GPS World

Tag: The System

  • The System: LightSquared Interference with GPS

    And the Beat Goes on

    Developments in the LightSquared saga came fast and furious in June; highlights are listed below and briefly recapped in the adjacent news story. It will be dated by the time you receive this issue, as it went to press three weeks prior.

    For current events, see Top Story and Latest News, and the full versions of stories abridged here. The Navigate, Survey Scene, and GNSS Design & Test e-newsletters, free at env-gpsworld-integration.kinsta.cloud/subscribe, will keep you up to date.

    In chronological order, from late May to late June:

    • LightSquared Las Vegas Test Towers Flawed, FCC Filing Shows
    • House Bill Ensures FCC Takes No Action that Would Harm Military Use of GPS
    • Test Data Shows LightSquared Slams Medium, High-Precision GPS Receivers
    • PNT Advisory Board Finds Interference, Says Move It
    • LightSquared, FCC Rebuttals Distort Record
    • NPEF Report on Military Receivers Calls for FCC Recision
    • LightSquared Asks for, Receives Extension on Final Interference Report
    • Claims of LightSquared Solution Discounted
    • Air Transport Association Tells Congress to Protect GPS
    • Interference with GPS Poses Major Threat to U.S. Economy
    • LightSquared Applies to International Telecommunications Union for Global Signal

    Flawed Test Towers

    Results from a key round of field tests conducted near Las Vegas, Nevada, may show overly optimistic results regarding the effects of the LightSquared terrestrial signal on GPS receivers. According to a LightSquared addendum filed with the Federal Communications Commission (FCC) a week after the May 16 Working Group report, the company’s equipment broadcast during the tests at lower-than-planned levels for its eventual deployment across the United States. Further, LightSquared may not currently be prepared or equipped to broadcast according to the terms of its business plan or its conditional waiver.

    LightSquared does not appear to have developed the full software suite nor possess the full equipment to implement the plan the company says has been in preparation for many years. Critical testing was conducted under conditions that do not truly replicate what may be the case should the FCC allow the plan to go forward.

    House Bills Target the Waiver

    On May 27, the U.S. House of Representatives passed a bill stating that the FCC shall not provide final authorization for LightSquared operations until Defense Department concerns about GPS interference have been resolved. The bill then went to the U.S. Senate for its action.

    On June 23, the House Appropriations Committee approved action that would stop the FCC from expending any funds related to the LightSquared conditional waiver until all concerns have been resolved about interference with GPS. The amendment passed in a unanimous voice vote by the full committee, underscoring growing congressional concern about harm to GPS.

    The House actions and a letter to the FCC signed by 32 U.S. senators may presage a showdown over the issue between Congress and the president, who has promised increased broadband access. A 4G wireless network providing this access could be facilitated by LightSquared sales of service via its tower transmitters to wireless carriers. LightSquared has already signed a $20 billion, 15-year deal with Sprint.

    Tests Slam High-Precision Receivers

    Data from Las Vegas field tests show that wide-bandwidth, high-precision GPS receivers started feeling the effects of the LightSquared transmission about 1,800 meters from the tower. Medium-bandwidth high-precision GPS receivers started feeling the effects of the LightSquared transmission at about 1,200 meters from the tower. In each case, there was about a 200-meter buffer from when the GPS receivers started to feel the effects of the LightSquared transmission to the GPS receiver being jammed, at 1,600 meters and 1,000 meters respectively.

    GPS World has received further details of the tests but has not been authorized to publish them yet.

    Deere & Company, a major provider of precision agriculture equipment and services, notified the FCC on May 26 of substantial interference with its GPS receivers by the LightSquared signal. Deere receivers registered impact of and interference by the LightSquared signal as far away as 22 miles from a transmitter. Further, the company has found no practicable technical solution to the problem.

    PNT Advisory Board: Move ATC

    At its June 9–10 meeting, the National Space-Based Positioning, Navigation and Timing (PNT) Advisory Board found that GPS services cannot be assured if the LightSquared plan is approved, and that the only viable option for continued availability of GPS as well as new wireless broadband is to find another spectrum for LightSquared not adjacent to the GPS frequency.

    The formal recommendation reads: “The provision of GPS services cannot be assured if the LightSquared proposal for satellite and terrestrial broadband provision using the MSS L-Band receives final approval.

    “The only reasonable and viable option to continue ubiquitous availability of GPS and the provision of a new 4G wireless broadband capability would be for the FCC to assign an alternate frequency spectrum to LightSquared that has little or no probability of affecting the delivery or utilization of GPS/GNSS services.”

    During the discussion, one advisory board member, a former goveronor of the state of Wyoming, told presenter Jeff Carlisle of LightSquared, “Your definition of mitigation seems more tied to a legal argument than a common-sense argument.”

    Rebuttals Distort Record

    Claims by LightSquared’s Carlisle and FCC chair Julius Genachowski, that the GPS industry knew long ago about LightSquared’s plan for powerful terrestrial transmitters, contradict the truth. Examination of FCC filings show that the GPS industry knew about and agreed to a plan by a previous ownership of the company, for a different purpose, with a different business concept, and employing a completely different technological approach, one that would not have harmed GPS transmissions and disabled GPS users the way the current LightSquared plan does.

    The terrestrial broadband operations first unveiled in November 2010 cannot be described as ancillary to the purpose for which Lightsquared predecessors Motient, MSV, and SkyTerra received their spectrum and licenses — that is, to provide a service that was primarily a mobile satellite service. The November letter to the FCC described a new business model that turns the original concept on its head. LightSquared for the first time revealed plans to build a “nationwide network of 40,000 terrestrial base stations,” and stated that “the capacity of its fully deployed terrestrial network across all base stations will be tens of thousands of times the capacity of either of [its] satellites.”

    The deviations from established policy required to accommodate LightSquared’s new business model are not technicalities. They represent a fundamental change to a complex and interrelated set of rules that were carefully designed to protect GPS users from interference.

    The predecessor companies had to protect their own primary satellite operations from interference. The protection that their own satellite operations required was also sufficient — at that time — to protect GPS receivers. The terrestrial network and powerful signal LightSquared now proposes bear no resemblance to the operations the FCC authorized in 2003.

    Military Report Calls for FCC Retreat

    The National PNT Engineering Forum concluded after testing classified and GPS receivers under LightSquared terrestrial transmission conditions: “Significant concerns remain that operation of an ATC integrated service as originally envisioned by the FCC cannot successfully coexist with GPS.”

    The NPEF report calls for rescinding the FCC waiver for LightSquared terrestrial transmissions, conducting more thorough studies on impacts, and revisiting the 2003–2010 authorizations. The group tested a variety of military receivers under classified categorization, also known as “government receivers.”

    Final Report Withheld

    At the last minute of a June 15 deadline for the final Working Group report on interference, LightSquared asked for a two-week extension. Federal regulators granted the request, and the final report is now due on July 1.

    A spokesperson for the Coalition to Save Our GPS revealed that “The Working Group results show devastating interference to GPS and no proven method of mitigation. Delay will not change these results. These results are the same results the FCC had had before it granted the waiver.”

    Some Solution. Three days after requesting the delay, LightSquared announced it had solved the problem, by proposing to broadcast only from the lower end of its permitted spectrum band. GPS experts countered that this would still disable the functioning of high-precision receivers.

    Air Transport Opposes Waiver

    The Air Transport Association and the Aircraft Owners & Pilots Association told Congress that the only acceptable mitigation is for LightSquared’s operations to be moved outside of the L-band and away from GPS. “With so much of the early evidence showing that LightSquared’s proposed network would potentially endanger nearly every flight operating in U.S. airspace, it seems evident that no further development of this system can be allowed.”

    Going Global

    LightSquared has filed documents relative to the International Telecommunications Union, signaling intent to use its entire band at the full authorized power. The company’s goal appears to be to work internationally, circumventing U.S. regulation, to obtain permits to broadcast a terrestrial signal globally.

  • The System: Third Report by LightSquared/GPS Technical Working Group

    Plus: Locata as Alternative PNT, Indian SBAS, Galileo Launch

    Slow but steady progress of the Working Group (WG) convened by the Federal Communications Commission (FCC) to study the GPS overload/desensitization issue is related in the group’s Third [monthly] Pogress Report, filed with the FCC on May 16. For the third consecutive time, the report contains little in terms of actual results of testing for interference/desensitization of GPS receivers by the proposed LightSquared terrestrial signal. It continues to carefully lay out the ground rules adopted by several subteams for testing the particular receivers in their domain. As of the date of filing, it reported, “testing is underway for six device categories and has been completed for the Space-Based Receivers category.”

    As related in May’s The System, the Working Group has self-divided into sub-teams.

    Aviation Sub‐Team. Laboratory testing was scheduled to be completed by May 20, conducted by Zeta Associates. The team’s report is being compiled, and some receivers were to be made available for field testing near Las Vegas.

    The Federal Aviation Administration (FAA) issued a flight advisory warning pilots that GPS service in one area of Nevada could be “unreliable or unavailable” May 16–27, during LightSquared testing. Tests were to be conducted in six-hour blocks.

    “Pilots are strongly encouraged to report anomalies during testing to the appropriate ARTCC to assist in the determination of the extent of GPS degradation during tests,” said the advisory.

    Cellular Sub‐Team. Two of the three laboratories engaged to perform radiated and conducted testing have added work shifts to complete their processes by the TWG’s deadline; the third lab is being configured. Forty-five models of GPS-enabled cell phones will undergo testing, following a detailed procedure described in Appendix D to the report.

    General Location/Nav Sub‐Team. This team recently added new members representing public safety users at the request of the National Public Safety Telecommunications Council (NPSTC). See related article, “LightSquared Interference with Emergency Service.“ The sub‐team has accumulated live‐sky GPS test data for use in dynamic testing scenarios, and plans further field tests in the Las Vegas, Nevada, area, described in Appendix G.

    High-Precision, Networks, Timing. The sub teams have completed testing of all devices in the NAVAIR lab facility. Some team members expect to have some receivers of the same models that have been tested by NAVAIR available for field testing in Las Vegas, and are working to develop test procedures for the field tests.

    Space-Based Receivers. The team completed its laboratory testing activities as reported on April 16, and is now reviewing the initial draft analysis of the impacts.

    Senate Letter

    Meanwhile, the U.S. Senate is showing increasing signs of life in response to the problem. As of May 23, a total of 32 senators had signed a letter to the FCC initially drafted on April 15 by two U.S. senators from the heartland, Pat Roberts (Republican, Kansas) and Ben Nelson (Democrat, Nebraska). The joint public letter urges action in the form of “asking the FCC to take all necessary steps to protect GPS.”

    What sway, if any, the Senate holds over the FCC, which forms part of the executive (presidential) branch of government, remains unclear. However, the letter does signal some heightened interest in Washington, presumably as a result of hearing from constituents. Kansas and Nebraska, of course, have large-scale farming activity, in which precision agriculture driven by GPS plays a significant role.

