver.

    Scott Burgett, software engineering manager for Garmin International, said, “It is almost impossible to design new products compatible with LightSquared’s proposed system without knowing its technology’s end state.” He estimated 10–15 years to properly retrofit Garmin devices, which are widely distributed in general aviation, personal navigation, car navigation, and other sectors, so that they could coexist with LightSquared.

    The panel was moderated by Tom Stansell of Stansell Consulting, who concluded, “I think we learned, thanks to Javad, about a very clever solution to a particular problem for a particular range of products — the products he is most familiar with. It may or may not fit in some of the other applications.

    “What we have not addressed is the elephant in the living room,” Stansell continued. “That is the cost, and time delay, and changeover process if LightSquared is allowed to go forward. Will it be the lower 10, upper 10? That has to be resolved. There are very large questions remaining to be discussed, and [they] may or may not be fully solved in a short period of time.”

    Constellation Updates

    Where Is Compass ICD?

    The long-awaited signal interface control document (ICD) for China’s Beidou/Compass GNSS has not yet appeared, despite an announcement at the ION-GNSS conference by Chinese delegates that ICD document v1.0 will be published in 2011, “probably” in the month of October. When it does appear, it should be available for download on the Compass website, www.beidou.gov.cn (as yet without an English version), also at www.compass.gov.cn.

    The delay in publishing a document may reflect a system very much in formulation, with ongoing discussions among the principal parties to its design, with different views on system architecture and possibly even final signal structure. This was one possible conclusion that could be inferred — a dynamic system in formation and growing rapidly — from varying reports given by different Chinese representatives, governent and academic, at the ION Compass session.

    There was some disagreement among panelists at that time as to, for example, the final targeted number of satellites in the system: either 30, or 35.

    The ICD has been rumored to be available previously to receiver manufacturers within China, creating some disgruntlement among companies outside the country. One of the ION panelists affirmed that GPS/Compass chips and receivers are being actively developed by many Chinese manufacturers and research institutes.

    The next BeiDou/Compass launch, which will be for the system’s fifth inclined geosynchronous orbit satellite, is expected during the first few days of December, according to web discussions. As of press time for this magazine, there had been no official announcement on the Chinese official government BeiDou website, www.compass.gov.cn.

    The site has posted Chinese and English versions of a document titled “Report on the Development of BeiDou (COMPASS) Navigation Satellite System (V1.0)” by the China Satellite Navigation Office. The pages are viewable as separate images.

    Galileo Under Control

    Europe’s first two in-orbit validation satellites reached their final operating slotss 23,222 kilometers above Earth, have been activated, and are now undergoing tests of their navigation payloads, reports the European Space Agency (ESA).

    Marking the formal end of their Launch and Early Operations Phase, control of the satellites passed on November 3 from the French space agency (CNES) center in Toulouse to the Galileo Control Centre in Oberpfaffenhofen, Germany.

    Oberfaffenhofen, operated by the German Aerospace Center (DLR), will be in charge of the satellites’ command and control for the whole of their 12-year operating lives. The navigation signals are being checked out by ESA’s ground station in Redu, Belgium, where a 20-meter antenna measures the shape of the signals to a high degree of accuracy. Once the navigation payload is fully checked out and activated, a second Galileo Control Centre in Fucino, Italy, will oversee all navigation services. All activities are performed under contract to SpaceOpal, a joint subsidiary of DLR and the Italian company Telespazio.

    GLONASS as Expected

    The Satellite System Mission Control Center of the Russian Ministry of Defence, with the ISS-Reshetnev Information Computation Center, established communication with the three GLONASS satellites launched November 4. The satellites are earth- and sun-oriented, and their subsystems are functioning properly.

    According to NORAD tracking, the three satellites were inserted into Plane 1. This was expected as there are only seven active satellites in this plane, whereas the other two planes have a full complement of eight satellites. Orbit slot 3 in Plane 1 is currently vacant. According to Nikolay Testoyedov, ISS-Reshetnev general designer and director general, the new satellites will ensure the operation of a complete 24-satellite GLONASS constellation, and allow creating the necessary orbital reserve.

