GPS World

Tag: LightSquared

  • Out in Front: The Daughter of Time

    “Truth,” wrote Sir Francis Bacon, “is the daughter of time.”

    He meant that any account, repeated often enough by different people in different places, at different junctures, eventually becomes accepted as historical fact, or truth, by those with no direct knowledge of the matter.

    That’s why it is so important to repudiate and expose lies at every encounter. Never, ever let one pass. Even when it’s the same one that you dispelled yesterday — or thought you had taken care of. One thing about liars, they keep coming back. They don’t give up.

    Would you give up, if you had $20 billion at stake?

    I wrote an online column on this topic recently: “LightSquared, FCC Rebuttals Distort Record.” These distortions were so blandly crafted that they were picked up and passed on by a number of other parties who should have known better, including at least one colleague of the press who writes for a wireless industry publication.

    Come to think of it, you do have $20 billion at stake — and much more. We all do. To the tune of more than $67.6 billion in direct economic benefits in the United States alone, provided by GPS. Or $96 billion per year in direct economic costs should GPS be disrupted. See the System news in this issue, “The Economics of Disruption,” for what you stand to lose.

    If you think the recent amendment to the 2012 Budget, cutting off FCC funds in this matter, should settle LightSquared hash, think again. The company is back with a new solution. Same as the old solution. Just with the pieces moved around. And it has taken its game up a notch, signaling intent to apply to the International Telecommunication Union for authority to broadcast powerful terrestrial signals all over the world.

    All over the world. Calculate the costs of that. For our international readers, this may mean trouble for GLONASS and Galileo too.

    Written to your congresspeople about this? Bravo if you have. Write again. They are not tired of hearing from you. There’s a lot they don’t know, that you do, particularly if you read the news accounts here and online. Forward links freely; they are information-laden and they are there for you to use.

    Not written to anyone yet? The headline of this column also served as the title of a novel by Josephine Tey, concerning Richard III, King of England. You know the evil hunchback murderer of Shakespeare’s play? We recall him as such because someone (his rival Henry VII) was particularly adept at lying and getting others, including Shakespeare, to repeat the lie — with none to dispute.

    GPS could become a forgotten hunchback of history. Act now.

  • 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.

  • Letters to the Editor: LightSquared Satellite Case Skimpy

    LightSquared Satellite Case Skimpy

    Thank you for the story “LightSquared, FCC Rebuttals Distort Record.” One thing worth clarifying: you state, “It appears that the purpose of Lightsquared’s satellite service is, now, to provide ancillary service in remote areas not covered by the ubiquitous primary terrestrial network, or in the event that the terrestrial network is destroyed — exactly the opposite of what the FCC authorized and the GPS industry had understood and agreed to.”

    But even this can’t work unless they are going to limit the number of subscribers in remote areas. A 4G user will expect decent wireless data throughput, but the subscriber’s connection is shared with other users within a spotbeam covering a large area. All connections must fit within the bandwidth of the single beam.

    Cell networks get around this problem by frequency re-use, possible since each cell covers a small geographic region. The key characteristic of a cellular network is the ability to re-use frequencies to increase both coverage and capacity.

    Admittedly, the LightSquared satellite, SkyTerra-1, is a very sophisticated space vehicle with a record 500 spotbeams. However, it provides a maximum user data rate of 300–400 Kbps, quite a bit short of what you would expect from a 4G-LTE connection. And at 400 Kbps, a 20-MHz spotbeam could still support only 50 to 100 connections.

    Another problem with using the satellite link is that although they have managed to solve the problem of requiring a special user handset, the user will still have to be outdoors and in the open to communicate with the satellite. And it is a geostationary satellite, which means high latency — at least 1/4 second. Using this for voice would create user annoyance.

    LightSquared should stop using the word “ancillary” and stop pretending that their network has a significant satellite component. It is going to have to be all ground-based if they are to provide 4G connectivity. It’s really starting to sound like the satellite is just a way for LightSquared to meet their FCC requirement.

    — Mike Whitehead
    VP Technology, Hemisphere GPS
    [Ed: citations and some discussion ommitted for space; available on request.]

    On Eric Gakstatter’s Survey columns:

    Keep up the good work. I find your e-newsletter columns the best way to stay informed [on the LightSquared issue].

    — editor, survey magazine

    Sounding Off

    When someone comes onto the basketball court with a hockey stick, the referees should not negotiate rule changes. Anything that allows LSQ to proceed either on the high or low ends of their allocated spectrum will in the long run be a blow to PNT users and suppliers worldwide. While this may very well end up as a compromise to the detriment of us all, now is not the time to concede any ground. He who flinches, loses, and this is not the time for engineers to give ground. It will set a precedent that lawyers will use again to decimate the spectrum in the future.

    —Informed particpant

  • Expert Advice: Critical Offshore Applications of SBAS GNSS

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    James D. Litton, President/CEO, Litton Consulting Group

    Precise positioning of many different kinds of vessels and other equipment depend upon satellite-based augmentation systems (SBAS) of GNSS, principally GPS and GLONASS at this time. The applications range from exploration to production and delivery of hydrocarbons to shore-based installations and navigation of very large crude carriers, or oil tankers. Decisions and recommendations are strongly needed to keep these services free from interference.

    It is fallacious to think that because LightSquared or similar use of out-of-band high-power terrestrial radiation would be confined to a continental region (physically impossible, in any case), that no harm would accrue to offshore navigation assets. The three principal suppliers of these offshore precise positioning services are Fugro’s Starfix services, C&C Technology’s C-Nav which utilizes John Deere/NavCom’s StarFire systems, and Subsea 7’s Veripos system.

    All of these systems depend upon GNSS reference receivers placed around the world in networks which depend upon corrections that are derived from regionally sited reference stations. The 10-centimeter level of precision now required for many of the most dangerous and valuable applications requires, in turn, centimeter-level accuracy in base stations in the United States and elsewhere in the world.

    Inmarsat frequencies allocated to these applications for delivery of the differential corrections generated by these reference stations have been in use for both the huge number of land applications (agriculture, infrastructure development, river and harbor navigation, seismic exploration, pipeline surveys, etc) and offshore applications. Changing these frequencies is feasible only at great cost to both Inmarsat and the many on- and offshore uses. Inmarsat may be compensated by LightSquared for its costs, but not so the many millions of dollars of expense to offshore and onshore operators in down time, redesign and reprogramming of receivers, and suspension of critical operations.

    The offshore applications outlined here are just a few of the more familiar. No attempt has been made to capture all of these applications in this short memorandum, but operators in this industry, represented by the National Ocean Industries Association (NOIA), have made their position clear in the attached letter to the FCC.

    Major Offshore Applications

    Exploration. Modern seismic exploration depends upon seismic streamers many kilometers long. Several such streamers (containing thousands of hydrophones for capturing reflections from deep beneath the ocean floor and determining the structure and composition of the strata which may contain hydrocarbons) are towed by each ship. The seismic profiles which result are depicted in three dimensions with great precision. Discovery and assessment of such strata depend sensitively upon the positioning accuracy of these streamers, which, in turn, depend sensitively on the position of the vessel with respect to the center of the earth, because the vessel’s trajectory is the reference for the relative positioning of the streamers by magnetic and inertial means, sometimes augmented by GNSS receivers integrated into the seismic streamers.

    Drilling. Increasingly, drill rigs and drill ships are placed and maintained in position by dynamic positioning systems that depend upon augmented GNSS systems for stabilizing the massive structures over the well head. In deep water (more than 5,000 feet), only dynamic positioning through the use of massive thrusters (such as those employed by the Deepwater Horizon vessel of Transocean in the Macondo well disaster, commonly referred to as the BP disaster) is feasible. With as much as 10,000 feet of riser attached to these drill ships between the well head and the ship, safe operation is critically dependent upon very precise positioning of the vessel. Further, down-hole positioning depends upon inertial and wireline systems, which are calibrated by the use of augmented GNSS systems.