    The two original authors state that “the International Bureau, a sub-organization within the FCC, granted a conditional waiver to allow a single company, called LightSquared, to build tens of thousands of ground stations that may cause widespread interference to neighboring GPS signals.”

    The letter goes on to outline the many key roles that GPS plays in economic activity and specifically in “economic recovery,” public safety, aviation, and national defense. “Reliable GPS affects virtually every American,” Nelson and Roberts assert.

    They close by “calling on the FCC to ensure that GPS is not compromised in any way. To do so, the full commission must be involved and require LightSquared to objectively demonstrate non-interference as a condition prior to any operation of its proposed service. Anything less is an unacceptable risk to public safety.”

    The latest signer, Senator Chuck Grassley of Iowa, writes on his website that “Given the FCC’s haste so far, I worry that LightSquared will not have interference problems resolved before given the green light to become fully operational. Farmers shouldn’t have to worry that they’re planting the correct seed or applying the precise amount of fertilizer needed for the soil to optimally produce the crop, and ambulance drivers shouldn’t have to weather taking a wrong turn or driving into a ditch because a new system is scrambling their existing navigational technology.”

    Grassley adds, “If anything, the shadows around the LightSquared project should have led the FCC to proceed with caution rather than step on the gas. Yet the opposite happened. The agency originally planned to take public comment on a key regulation necessary for green-lighting the project for only one week. The commission relented and held the comment period open longer only after consumers and affected businesses protested.”

    Defense. Congressman Mike Turner included language in the National Defense Authorization Act (NDAA) that requires the Secretary of Defense to notify Congress if he determines there is widespread interference with the military’s use of GPS caused by a commercial communications service. Turner, the House Armed Services Subcommittee chairman on Strategic Forces, has legislative jurisdiction over space and satellite systems, and included the provision in his Mark of the NDAA.

    LightSquared Interference with Emergency Services, Public Safety

    Law enforcement, emergency medical service (EMS), and fire first-responders in the state of New Mexico who participated in LightSquared/GPS interference testing at Holloman Air Force Base have submitted reports verifying a negative effect of LightSquared transmissions on their GPS equipment.
    A cover letter from the New Mexico E-911 program director states that the reports “substantiate concerns that the LightSquared network will . . . jeopardize 911 and public safety nationwide.”

    The director of emergency services for Otero County, New Mexico, writes that “during the testing process the [ambulance’s automatic vehicle location] unit was limited to only being able to see 7 satellites at any location and upon moving just 50 yards from our position at the test site towards the [LightSquared] tower were diminished to 3 or 4 satellites and at 60 yards unable to establish any satellite connections. This is still approximately 1/8 of a mile from the tower.”

    The tests were conducted on April 15 and 16 of this year at Holloman Air Force Base, in a live sky environment.

    Locata Flight Results; ICAO to Weigh for Alternative PNT

    “The Need for an Alternative PNT” was presented to the International Civil Aviation Organization’s (ICAO) 10th meeting in Montreal, Canada, on May 19 by the Australian delegation, proposing a new method for alternative position, navigation, and time (APNT). ICAO accepted the paper, and the Locata technology it describes, placing it on the table as a potential back-up to GPS. The organization will take up the discussion at its next meeting in October.

    Locata Corporation of Griffith, Australia, also released preliminary post-processing analysis on data collected during its APNT flight trial on May 9. An aircraft fitted with a Locata receiver and several truth-reference devices recorded data for three hours while flying at approximately 7,000 feet. The Locata receiver tracked a ground-based network of six LocataLites, which provided positioning signals to cover an area of approximately 1,500 square kilometers. The aircraft flew pre-defined patterns that gave varying distances to LocataLites (3–49 kilometers) during the test.

    During this trial, the Locata first acquired and tracked LocataLite signals at a range of 51.9 kilometers, according to the company, which provided an early-stage assessment of the performance of the Locata pseudorange-based (code) solution against a high-precision carrier-phase differential GPS solution. Figure 1 shows the difference in East, North, and Height between the high-precision GPS truth carrier solution and the Locata code solution. Relative to the high-precision GPS, the Locata code solution has a 95 percent RMS in horizontal of 2.1 meters and 3.2 meters in vertical. The company attributed the larger difference in the vertical to worse dilution of precision in the vertical component for this specific physical deployment of its network. Over this test data analysis, the Locata’s average VDOP of 3.3 compared to an average HDOP of 1.5.

    One test objective, the company stated, was to obtain information on the significant tropospheric effects inherent in a ground-based system over these sorts of ranges. Further detailed analysis is now underway to measure and then reduce the residual biases present in the Locata code solution. For this first-pass data analysis these biases are approximately –0.8 meters in North and –1.1 meters in height. When these residual biases are further analyzed and reduced, Locata anticipates that the 95 percent RMS code-solution accuracies will improve to better than 1 meter horizontal and 2.5 meters vertical.

    Locata emphasized that this is an early-stage analysis of first flight tests, expressly designed to provide data for a better understanding of the Locata system’s performance characteristics in ICAO-type APNT applications, and for a USAF-contracted LocataNet deployment at White Sands Missile Range that will cover more than 6,500 square kilometers. Further flight trials are planned in the near future to refine the system.

    In Q3/2011 Locata expects papers to be published on carrier-phase performance observed over multiple flights, with presentations during ION 2011 Conference in Portland, Oregon.

    Figure 1. Difference in East, North, and Height between preliminary Locata pseudorange-based solution and high-precision differential carrier-phase GPS solution.

    Indian SBAS Aloft

    The Indian Space Research Organisation successfully launched a GSAT-8 satellite, carrying a GPS-Aided Geo Augmentation Navigation (GAGAN) satellite-based augmentation system (SBAS) transponder, on May 21, aboard an Ariane-V launch vehicle, from Kourou, French Guiana. The satellite will be stationed at 55 degrees east longitude.

    Galileo Picks October 20

    The first two operational/validation satellites of the Galileo project received a launch date of October 20 of this year. Antonio Tajani, European Commission vice-president for industry and entrepreneurship, predicted that this will keep the system on track for provision of “three early services in 2014/2015 based on an initial constellation of 18 satellites.”

  • The System: Second Report by LightSquared/GPS Technical Working Group Maps Terrain, Does Not Yet Explore

    Plus: GLONASS CDMA Tracked, Third Beidou-2 Launched

    The second report from non‐governmental members of the LightSquared/GPS Technical Working Group (TWG) was filed with the Federal Communications Commission (FCC) on April 15. For those anxious to see actual results of interference/desensitization of GPS receivers by the proposed LightSquared terrestrial signal — or, conversely, absence of said results — the report does not contain any such hard news. It relates the set-up of TWG work sub-teams to test various categories of GPS devices and receivers.

    The sub-teams have identified laboratories for testing activities, developed test plans, and identified devices, receivers, and systems to be tested. Attachments to the report include current draft test plans and the current list of devices and receiver models submitted for testing by companies.

    The following sections summarize the testing laboratories and devices selected for testing by each sub-team:

    • aviation
    • cellular
    • general location/navigation
    • high precision, networks, and timing. These three sub-teams are collaborating to a large extent.
    • space-based receivers.

    The full report also includes a “high-level description of test plan” by each sub-team.

    Aviation Sub‐Team. The aviation sub‐team will rely primarily on testing, funded by the Federal Aviation Administration (FAA), that will be performed at Zeta Associates Incorporated of Fairfax, Virginia.

    Additional testing is planned by the U.S. government at White Sands Missile Range and Holloman Air Force Base, both in New Mexico, for use by the National PNT Engineering Forum (NPEF) LightSquared Working Group. These results will be considered for inclusion in the TWG Final Report by the aviation sub‐team. Presumably, this group will test military receivers, under classified categorization.

    The aviation receivers are representative of those in use today. Their selection was based mainly upon device availability (those already owned by the FAA Technical Center). They are: Canadian Marconi GLSSU 5024; Garmin 300XL; Garmin GNS 430W; Garmin GNS 480; Rockwell Collins GLU‐920 multimode receiver; Rockwell Collins GLU‐925 multimode receiver; Rockwell Collins GNLU‐930 multimode receiver; Symmetricomm timing card (used for an FAA automation system); WAAS NovAtel G‐II ground reference station; and Zyfer timing receiver (used for the WAAS ground network).

    Cellular Sub‐Team. The cellular sub‐team is in the process of engaging PC TEST, Columbia, Maryland; CETECOM, Milpitas, California; InterTek, Lexington, Kentucky; and ETS Lindgren, Cedar Park, Texas, for device testing.

    The cellular sub‐team expects to test approximately 50 different device models. The selections represent current and legacy devices and have been prioritized based on sales volumes. While it is expected that there will be some representation of data‐only devices and femtocells, the testing will focus largely on handheld devices.

    Those designated for testing are: Apple iPhone 4 (GSM and CDMA); HTC A6366; HTC ADR6200; HTC ADR63002; HTC ADR63003; HTC ADR6400L; HTC Touch Pro 2; LG Lotus Elite; LG Rumor Touch; LG VN250; LG VS740; LG VX5500; LG VX5600; LG VX8300; LG VX8360; LG VX8575; LG VX9100; LG VX9200; Motorola A855; Motorola DROID X; Motorola VA76R; Motorola W755; Nokia 6650; Nokia E71x; RIM 8330C; RIM 8530; RIM 9630; RIM 9650; RIM 9800; Samsung Moment; Samsung SCH‐U310; Samsung SCH‐U350; Samsung SCH‐U450; Samsung SCH‐U640; Samsung SCH‐U750; Samsung SGHi617; Samsung SGHi917; Sierra Wireless 250 U USG 3G/4G; and Sony Ericsson W760a.

    General Location/Navigation. This sub-team has chosen Alcatel/Lucent as its initial facility for testing. Twenty-six devices were selected based on nominations by manufacturers represented on the sub‐team, considering the percentage of the installed user base.

    They include: Garmin Forerunner 110 and 305; Garmin ETREX‐H; Garmin Dakota 20; Garmin Oregon 550; Garmin GTU 10; BI Inc. ExacuTrack One; Garmin GPS 17X; Garmin GPSMAP 441; Hemisphere Vector MV101; GM OnStar (model TBD); Garmin GVN 54; TomTom XL335; TomTom ONE 3RD Edition; TomTom GO 2505; Garmin nűvi 2X5W, 13XX, 3XX, and 37XX; Garmin GPSMAP 496; Garmin aera 5xx; Honeywell Bendix/King AV8OR; Trimble iLM2730; Trimble TVG‐850; Trimble Placer Gold; and Hemisphere Outback S3.

    High Precision-Networks-Timing. The HPN&T sub‐teams are collaborating extensively to develop joint test plans and procedures. The joint sub-teams have chosen the U.S. Navy’s NAVAIR facility for testing.