    GPS GEO-MEO Floated

    In a presentation titled “Analysis of Alternatives  for Future GPS Architecture; Considerations for Constellation Sustainment,” made to the U.S. PNT Advisory Board on November 9, Kirk Lewis, senior advisor from the Institute for Defense Analyses (IDA), put forth the concept of “boosting” GPS III payloads onto commercial geostationary Earth-orbit (GEO) satellites.

    After concluding that the current program of launches and orbit costs extending into the Block III-C generation is not sustainable, Lewis presented several alternatives, but quickly eliminated two that involved low-Earth-orbit satellites and non-space options, due to technical, scheduling, and performance issues. Remaining in play are “potential and realistic” GEO and mid-Earth orbit (MEO, the configuration of the present GPS constellation) options, used individually or in combination.

    IDA analysis found that two GEO satellites, separated by 15 degrees or more longitude, supplied almost the same signal performance as adding six MEO satellites. The presentation is available at www.pnt.gov/advisory/2011/11/.

  • The System: Galileo IOV Satellites Now in Orbit

    The first two satellites for Europe’s Galileo global navigation satellite system were lofted into orbit October 21 by the first Russian Soyuz vehicle ever launched from Europe’s Spaceport in French Guiana in a milestone mission, reports the European Space Agency (ESA).

    The launch occurred one day after initially scheduled to resolve a problem with the ground-support fueling system.

    The Soyuz VS01 flight, operated by Arianespace, started with liftoff from the new launch complex in French Guiana at 10:30 UTC on October 21. All of the Soyuz stages performed as expected and the Fregat-MT upper stage released the Galileo satellites into their target orbit at 23,222 kilometers altitude, 3 hours 49 minutes after liftoff.

    The two Galileo satellites are part of the In-Orbit Validation (IOV) phase that will see the Galileo system’s space, ground, and user segments extensively tested. During initial operations, the satellites will be controlled by a joint ESA and CNES French space agency team in Toulouse, France. Once that week-long phase ends, the satellites will be handed over to the Ober-pfaffenhofen Galileo Control Centre near Munich, operated by the DLR German Aerospace Center, which will be responsible for routine operations. Operating the satellite payloads to provide navigation services will be the task of the Fucino Control Centre, near Rome, operated by Telespazio.

    The next two Galileo satellites, completing the IOV quartet, are scheduled for launch in summer 2012. Together, alll four are intended to prove the design of the Galileo system in advance of the other 26 satellites.

    These first four satellites, built by a consortium led by EADS Astrium Germany, will form the operational nucleus of the full Galileo satnav constellation. According to ESA, the satellites combine the best atomic clock ever flown for navigation — accurate to one second in three million years — with a powerful transmitter to broadcast precise navigation data worldwide.


    Artist’s depiction of a Galileo satellites being ejected from the dispenser.

    Second IIF Good Now

    The second GPS Block IIF satellite, SVN63/PRN01, launched in mid-July, was finally set healthy on October 14. The delay in bringing the satellite into service was due, in part, to extended testing of the cesium atomic frequency standard (AFS) on the satellite.
    GPS IIF satellites carry three AFSs: one cesium and two rubidiums. The performance of the cesium AFS, independently confirmed, was poor. A switch to one of the rubidium AFSs took place on October 5.

    U.S. Agencies Speak Out on LightSquared; Others Hide Their Cards

    The U.S. House of Representatives Committee on Science, Space, and Technology has released some of the impact statements provided by federal agencies to the National Telecommunications and Information Administration (NTIA). The reports reveal deep concerns about and opposition to the LightSquared proposal, and detail cost estimates and other adverse impacts to government-wide operations should it go forward.

    The NTIA itself has refused to make these agency reports public, rebuffing a Freedom of Information Act (FOIA) request by GPS World magazine and, so far, giving the same response to congressional committees on both the House and Senate side.