    Production. Production platforms range from single sites over a single well to massive platforms with undersea pipelines and risers connecting them to manifolds on the sea floor, which in turn are connected to multiple well heads in an area. This infrastructure is placed, maintained, and monitored with the use of SBAS systems integrated with acoustic systems. Use of remotely operated vehicles and autonomous underwater vessels or vehicles, submarines equipped with sensors that can image and manipulate underwater structures, for these purposes is prevalent.

    Station Keeping. Supply vessels, crew vessels, special-purpose vessels, and helicopters are positioned relative to the drill rig, seismic vessel, production platform, and pipeline-laying vessel by SBAS systems fused with other sensors such as lasers and microwave distance-measuring equipment. A huge drill ship, for instance, moving about in response to ocean dynamics but centered on the well head, cannot be docked to a supply vessel solely with ropes and cables. Each vessel must be free to move but to move synchronously with each other. Because of the huge masses involved, the velocity of each relative to the other must be kept as near zero as possible. Centimeter-level precision is required for this purpose. In all of the applications listed above, at various stages, vessels require station keeping with other vessels to very precise relative distances and velocities.

    Containment and Recovery. When there is a requirement for a flotilla of vessels such as attended the Macondo blow-out event, there are as many as a hundred large and small vessels in a relatively small area, with the need for central control (by the U.S. Coast Gaurd in this case) and collision-avoidance systems. These systems also depend upon having precise GNSS, mostly using SBAS systems.

    Further application details and additional critical applications can be provided upon request.

    Jim Litton is the President of the Litton Consulting Group, Inc. (LCG).  His GPS-related experience includes being the Chief Engineer at Magnavox during the GPS phase I development, contributing to analysis of ionospheric effects and senior vice-president and general manager of the Magnavox Commercial GPS Division before forming the Litton Consulting Group in 1992. He co-founded NavCom Technology in 1994.  He holds the Hays award from the ION for 1996 and is co-inventor on a codeless GPS receiver patent.   

  • Expert Advice: Energy Production Concerns about LightSquared

    RandallLuthi_W
    Randall Luthi, President, National Ocean Industries Association

    By Randall Luthi, President, National Ocean Industries Association

    To: Mr. Julius Genachowski,
    Chairman, Federal Communications Commission
    Ref: LightSquared, Inc.,
    L-Band allocations impacting GPS FCC File No. SAT-MOD-20101 1 IS-00239

    Dear Chairman Genachowski:

    The National Ocean Industries Association (NOIA), which represents approximately 270 member companies involved in outer continental shelf (OCS) energy production throughout the United States, is gravely concerned over the pending allocation of Mobile Satellite Services (MSS) spectrum to LightSquared, Inc. for terrestrial high-powered transmissions. LightSquared’s proposed transmission structure will adversely impact GPS and Inmarsat signals along our coastlines, both of which are critical to marine operations. Specifically, NOIA is concerned that:

    1. Coastal and near shore GPS operations will be impacted even at (promised) reduced LightSquared power levels. While NOIA understands that LightSquared will be required to reduce its tower transmission power along the coastline, their reduced power transmissions will still be many orders of magnitude greater than GPS signals, virtually guaranteeing interference for users in coastal and near-shore areas.

    2. GPS receiver types used by NOIA members will be impacted substantially. NOIA members primarily use high-precision GPS receivers for their high-accuracy coastal and near shore work. High-accuracy GPS receivers require a wide-band front end, which will be seriously impacted by LightSquared transmissions.

    3. Inmarsat-linked DGPS corrections will have interference. Virtually all of the high-accuracy GPS work requires the use of differential GPS corrections transmitted by Inmarsat in “L” band. These corrections will be jammed by the LightSquared signal. Implications are, for example, dredging or excavation work in areas near buried high-pressure natural gas pipelines. This work will become much more dangerous due to inaccurate, intermittent, or unreliable GPS readings.

    4. Offshore oil and gas operations will be impacted because of interference on land. LightSquared interference from their 40,000 proposed transmission sites across the nation will interfere with dozens of high-accuracy DGPS reference stations used to generate differential corrections for offshore use and high-accuracy operations on shore. Because of this land-based interference with high-accuracy GPS reference stations, hundreds and possibly thousands of coastal users will be impacted. High-accuracy differential GPS corrections are used by a wide cross-section of marine users including dynamically positioned drilling rigs, pipeline construction vessels, rig supply vessels and others. Loss of GPS corrections or erroneous differential GPS corrections due to shore-based interference can cause a floating drilling rig to deviate from station resulting in catastrophic blowouts, environmental damage, and fatalities.

    5. LightSquared will cause interference with Inmarsat. NOIA understands that LightSquared has paid Inmarsat, and will continue to pay Inmarsat a fee, to “endure the pain” caused by the interference. However, Inmarsat’s customers, including virtually all NOIA members, will still be required to endure the pain. Isotropic Inmarsat antennas will be impacted the most. NOIA understands that Inmarsat plans to move user frequencies at their cost. However, NOIA cannot be assured that this solution is viable given the financial drivers LightSquared is offering Inmarsat; it is not reasonable to assume that Inmarsat can compensate thousands of users for the costs of making the changes, even if the equivalent frequencies and powers are available.

    6. NOIA is concerned that the FCC was premature in its decision to issue a waiver to LightSquared. Unlike the FCC’s historic test-then-approve, NOIA is concerned that the FCC has fast-tracked the effort and has improperly and unnecessarily implemented an approve-then-test procedure for this applicant. NOIA is concerned that the FCC may have directed findings of the professional staff in its decision making.

    7. NOIA believes that millions of land and airborne GPS and DGPS user groups will be severely impacted by LightSquared transmissions. In conclusion, NOIA and its 270 member companies are extremely concerned that high-end GPS, DGPS, and the associated GPS reference stations will be interfered by LightSquared transmissions in the band previously protected for the very low power signals typical of satellite communications. The real-time GPS positioning needs of NOIA member companies are critical to the safety and success of their operations, and although these operations are at-sea they are totally dependent on shore-based GPS reference receivers, therefore LightSquared’s land-based operations will affect the offshore regions as well. With the marine industry’s giant assets including very specialized 2 vessels of all types completely dependent on GPS, the safety and environmental implications of GPS interference is astronomical. NOIA is concerned that other specialized Inmarsat installation members will also be disrupted.

    Finally, NOIA believes that the FCC is moving too quickly and needs to step back and make its decisions based on sound science, understanding that national wireless coverage is being pursued with all deliberate speed by several knowledgeable industrial groups that have paid for the value received from their frequency allocations. It does not need this asymmetric and competition-reducing spectrum grab by a group without the years of experience and trust of those who are building the infrastructure to accomplish the very laudable outcome that is ostensibly LightSquared’s motivation.

  • LightSquared Goes Global; GLONASS, Galileo May Be at Risk, Too

    Recent events, some of them summarized here, may appear to have dealt setbacks to LightSquared, the boundless opportunist of wireless broadband that just happens to interfere with GPS. But the company has not run out of moves yet. Would you, if you had $20 billion at stake? The latest gambit, led by lawyers and cloaked in jargon, appears to be an end-run around the U.S. government to appeal to the International Telecommunications Union, which has ultimate and international authority over spectrum. Watch out, GLONASS and Galileo — and U.S. troops operating in foreign theaters.

    GPS World has received copies of three “fact sheets” authored by two lawyers and a strategic consultant. The documents are addressed to ITU-R WP 4C, the International Telecommunications Union Working Party that handles mobile satellite services (MSS) and radio determination satellite service (RDSS spectrum) and orbits. One document is titled “ Compatibility between Complimentary Ground Componenet in the 1525–1559 Mhz and 1626.5–1660.5 Mhz Bands and Other Service.” All three documents appear to be cover sheets for longer treatises, and their language and citations are not entirely clear to me, as my legal and regulatory background leaves something to be desired.