    To be tested are: Hemisphere R320; Hemisphere A320; Deere iTC; Deere SF‐3000; Deere SF‐3050; Trimble MS990; Trimble MS992; Trimble AgGPS 252, AgGPS 262, AgGPS 442, and AgGPS EZguide 500; Trimble CFX 750; Trimble FMX; Trimble GeoExplorer 3000 series GeoXH and GeoXT; Trimble GeoExplorer 6000 series GeoXH and GeoXT; Trimble Juno SB; Trimble NetR9 and NetR5; Trimble R8 GNSS; Trimble 5800; Leica SR530; Leica GX1200 Classic; Leica GX1230GG; Leica GR10; Leica Uno; Leica GS15; Topcon HiPer Ga and HiPer II; Topcon GR‐3 and GR‐5; Topcon MC‐R3; Topcon NET‐G3A; Topcon TruPath/AGI‐3; NovAtel PROPAK‐G2‐Plus; NovAtel FLEXG2‐STAR; NovAtel FLEXPAK‐G2‐V1, FLEXPAK‐G2‐V2 and FLEXPAK6; NovAtel PROPAK‐V3; NovAtel DL‐V3; Septentrio PolaRx3e; and Septentrio AsteRx3.

    Timing receivers: FEI‐Zyfer UNISync GPS/PRS; TruePosition GPS timing receiver; Symmetricom SSU 2000 (Motorola M12M); Symmetricom Time Provider 1000/1100 (Furuno GT‐8031); Symmetricom TimeSource 3500 (XR5 (Navstar/Symmetricom); Trimble Resolution T; Trimble Accutime Gold; Trimble Resolution SMT; Trimble MiniThunderbolt; NovAtel OEMStar; NovAtel OEM4; and NovAtel OEMV3.

    Space‐Based Receivers. Lab testing has been conducted at the NASA Jet Propulsion Laboratory (JPL) in California. The receivers are used by NASA for space‐based missions and high-precision science applications. The TWG agreed that these would be tested at JPL by NASA, with participation by LightSquared personnel, and the results provided to the TWG; see Appendix G

    The devices tested are current or representative of GPS receivers in use by NASA or planned for use in the near future for space and science applications: TriG (NASA Next‐generation Space Receiver) and IGOR (Space Receiver).

    NASA/JPL also tested the following high-precision receivers and shared the results with the HPT&N sub‐team: JAVAD Delta G3T (High Precision‐IGS) and Ashtech Z12 (High Precision‐IGS).

    Conclusion. For all sub-teams, analyses will consider both LightSquared’s expected transmit power of 62 dBm per channel and its maximum authorized transmit power of 72 dBm per channel.

    The WG co‐chairs will update the Commission on its progress in a subsequent report on May 16.

    The April 15 TWG report contains these appendices: Working Group Roster; List of Receivers and Devices; Aviation Test Procedure; Cellular Test Plan Draft; General Location/Navigation Test Plan Draft; High Precision/Networks/Timing Test Plans Draft; Space‐Based Receivers Test Process.

    GLONASS CDMA: New Era’s Dawn Glimpsed from Multiple Receivers

    The newest Russian satellite, launched on February 26, began transmitting its new code-division multiple-access (CDMA) signal on April 7. In a clear break from all previous GLONASS signals, which are frequency-division multiple-access (FDMA), the new signal is expressly designed to be interoperable with current and future GPS signals, and with the coming Galileo signals, all of which have a CDMA structure. Thus, a new era of GNSS, truly global navigation satellite systems, began on April 7.

    JAVAD GNSS was the first company to announce that it had tracked CDMA signals of the GLONASS-K satellite in
    the L3 GLONASS band. Data was logged at the company’s Moscow office on April 8 from 02:30 until 07:30 UTC. The satellite’s pseudorange (in chips) and signal-to-noise ratio (in relative numbers) are shown in Figures 1 and 2.

    Figure 1. GLONASS-K’s pseudorange in chips, courtesy of JAVAD GNSS. The y-axis goes from 0 to 12,000 in increments of 2,000; the x-axis goes from 0 to 500 in increments of 100. (Click to enlarge.)
    Figure 2. GLONASS-K’s signal-to-noise ratio (in relative numbers), courtesy of JAVAD GNSS. The y-axis goes from 0 to 10,000 in increments of 2,000; the x-axis goes from 0 to 500 in increments of 100. (Click to enlarge.)

    On April 11, the satellite’s code-minus-phase and signal-to-noise ratio were tracked (Figures 3 and 4). Data quality is quite similar to GPS, according to the company.

    Figure 3. GLONASS-K satellite’s code-minus-phase data (courtesy of JAVAD GNSS). (Click to enlarge.)
    Figure 4. GLONASS-K satellite’s signal-to-noise ratio (courtesy of JAVAD GNSS). (Click to enlarge.)

    Future GLONASS satellites of the K1 and subsequent K2 generations will broadcast CDMA signals in multiple frequency bands. GLONASS-K satellites are markedly different from their predecessors. They are lighter, use an unpressurized housing (similar to that of GPS satellites), have improved clock stability, and a longer, 10-year design life. There will be two versions: GLONASS-K1 will transmit a CDMA signal on a new L3 frequency, and GLONASS-K2 will in addition feature CDMA signals on L1 and L2 frequencies. The CDMA signal in the L3 band has a center frequency of 1202.025 MHz.

    The new generations of GLONASS signals and satellites are described in detail in the April “Innovation” column of GPS World, edited by Richard Langley.

    Septentrio Navigation of Leuven, Belgium, also tracked GLONASS CDMA L3 signal with its AsteRx3 receivers. Figure 5 shows the C/N0 in dB-Hz of the legacy L1-C/A signal and of the data component of the new L3 CDMA signal. The graph covers the time span starting at 20:30 (UTC) on April 10 and ending at 02:00 on April 11. Figure 6 shows the de-trended code minus phase from L1-C/A and L3 signals. Such a plot provides a glimpse of the code measurement multipath and noise, according to the company.

    Figure 5. GLONASS-K1 AsteRx3 measurements; C/N0 in dB-Hz of L1-C/A and L3 CDMA (courtesy of Septentrio Navigation).
    Figure 6. GLONASS-K1 AsteRx3 measurements; de-trended code minus phase of L1-C/A and L3 CDMA (courtesy of Septentrio Navigation).

    Topcon Positioning Systems (TPS) also released data on the new signal, stating that signals from the new satellite “provide an additional accuracy advantage over older satellites.” Figures 7 and 8 show data from the company’s Moscow office.

    Figure 7. Pseudorange-phase of four signals transmitted by the new K1 satellite (courtesy of Topcon Positioning Systems). (Click to enlarge.)
    Figure 8. Signal-to-noise ratios of four signals transmitted by the new K1 satellite (courtesy of Topcon Positioning Systems). (Click to enlarge.)

    Finally, the German Aerospace Center’s Institute of Communications and Navigation recorded the spectrum of the GLONASS CDMA signal, captured with a 25-meter dish antenna, Raisting Satellite Earth Station, near Munich.

    The signal spectrum spans at least 40 MHz (Figure 9). It contains additional sidelobes not shown in the plot. The plot indicates total power of all components of the transmitted signal.

    Figure 9. GLONASS CDMA signal’s power over frequency (courtesy of the German Space Agency, DLR).

    Third Beidou-2 IGSO Launched

    China’s BeiDou-2 (Compass) satellite launched on April 9 has attained a circularized orbit, joining two inclined geosynchronous orbit (IGSO) satellites to form a mini-constellation centered on an east longitude of about 120 degrees. While BeiDou-IGSO-3’s orbit might still be tweaked slightly, it is clear that the orbits of the three satellites are arranged so that there will always be one satellite with a high elevation angle over China, according to the CANSPACE news service operated by the University of New Brunswick.

    The latest spacecraft joins four geostationary satellites, a middle-Earth orbiting vehicle, and the two other IGSO satellites now on orbit. As the first Chinese launch in 2011, the new arrival presages much activity to come. With eight now flying, six more spacecraft are scheduled to rise by 2012, completing a 14-satellite constellation to provide a regional service over eastern Asia. The regional system will consist of five geostationary or GEO, five IGSO, and four medium-Earth orbit satellites.

    Long-range plans envision a 35-satellite constellation providing global service by 2020: 27 MEOs, 5 GEO satellites, and 3 IGSOs. The satellites will transmit signals on the 1195.14–1219.14 MHz, 1256.52–1280.52 MHz, 1559.05–1563.15 MHz, and 1587.69-1591.79 MHz carrier frequencies.

    Compass satellites have an announced lifespan of eight years.

    Three IGSO satellite tracks over China (image courtesy of CANSPACE).

     

  • The System: First GPS Intereference Report Sent to FCC

    First Overload Interference/Desensitization to GPS Receivers, Systems, and Networks Report to FCC

    The joint working group co-led by the U.S. GPS Industry Council and Lightsquared, investigating potential problems of LightSquared/GPS interference, delivered its first monthly report on March 15 as directed by the FCC. The report (PDF) lays out a schedule for receiver selection and testing and names 34 members, two working group co-chairs, and four information facilitators of a technical working group (TWG) supervising and analyzing the assessment of GNSS receivers operating under conditions of a dense national network of high-powered cell-phone transmitters. “TWG members represent a diverse group of interested parties including equipment and chipset manufacturers, aerospace/aviation companies, wireless providers, engineering firms, public safety, and various federal agencies. Additionally, several individuals have volunteered to be advisors to the TWG,” said the report.

    The TWG held its first meeting on March 3 in Arlington, Virginia, and via a conference bridge for members around the globe who were unable to attend in person. In that and subsequent teleconferences, the TWG focused on the first seven items from the Work Plan:

    Establish pertinent analytical and test methodologies and assumptions underlying the test regime: definition of harmful interference, relevant information regarding terrestrial broadband network, interference analysis assumptions, and evaluation of potential test methodologies.

    • Select categories of receivers and receivers to be tested.
    • Develop operational scenarios.
    • Establish methodology for analyzing test results.
    • Derive test conditions based on the established operational scenarios.
    • Write test plan and procedures.
    • Identify and engage appropriate test facilities.

    LightSquared provided technical details to the TWG regarding the equipment planned for its terrestrial broadband deployment, including the channelization plan, output power, out-of-band emission (OOBE) characteristics, and emissions mask.

    The GPS community is concerned that desensitization/overload due to strong signals outside of the GPS band may cause GPS receivers to operate in a non-linear mode with reduced gain (that is, gain compression) for the desired GPS signal. Other receiver impairments may also arise as a result of the nearby strong signals.

    The TWG has agreed to move forward with a combination of laboratory-based and field-based testing programs. Field testing will be performed at outdoor test locations using transmitters, filters, and antennas similar to those that LightSquared plans to deploy in its commercial operations.