    Missing in Action. The House Committee does not yet have access to all the agency statements; still missing are those from:

    • the Department of Homeland Security,
    • the Department of Commerce,
    • the National Oceanic and Atmospheric Administration,
    • the National Institutes of Standards and Technology.

    The House committee has written to those departments asking for their reports; GPS World has also filed further FOIA requests specifically with those agencies. The Department of Defense impact statement is presumed to be classified.

    Seventy-Two Billion. The Federal Aviation Administration (FAA) impact statement is the strongest statement of those provided so far to the House committee. It asserts, among many other findings, that the LightSquared proposal would cost the aviation community at least $72 billion, preclude elimination/reduction of an estimated 794 air-traffic fatalities over the next 10 years, set back planned air-traffic safety and efficiency measures by that same period, affect U.S. leadership in aviation, and damage the international market for U.S. satellite technology.

    “FAA cannot conclude that operations using just the lower portion of the spectrum are compatible with civil aircraft receivers without definition of LightSquared’s end-state deployment and further study,” the FAA said. “Proposed LightSquared deployment (both upper and lower channels by 2014) would result in an estimated aviation community cost impact of at least $72 billion and delay NextGen implementation by approximately 10 years.

    “Proposed LightSquared operations would severely impact the efficiency and modernization of the safest, most efficient aerospace system in the world.”

    Not Feasible. The National Aeronautics and Space Administration stated, in part:

    “NASA feels that due to the severity of the operational impacts, to both government and commercial users, it is conclusive that LightSquared’s implementation on the upper 10-MHz is not feasible in the near or long-term.”

    Constellation Updates from ION-GNSS

    During the Civil GPS Service Interface Committee (CGSIC) meeting held in conjunction with the ION GNSS 2011 conference in September, several presentations were given on the status and future of the global navigation satellite systems. Here are highlights, with updated information from elsewhere:

    GPS. As of today, 30 satellites are in operation and set healthy. SVN27/PRN27, a Block IIA satellite launched in 1992, was decommissioned on August 10, 2011. The satellite has been removed from broadcast almanacs but continues to transmit L-band signals, presumably for end-of-life testing.

    SVN35 returned to active service, once again, this time as PRN30, on August 16, to replace SVN30/PRN30, which was decommissioned from active service on July 20. SVN35 is being moved to the B1-F slot, previously occupied by SVN30.

    There are currently four backup or residual satellites: SVNs 30, 32, 37, and 49. SVN30 is deemed no longer usable and there are plans to dispose of it.

    SVN24/PRN24, a Block IIA satellite launched in 1991 and the second oldest active GPS satellite, reportedly experienced a reaction wheel failure on September 30. It has stopped broadcasting L-band signals.

    GLONASS. Currently, 23 GLONASS satellites transmit usable L-band signals; 22 are set healthy. The first GLONASS-K1 satellite is still undergoing flight tests and is set unhealthy. According to Sergey Revnivykh, deputy director general, Central Research Institute of Machine Building of the Russian Federal Space Agency, the satellite will likely not be set healthy for users in the near future, not even for just the legacy FDMA signals. It will be considered a backup satellite that could be pressed into service if necessary. This decision was taken based on the fact that five GLONASS-M satellites are scheduled to launch this fall — indeed, one did so on October 2 — and they should be adequate to maintain a healthy 24-satellite constellation for some time. The current GLONASS signal specification cannot handle more than 24 operational satellites.

    CDMA signals will be available to users from in-orbit GLONASS-K satellites by 2014.