    However, they announce their purpose as “to modify and refine the example methodology to calculate aeronautical mobile satellite (route) service spectrum requirements,” and “to address ongoing Integrated Mobile Satellite Service Complimentary Ground Component compatibility matters,” and finally “to update the Integrated Mobile Satellite Service Complimentary Ground Component technical characteristics based upon the most recent information regarding CGC deployment plans in this frequency band.”

    One source familiar with the documents, who did not wish to be named, commented that “One should interpret what LightSquared is doing with ITU as a bellwether indication of intent to use the whole band at the full authorized power, no matter how they spin ‘protect GPS’ in their press releases. 



    “At first blush, the filings look innocuous; let me assure you, they are not. This is the first salvo. Watch what they do, much more than what they say.

    

“These are fact sheets intended to inform the U.S. government that LightSquared intends to develop papers with the intent to get the U.S. government to approve the papers to be sent to the ITU WP-4C, the Working Party that handles MSS and RDSS spectrum & orbits. The ultimate goal is to work internationally to allow LightSquared to allow ancillary terrestrial component (ATC) broadcast globally.”

    The three so-called fact sheets are appended here.

    In other developments, going now in reverse chronological order, from most recent to early June:

    Congressional Activity

    On June 23, the U.S. House of RepresentativesAppropriations Committee approved the fiscal year 2012 Financial Services and General Government Appropriations bill. One amendment to the bill prohibits funding for the Federal Communications Commission (FCC) to remove conditions on or permit certain commercial broadband operations until the FCC has resolved concerns of harmful interference by these operations on GPS devices. The amendment was adopted on a voice vote. More details here.

    Previously, 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.

    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.

    Money Talks

    A report on “The Economic Benefits of Commercial GPS Use in the United States and the Costs of Potential Disruption” was presented by during a June 21 webinar sponsored by the Coalition to Save Our GPS.  The report estimates that “the direct economic benefits of GPS technology on commercial GPS users are . . .  over $67.6 billion per year in the United States,” but also that ““the direct economic costs of full GPS disruption to commercial GPS users and GPS manufacturers are estimated to be $96 billion per year in the United States.”

    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.

    “This comes out of the blue, without the knowledge, agreement or consensus of the industry group studying the problem,” riposted the Coalition to Save Our GPS. “That may well be because virtually nothing has actually changed in this “new” proposal relative to what LIghtSquared pledged at the outset of testing. The power levels don’t change. Nor do the frequencies. In fact, the only thing that has changed is the order in which the channels within the band adjacent to GPS would be deployed.

    “LightSquared’s announced “solution” has two components:

    “1. LightSquared acknowledges that “[e]arly test results indicated that one of LightSquared’s 10MHz blocks of frequencies poses interference to many GPS receivers.” LightSquared states that for “the next several years” it would not operate in this band – which is directly adjacent to GPS spectrum and is referred to as the “upper MSS band.” During this period, LightSquared would commence operations in a second 10 MHz block of the MSS band , referred to as the “lower MSS band,” slightly further away from GPS.

    “2. According to the proposal ‘LightSquared will modify its FCC license to reduce the maximum authorized power of its base-station transmitters by over 50 percent. This action will limit LightSquared to the power it was authorized to use in 2005.’

    “This so-called solution is not a solution in any shape, form or fashion,” continues the Coalition. “This is not a move to an alternative frequency band. Nor is it a reduction in power relative to what has been tested from the beginning. The “solution” would cause massive disruption to many critical U.S. economic sectors, initially including public sector users of high precision GPS, later followed – af
    ter “the next several years” — by other GPS users. The only real solution to the LightSquared interference problem is to move out of the MSS band altogether."

    Click here for the full document, “New ‘Solution’ Is a Non-Starter.”

    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.”

    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.”

    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.

    For further commentary in this vein, see LightSquared, FCC Rebuttals Distort Record.

    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 its meeting, the Advisory Board heard directly from one representative of LightSquared, the company’s executive vice president, regulatory affairs and public policy, Jeff Carlisle, and from Jim Kirkland, vice president and general counsel, Trimble Navigation, speaking on behalf of the Save Our GPS Coalition.  
"Without knowing otherwise," commented one observer, "one might have thought they were talking about two different sets of FCC actions. Their interpretations of FCC actions were completely orthogonal to each other."

    During the discussion, one Advisory Board member, a former governor 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.”

    
Other speakers on the LightSquared/GPS panel included Dean Bunce, co-chair of the National PNT Engineering Forum (NPEF), which has had responsibility for testing various classified GPS receivers under LightSquared conditions; and Robert Frazier of the Federal Aviation Administration (FAA) Spectrum Planning and International Office. 


    Most of the presentations from the meeting are now posted online.

    Another observer at the Advisory Board meeting opined of the LightSquared presentation and subsequent replies to questions from board members, “I’ve seen weasels before, but not like this. Misinformation, mis-statements, reversals and take-backs, outright lies.”

    Tests Slam Hi-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. For further details, see this article.

    GPS World has received further details of the tests but not an authorization 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.

     

  • LightSquared: High-Precision Receivers Are Collateral Damage

    Originally, the LightSquared/GPS Technical Working Group’s (TWG) report was due to the FCC on June 15, 2011. LightSquared requested from the FCC, and received, a two-week extension to submit their report. Three days later, LightSquared announced it found a solution to the GPS interference problem. Its new proposed solution is not good news for the high-precision GPS user community. Instead, it’s a threat directed squarely at high-precision GPS users like you and me. Do you recall what I wrote a month ago? It’s ringing true with the latest LightSquared proposal.

    “I’m going to keep this simple. You, the high-precision GPS user, are likely going to be considered collateral damage.

     

    The military is going to be accommodated in the name of national security. The aviation industry is going to be accommodated in the name of safety-of-life. The auto navigation industry is going to be accommodated because they are high-profile. The high-precision user is going to be thrown under the bus because we are the most difficult to accommodate (technically) and don’t have a high profile nor are perceived as significant enough to accommodate.”

     

    If you recall, the TWG consists of LightSquared and GPS industry representatives tasked with testing the effect that LightSquared’s proposed system may have on GPS. Four of the five sub-teams were ready to file their final report with the FCC on June 15. LightSquared’s sub-team, according to the Coalition to Save Our GPS webinar on Thursday June 16, was only sub-team not ready to file its report.

    Ok, so after the FCC granted LightSquared the two-week extension, I’m thinking we have a two-week hiatus from the LightSquared discussion as LightSquared compiles and prepares their July 1 submission.

     

    Nope, not a chance.

    On Monday, a mere three business days after they requested a two-week extension from the FCC,  LightSquared announced they’ve found a solution to the GPS interference problem and issued a statement titled “LightSquared Solution to GPS Issue Will Clear Way for Nationwide 4G Network.”

    LightSquared’s solution is to temporarily abandon the upper frequency they originally planned to roll out (1550-1555 MHz) and rollout its service using the lower spectrum I refer to as “modified” (1526-1536 MHz) in Figure 1.

    It’s important to remember that the lines separating frequency spectrums are not “brick walls.” There is signal “roll off” that results in a gray area between spectrums. That’s the reason the LightSquared upper frequency at 1550-1555 MHz was slamming GPS. Even though it is apparently separated from GPS L1, the sheer power of the LightSquared signal at 1,500 watts significantly bled into the red RNSS zone (1559-1610 MHz) in Figure 1.

     

                                                  Figure 1: FCC Spectrum Dashboard

    Using only the lower frequency spectrum (1526-1536 MHz), LightSquared claims that they are “largely free of interference issues with the exception of a limited number of high-precision GPS receivers that are specifically designed to rely on LightSquared’s spectrum.” LightSquared’s CEO said that this solution will accommodate 99.5% of the GPS receivers.