    Other items of interest in the report:

    Definition of Harmful interference at the GPS/GNSS/Augmentations/L-Band Receiver. “The TWG members have discussed a number of receiver parameters related to the definition of harmful interference. In the FCC Rules, harmful interference is defined as ‘interference which endangers the functioning of a radionavigation service or of other safety services or seriously degrades, obstructs, or repeatedly interrupts a radiocommunication service operating in accordance with [the ITU ] Radio Regulations.’

    “Harmful interference affects different types of receivers in different ways. The key factors that pertain to the functioning of GPS receivers and/or whether service is degraded, obstructed, or interrupted are accuracy (position, velocity, time), availability (ability to perform a given function), coverage (within what space can a function be performed), integrity (what is the probability that the results are correct), and continuity (what is the probability that a given function can be completed). Metrics for harmful interference are developed from an understanding of the consequential relationship between negative impacts and receiver parameters, which include effective C/N0, PVT accuracy, time to first fix, loss of lock, cycle slips, etc. The signal conditions to be taken into account are defined in the GPS Standard Positioning Service (SPS) Performance Standard, 4th Edition, Interface Specifications (ISs), GPS policy, and both the present and planned future signal environments will be considered.Environmental and field conditions in which GPS receivers operate will also be considered.

    “It should be possible to assess interference impact, up to that which includes harmful interference, using metrics in terms of receiver parameters that include measurable changes in effective C/N0 as well as position accuracy, time to first fix, loss of lock, cycle slips, etc. Related to this discussion is whether there is any margin that could be budgeted for terrestrial broadband operation, and if so, what that amount could be. When considering systems guaranteed for safety-of-life operations, there may be very little or no margin.

    “There is general agreement within the TWG that the device testing protocols should include changes in effective C/N0 and degradation of other key performance measures so as not to exclude data that might be relevant for the post-testing analytical phase using operational scenarios.

    Overload interference/desensitization at the GPS/GNSS/Augmentations/L-band Receiver. “Desensitization/overload due to strong signals outside of the GPS band may cause the GPS receiver to operate in a non-linear mode with reduced gain (i.e., gain compression) for the desired GPS signal; there may also be other receiver impairments caused by strong signals outside the GPS band. The TWG will consider these mechanisms further after testing is underway and sufficient samples are available to adequately assess such mechanisms.”

    Evaluation of Potential Test Methodologies. “The TWG has agreed to move forward with a combination of laboratory-based and field-based testing programs. Laboratory tests are repeatable, allow for the creation of a fully controlled environment and the ability to test multiple scenarios and many devices in an efficient, repetitive manner. Field tests expose devices to a real-world environment where measurements can be performed at various distances and morphologies from terrestrial broadband network sites in order to gauge the effects of distance and physical environments on terrestrial broadband signal strength and potential interference. One advantage of field testing is that it captures a complete, live test environment comprehensively and helps develop keener testing or analysis insights that modeling cannot offer. The major disadvantage or concern is that field testing uses the present environment, not the environment that might exist at some future or past time. Interference testing analysis has to consider worse-case assumptions, and not only the current test reality.

    “Laboratory testing will be performed either using conducted testing, where devices are connected directly to transmission sources via 50 ohm connectors, or through radiated testing in anechoic or other radiated emissions chambers. While conducted testing is the preferred laboratory methodology, anechoic chambers will be used where conducted testing is not practical, is not recommended by the manufacturer, or where connectorized devices cannot be made available within the established test timeline.

    “Field testing will be performed at outdoor test locations that will utilize transmitters, filters, and antennas similar to those that will be deployed by Lig
    htSquared in its commercial operations.”

    The TWG identified seven categories of receivers that it considers representative of non-military GPS user equipment operating in the United States: aviation, cellular, general location/navigation, high precison, timing, space-based receivers, and networks.

    Seven sub-teams are focusing on these receiver categories. The sub-teams are responsible for determining device selection and prioritization criteria, defining operational scenarios, listing testing conditions and test plan procedures, and recommending appropriate test facilities.

    Save Our GPS Coalition Forms

    Representatives from a variety of industries and companies have formed the Coalition to Save Our GPS to resolve what it terms a serious threat to the national positioning, navigation, and timing service: the FCC conditional waiver to Lightsquared allowing expansion of terrestrial use of the satellite spectrum immediately neighboring that of GPS, potentially causing severe interference to millions of GPS receivers.

    “GPS is essential to Americans every day — it’s in our cars, the airplanes in which we fly and the ambulances, police cars, and fire trucks that help keep us safe. It’s also used in many industrial applications and even synchronizes our wireless, computer, and utility networks,” the group stated. “LightSquared’s plans to build up to 40,000 ground stations transmitting radio signals one billion times more powerful than GPS signals as received on earth could mean 40,000 ‘dead spots’ — each miles in diameter — disrupting the vitally important services GPS provides.”

    The Coalition (www.SaveOurGPS.org) includes representatives from aviation, agriculture, transportation, construction, engineering, surveying, and GPS-based equipment manufacturers and service providers.

    Initial members of the coalition are the Aeronautical Repair Stations Association, Air Transport Association, Aircraft Owners and Pilots Association, American Association of State Highway and Transportation Officials, American Rental Association, Associated Equipment Distributors, Association of Equipment Manufacturers, Case New Holland, Caterpillar Inc., Edison Electric Institute, Esri, Garmin, General Aviation Manufacturers Association, Deere & Company, National Association of Manufacturers, OmniSTAR, and Trimble. More members are expected to join in the near future.

    The following is from a statement issued by the coalition:

    “[In] The unusual waiver granted in January to LightSquared by the FCC . . . the usual FCC process of conducting extensive testing followed by approvals was not followed. Instead, the process was approve first, then test. Additional safeguards are needed, so the coalition recommends:

    “The FCC must make clear, and the NTIA must ensure, that LightSquared’s license modification is contingent on the outcome of the mandated study. The study must be comprehensive, objective, and based on correct assumptions about existing GPS uses rather than theoretical possibilities.

    “The FCC should make clear that LightSquared and their investors should not proceed to make any investment in operating facilities prior to a final FCC decision (or at least make it explicit that they do so at their own risk). While this is the FCC’s established policy, it failed to make this explicit in its order.

    “Further, the FCC’s, and NTIA’s, finding that ‘harmful interference concerns have been resolved’ must mean ‘resolved to the satisfaction of preexisting GPS providers and users.’ Resolution of interference has to be the obligation of LightSquared, not the extensive GPS user community of millions of citizens. LightSquared must bear the costs of preventing interference of any kind resulting from operations on LightSquared’s frequencies.

    “This is a matter of critical national interest. There must be a reasonable opportunity for public comment of at least 45 days on the report produced by the working group.”

    WAAS Official Again

    The Federal Aviation Administration (FAA) announced on March 18 that WAAS PRN 135 has resumed normal operations. “The WAAS team recently received the final report from Lockheed Martin on the failure of Galaxy 15,” reported FAA GNSS program manager Leo Eldredge. “After a review of that report, the team determined that the satellite was ready to be returned to operations.”

    The FAA said that PRN 135 is currently located at ~120°W and enroute to its final destination of 133.1°W, but is now broadcasting operational corrections that can be used by both aviation and ground users, including those in Northwest Alaska.

    In April 2010, satellite operator Intelsat reported it had lost contact with PRN 135 (named Galaxy 15) and it was drifting uncontrolled. At that time, the FAA reported that it would drift out of WAAS service within a few weeks. Instead, PRN 135 remained within a usable condition/location, although drifting east, until December 2010, when it ceased operating. On December 23, Intelsat reported that the power from the Galaxy 15 battery completely drained during its loss of Earth lock and the baseband equipment command unit reset, as it was designed to do. Shortly thereafter Galaxy 15 began accepting commands, and Intelsat engineers began receiving telemetry in the operations center.

    Intelsat determined that static electricity charge caused the initial failure, and has uploaded new software to prevent the event from occurring again. There are now three operational WAAS GEO satellites:

    ◾ PRN 133 located at 98°W.

    ◾ PRN 135 located at 133.1°W (currently at ~120°W); will arrive at 133.1°W on or about April 4, 2011.

    ◾ PRN 138 located at 107.3°W.

    EGNOS SOL Operational

    The European Geostationary Navigation Overlay Service (EGNOS) was declared operational for safety-of-life (SOL) services on March 2. The service consists of GPS corrected signals intended for transport applications, particularly aviation, where lives could be endangered if the performance of the navigation system is degraded.

    The SOL coverage area, expected performances, and conditions of use are described in the EGNOS Safety-Of-Life Service Definition Document (SDD, see env-gpsworld-integration.kinsta.cloud/egnosSOL). The two operational EGNOS satellites — Inmarsat-3-F2/AOR-E at 15.5 degrees west longitude using PRN code 120, and Artemis at 21.5 degrees east longitude using PRN code 124 — now transmit Message Type 2, indicating that the signals are available for safety-critical purposes.

    Air-navigation service providers can now publish SBAS precision approach procedures, localizer performance with vertical guidance (LPV), based on EGNOS. On March 22, EGNOS operator European Satellite Services Provider published the first EGNOS LPV approaches for use at Pau Airport, near the Pyrénées in southern France.

    EGNOS improves accuracy and provides integrity to the GPS signal over most of Europe and parts of North Africa. The system uses a monitoring network of 40 ground stations to provide the corrections with 99.9 percent availability over the core service region. Accuracy is measured by GPS user equivalent range error typically about 4.2 meters after EGNOS corrections for GPS signals from satellites at a 5-degree elevation, and 2.4 meters for satellite signals arriving from a 90-degree elevation. If reliability falls below a minimum level, EGNOS users are alerted within six seconds.

    Russian SBAS Satellite Passes Transponder Tests

    The Luch-5A geostationary communication satellite under construction has successfully completed a cycle of transponder tests. The satellite includes a transponder for the System for Differential Correction and Monitoring (SDCM), the Russian satellite-based augmentation system. SDCM will provide integrity monitoring of
    GPS and GLONASS satellites and differential corrections and analyses of GLONASS performance: real-time differential corrections with horizontal accuracy of 1–1.5 meters, vertical of 2–3 meters.

  • The System: Test Data Predicts Disastrous GPS Jamming by FCC-Authorized Broadcaster

    Representatives of the GPS industry presented to members of the Federal Communications Commission (FCC) laboratory evidence of interference with the GPS signal by a proposed new broadcaster on January 19 of this year. The meeting and subsequent filing did not dissuade FCC International Bureau Chief Mindel De La Torre from authorizing Lightquared to proceed with ancillary terrestrial component operations, installing up to 40,000 high-power transmitters close to the GPS frequency, across the United States.

    The document describing the testing states that the Lightsquared initiative “will have a severe impact on the GPS band” and “will create a disastrous interference problem for GPS receiver operation to the point where GPS receivers will cease to operate (complete loss of fix) when in the vicinity of these transmitters.”