     

    QZSS. The Japanese press reported that a government ministerial council consisting of the entire cabinet and headed by Prime Minister Yoshihiko Noda has taken the decision to expand the Quasi-Zenith Satellite System to seven satellites and will seek 4.1 billion yen (about $53 million) in the fiscal 2012 national budget to start the process. According to Hiroshi Nishiguchi of the Japan GPS Council, QZSS has a top priority in the budget.
    The future QZSS constellation structure is still under design. Nishiguchi stated that the constellation could involve a mixture of inclined geosynchronous orbit (IGSO) and geostationary Earth orbit (GEO) satellites. For a seven-satellite constellation, options include three IGSOs + four GEOs, or four IGSOs + three GEOs, or five IGSOs + two GEOs. He said that hopefully the funding and the future constellation structure will be known by the end of the year.

    Beidou-2/Compass. A special Compass workshop (see also the October issue of GPS World) stated that there are nine Compass satellites “in service.” But that may not be correct. While nine Beidou-2 or Compass satellites have been launched, Beidou G2, the first GEO to be launched, appears to be uncontrollable and is in a librating orbit. Some reports, perhaps overly optimistic, claim this satellite is undergoing “in-orbit maintenance.”

    The last IGSO satellite to be launched, Beidou IGSO4, may not be in service yet. One workshop presenter indicated that the currently used constellation consists of three GEOs and three IGSO satellites. It seems that the medium Earth orbit (MEO) satellite, Beidou M1, is not considered useful for actual applications at the present time. It was also stated that this satellite is undergoing “in-orbit maintenance.”’

    Two more Beidou-2/Compass satellites are to be launched in 2011 and five satellites are to be launched in 2012 to bring the number of operational satellites to 14 by the end of 2012: five GEOs, five IGSOs, and four MEOs. This is a sufficient number of satellites to provide the planned regional Phase II service. A 30-satellite global service, expected by 2020, will reportedly use three GEOs, three IGSOs, and 24 MEOs.

    Beidou-2/Compass will also offer a 1-meter level differential service.

    A Beidou-2/Compass Interface Control Document (ICD) is to be published this month. As of press time for this magazine, it had not yet appeared.

    — Richard B. Langley

  • The System: Compass Signal ICD this Month

    The long-awaited signal interface control document (ICD) for China’s growing GNSS will appear this month, according to representatives of the system who spoke in a “Compass: Progress, Status, and Future Outlook” workshop as part of ION GNSS and the CGSIC meetings in Portland in September.

    The ICD has been rumored to be available previously to receiver manufacturers within China, creating some disgruntlement among companies outside the country. One of the workshop panelists affirmed that GPS/Compass chips and receivers are being actively developed by many Chinese manufacturers and research institutes.

    The ICD announcement came among many valuable pieces of information presented during the pre-ION workshop, sponsored by the International Association of Chinese Professionals in Global Positioning Systems and chaired by Jade Morton, professor of electrical and computer engineering at Miami University, Ohio.

    Xiancheng Ding of the Beidou Program Office described Compass as a demo system in transition to an operating navigation system. Two more satellites will launch in 2011, making a total of five new space vehicles this year,as part of a total “simple navigational system” of nine satellites that has been built up, and what is termed a test system over the Asia-Pacific region, to be complete by the end of the year.

    Five more satellites will rise into orbit in 2012, and the system will gradually extend its coverage and improve its performance. Compass will start official regional service by the end of 2012, meeting user requirements in the Asia-Pacific region.

    ICD document v1.0 will be published in 2011, and probably in the month of October. It will be available for international download on the Compass website (as yet without an English version).

    There was some disagreement among panelists as to the final targeted number of satellites in the system: either 30, or 35. Subsequent comments indicated that much of the structure may still be under discussion. The impression given was very much of a dynamic system in formation and growing rapidly.

    In a presentation on “Preliminary Results of GPS/Compass Integrated Positioning and Navigation,” Uanxi Yang of China’s National Administration of GNSS and Applications reported integrated navigation with a Unicore UB 240 Compass/GPS receiver with up to 9-centimeter accuracy, and also mentioned a Shanghai Huace Compass/GPS receiver. Some systematic errors in Compass positioning were reported, and attributed to the sparse satellite distribution currently.