    Uh oh, guess who the remaining .5% are? Yes, your high-precision GPS receiver. One half of one percent is about the percentage of high-precision GPS receivers with respect to the total GPS market size in the U.S.

    I’m pretty confident that LightSquared isn’t weighting the receivers, so that means a $2 GPS chip inside a mobile phone carries the same weight as your $15,000 RTK receiver. But obviously the impact on our infrastructure and economy differs by orders of magnitude between the two.

    Remember last month when I wrote that high-precision GPS receivers might be thrown under the bus and considered collateral damage (LightSquared: It’s Worse than You Think)? The latest LightSquared proposal is what I was referring to. High-precision GPS receivers are the most difficult to accommodate, and LightSquared is thinking that if they tell the FCC (and the world) that they’ve taken care of 99.5% of the GPS receivers in the U.S., the other .5% can deal with it.

    It’s not yet clear how LightSquared broadcasting on 10L (1526-1536 MHz) will affect high-precision receivers. We should see some of those details at the end of the month when all reports are filed with the FCC.

    But either way, it’s clear that LightSquared broadcasting in the 1526-1536 Mhz spectrum would slam OmniSTAR and Deere & Co. Starfire users as you can see in Figure 1.

    Not so fast, say GNSS engineers. What about GLONASS, Galileo, and Compass?

    Russia’s GLONASS satellites are increasingly being used by high-precision receivers. In fact, it’s safe to say that all major manufacturers sell GPS/GLONASS receivers, which is an expensive option on most receivers. However, it’s relatively easy to justify the additional expense due to the productivity gains from the additional GLONASS satellites. Generally speaking, more satellites equals less down-time.

    The problem is that the U.S. government has no vested interest in protecting the GLONASS spectrum.

    The FAA doesn’t care about it. The U.S. military doesn’t care about it. The first-responders don’t care about it. Although GLONASS is starting to show up in consumer GPS chips, it’s not being used in those markets like it is in the high-precision markets such as surveying, engineering, construction, agriculture, GIS, and various machine control applications. Therefore, no GLONASS testing was performed at the Maryland test site (simulator not configured to output GLONASS) and little or no testing was done using GLONASS at the New Mexico or Las Vegas sites unless individual companies took it on themselves.

    Some say that GLONASS will get hammered by LightSquared mobile phones.

    To this point, most of the talk has been about GPS interference from LightSquared transmitters in the 1525-1559 MHz spectrum. We also need to be aware of LightSquared mobile phones, of which they intend to field 250 million — 100 million by the end of 2012. While LightSquared has control over the filtering on their transmitters, it have no control over the filtering used in mobile phones designed to use their system.

    I’ve heard there is some mention of LightSquared mobile phones in the reports that are to be filed with the FCC, but not made public yet. However, no LightSquared mobile phones exist today so it’s only possible to simulate them in a lab environment using a lot of design assumptions.

    The uplink frequency used by LightSquared mobile phones (to talk to the nearest tower) is in the range 1626.5-1660.5 MHz. That frequency is getting close to the top end of GPS and really close to GLONASS L1 which has a range of ~1598-1605.4MHz.

    According to one RF engineer I’ve spoken to, “We already know that Iridium (1616-1626.5 Mhz) and Inmarsat cannot co-exist in the upper band and seeing that the LightSquared handset transmit frequency is in that same spectrum, I think GLONASS in the U.S. is toast.”

    The future of GNSS receivers is definitely trending towards integrating GPS, GLONASS, Galileo, Compass, etc. signal
    s. A section of the NPEF report (mentioned above) succinctly describes the interference issue with GNSS receivers.

    Another approach examined involves limiting the LightSquared transmissions to the lower 5 or 10 MHz channel of their planned deployment. However, while this approach would protect a limited number of GPS applications other applications would still be susceptible to interference. Using this approach it may be possible to protect classes of GPS receivers, primarily those with greater receiver selectivity. However, some classes of GPS receivers would still not be protected under this mitigation technique. Receivers having wider RF front-end characteristics, such as those used for scientific and commercial uses requiring high-precision measurements, and some receivers capable of receiving multiple signals from different GNSS systems (e.g., GLONASS) would remain susceptible. Additionally, the use of only the lower LightSquared channel would provide only a temporary solution to the existing interference problems as 4G LTE levels of service may not be possible. Thus, even if allowed, the FCC’s objectives and service conditions on the LightSquared license would not be met.

    Finally and on a slightly different note, the future GPS L1C signal and L1 signals proposed by Galileo and Compass are a wider band than the current GPS L1 CA, which means they are likely more subject to interference from the LightSquared system.

     

    FCC Chairman Julius Genachowski: “As I have stated previously to Congress, the commission will not permit LightSquared to begin commercial service without first resolving the commission’s concerns about potential widespread harmful interference to GPS devices. Under no circumstances would I put at risk our nation’s national defense or public safety.”

    The FCC has stated on numerous occasions that LightSquared won’t be allowed to begin commercial service until GPS interference issues are resolved, but what does that really mean?

    Chairman Genachowski has also stated that “It should come as no surprise to anyone involved in the LightSquared matter that the company was planning for some time to deploy a major terrestrial network in the spectrum”. He’s implying that all parties involved should have prepared for this moment, and if the GPS industry didn’t, it should bear some of the burden. This is bad news indeed.

    Bottom line: The FCC is not looking out for your interests. The National Broadband Plan is heavy on their minds. I can clearly see the FCC thinking “in the interest of the bigger picture, the high-precision GPS user community can deal with it since its only .5% of the total GPS market.”

    We need to squash this new proposal by LightSquared in a hurry. It’s a threat directed squarely at the high-precision GPS user community.

     

    LightSquared Consultant claim: in the GPS industry’s “insatiable thirst for precision,” it made poor engineering decisions that made GPS receivers more vulnerable to interference from neighboring bands.

    Although it appears the statement is from an independent consulting firm, PRTM consultant Dan Hays is a Harbinger crony so don’t let it fool you into thinking it’s anything but another piece of LightSquared propaganda.

    But, let’s visit the subject for a minute to clarify because LightSquared has also claimed that high-precision GPS receivers are somehow at fault because they “are looking in our spectrum”.

    Jim Kirkland, VP and General Counsel for Trimble Navigation, said it well when I presented Mr. Hays’ statement during the Coalition to Save Our GPS webinar last Thursday. Mr. Kirkland responded:

    “… we’ve engineered our products to use services that are available for payment to LightSquared’s predecessors. That’s a critical point…these precision receivers are designed to receive MSS signals to make the services better and they pay for those services to Skyterra (owned by LightSquared) and Inmarsat (LightSquared vendor). So if that’s a bad design decision that we decided to design our receivers so that our customers could pay money to Skyterra (LightSquared), that’s one of the more absurd things I’ve heard in this whole debate.”

     

    What he’s talking about is that OmniSTAR pays SkyTerra (LightSquared) to lease bandwidth on their satellite to deliver corrections to high-precision GPS users on the ground. Yes, if you pay OmniSTAR for their VBS, HP, or XP service, then a portion of what you pay goes to LightSquared. The irony is as thick as molasses. Furthermore, Deere & Co/Navcom offer a similar service called Starfire in which they lease satellite bandwidth from Inmarsat. LightSquared and Inmarsat are connected. Based on an original agreement signed in December 2007 between LightSquared’s predecessor and Inmarsat, Inmarsat is to receive hundreds of millions of dollars from LightSquared towards “the re-banding and efficient reuse of L-band radio spectrum covering North America.”

    Essentially, what LightSquared is doing is selling the GPS industry their satellite-to-earth wireless services (a la OmniSTAR), but they are complaining that the GPS industry has designed GPS receivers to utilize services in which LightSquared gets paid. Is that a “poorly designed GPS receiver”?