    On January 26, the FCC waived its own rules and granted permission for the potential interferer to broadcast in the L Band 1 (1525 MHz–1559 MHz) from powerful land-based transmitters. This band lies adjacent to the band (1559–1610 MHz) where GPS and other GNSSs operate.

    The FCC called for further testing to be led by LightSquared and completed by June 15.

    Prior to the decision, representatives of the U.S. GPS Industry Council and GPS manufacturers Garmin and Trimble presented “Experimental Evidence of Wide Area GPS Jamming That Will Result from LightSquared’s Proposal to Convert Portions of L Band 1 to High Power Terrestrial Broadband,” to five members of the FCC’s Office of Engineering and Technology, including its chief, two members of the FCC International Bureau, one from the Public Safety and Homeland Security Bureau, and two from the Wireless Telecommunications Bureau.

    A full PDF of “Experimental Evidence of Wide Area GPS Jamming” is available.

    The document conveys results of testing on a common portable consumer automotive navigation device and on a common general aviation receiver. The consumer GPS device began to be jammed at a power level representing a distance of 3.6 miles (5.8 kilometers) from the simulated LightSquared transmitter. The consumer device lost a fix at 0.66 miles (1.1 kilometers) from the transmitter.

    The Federal Aviation Administration (FAA)-certified aviation receiver began to be jammed at a distance of 13.8 miles (22.1 kilometers) and experienced total loss of fix at 5.6 miles (9.0 kilometers) from the transmitter.

    During the laboratory testing, GPS signals were simulated by a Spirent GSS6560 GPS simulator, representing a constellation of 31 GPS satellites, the current configuration. LightSquared’s signal was simulated using a Rhode and Schwartz SMIQ-03S signal generator with digital modulation, amplified to achieve the relevant signal strengths. Full technical specifications and parameters are described in the Experimental Evidence document linked above.

    The industry report concludes: “The proposed LightSquared plan . . .  will deny GPS service over vast areas of the United States.”
    In its decision document on January 26, the FCC not only authorized LightSquared to proceed, it turned up its nose at assertions that the entire process had been conducted in near-stealth mode as well as on an accelerated track.

    LightSquared was established in mid-2010 by “an experienced team of global telecommunications executives and investors.” From 2001 to 2005, Lightsquared executive vice president Jeff Carlisle served as deputy chief and then chief of the FCC’s Wireline Competition Bureau.

    See also “Act Now to Protect GPS Signal.”

    and

    “The FCC’s Decision on LightSquared: High-Precision Users Would Be Affected Most.”

    Galileo’s GATE Opened

    The Galileo Test and Development Environment (GATE) in Berchtesgaden, Germany, officially opened on February 4. The system operator, IFEN GmbH of Poing, Germany, jointly with the German Federal Minister of Transport, Building and Urban Development, announced the opening for use by commercial and organizational entities seeking to test equipment with the coming Galileo signals. GATE was developed on behalf of the German Aerospace Center (DLR) with funding by the German Federal Ministry of Economics and Technology.

    The test area extends across a valley of approximately 65 square kilometers, southeast of Munich, where antennae atop surrounding peaks broadcast the various Galileo signals. Technical details and specifications of the test environment are at www.gate-testbed.com.

    The GATE infrastructure is capable of transmitting the Galileo Open Service, the Safety-of-Life Service (functional, with certification as a next step), the Commercial Service, and a Public Regulated Service  dummy signal.

    The GATE system upgrade has been further extended to also support user integrity testing, simulating simple alarm-triggering events on the system/satellite level, supporting GPS and GATE/Galileo dual-constellation receiver-autonomous integrity monitoring (RAIM), individual user integrity test scenarios, and tests of receivers with different RAIM functionalities.

    Next-Generation GLONASS

    As this magazine goes to press, a Soyuz rocket carring a new GLONASS-K1 satellite has moved to the Plesetsk Cosmodrome launch pad for a scheduled blast-off on February 24. Assuming all goes well, the satellite’s eventual transmissions will include Russia’s new CDMA signal on a GLONASS L3 frequency. Further information and photos will be posted to env-gpsworld-integration.kinsta.cloud/glonassk.

    In Other Developments. Roscosmos, the Russian space agency, said it lost contact with a military satellite launched on February 1, a painful incident following the failed launch of three GLONASS-M satellites in December.

    The Geo-IK-2 satellite, designed for geodetic studies, remains in its transfer orbit because the upper stage failed to restart for its second circularizing burn. Based on the GLONASS-M bus, Geo-IK-2 carries laser reflectors, GPS/GLONASS receiving equipment, and an altimeter. Communications with the satellite have been re-established but it is not clear how useful it will be in its current orbit.

    Galileo IOV August Launch

    The European Space Agency announced that the first two Galileo in-orbit validation (IOV) satellites will rise on August 31. They will ride aboard a Soyuz-ST-B rocket from the Kouros, French Guiana, Space Center. There was no word about the third and fourth IOV satellites, which had at one point been scheduled for an October launch, at a time when the first two were penciled for a June launch.

    JAVAD Receivers Track Compass B1 Signal

    JAVAD GNSS has announced that, with modified firmware, all of the company’s receivers can now track the Chinese Compass B1 signal. The company states that Compass is the sixth GNSS system that its receivers can track, joining GPS, GLONASS, Galileo (the two GIOVE in-orbit validation experimental satellites), SBAS (the European Geostationary Navigation Overlay Service or EGNOS), and Japan’s Quasi-Zenith Satellite System (QZSS).

    JAVAD GNSS made available several plots, shown here. One is a log file, collected on JAVAD’s TR_G3TH board in Moscow during the last weekend in January, reporting up to 26 satellites from the various systems, locked simultaneously. Also provided below are several other plots showing the new capability.

    The company further stated that it will add Compass tracking to almost all receivers in near future, as a firmware upgrade.

  • GLONASS K-1 Launch Delayed Twice, Rescheduled for Tomorrow

     


    GLONASS-K is moved to the launchpad.

    News courtesy of CANSPACE listserv.

    According to a Roscosmos report, the state commission governing rocket launches will launch GLONASS-K1 on February 26 at 03:06 UTC. The launch of GLONASS-K1 has been pushed back for “technical reasons.” The original schedule called for a February 24 launch.

    Quoting the commander of the Russian Space Forces, Lieutenant-General Oleg Ostapenko, an Interfax news item stated that there was insufficient time to ready the rocket for launch february 25, though it was announced as a launch date following the scrub on February 25. “The probability of a launch on the 26th is very high,” Ostapenko said.

    Meanwhile, Komsomolskaya Pravda quoted an unnamed space industry official as saying that if the launch is not held tomorrow, it will be put off for a month. “[The decision will be] once again to be safe, rather than to carry out the launch, which for technical reasons, was postponed for the second day in a row. Without further checks, and to eliminate technical problems, no one [wants to] take responsibility to conduct the launch,” he said.

    Gazeta.ru, an online Russian newspaper, has carried a report in which Nikolai Testoedov, the chief designer and CEO of Information Satellite Systems Reshetnev states that seven GLONASS satellites will be launched this year. In addition to GLONASS-K satellites being launched this month and in December, five GLONASS-M satellites will be launched. Three will be launched on a Proton-M rocket from Baikonur (this launch is expected in June). He said that, in addition, two GLONASS-M satellites will be launched on the Soyuz-2 rocket from Plesetsk. The first of the five GLONASS-M satellites is to be delivered to the customer on February 28.

  • The System: FCC Asked to Authorize Potential Interferer

    In November, December, and January, a regulatory drama with high potential impact on the GPS signal and domestic U.S. GPS users began unfolding before the Federal Communications Commission (FCC). As this magazine goes to press on January 24, the issue remains far from resolved, although hearings and far-reaching decisions may have transpired by mid-February.

    A company called LightSquared applied to the FCC in late November for modification of its authority for ancillary terrestrial component (ATC). It asked the FCC to grant it permission to broadcast a co-primary terrestrial wireless service in the L-band frequencies typically reserved for space systems and radionavigation satellite services. Lightsquared wants to broadcast in those frequencies, not only from space but from powerful terrestrial transmitters that could effectively overload the GPS signal for millions of users in metropolitan areas across the United States. LightSquared asked the FCC to fast-track its request.

    The National Telecommunications and Information Administration (NTIA) has expressed its concern that LightSquared’s proposal to sell wholesale terrestrial-only services could interfere with navigation and E-911 systems. NTIA is concerned that terrestrial-based devices operating in the mobile satellite services band could interfere with GPS timing receivers, aeronautical communications, and the Inmarsat mobile satellite service used by the Department of Defense.

    Write to Congress. Members of the GPS community who are concerned by the proposal may contact their Congressional representatives, to advocate for a fully independent technical study by the NTIA before the FCC takes any action. Contact information and appropriate case file numbers are given at env-gpsworld-integration.kinsta.cloud/fcc.

    The FCC may have decided not to follow the Administrative Procedures Act, which directs it to consider a waiver request under an open and transparent rule-making, so that all affected parties may comment. It appears that the FCC could grant a waiver to LightSquared for a terrestrial wireless broadband service, but condition the service going operational on interference studies. Lightsquared has proposed that such studies be conducted under its own direction.

    Voices within the GPS community have asked for an independent, third-party, unbiased technical analysis to precede a fact-based rule-making, rather than a study organized and led by the interested party.

    LightSquared previously received authorization to build a hybrid network using satellite and terrestrial-based communications. The waiver would allow its wholesale customers to offer terrestrial-only services. The company’s buildout is scheduled to include a 40,000-cell-site terrestrial network deployed by Nokia Siemens Networks that will cover around 90 percent of the population of the United States.

    The trade publication RCR Wireless reported that Lightsquared may have run short of funds. “The company has raised about $2 billion to date. Reuters is reporting that Harbinger Capital Partners, which is funding LightSquared, has let some employees go as it attempts to right-size the company. The Harbinger fund now is valued at about $7 billion, a steep drop from the $26 billion it once counted.” The finding may shed light on why Lightsquared sought fast-track approval over winter holidays.

    24+3 GPS Configuration

    The U.S. Air Force 50th Space Wing announced completion of phase one of the two-phase GPS constellation expansion called Expandable 24, also known informally as 24+3, to increase global coverage and provide users with more robust satellite availability.
    Phase one concluded when the last of three satellites that began repositioning maneuvers in January, 2010, completed its journey on January 18. Phase two, a repositioning of three more satellites, started in August 2010 and is expected to end in June of this year. At that time, the GPS constellation will attain the most optimal geometry in its 42-year history, maximizing GPS coverage for all users.

    GPS IIF-2. The second satellite of the next generation, GPS IIF-2, received a launch date of June 23 from Cape Canaveral, Florida.