    Yang concluded with the exhortation, “Reasonable Wishes for Compass!” emphasizing the delegation’s desire to continue working diligently on, but with realistic expectations for, the new system.

    Orbit Roundup

    In other satellite news and debuts anticipated around the world:

    GPS. Back-channel reports say the cesium clock aboard SVN-63, the second IIF satellite, is not functioning properly, and that this is at least one reason why the satellite, turned over to 2SOPS control on August 19, has not been set healthy to users.

    [Correction: The September issue and env-gpsworld-integration.kinsta.cloud mistakenly reported that SVN-63 had been set operational on August 23. This is not the case. As of September 29, the satellite is still not healthy to users.]

    After repeated attempts to get the clock working, operators are ready to switch to a rubidium clock onboard, and may already have done so.

    GLONASS. The launch of GLONASS-M No. 42 from Plesetsk is scheduled for October 1. GLONASS-M Nos. 43, 44, 45 from Baikonur may occur as early as November 2. GLONASS-M No. 46 from Plesetsk is now scheduled for November 22. The launch of the next-generation GLONASS-K1 No. 12 from Plesetsk will likely slip to 2012.

    The K1 satellites will not be set healthy, but held in reserve only. The remaining M-generation vehicles launching this year will fill up the 24 almanac slots. GLONASS will have plenty of satellites held in reserve.

    Luch-5A, a Russian geostationary communications satellite that includes an SBAS payload, will launch on December 10 from Baikonur.

    FCC Calls for More Testing on LightSquared Interference

    The U.S. Federal Communications Commission (FCC)issued a Public Notice on September 14 stating that additional testing is necessary to ensure that LightSquared’s broadband network will not interfere with GPS.

    The notice states: “Following extensive comments received as a result of the technical working group process required by the International Bureau’s Order and Authorization dated January 26, 2011, the Federal Communications Commission, in consultation with NTIA, has determined that additional targeted testing is needed to ensure that any potential commercial terrestrial services offered by LightSquared will not cause harmful interference to GPS operations….

    “For more than three months, the technical working group, comprised of more than 120 participants including representatives from the Department of Defense, Department of Transportation and other federal agencies, the GPS community, various telecommunications companies and LightSquared, conducted an extensive set of tests, and LightSquared submitted a final report on June 30, 2011. The technical working group effort identified potential for harmful interference from LightSquared’s originally proposed deployment based on operation of terrestrial transmitters in both the upper and lower 10 MHz portions of its spectrum. The FCC issued a public notice on June 30, 2011, seeking comment on the report.

    “LightSquared submitted proposed mitigation techniques to remedy the interference to GPS simultaneously with the technical working group final report. Notably, LightSquared proposed to revise its planned deployment to operate terrestrial transmitters only in the lower 10 MHz of its spectrum. The results thus far from the testing using the lower 10 MHz showed significant improvement compared to tests of the upper 10 MHz, although there continue to be interference concerns, e.g., with certain types of high precision GPS receivers, including devices used in national security and aviation applications. Additional tests are therefore necessary.”

    Galileo Counts Down to October 20 for First Validation Satellites

    The first flight of a Russian rocket, Soyuz, from Europe’s spaceport in French Guiana will carry the first two satellites of Europe’s Galileo navigation system into orbit on October 20, and the European Space Agency is reporting on the preparations.

    The Soyuz launcher will be rolled out horizontally to the launch pad on October 14 and raised into its vertical launch position. The upper composite, comprising the Fregat upper stage, payload and fairing, will then be hoisted on top of Soyuz.

    The two Galileo satellites arrived from the Rome facility of Thales Alenia Space Italy, also in mid-September. In 2012, a second pair of satellites will join them in orbit, with the task of proving the design of the Galileo system in advance of the other 26 satellites. The four satellites, built by a consortium led by EADS Astrium Germany, will form the operational nucleus of the full Galileo satnav constellation. They combine reportedly the best atomic clock ever flown for navigation — accurate to one second in three million years — with a powerful transmitter to broadcast precise navigation data worldwide.