    I’ve even heard, through the grapevine, that some legislators are regurgitating this nonsense of “poorly designed GPS receivers.” Maybe there’s no ill-intent, but it’s either that or a fair amount of ignorance.

    Logically, many of today’s high-precision GPS receivers have OmniSTAR/Starfire capability built into their antennas and RF front-ends to look into the 1525-1559 Mhz spectrum for the OmniSTAR/Starfire signals. They don’t focus on particular frequencies in that band because the frequencies change periodically as OmniSTAR users can attest. Also, even if you have the OmniSTAR/Starfire capability turned off in your receiver, the antenna is still designed to look into that band so there’s no way around it.

    Like I mentioned earlier, even if your receiver isn’t designed to utilize OmniSTAR/Starfire, no one knows yet if it might be affected by the LightSquared 5L/10L signal.


    Where do we go from here?

    There’s a lot more to talk about on this issue. It’s as critical as it’s ever been that you make you concerns known to your state senators and representatives as well as the FCC. Scroll to the bottom of this article for web links and contact information.

     

    Free Webinar – Thursday, June 23. LightSquared: What it means to the GPS Surveying/Mapping User Community

    Thursday, June 23, I will conduct a webinar to discuss the LightSquared issue as it relates specifically to the GPS Surveying/Mapping community (high-precision users). Joining me will be Dr. Mike Whitehead, VP of Technology at Hemisphere GPS. He’s a leading GNSS design engineer and can speak clearly about the technical ramifications of LightSquared interference on high-precision GPS receivers. Click here to sign up for the webinar. Sign up even if you can’t attend the live webinar on Thursday because you’ll be sent an email on how to view the archived presentation that you can listen/view at your convenience.

     

    Light
    Squared coverage at the Esri Survey Summit (July 7-12, San Diego, CA)

    Esri has coordinated comprehensive coverage of the LightSquared issue at this years Survey Summit. Remember, this year the Survey Summit is combined with the ACSM (American Congress on Surveying and Mapping) annual conference so the turnout should be very good.

    On Friday, July 8th @ 2pm at the Survey Summit, I’ll be giving a 60 minute presentation entitled “GPS/GNSS Technology Update” focused on covering the latest developments in GPS/GNSS. I will cover the latest LightSquared news as well as other recent GPS/GNSS technology developments.

    On Saturday, July 9th @ 3:30p and 4:00p respectively, Jeffrey Carlisle from LightSquared and Peter Large from Trimble Navigation will give 30 minute presentations on the GPS/LightSquared interference issue.

    On Sunday, July 10th @ 8:00a-10:00a there will be a GPS/LightSquared discussion panel consisting of myself, Peter Large, Jeff Carlisle, Curt Sumner (ACSM), John Matonich (NSPS), and Dr. Javad Ashjaee. The panel discussion will be moderated by Joe Paiva. This will be the first panel discussion in the industry focused on the high-precision GPS/LightSquared interference issue.

    Following the discussion panel, at 10:30am-Noon,  there will be a strategy session designed to plan actions that surveyors (high-precision users) can take to avoid becoming collateral damage.

    ———————–

    Take Action Now
    The Coalition to Save Our GPS has posted guidance on its website as to how to submit your comments. They are:
    Voice your concerns directly to Congressional Representatives
    To voice your concerns about GPS interference, you can send letters, emails, faxes, call or visit your Congressional representatives’ office in person to explain how you use GPS as a local business and what the impacts of interference would be to the local economy.
    Contact Your Local Senator
    Ask your Senator to support and co-sign the letter from Senators Roberts (R-KS), Nelson (D-NE) and nearly a third of the U.S. Senate: explain how you use GPS in your state and what impact interference or any compromise of the GPS service would have on you and the local economy.
    Write Your Representative
    The Washngton Wire reported this week that “A bipartisan group of 66 House members asked the FCC Tuesday to protect global positioning systems from interference from wireless broadband start-up LightSquared…”
    Please include: “Coalition to Save Our GPS and FCC File No. SAT-MOD-20101118-00239” in your correspondence.
    Send your comments directly to the Federal Communications Commission (FCC)
    Email the FCC: [email protected]
    For your ready reference, below are the actions the Coalition is seeking from the FCC:
    1. The FCC must make clear, and the NTIA must ensure, that LightSquared’s license modification is contingent on the outcome of the mandated study unequivocally demonstrating that there is no interference to GPS. The study must be comprehensive, objective, and based on correct assumptions about existing GPS uses rather than theoretical possibilities. Given the substantial pre-existing investment in GPS systems and infrastructure, and the critical nature of GPS applications, the results of studies must conclusively demonstrate that there is no risk of interference. If there is conflicting evidence, doubts must be resolved against the LightSquared terrestrial system. The views of LightSquared, as an interested party, are entitled to no special weight in this process.
    2. The FCC should make clear that LightSquared and its investors are proceeding at their own risk in advance of the FCC’s assessment of the working group’s analysis. While this is the FCC’s established policy, the Commission’s International Bureau failed to make this explicit in its order.
    3. 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 emanating from their devices, and if there is no way to prevent interference, it should not be permitted to operate. GPS users or providers should not have to bear any of the consequences of LightSquared’s actions.
    4. 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 and further FCC actions on the LightSquared modification order should take place with the approval of a majority of the commissioners, not at the bureau level.
    Thanks, and see you next time.
    Follow me on Twitter at http://twitter.com/GPSGIS_Eric

  • LightSquared, FCC Rebuttals Distort Record

    A claim frequently made by LightSquared spokesperson Jeff Carlisle, and recently by FCC chairman Julius Genachowski, that the GPS industry knew long ago about LightSquared’s plan for powerful terrestrial transmitters, would be a telling point — if it were true. But it is not. The verifiable fact is that the GPS industry knew about and agreed to a plan by a previous version 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 plan does. Calling the 2010 LightSquared plan the same as the 2003 Motient plan is running a wolf in sheep’s clothing.

    The GPS industry worked cooperatively with previous incarnations of LightSquared, known variously as Motient, Mobile Satellite Ventures Subsidiary LLC, and SkyTerra, to facilitate the provision of ancillary terrestrial component (ATC) service: a terrestrial service authorized by the Federal Communications Commission (FCC) as an ancillary component of an integrated satellite offering.

    [Definition of ancillary: Providing necessary support to the primary activities or operation of an organization, institution, industry, or system.]

    The Record. Since at least 2003, the FCC has contemplated terrestrial operations as an ancillary supplement to a primarily satellite-based service. And since 2003, the GPS industry has been aware of this, and cooperated with it. The plan involved no foreseeable harm to the GPS signal or millions of GPS users. In fact, its very design to protect its own satellite signals also protected GPS signals from interference.

    LightSquared’s predecessors — Motient, MSV, and SkyTerra, in succession — presented a series of technical proposals in limited proceedings, and the FCC accepted a series of incremental modifications of its technical rules, all against the backdrop of the fundamental requirement: that the terrestrial operations would be ancillary to and fully integrated with a primary satellite service. The GPS community evaluated changes in the technical rules in this context and did its best to cooperate in technical modifications that would apply to terrestrial operations subject to these fundamental constraints.

    More to the point, those 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. Because of these companies’ self-interest in protecting their own satellite signals in-band, the GPS industry focused its efforts on limiting out-of-band emissions from the anticipated ATC operations to GPS reception in the adjacent spectrum band, as evidenced by the agreements reached between the parties involved.

    Ring in the New. The present situation is completely different. The current owners of LightSquared — entities affiliated with the New York hedge fund Harbinger Capital Partners — took over SkyTerra in March 2010.  That’s when everything changed.  A new senior management team, a new business plan, and a new technological implementation: 40,000 powerful terrestrial transmitters adjacent to the L1 band in which GPS operates. Nothing previously seen by the FCC or the GPS industry even hinted at this approach.