    EC: $1 Trillion in Europe Depends on GPS

    The European Commission (EC) presented its mid-term review on the development of Galileo and the European Geostationary Navigation Overlay Service (EGNOS). The report reiterates previous statements that Galileo will deliver initial services in 2014 — despite outside and unofficial speculation that the date may slip to 2015. The report also estimates that 6–7 percent of the gross domestic product (GDP) of developed countries in Europe, an amount that equals €800 billion ($1 trillion U.S.) depends on satellite navigation; that is, on GPS, for the time being.

    A December editorial in this magazine hypothesized that, on that basis, roughly $3 trillion of the global economy depends on GPS.

    Costs Rising. An EC message to the European Parliament and European Council served notice that reaching full operational capability for Galileo will cost €1.9 billion more than the €3.4 billion already allocated. The EC foresees an average annual expense of €800 million to operate Galileo and EGNOS.

    The administrative body for the European government issued one of its strongest statement yet as to the value of the satnav systems, however. “The ultimate objectives are not being called into question.” EC Vice President Antonio Tajani added, “We are satisfied with the progress made so far and committed to bringing this project to fruition.” The EC indicated its willingness to find alternative methods of financing the project.

    Check-up. Meanwhile, the first in-orbit validation (IOV) satellite goes through readiness testing at the European Space Agency’s technical center in the Netherlands. Four identical Galileo IOV satellites are in preparation, and the first to be completed has been selected for qualification testing, as the Protoflight Model (PFM). Satellite payloads were designed, developed, and assembled by EADS Astrium in Portsmouth, UK, with the overall satellite designed and developed by Astrium in Ottobrunn, Germany, and assembled by Thales Alenia Space in Rome, Italy.

    The PFM will endure simulated launch vibrations on an electrodynamic shaker, followed by sudden shocks simulating those during separation from the launch vehicle. Finally, it will take an acoustic battering matching the launcher’s sound pressure and frequency. The Galileo IOV satellites will be launched two at a time; a dispenser will hold them together within the launcher fairing and eventually release them in orbit. Pyrotechnic devices will shoot them safely away from the dispenser and each other.
    Once ESTEC testing is complete in February, the PFM will be reunited with the rest of the IOV quartet in Italy for a follow-up round of thermal vacuum testing, to prove that they can withstand the temperature extremes of space. Finally, the satellites will travel to Europe’s spaceport in Kourou, French Guiana in South America, to be launched on Russian Soyuz rockets.

    Pictured: Galileo protoflight model runs through its test paces at ESA.

    Michibiki Produces 3-Centimeter Accuracy

    According to a report in the Japanese business daily Nikkei, researchers in Japan conducted a test that yielded continuous 3-centimeter positioning accuracy for a car driving at 20 kilometers (approximately 12 miles) per hour, using a conventional GPS receiver equipped to receive corrections from the new QZSS satellite Michibiki. The authors imply that, unaided, the same equipment would have produced accuracy in the range of about 10 meters.

    The report also states that the Japan Aerospace Exporation Agency (JAXA) and Mitsubishi, who have partnered to develop and launch the Quasi-Zenith Satellite System (QZSS), have conducted further tests shown that the augmentation system maintains its accuracy with cars driving up to 80 kilometers (48 miles) per hour.

    QZSS’s current Michibiki satellite can cover Japan for eight hours a day; two additional satellites, planned for the future, will join it to provide continuous coverage and GPS corrections over mainland Japan and parts of Australia.

    As a commenter from the United States pointed out, “There’s nothing new about 3-centimeter GPS accuracy. The surveying, construction, and agriculture industries have been using 2–5 centimeter level real-time kinematic GPS technology for well over a decade. Post-processing can get GPS accuracy down to the millimeter level and measure tectonic plate movements. By the way, Michibiki (aka QZSS) does not work without GPS. The United States helped Japan build QZSS.”

    Nonetheless, if the tests used a conventional, consumer-grade GPS receiver, the results are indeed impressive. The availability that a full QZSS constellation will bring — the explicit goal of the project — in Japan’s skyscraper-dominated urban landscape should enable many heretofore impractical or impossible projects in car navigation, construction, tracking and monitoring, and location-based services.

     

    Shelton Space Commander

    Gen. William L. Shelton assumed command of Air Force Space Command (AFSPC) on January 5. Shelton replaces Gen. C. Robert Kehler, who will take over at the U.S. Strategic Command.

    Shelton has served in various assignments, including research and development testing, and space operations. As commander of AFSPC, he is responsible for organizing, equipping, training, and maintaining mission-ready space and cyberspace forces and capabilities for North American Aerospace Defense Command, U.S. Strategic Command, and other combatant commands around the world. Shelton also oversees Air Force network operations; manages a global network of satellite command and control, communications, missile warning and space launch facilities; and is responsible for space system development and acquisition. AFSPC is comprised of more than 46,000 professionals, assigned to 88 locations worldwide and deployed to an additional 35 global sites.

     

    Des Dorides for European GNSS Supervisory Agency

    Carlo des Dorides of Italy will head the European GNSS Agency, formerly known as the European GNSS Supervisory Authority (GSA). The Czech Republic’s Transport Ministry joined the European Commission (EC) in making the announcement. The GSA will gradually move its headquarters to Prague over the next two years.

    “The election of the Italian candidate is unambiguously good news for both the Czech Republic and Galileo itself,” said Karel Dobes, the Czech government envoy for the Galileo system. “His idea of the future shape of the agency rests in a stronger and greater agenda than nowadays, which would provide greater opportunity for our firms to get lucrative orders. It is a business with the highest value added, thanks to which local firms and the whole Czech Republic may get billions of crowns in the future.”

    Des Dorides was profiled by GPS World magazine as one of the 50 Leaders to Watch in GNSS in 2006. At that time he was head of the Concession Division of the Galileo Joint Undertaking, the GSA’s predecessor.

     

    GLONASS Goes for 
Ten-Year Plan

    The GLONASS plan for 2011–2020 is ready and now undergoing the final stages of approval, Sergey Revnivykh, Deputy Director General of the Central Research Institute of Machine Building of the Federal Space Agency, told a Russian business newspaper.

    “In March–April, the program will be presented to the government. I can say that the amount [of funding] is sufficient to meet the prospective demands of consumers and ensure parity with other navigation systems. During the program period, 2012-2020, GLONASS, in [terms of its] parameters will not yield to the planned development of the GPS and Galileo systems.”

    According to Revnivykh, by 2019 the GLONASS constellation will consist entirely of new-generation GLONASS-K satellites. In addition to existing FDMA signals, they will transmit CDMA signals in the format of CDMA (the same format as GPS and Galileo) and their service lifetime will increase to 10 years. Flight testing of a GLONASS-K prototype, originally scheduled for December 27, was postponed to a later date, to be determined in early February.

    Two prominent executives associated with GLONASS were dismissed, and the program came under increased scrutiny after a launch disaster drowned three new satelites in the Pacific Ocean.

  • The System: GLONASS Blows Itself off Course

    Surplus fuel loaded in error onboard the launch rocket caused loss of three new GLONASS satellites on December 5. The mishap burdened the DM-3 booster rocket with an excess of 1.5 to 2 tons of fuel, causing it to deviate from its course after blast-off and dive into the Pacific Ocean instead of reaching orbit altitude — dashing hopes for an imminent, nearly full global operational GLONASS capability.

    “The problem was not with the fuel service unit at the launching site, but with one of the sensors showing the fuel level,” said Gennady Raikunov, the head of the Central Scientific Research Institute of Machine Building. “We do not rule out the factor of human error,” he said, adding that the Russian corporation Energia may be linked to the incident.

    News correspondent Peter de Selding, writing in the December 10 issue of Space News, reported that a new version of the Block DM upper rocket stage, which was used for the GLONASS launch, features larger propellant tanks than earlier versions. The DM stage is built by RSC Energia of Korolev, Russia.

    “In what appears to have been a remarkable oversight,” de Selding wrote, “the personnel fueling the Block DM stage for the GLONASS launch did not account for the larger tanks. That led to loading between 1,000 and 2,000 kilograms more propellant on the Block DM stage than what had been planned for the mission. As a result of the excess propellant, the Proton’s third stage, suffering from the additional weight it was carrying, underperformed, placing the Block DM stage and the stack of GLONASS satellites into a lower-than-planned suborbital drop-off point.”

    Get Back on That Horse. On December 12, the next-generation GLONASS-K1 satellite, serial number 11, was shipped to the Plesetsk Cosmodrome about 800 kilometers north of Moscow. According to manufacturer ISS Reshetnev, the satellite will transmit five navigation signals: two signals of normal and two of high precision in the L1 and L2 frequency bands, and a new code-division multiple-access (CDMA) civil signal in the L3 band (1205 MHz). The last is destined to shift the Russian constellation at least partly towards CDMA signal broadcast, in line with GPS and Galileo. It points towards possible and eventual interoperability of some kind between the systems.

    Launch is scheduled for December 27 or 28 on a modernized Soyuz-2.1.b rocket equipped with a Fregat upper stage.

    March FOC Vowed. Anatoly Perminov, the head of Roscosmos, the Russian Federal Space Agency, has stated that the setback is temporary and he plans to have a full 24-satellite constellation functioning by next March. He plans to accomplish this by repositioning one of the satellites now in maintenance and then bringing it back on line and by launching two more satellites over the next few months.

    Galileo Supervisory Authority enroute to Prague

    The Czech Republic has after an intensive multi-year lobbying effort landed a Galileo plum: the siting of the European GNSS Supervisory Authority (GSA) headquarters in its capital. The GSA has for the past three years worked out of Brussels, and longer prior to that, under the title Galileo Joint Undertaking.
    An official with the GSA told GPS World informally, “I can confirm: the decision has been adopted today by the Competiveness Council. However the move might not be immediate. The Commission claimed (rightly) to be involved in the timing of the move to minimize disruption, to ensure continuation of the ongoing work, and to avoid the disruption of the progress towards the FOC of Galileo. The financial repercussions must also be assessed.”

    In an interview on Czech television, Czech Prime Minister Petr Necas called the decision a success for the entire country. “This is very good news because this will bring the most advanced technologies to the Czech Republic and, accordingly, one of most technologically advanced systems in the European Union will be controlled from here, from the Czech Republic,” he said.

    Necas’ statement was not entirely accurate, as the GSA does not actually control any technology. The Galileo constellation of current (two) and future (from four to 18) satellites remains firmly in the control of the European Space Agency (ESA), administratively based in Paris with many technical activities undertaken in Noordwijk, the Netherlands, and further under the thumb of the European Commission (EC), irrevocably grounded in Brussels.
    Upcoming tasks faced by the GSA include most importantly the commercialization of Galileo — which may be seen as largely a marketing activity — and security accreditation and the operation of the Galileo security center.