    The first Soyuz to rocket up from a port outside Baikonur in Kazakhstan or Plesetsk in Russia, the launch will take place from a new facility 13 kilometers northwest of the Ariane 5 launch site. French Guiana is much closer to the Equator than other launch possibilities, so each Galileo effort will benefit from the Earth’s spin, increasing the maximum payload into geostationary transfer orbit from 1.7 tons to 3 tons.

  • The System: 2 SOPS Takes Over Second IIF

    The U.S. Air Force 50th Space Wing’s 2nd Space Operations Squadron took command and control of the second GPS Block IIF satellite on August 19. SVN-63 (PRN 01) was set healthy on August 23.

    The total of 12 next-generation GPS IIF satellites built by Boeing will provide improved accuracy through advanced atomic clocks, a longer design life than legacy GPS satellites, and a new signal, L5, that will benefit civil aviation and safety-of-life applications.

    The Space and Missile Systems Center’s GPS Directorate at Los Angeles Air Force Base remained in control of the satellite during a 30-day on-orbit check-out period before hand off.

    The constellation is more robust and capable than at any other time in its history, the GPS Wing said. Members of 2 SOPS operate the largest Department of Defense satellite constellation via the Master Control Station and a worldwide network of monitoring stations and ground antennas.

    Recalls IIA to Duty. For only the second time in a quarter century, Air Force officials plan to transition a decommissioned GPS satellite back to active status. 2 SOPS staff noticed in late May that the clock on the GPS IIA SVN-30 was starting to malfunction. 2 SOPS engineers and counterparts at Boeing and Aerospace Corp. developed a plan to bring SVN-35 back in to service to replace the ailing bird. The 18-year-old satellite was decommissioned from active service in 2009 to make room for the eventual deployment of the latest GPS Block IIR vehicle; however, its navigational signal continued to function properly.

    “We keep on-orbit spares for exactly this purpose,” said Lt. Col. Jennifer Grant, 2 SOPS commander. “The robustness of our current constellation and the recent completion of the Expandable 24 architecture provide us with the flexibility to perform replacements like this with minimal impact to global users.”

    OCX Hits Bump: Does Not Pass Preliminary Design Review

    The next-generation GPS Ground Control system (OCX) under the direction of prime contractor Raytheon did not pass the recently concluded initial Preliminary Design Review (PDR).

    Not passing this critical PDR inspection so early in the OCX process and in the current fiscal environment (Congress has already trimmed the modernization budget and shifted elements to the right) constitutes a blow to the GPS modernization effort. It adds to the worry concerning the OCX-GPSIIIA gap having to do with the ability to launch the Lockheed-produced GPS IIIA space vehicles (SVs) and payloads that are scheduled to be ready for launch a full 14–16 months before the OCX ground system was originally scheduled to be able to control the launch.

    That timeline undoubtedly stretches to the right with this development.

    The PDR is a formal inspection by the government acquisition agency — the Air Force’s GPS Directorate in this case — of the high-level architectural design of the OCX automated systems and the associated C2 software. The PDR, critical for any military project but especially so for the new GPS Ground C2 system, is conducted to achieve confidence that the design satisfies the functional and nonfunctional requirements and conforms with the overall enterprise architecture. Overall project status, proposed technical solutions, evolving software products, and all associated documentation are reviewed at a high level during the PDR to determine completeness and consistency with contractual standards. The PDR also serves to raise and resolve any technical and/or project-related issues, and to identify and mitigate project, technical, security, and/or business risks affecting continued detailed design and subsequent development, testing, implementation, and operations and maintenance activities.

    Typically during a PDR the government has several choices concerning the outcome. It can:

    • Approve
    • Approve conditionally
    • Withhold approval
    • Disapprove or fail the program.

    In this case, the government chose to withhold approval and not approve conditionally or formally fail until all PDR action items are reviewed.