    LightSquared now proposes an extensive deployment of terrestrial transmitters, operating independently of its satellite offering, which will create interference to GPS far beyond what was contemplated by prior FCC policy and applicable rules. GPS operators understood and agreed that satellite operators in the Mobile Satellite Service (MSS) band could deploy terrestrial service on an ancillary basis to complement satellite-based services in areas where satellite reception was weak. But there was never any agreement to, nor awareness of, the kind of dense and very powerful terrestrial network that LightSquared now seeks to install.

    LightSquared spokesperson Carlisle paints his organization as involved in prior communication to and negotiations with the GPS community in connection with the ATC rules. This disguises an essential point. That was a different organization, with a different ownership and leadership, a different business plan, and a different technology to back it up.

    Carlisle himself says so in a November, 2010 update letter to the FCC, which is when the rumbling really began.

    “In the six years since LightSquared’s [initial terrestrial] application was granted, control of the company has been transferred and its business plans have evolved.”

    FCC chairman Julius Genachowski picked up the ball in a recent letter replying to Senator Charles Grassley’s concerns about LightSquared interference. “It should be no surprise to anyone involved in the LightSquared matter that the company was planning for some time to deploy a major terrestrial network in the spectrum adjacent to GPS.”

    If an untruth is repeated enough times in enough different places, it begins to pass itself off as the truth.

    Two to Ponder. The evolution of LightSquared’s business model involves two key elements, both of them at odds with established FCC policy, not to mention GPS viability — and thus not reasonably anticipatable by anyone.

    First, LightSquared’s proposed terrestrial broadband operations cannot be described as ancillary to the primary purpose for which its predecessors, Motient, MSV, and SkyTerra, received their spectrum and licenses — that is, to provide a service that was primarily a mobile satellite service.

    Second, a requirement for the ATC service in the MSS band was that any terrestrial service be integrated with the satellite service. LightSquared’s new business model contemplates no meaningful integration of terrestrial service with satellite service.

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

    On Its Head. The November 2010 Lightsquared 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.”

    Under the only combined satellite/terrestrial service plan described in the letter, an end user would be provided with basic usage (that is, usage before additional charges apply) of one gigabyte of terrestrial wireless broadband usage but only 500 kilobytes of satellite date usage, less than what is needed to send a single email in many cases.

    It appears that the purpose of Lightsquared’s satellite service is, now, to provide ancillary service in remote areas not covered by the ubiquitous primary terrestrial network, or in the event that the terrestrial network is destroyed — exactly the opposite of what the FCC authorized and the GPS industry had understood and agreed to.

    In 2003, the FCC stated that: “We will authorize MSS ATC subject to conditions that ensure that the added terrestrial component remains ancillary to the principal MSS offering. We do not intend, nor will we permit, the terrestrial component to become a stand-alone service.”

    LightSquared now claims, and at least one FCC commissioner wants Congress to believe, that the GPS industry should have anticipated that what was bedrock when the FCC adopted its ATC rules would become quicksand by 2011. But there is no language in prior Commission orders that might have put the GPS community on clear notice that the rules of the game were likely to be changed in such a fundamental way.

    The Distortion. LightSquared has mischaracterized the GPS community’s earlier cooperation as permission to extend the technical rules, without further consideration, to the fundamentally different, new and far more threatening mode of operation now proposed by its 2010 re-incarnation.

    When the FCC first authorized ATC, it made it clear that in the event that services in bands adjacent to ATC operations, like GPS, suffered harmful interference, it would be the responsibility of the ATC operator, not the GPS provider, to cure that interference. If LightSquared cannot demonstrate that it will not cause – or that it alone will ameliorate – harmful interference to GPS operations, it must not be permitted to initiate service.

    A cursory examination of Carlisle’s and Genachowski’s backgrounds reveals nothing pertaining to engineering or technical knowledge. Both are lawyers. Such professional experience has proven to go far in Washington D.C., of course. That and a line of talk.

    Interestingly, Carlisle served as deputy chief and then chief of the FCC’s Wireline Competition Bureau from 2001 to 2005 — the period during which the earlier, less harmful ATC agreement was reached.  Carlisle managed the development of FCC policies on broadband and competitive entry into the local exchange market, and was the architect of FCC policies on bankruptcy of common carriers.

    Genachowski has a long-term and reportedly close relationship with President Obama, who appointed him to the FCC chairmanship.  His background as a Supreme Court law clerk has led some to speculate that he may play a strong role in determining legal strategy on FCC court cases. His official bio states that “Prior to his FCC appointment, Genachowski spent more than a decade working in the technology and media industries as an executive, investor, and board member.”

    The GPS industry is amply on record as supporting the goal of ensuring that all Americans have access to broadband services, and President Obama’s goal to make more spectrum available for wireless broadband operations. However, pursuit of those goals cannot jeopardize the many critical functions performed by GPS in the national economy, security, or defense, and the overall U.S. infrastructure.

  • 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.”

  • LightSquared: It’s Worse than You Think

    Tired of hearing about LightSquared? Think it’s a bunch of panicking journalists hungry for something to write about? Listen, it usually takes a lot to get the hairs standing up on the back of my neck. On the LightSquared issue, they are at full attention.

    Why?

    The GPS receivers that would likely be affected the most aren’t military, automobile, aviation, mobile phones, etc. The GPS receivers that would be affected the most are the ones you use, the high-precision GPS receiver!

    This means any receiver designed to produce accuracies at meter-level or better (submeter, decimeter, centimeter receivers). This means surveying, engineering, construction, bridge/dam/structure/seismic monitoring, GIS, precision agriculture, mining, utilities/telecom, transportation, environmental, disaster management, and all sorts of machine control across a vast number of industries.

    Do the Math

    LightSquared is planning to construct 40,000 ground-based transmitters broadcasting 1,500W each across the U.S. These are targeted at metropolitan areas with high-density population. The will pop-up like mobile phone towers. What do you think a map looks like with 40,000 LightSquared transmitters overlaid on the current infrastructure of CORS (1,500+ GPS receivers in the U.S.) and RTK networks (100+ consisting of several thousands of receivers in the U.S.)?

    Do you use OPUS? Do you use CORS? Do you use an RTK network? Do you use WAAS corrections? Do you use OmniSTAR? Do you use StarFire? Do you operate your own high-precision base station (real-time or post-processing)? I do not know one high-precision user who does not use one of the aforementioned technologies in their GPS operations. All of the above technologies are in jeopardy.

    I’m going to keep this simple. You, the high-precision GPS user, are likely going to be considered collateral damage.

    The military is going to be accommodated in the name of national security. The aviation industry is going to be accommodated in the name of safety-of-life. The auto navigation industry is going to be accommodated because they are high-profile. The high-precision user is going to be thrown under the bus because we are the most difficult to accommodate (technically) and don’t have a high profile nor are perceived as significant enough to accommodate.

    In other words, the high-precision user will be told to “deal with it.”

    What Does “Deal with It” Mean?

    It’s not clear at this point, but without any hardware modification, your receiver performance will likely be degraded (weakened or lost signal) in metropolitan areas, and to a lesser extent in rural areas. That totally depends on where LightSquared decides to place its towers. Very soon, with the final Working Group report due to the FCC (June 15), we will see how serious the interference will be.

    GPS receiver manufacturers would likely offer some sort of hardware upgrade, if possible. You can bet that they won’t support upgrading older hardware and it’s possible some newer hardware won’t be retrofittable, so the upgrade turns into a “trade-in” with a hefty price tag. But beware that a hardware upgrade doesn’t mean it will solve the problem, but rather minimize it.

    In order to have a chance of not being forgotten or dismissed as collateral damage, you need to jump loudly and with resolution to raise awareness with your congressperson and the FCC about the importance of GPS to your operations. If you’re an international user, write the FCC.

    You can view the list of submissions made to the FCC by clicking here. Deere & Co. as well as Fugro and many others provided very clear and concise comments.