    Several countries vied to host the agency, and in the final days Prague was competing against Noordwijk itself for the post. The siting of the GSA outside the EU’s Western European core represents a nod to its pledge to include newer Eastern members in governing activities, specifically to give preference to new member states when looking for headquarters for its new agencies. Before the vote, the Czech Republic was one of four member states that joined the EU in 2004 that had not yet been chosen to host an EU agency or body.

    The X-37B, debriefing after its 220-day experimental mission.

    Unmanned Spacecraft Returns Home

    The U.S. Air Force’s first unmanned re-entry spacecraft landed at Vandenberg Air Force Base on December 3, after a 220-day maiden voyage, conducting on-orbit experiments. The X-37B, named Orbital Test Vehicle 1 (OTV-1), is a totally autonomous vehicle that depends a great deal upon GPS for
    mission success.

    GPS provided a significant contribution to the X-37B’s re-entry and landing — the first unmanned spacecraft that landed like an aircraft. It fired its orbital maneuver engine in low-Earth orbit to perform an autonomous reentry before landing.

    The Air Force’s newest and most advanced re-entry spacecraft, X-37B performs risk reduction, experimentation, and concept of operations development for reusable space vehicle technologies.

    The Air Force is preparing to launch the next X-37B, OTV-2, in spring 2011 aboard an Atlas V booster.

    Overall, the program “has huge implications for the future of unmanned space flight and for the capabilities of the USAF and DoD missions in space. The GPS is a key component of this capability.”

    “To go much farther,” an informed source told GPS World, “gets me into territory that I cannot discuss in this venue.”

  • The System: QZSS Puts L1C on the Air

    QZSS Puts L1C on the Air

    JAVAD Receivers Track the First Truly Interoperable Signal

    JAVAD GNSS engineers in Moscow have released plots of the C/A, L2C, L5, SAIF, and the new L1C signals broadcast by Japan’s QZSS Michibiki, the first satellite to transmit L1C.

    The company stated that all of its current GNSS receivers can track QZSS signals with a software update that is available as an option to purchase.

    A new civil signal, L1C is designed to be interoperable among GNSSs. Currently, agreements are in place between the U.S. GPS, Europe’s Galileo, and Japan’s QZSS systems regarding broadcast and use of L1C. The U.S. system is not destined to add the L1C signal until the GPS III block of satellites, still more than three years out.

    The SAIF (Submeter-class Augmentation with Integrity Function) signal is a GPS augmentation with information on positioning correction and system health. The QZSS L1-C/A, L2C, L5, and L1C signals are GPS augmentation signals that can be operated reciprocally with positioning signals provided by GPS. The figures supplied by JAVAD GNSS show SNR (top) and code-minus-phase (bottom) plots for L1C.

     

    Plot of QZSS L1C signal, SNR.

    Plot of QZSS L1C signal, code minus phase (above).


    EC’s Galileo Manager Discusses Progress, Interoperability

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

    The full conversation is available here. Here are a few extracted quotes:

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

    Challenges. “It is time that Galileo delivers something concrete. We’ve had many years of discussion behind us on whether the system will come, and if it will come, and how it will come, and what it will look like, and all the rest. For my part, I’m very happy to see that in 2011, we plan to launch.

    The first four satellites are on the way; they are almost ready. About half the ground infrastructure is currently under implementation, we have every couple of months the opening of another ground station around the world. With this, the system becomes a reality, and I think once the satellite launches will go across television screens in the whole world, people will see that the system is becoming a reality. And I think that is desperately needed in order to give it a sense that things are moving forward. I’m really looking forward to that. That is a piece of good progress we have achieved over the last couple of years.

    Constellation. “There is a bit of a discussion for some reason in Europe, for some reason some people seem to think that we could do away with 18 satellites. Well, from me you will hear a solid ‘No.’

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

    Click here for the full discussion, spanning many topics.

    GPS Control Upgrade

    The U.S. Air Force 2nd Space Operations Squadron is scheduled to release the next software upgrade for the GPS ground system in early December, as part of an ongoing effort to improve and maintain the GPS Operational Control Segment before the next-generation GPS Control Segment is deployed in 2015. The upgrade is expected to be completed in early January 2011. The upgrade does not change the navigation message and should be transparent to GPS users. Tests have shown that the navigation message produced by the new software is identical to that produced by the current ground software. While no anomalies are expected, civilians experiencing any anomalies should contact the Coast Guard Navigation Center at (703) 313-5900.

    GLONASS Launch Fails

    The Russian Federal Space Agency announced that the December 5 launch of three GLONASS-M satellites ended in failure when the Proton-M rocket’s Block DM upper stage and its three payloads crashed into the Pacific Ocean about 1,500 kilometers (932 miles) northwest of Honolulu. Although an investigation will look into the exact cause of the failure, early unconfirmed reports indicate a software error. According to the Russian News Agency RIA Novosti, incorrect calculations were loaded into the rocket’s onboard computers.

    Compass Settles, Moves

    The Beidou/Compass G4 satellite launched on October 31 achieved geostationary orbit by November 6. The satellite is positioned at about 160 degrees east longitude. G4 is the furthest east of the operational Beidou geostationary satellites. Meanwhile, the orbital location of the Beidou 1A satellite has been changed.

    On or about October 27, as indicated by NORAD tracking data, the satellite underwent a significant delta-V, raising its orbit by about 200 kilometers. Its orbit had been slightly drifting for a few weeks before the maneuver, and there was speculation that the satellite had been placed in a disposal or graveyard orbit. However, on November 24 a second delta-V was observed that returned the satellite to the geostationary belt.

    The two maneuvers placed the satellite at a new location at about 60 degrees east longitude — the furthest west of any of the Beidou satellites. The satellite may eventually end up at 58.75 degrees east, one of the Beidou orbital slots registered with the International Telecommunication Union.

    The geostationary satellite, the first for the demonstration regional Beidou system or Beidou-1, was launched on October 30, 2000, and positioned at 140 degrees east longitude. Following several years of use, there were unofficial reports that the satellite was no longer functional. However, station-keeping was maintained, implying some usefulness of the satellite. It remains unclear how functional the satellite is and whether it is still useful for the Beidou-1 demonstration system.

  • The System: Galileo PRS Delivery in Question

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

    Space, Ground Work Package Signed

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

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

    Money Trouble

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

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

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

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

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

    Space Agency Acts on Security, IP Concerns

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

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

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

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

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

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

    SatNav Briefs

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

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

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

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

  • The System: GLONASS Forecast Bright and Plentiful

    At the Civil GPS Service Interface Committee meeting in Portland, Oregon, on September 20, Sergey Revnivykh, Deputy Director General of Roscosmos’s Central Research Institute of Machine Building, reported on the status and future of GLONASS.

    He provided a number of details on the present constellation and how it will be augmented in the future, stressing that GLONASS is doing well and that a full constellation of 24 primary satellites will be in operation within months. The average signal-in-space range error has improved by a factor of five in the past three years and presently stands at about 1.8 meters (one sigma).

    Figure 1. The GLONASS satellite generations through GLONASS-K2.
    Figure 1. The GLONASS satellite generations through GLONASS-K2.
     

    The present constellation consists of 20 healthy satellites with two reserve satellites, GLONASS 714 and 726. Revnivykh stated that GLONASS 726 had a failure of its navigation payload. It is known that the signal generator on the satellite is faulty and it had been set unhealthy since August 31, 2009. Nevertheless, it was placed in reserve status on March 19, 2010. GLONASS 714 is nominally healthy and could be brought back to service if needed. These initial reserve satellites are also being used to train the ground team to operate spare satellites in a full or nearly full constellation.

    GLONASS 727, in orbital slot 3, which was taken out of service on September 8, has also had a failure of its navigation payload and may not be returning to service. The three new satellites launched on September 2 are expected to enter service in early October. About 11 more GLONASS-M satellites will be launched by the end of 2012.

    Revnivykh announced that there will be two versions of the new GLONASS-K satellites: GLONASS-K1 and GLONASS-K2. GLONASS-K1 satellites will have a 10-year design life and a daily clock stability of 5 x 10-14.

    The first GLONASS-K1 satellite will be launched this December from the Plesetsk Cosmodrome about 800 kilometers north of Moscow. This will be the first launch of a GLONASS satellite from other than the Baikonur Cosmodrome. Only one more GLONASS-K1 satellite will be built and launched after that. The K1 satellites will test an open service CDMA signal on the GLONASS L3 frequency in the 1205 MHz band. Although the launch of the first GLONASS-K1 satellite will occur in December, the design process for the CDMA signal structure is not yet finished, according to a subsequent e-mail message from Dr. Revnivykh. When the process is completed, the structure will be made public.

    A completely new design, GLONASS-K2, will start launching in 2013. GLONASS-K2 satellites will have a 10-year design life and a daily clock stability of 1 3 10-14. Besides the CDMA signals on L3, CDMA signals will also be transmitted on L1 and L2. The GLONASS-K satellites will transmit the legacy FDMA satellites in addition to the CDMA signals.

    A modernized GLONASS-K satellite, GLONASS-KM, for launch after 2015, is now under study. In addition to transmitting legacy FDMA signals on L1 and L2 and CDMA signals on L1, L2, and L3, CDMA signals may also be transmitted on the GPS L5 frequency at 1176.45 MHz. Also being studied is an alternative to the present three-plane, equally spaced satellite constellation. A different constellation design would be possible using CDMA signals. Such a move would require that the legacy FDMA signals be switched off. Revnivykh stated that any such move would require at least 10 years’ advance notice.

    The signals that will be transmitted by the future generations of GLONASS satellites as well as those transmitted by the initial GLONASS satellites and the GLONASS-M satellites now on orbit are shown in Figure 2.

     
    Figure 2. Signals transmitted by the different generations of GLONASS satellites. OF 5 open-access FDMA, SF 5 special (military) FDMA, OC 5 open-access CDMA, OCM 5 open-access CDMA modernized.
    Figure 2. Signals transmitted by the different generations of GLONASS satellites. OF 5 open-access FDMA, SF 5 special (military) FDMA, OC 5 open-access CDMA, OCM 5 open-access CDMA modernized.

    Revnivykh also spoke on the satellite-based augmentation system under development, System for Differential Correction and Monitoring (SDCM). Correction and integrity data will be transmitted by Luch geostationary communication satellites now under development. Luch 5A, to be launched in 2011 and positioned at 16°W longitude, and Luch 5B, to be launched in 2012 and positioned at 95°E longitude, will transmit signals on an L1 frequency. Luch 4, to be launched in 2013 and positioned at 167°E longitude, will transmit on two frequencies. The three satellites will provide almost global coverage. The satellite payloads are under development.

    According to Revnivykh, the SDCM will make use of 12 monitor stations currently in operation in Russia and one in Antarctica at Russia’s Bellingshausen research station. However, the SDCM website indicates only 10 Russian stations currently in the test network. This anomaly might be explained by the fact that some locations have multiple monitor stations. Eight more monitor stations will be added in Russia and five more outside Russia. Revnivykh showed a map revealing the locations of the additional overseas stations as Cuba, Brazil, Vietnam, Australia, and an additional station in Antarctica. It is not intended, at least initially, that these stations would be used in generating the orbit and clock data broadcast by the GLONASS satellites themselves.