    LightSquared Interference

    For the first time in several months, there is little in the way of concrete news to report on this topic — as of press date August 24. The Federal Communications Commission weighs its options and scrutinizes the further data that it has requested: the number and lifespan of GPS receivers that will be interfered with, and the number of terrestrial base stations LightSquared plans to deploy. Here are highlights from the “LightSquared Watch” webinar on August 18:

    GPS is arguably the most efficient use of spectrum the world has ever seen; almost a billion people benefit from the GPS signal that is available today. This use represents a massive installed base and source of innovative advantage for the United States. Most importantly, it represents a high degree of trust and confidence in the United States and its stewardship of GPS.
    — Scott Pace

    Misinformation is rampant, and the pressure for action before analysis characterized the early stages of this process. History was reinterpreted, and the facts twisted to fit desired reality. We have heard lawyers’ assertions versus engineers’ judgements — with only the latter supported by verifiable data.
    — Jules McNeff

    Launches Round the World

    China launched a fourth inclined geosynchronous orbit (IGSO) satellite in the Beidou/Compass navigation system on July 26. Its orbit is currently centered on an East longitude of about 93 degrees, some distance away from the other three IGSO satellites. Plans call for completion of a 14-satellite constellation by 2012.

    A single GLONASS-M satellite was set to be launched on August 26. Five further GLONASS launches are planned this year: a triple and a single GLONASS-M launch in October, and the second GLONASS-K1 satellite in December.

    The first two Galileo In Orbit Validation satellites are set to be launched from French Guiana on October 20, with two more following them into orbit by mid-2012.

  • The System: Technical Report on LS/GPS Interference

    Once again, developments in the news outpaced print technology’s ability to keep up in the LightSquared saga. Shortly after the July issue went to press on June 27, the TWG final report appeared on June 30. Thus you readers, who received the magazine circa July 15, held old news in your hands. Likely this will occur again.

    Chronologically in this section, from late June to mid-late July:

    Final Report of Technical Group

    The final report to the Federal Communications Commission (FCC) by the technical working group (TWG) tasked to analyze effects of powerful terrestrial L-band transmitters on the GPS signal and services finally appeared on June 30, nearly two weeks after its assigned date. LightSquared had requested an extension and used the time to write many pages of self-justification and legal argument of the company’s case. But the facts are clear: the LightSquared signal would devastate services for users of all GPS receivers tested.

    “Based on the analysis performed, LightSquared should not be permitted to use the L-Band spectrum for a densely-deployed, non-integrated terrestrial-only network. Such a network would cause unacceptable interference to GPS operations, wiping out an installed base of over 500 million units used in a wide array of public safety, aviation, industrial, and consumer applications. While mitigation techniques utilizing filters were discussed in theory, they could not be tested as part of the WG effort because filters do not exist, even in prototypes. No information considered by the WG demonstrated that any mitigation techniques — other than relocation of the proposed terrestrial network to an alternative band — would be successful.” (From the U.S. GPS Industry Council’s overview)

    The final report is not easy to find on the FCC’s labyrinthine website. Download it here.

    LightSquared COO, President Gone

    Harbinger Capital Partners, the hedge-fund firm that owns LightSquared, announced on July 6 that its chief operating officer had resigned by “mutual agreement.” Peter Jenson’s exact role in the application for a FCC conditional waiver is unknown at this time; however, it is certain to have been key.

    On June 30, the date of the TWG report, Harbinger Group Inc., a publicly traded company majority-owned by Harbinger Capital, appointed Omar Asali as acting president, replacing Harbinger founder Phil Falcone, who continues as chairman and chief executive.

    DoD, DoT Say Hands Off L-Band

    The U.S. Departments of Defense and Transportation declared their strong opposition to the LightSquared plan in a June 14 letter to the National Telecommunications and Information Administration (NTIA).