    The Coalition to Save Our GPS has posted guidance on its website as to how to submit your comments. They are:

    Voice your concerns directly to Congressional Representatives

    To voice your concerns about GPS interference, you can send letters, emails, faxes, call or visit your Congressional representatives’ office in person to explain how you use GPS as a local business and what the impacts of interference would be to the local economy.

    Contact Your Local Senator

    Ask your Senator to support and co-sign the attached letter from Senators Roberts (R-KS) and Nelson (D-NE): explain how you use GPS in your state and what impact interference or any compromise of the GPS service would have on you and the local economy.

    United States Senate Letter from Pat Roberts (R-KS) and Ben Nelson (D-NE)

    Find Your Local Senator

    Write Your Representative

    Find Your U.S. House of Representatives

    Please include: “Coalition to Save Our GPS and FCC File No. SAT-MOD-20101118-00239” in your correspondence.

    Send your comments directly to the Federal Communications Commission (FCC)

    Email the FCC: [email protected]

    For your ready reference, below are the actions the Coalition is seeking from the FCC:

    1. The FCC must make clear, and the NTIA must ensure, that LightSquared’s license modification is contingent on the outcome of the mandated study unequivocally demonstrating that there is no interference to GPS. The study must be comprehensive, objective, and based on correct assumptions about existing GPS uses rather than theoretical possibilities. Given the substantial pre-existing investment in GPS systems and infrastructure, and the critical nature of GPS applications, the results of studies must conclusively demonstrate that there is no risk of interference. If there is conflicting evidence, doubts must be resolved against the LightSquared terrestrial system. The views of LightSquared, as an interested party, are entitled to no special weight in this process.
    2. The FCC should make clear that LightSquared and its investors are proceeding at their own risk in advance of the FCC’s assessment of the working group’s analysis. While this is the FCC’s established policy, the Commission’s International Bureau failed to make this explicit in its order.
    3. 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 emanating from their devices, and if there is no way to prevent interference, it should not be permitted to operate. GPS users or providers should not have to bear any of the consequences of LightSquared’s actions.
    4. 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 and further FCC actions on the LightSquared modification order should take place with the approval of a majority of the commissioners, not at the bureau level.

     

    Lastly, following is the list of high-precision GPS receivers that the Working Group (consisting of US GPS Industry Council representatives and LightSquared representatives) have chosen to test:

    Hemisphere R320 (with A52 antenna)
    Hemisphere A320 (with Integral antenna)
    Deere iTC (with Integral antenna)
    Deere SF‐3000 (with Integral antenna)
    Deere SF‐3050 (with Aero antenn
    a)
    Trimble MS990
    Trimble MS992
    Trimble AgGPS 252
    Trimble AgGPS 262
    Trimble AgGPS 442
    Trimble AgGPS EZguide 500
    Trimble CFX 750
    Trimble FMX
    Trimble GeoExplorer 3000 series GeoXH
    Trimble GeoExplorer 3000 series GeoXT
    Trimble GeoExplorer 6000 series GeoXH
    Trimble GeoExplorer 6000 series GeoXT
    Trimble Juno SB
    Trimble NetR9 (with Zephyr 1 antenna)
    Trimble NetR9 (with Zephyr 2 antenna)
    Trimble R8 GNSS (with Integral antenna)
    Trimble 5800 (with Integral antenna)
    Trimble NetR5 (with Zephyr 1 antenna)
    Trimble NetR5 (with Zephyr 2 antenna)
    Leica SR530 (with AT502 antenna)
    Leica GX1200 Classic (with AX1202 antenna)
    Leica GX1230GG (with AX1202GG antenna)
    Leica GR10 (with AR10 antenna)
    Leica Uno (with GS05 antenna)
    Leica GS15 (with Intergral antenna)
    Topcon HiPer Ga
    Topcon HiPer II
    Topcon GR‐3 (with Integral (5/8) antenna)
    Topcon GR‐5 (with Integral (5/8) antenna)
    Topcon MC‐R3 (with MC‐A3/cabled (5/8) antenna)
    Topcon NET‐G3A (with CR‐G3/cabled (5/8) antenna)
    Topcon TruPath/AGI‐3 (with Integral (special mount) antenna)
    NovAtel PROPAK‐G2‐Plus (with GPS‐702/GPS‐701 antenna)
    NovAtel FLEXG2‐STAR (with GPS‐701GGL/GPS‐701 antenna)
    NovAtel FLEXPAK‐G2‐V1 (with GPS‐701GGL/GPS‐702 antenna)
    NovAtel FLEXPAK‐G2‐V2 (with GPS‐702GGL/GPS‐702 antenna)
    NovAtel PROPAK‐V3 (with GPS‐702GGL/GPS‐702 antenna)
    NovAtel DL‐V3
    NovAtel FLEXPAK6 (with GPS‐702GGL/GPS‐702 antenna)
    Septentri PolaRx3e (with PolaNt GG antenna)
    Septentrio AsteRx3 (with PolaNt G antenna)

     

    Thanks, and see you next time.

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

     

     

     

     

     

  • Q&A from L5 and LightSquared Webinars

    In late March, I conducted a webinar titled “A Closer Look at L5: The Future of High-Precision GNSS,” in which I discussed the impact that the new GPS L5 signal/frequency may have on high-precision users. Then, in April I was part of a discussion panel-format webinar titled “LightSquared: Our Story So Far.” Many questions and comments arose from both webinars, and I’ll attempt to address those in this column.

    First of all, the day after the March 17 webinar, I published a summary with some links and illustrations. If you want to review it to refresh your memory or get a quick overview if you didn’t attend the webinar, click here.

    During the March 17 webinar, I conducted several polls. Following are the poll questions with accompanying pie charts to illustrate the results. I think polls are a great tool to gain a better understanding of what your colleagues are thinking.

    Poll #1: Does your organization use dual frequency GPS (L1/L2) receivers?

    Gakstatter comment: Nothing earth-shattering, but good to know most of the audience members polled are high-precision users.

    Poll #2: When do you plan on upgrading your GPS receivers to take advantage of the new L2C and L5 signals?

    Gakstatter comment: I think the large number of “I don’t know” answers is due to two major variables. #1 is the economy. If the economy was healthy, I think folks would be more inclined to take the risk upgrade to the latest technology. #2 is the unclear status of GPS and Galileo (and other GNSS). If there was a launch schedule that people knew they could count on and plan for, I think users would be more inclined to upgrade sooner rather than later.
    Poll #3: Do you believe that GPS and Galileo will meet their projected deployment dates of 2014/2015?
    Gakstatter comment: I understand the skepticism about GPS and Galileo staying on schedule. I don’t think the GPS schedule can push out too far because the FAA requires a full constellation of GPS satellites broadcasting L5 by 2019. The Galileo program is under a lot of pressure to deliver something to the user community. A very important milestone this year is the scheduled September launch of the first two operational Galileo satellites, followed by the launch of a second pair the first quarter of next year. This is an opportunity for the Galileo program to set a new tone and sense of urgency with the user community.
    Poll #4: How concerned are you that LightSquared’s initiative might interfere with your GPS operations?
    Gakstatter comment: Since the March 17 webinar, there’s been much more information released and published about LightSquared’s potential effect on GPS. In April, I participated in a webinar about LightSquared’s potential effect on GPS with my portion of the webinar specifically addressing high-precision users. I will discuss this later in this article. But, suffice to say that this is a serious issue for the U.S. high-precision GPS user community. LightSquared isn’t going to walk away from this without putting up a big fight, and they have enough of an argument that I could see the FCC (Federal Communications Commission) folding or trying to negotiate a compromise. However, any compromise is likely to have a negative effect on the high-precision GPS user community. Best case scenario, there would be a hit in signal strength. Worst case, you’ll need a hardware upgrade.
    As I normally do, a number of questions were raised during the webinar and I will address them here to the best of my ability. I’ll start with the L5 questions and then address some of the questions regarding LightSquared that were asked from both the March and April webinar.