    Finally, Revnivykh stated that a GLONASS performance document will be released in the 2012–2013 time frame. His full presentation is available on the U.S. Coast Guard Navigation Center website (www.navcen.uscg.gov).
    Meanwhile, the three GLONASS-M satellites launched on September 2 have arrived at their designated orbital slots: GLONASS 736, plane 2, slot 9; 737, plane 2, slot 12; 738, plane 2, slot 16.

    The operating frequencies are not yet fully known. GLONASS 736, in physical slot 09, is currently undergoing experimental tests. It is included in the broadcast almanac at slot 16 and is transmitting on frequency channel -6. Stations in the International GNSS Service ground network are tracking the satellite. According to the Roscosmos Information-Analytical Centre, when the tests are completed, GLONASS 736 will transmit on channel -2 and be identified as slot 09 in the almanac. It is unclear if GLONASS 736 will replace GLONASS 722 also currently in slot 9, with the latter becoming a spare, or if GLONASS 736 will become the spare as previously inferred.

    GLONASS 737 and 738 have not started normal transmissions. Their assigned shared frequency channel is not yet known but -6 would be a likely candidate.

    Future GPS Control Segment Advances

    The Raytheon Company team developing the next-generation GPS Advanced Control Segment (OCX) successfully completed on schedule an integrated baseline review with the U.S. Air Force.

    When completed, GPS OCX will deliver a control segment designed to provide secure, accurate, and reliable navigation and timing information to military, commercial, and civil users. Raytheon is the prime contractor on the $886 million program. The team includes ITT, The Boeing Company, Infinity Systems Engineering, Braxton Technologies, and NASA’s Jet Propulsion Laboratory.

    Power Flex Positive

    From September 7 to 12, the U.S. Air Force Space Command (AFSPC) activated the long-awaited Flex Power demonstration for GPS, a power increase on L1 and L2. The trial of a new capability designed for military use under special circumstances was deemed a success, essentially going off without a hitch, according to Colonel David Buckman, AFSPC Command Lead for PNT, and Colonel Bernie Gruber, GPS Wing Commander.

    Officially, the flex power assessment ensured that the GPS control segment baseline (AEP 5.5) is properly integrated with the space segment with regard to command and control of High-Y Flex Power, a capability that increases the nominal transmit power of the desired signal by shifting power between signals (M-code and P(Y)) within a particular L-band. The net sum gain remains the same. High-Y Flex Power does not change total transmit power, does not affect phase stability between L1 and L2, is ICD-GPS-200E compliant, and does not affect the navigation message.

    Only a handful of 10-year-old reference receivers may have been adversely affected, possibly due to an outdated algorithm. Many government, commercial, and civil agencies were involved in the test, and hundreds of GPS receivers were closely monitored. As far as impacts to the overwhelming majority of global users, it was a non-event. The 2nd Space Operations Squadron (2SOPS) was able, over the course of five days, to make power changes to several GPS satellites without causing a phase shift and without the majority of users even knowing what was happening, although various announcements and press releases had appeared to alert them of the fact.

    All GPS satellites and signals have now returned to their normal power levels.

    Air Force Fends off GAO Zinger

    The U.S. Government Accountability Office has issued a follow-up to its alarming and much-criticized report, issued 16  months ago, on the health and prospects of the GPS constellation. Senior officers at the Air Force Space Command and Space and Missile Systems Center have characterized the new report as “overly pessimistic.”

    The report’s principal findings ­— that the Air Force continues to face challenges in launching its satellites as scheduled, which could affect the availability of the baseline GPS constellation, that on-orbit performance of IIF satellites remains uncertain, that a disconnect exists between GPS III and OCX, and that a predicted possible delay in GPS III could affect GPS constellation performance — are discussed and rebutted in detail by GPS World defense editor Don Jewell, with further commentary (paraphrased) by Air Force Space Command, in his October column.

    New Galileo ICD Embraced

    European Commission (EC) officials held a briefing during ION-GNSS in Portland for industry representatives, to discuss the new Galileo Open Service Signal-in-Space Interface Control Document (OS SIS ICD). Hosts Paul Verhoef and Michel Bosco said they were pleased with what they characterized as positive feedback from U.S., European, and Japanese industry representatives regarding collaboration and consultation over changes made in the ICD. The updated version is available.

    The EC grants free access to the technical information on the future Galileo open service signal: the specifications manufacturers and developers need to process data received from satellites. Anyone who wishes to use the intellectual property rights contained in the document simply needs to send an e-mail to [email protected] mentioning their request for a license agreement, which is without any exclusivity or geographic limitation.

    FAA Green-Lights ADS-B

    The U.S. Federal Aviation Administration (FAA) gave the go-ahead signal for full-scale, nationwide deployment of the satellite-based surveillance system called Automatic Dependent Surveillance – Broadcast (ADS-B) following its successful roll-out at four key sites. Air traffic controllers are now able to use the new technology to separate aircraft in areas with ADS-B coverage. Controller screens in those areas will show aircraft tracked by radar as well as aircraft equipped with ADS-B avionics, which broadcast their positions.

    The new system tracks aircraft with greater accuracy, integrity, and reliability than the current radar-based system, the FAA said. ADS-B targets on controller screens update more frequently than radar and display information including aircraft type, call sign, heading, altitude, and speed.

    Nationwide ADS-B coverage is scheduled to be complete in 2013. According to the FAA, every part of the country now covered by radar will have ADS-B coverage. More than 300 of the approximate 800 ADS-B ground stations that will comprise the entire network have been installed.

    By 2020, aircraft flying in controlled airspace in the U.S. must be equipped with ADS-B avionics that broadcast their position.

  • The System: Michibiki Takes Up Station and Other GNSS Constellation Updates

    The System: Michibiki Takes Up Station and Other GNSS Constellation Updates

    As this issue goes to press in late August, the first Japan Aerospace Exploration Agency Quasi-Zenith Satellite System (QZSS) space
    vehicle, nicknamed Michibiki, holds steady for a September 11 launch.

    QZSS will use multiple satellites in inclined orbits, placed so that one satellite always appears near zenith above Japan, well known for its high-rise cities. The design provides high-accuracy satellite positioning service covering almost all of the country, including urban canyons and mountainous terrain.

    QZSS Phase One will validate technological enhancement of GPS availability, performance, and application. Phase Two will demonstrate full system capability using three QZSS satellites, including Michibiki.

    The satellites will generate and transmit their own signals, compatible with modernized GPS signals. QZSS also transmits GPS corrections and availability data.

    Michibiki Profile. Dual-box shape with wing-type solar-array paddles; overall dimensions, 2.9 x 3.1 x 6.2 meters, paddles extending 25.3 meters; weight approximately 4,000 kilograms; altitude approximately 32,000–40,000 kilometers; inclination approximately 40 degrees;
    period, 23 hours 56 minutes.

    Compass. In early August, the first Beidou/Compass inclined geosynchronous orbit (IGSO) satellite achieved near-geosynchronous orbit. The mean east longitude of the sub-satellite ground point is currently 117 degrees, 19 minutes (see figure 1). This is one of the first, if not the first, satellite to use such a highly inclined circular geosynchronous orbit.

    QZSS-orbits
    Figure 1. Left, the orbit path of three QZSS satellites will eventually keep at least one of them directly over Japan at all times. Right, the inclined geosynchronous orbit of the fifth Compass satellite, launched in July, has a similar ground track and mission goal.

    Multi-GNSS Campaign. An international collaboration is poised to take advantage of a coming proliferation of satellites, led by Compass and QZSS but also including GPS, GLONASS, and Galileo, over the Asia/Pacific region. The website www.multignss.asia/campaign.html states, “The Asia and Oceania region is a unique place where the number of usable modernized navigation satellites will increase much faster than other areas in the world. We will see great improvement of PNT capability and hence there is a great opportunity to try, test, and validate new receiver hardware, algorithms, and applications in order to address user requirements.”

    The web page also carries an animation of the availability of more than 100 GNSS space vehicles that will operate over the region in the next decade. An initial campaign workshop in Bangkok, Thailand, in January drew 195 participants from 18 countries. A second workshop is scheduled for November 21–22 in Melbourne, Australia.

    GLONASS September. Three GLONASS-M satellites to be launched on September 2 completed pre-launch testing and mating to the upper stage of the booster rocket at Baikonur Cosmodrome. Numbered 36, 37, and 38, the satellites will constitute the Block 42 triad.

    GPS III Design: Done. The Lockheed Martin team developing GPS III has successfully completed the program’s Critical Design Review (CDR) phase, two months ahead of baseline schedule. CDR completion validates the detailed GPS III design to ensure it meets warfighter and civil requirements. It culminates many rigorous assembly, subsystem, element, space vehicle and system-level CDR events, validates the overall design maturity of the GPS III space vehicle, and allows Lockheed Martin to enter production phase. Col. Bernard J. Gruber, U.S. Air Force GPS Wing Commander, certified the completion. Lockheed Martin, ITT, and General Dynamics are working under a $3 billion development and production contract for up to 12 GPS IIIA satellites. The team is on track to launch the first GPS IIIA satellite in 2014.

    GPS Interface Specs. New IS-GPS-200E, IS-GPS-705A, and IS-GPS-800A documents have been posted to www.gps.gov/technical.
    SVN62 Rubidium Clock. The U.S. Naval Research Laboratory issued a preliminary report on the rubidium atomic clock currently in use on the SVN62 Block IIF satellite. While documenting excellent short-term performance, the report notes anomalous fluctuations in the clock signal with distinct 12-hour and 6-hour periodicities. The exact cause has not been identified although it is speculated that the fluctuations are of thermal origin like SVN-62’s L5 phase variance detected earlier. But note that the clock signal analysis relies only on L1 and L2 measurements.

    GPS IIF Got Active. The 50th Space Wing’s 2nd Space Operations Squadron formally took over command and control of the first Block IIF satellite on August 26 from the GPS Wing, and the satellite was set healthy on August 27, making 31 healthy GPS satellites on orbit.

    Advisory Board Update
    GPS World Editorial Advisory Board member Art Gower has been elected a Lockheed Martin Fellow, an honor recognizing pre-eminent technical individual contributors in the company, delivering mission success and vision by undertaking the most difficult technical challenges facing the company and its customers. Art started his career with IBM Federal Systems Division (now part of Lockheed Martin Integrated Systems and Global Solutions) in 1983, developing displays and performing navigation upload and command and control system engineering for the GPS control segment, and becoming chief engineer for the GPS control segment in 1990. He has spent the majority of his career working on GPS, GNSS, and SBAS systems.