    In their official statement, “The Departments continue to support the National Broadband Plan, but cannot do so at the expense of a global, ubiquitous utility such as the Global Positioning System. The Departments encourage further assessment of any alternative spectrum and/or signal configuration plans.” See www.pnt.gov.

    The Department of Homeland Security was conspicuously absent from the signatory line, as it has been in most public goings-on. Under pointed congressional questioning about its reluctance to enter the ring, a DHS spokesperson averred that the agency had been “carrying a lot of water.”

    Javad Says End P-Code Encryption

    To solve the LightSquared versus GPS controversy, Javad Ashjaee, president and CEO of JAVAD GNSS, has appealed directly to President Obama to discontinue the encryption of P-code, the restricted military GPS signal. “This policy is not helping national security. It is hurting both precision users and the broadband project. We need more broadband, for global, fast, and inexpensive real-time kinematic (RTK) GPS.”

    IIF II Up, Up, and Away

    The U.S. Air Force successfully launched GPS IIF-2 Space Vehicle Number (SVN) 63 aboard a United Launch Alliance Delta IV Medium rocket on July 16 from Cape Canaveral Air Force Station, Florida. This is the second in the series of 12 GPS IIF satellites that Boeing has on contract with the Air Force. Boeing reported the first satellite signals from space received within four hours. On July 20, stations of the International GNSS Service tracking network reported a signal from SVN63’s L-band transmitter. Testing will ensure health of L1, L2, and L5 signals beforethe satellite is turned operational; this is expected in August.

    The satellite joins the GPS constellation of 30 operational satellites. SVN-63 will assume plane D, slot 2A, replacing SVN-24 after nearly 20 years of service.

    The IIF satellites will provide greater navigation accuracy to users through improvements in atomic clock technology and a more robust signal for commercial aviation and safety-of-life applications, through the third civil signal (L5). GPS IIFs will have a longer design life of 12 years, and will continue to deploy the modernized capabilities that began with the modernized GPS IIR satellites, including a more robust military signal.

    A Boeing statement concluded: “With safety checks completed, checkout will begin under the direction of the Air Force GPS Directorate. Checkout includes payload and system checks to verify operability with the GPS constellation of satellites, ground receivers, and the Operational Control Segment system. Boeing will officially turn over SVN-63 to the Air Force 50th Space Wing and the 2nd Space Operations Squadron this fall after the spacecraft completes on-orbit checkout.”

    GPS III Design Review Completed

    Lockheed Martin successfully completed on schedule a system design review (SDR) for the GPS IIIB satellite increment under the U.S. Air Force’s next-generation GPS III program. The company is under contract to produce the first two of a planned eight GPS IIIA satellites, with first launch projected for 2014. The contract, which features a “back to basics” acquis
    ition approach, includes a Capability Insertion Program (CIP) designed to mature technologies and perform rigorous systems engineering for future GPS III increments.

    The GPS IIIB SDR established requirements for the capability insertion planned for the follow-on GPS IIIB satellites and “validated the satellite design will meet the ever-increasing demand of more than one billion GPS users worldwide.”

    GPS IIIA will deliver signals three times more accurate than current GPS spacecraft and provide three times more power for military users, while also enhancing the spacecraft’s design life and adding a new civil signal designed to be interoperable with international global navigation satellite systems.

    GPS IIIB will provide higher power modernized signals, a fully digital navigation payload capable of generating new navigation signals after launch and a Distress Alerting Satellite System payload that relays distress signals from emergency beacons back to search and rescue operations.

    Galileo Finds LS Interference

    The head of the European agency overseeing Galileo filed an official FCC comment, expressing strong concern about the Lightsquared terrestrial signal. Analysis in Europe shows that LightSquared transmissions “have considerable potential to cause harmful interference to Galileo receivers.”

    Video. Meanwhile, the European Space Agency has a video of Galileo in-orbit validation satellite assembly and testing. The first two satellites are destined to launch together at the end of October aboard a Russian Soyuz rocket, from the European spaceport in French Guiana. They will join two experimental satellites already on orbit. See video.