    On to the Questions

    Question #1: What impact will L5 have on RTK networks?

    Gakstatter comment: Great question. There’s only upside in having another GPS frequency to work with. Since the premise behind RTK Networks relies heavily on atmospheric modeling, L5 is going to help. It’s further separated, with respect to frequency, from L1 than L2 and the signal is much stronger than L2. L5 will go a long way in mitigating the effects of the atmosphere on high-precision GPS positioning.

    They logistics of implementing L5, by the manufacturers, into RTK Networks may not be so easy. I’m not sure that L5 has been defined well enough in the RTCM specifications and even if it was, I’m not sure how fast manufacturers would implement it. Take, for example, L2C. Even though there are eight satellites broadcasting L2C, I’m not sure there are any RTK Networks taking advantage of it and transparency between different rover manufacturers. However, my gut tells me that manufacturers will be more willing to jump on the L5 bandwagon with a sense of urgency due to the potential significant increase in receiver performance.

    Question #2: What could be a better frequency combination in terms of acheiving higher sensitivities: L2C/L5 or L1/L5?

    Gakstatter comment: This is another great question. Technically speaking, I’m guessing that L2C/L5 would be a higher-performing combination due to the significantly-improved code structure of L2C (longer code and improved error-correcting methods), which allows
    the signal to be acquired and tracked better in tough GPS conditions such as under tree foliage.

    Question #3: If I toggle on L2C in my current Trimble GNSS; that would give me an extra 8 SV broadcasting

    Gakstatter comment: Good, creative thinking, but it doesn’t work that way. You are already using those eight satellites with L1 C/A and L2P. If you utilize L2C from those satellites, you’ll get some marginal gain in performance (assuming the reference station is broadcasting L2C info), but nothing like adding eight additional satellites.
    Question #4: What accuracy can be expected from single frequency L5?

    Gakstatter comment: It’s going to be better than L1 C/A due to the stronger signal strength (4 x more powerful than L2C) and much longer code structure (than even L2C). With SBAS corrections, we’re seeing about 60cm now with L1 C/A. It will probably be slightly better than that and definitely more robust positioning in marginal GPS conditions.

    Question #5: What sort of base line distances can we expect to get with L5?

    Gakstatter comment: Using L5 will definitely help with longer baselines, but baselines are already pretty long. Look at the distance between reference stations in RTK Networks today. Some are pushing 70-80km. Will they go longer than 100km? I’m not sure. That would be cool, lowering infrastructure costs of setting up and operating RTK Networks.

    Question #6: Using RTK corrections the bandwidth requirements will increase with all these extra satellites will there be more efficient correction broadcast techniques like CMRx?

    Gakstatter comment: I agree. I think there will need to be an efficient way of getting the data from reference network to rover. That either means using up more bandwidth on your mobile phone data plan (if you aren’t using UHF/VHF/Spread spectrum radios) or manufacturer’s inventing more efficient formats. 

    Questions Regarding LightSquared

     

    LS Question #1: LightSquared is going to filter their signal heavily until it will not interfere. They have too much invested to fail.

    Gakstatter comment: I agree that LightSquared is not going to walk away from their huge investment. But even if they heavily filter the base transmitters (40,000 of them), I still think there will be some interference. The nature of high-precision GNSS receivers is that they have a wideband RF front-end to take into account better code tracking and accomodate other signals such as OmniSTAR and Starfire. 
    Also, since LightSquared can’t control the design/production of the mobile phones that will use their system, each of the mobile phones can potentially be a “mobile GPS jammer”. It’s one thing to know the fixed location of each of the 40,000 transmitters, but how about the tens of thousand, hundreds of thousands or millions of mobile phones using the LightSquared infrastructure.

    LS Question #2: What do you see as the future for OmniSTAR?

    Gakstatter comment: Obviously, OmniSTAR and Starfire people must have major concerns since they are well within the LightSquared frequency spectrum. Ironically, OmniSTAR currently leases satellite bandwidth from LightSquared to broadcast their corrections.

    I’m sure they are working on a solution, but I’m not privy to what the options they are considering.

    Another option is another delivery method such as NTRIP over mobile phone networks.

    LS Question #3: If the signal effects high precision users, it will also effect casual users(hunters, fishermen, and also field technicians – forestry inventory and utility asset mapping – will w ALL need to change the GPS devises currently used today?

    Gakstatter comment: It won’t affect casual users as much as high-precision users due to the inherent design of the receivers. But, you’re right about forest inventory, utility mapping, etc. which typically use high-precision receivers. If LightSquared is allowed to continue on their desired path, it’s possible that each high-precision receiver would need to be upgraded (or traded in). That’s the worst-case scenario.

    LS Question #4: Would better filters on the GPS receiver front-ends improve the concerns?

    Gakstatter comment: Yes, but it’s not clear if high-precision receivers would perform as well with such filters designed into the receiver.

     

    LS Question #5: Is the transmitter the cell phone or Lightsquare base station?

    Gakstatter comment: This is a bit outside of my area, but both are transmitters. The LightSquared base stations are designed to broadcast at 1,500 watts while the mobile phone’s highest transmission power is probably 1-3 watts while it’s first connecting to the network. The base stations are transmitting at the band adjacent to GPS on the lower end while the mobile phones transmit in the adjacent band above the GPS. I look forward to reviewing the data in the next working group report to the FCC which includes interference testing from both base station transmitters as well as mobile phones.

    LS Quest
    ion #6:     How does LightSquared affect L2C, if at all?

    Gakstatter comment: From what I know and have read, I don’t think it would have any direct affect on L2 since L2 is at 1227MHz, far from LightSquared’s frequency spectrum of 1525MHz to 1559MHz. Indirectly, it would have an affect on L2P as L1/L2 receivers need L1 to utilize L2P. That’s not the case with L2C, but remember there are only eight satellites broadcasting L2C at this time.

    Obviously, there is more to discuss. I didn’t touch on the affect on GLONASS receivers (yes, there is a potential problem too). The feedback I received from the LightSquared webinar is that many of you would like to have a webinar that is focused on LightSquared as it relates to the high-precision user (surveying, mapping, engineering, GIS, etc.). I plan to conduct such a webinar in early June. Stayed tuned for the announcement. Hopefully, I’ll have some interesting new data to present from the report due to the FCC on May 15.

    Lastly, I attended NOAA’s Space Weather Workshop last week in Boulder, Colorado. I plan on a more comprehensive write-up, but in the mean-time you can check out my Geospatial Solutions Weekly newsletter with some info on my visit there. I’m still working on a GPS space weather notification system I wrote about last summer. I’m getting closer to having something for you.

    Thanks, and see you next time.

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

  • Out in Front: Blinded by the Light

    To illustrate the fix we’re in, Logan Scott offered this analogy for out-of-band interference during the April webinar, “LightSquared and GPS: Our Story So Far.” We’re driving at night and come upon a bicylist with one of those little flashing lights. That’s the GPS signal. So far, so safe. We know the bicyclist’s position.

    Then around the bend comes a truck with its headlights on high-beam, in the adjacent lane, but brights set at our eye level. That’s the LightSquared signal.

    Where’s the bicyclist? Uh oh.

    That is not the only light off which we are fending. Some of it we generated ourselves — with help from neighbors and children and friends and employers and, well, just about anyone with a 
mobile online connection.

    Every time you:

    • download a map and driving directions to your cell phone or wireless-connected PND;
    • stream a movie to your cell phone (all right, so only youngersomethings of your acquaintance actually do this. They still have the eyesight for it);
    • while on the road, tap wirelessly into your company’s complex database of whatever kind that has been moved to “the cloud” in a cost-saving and efficiency-ramping measure;
    • download a Zen meditatation app to your mobile, one with scientifically designed binaural rhythms using embedded beats to induce a trance-like state through brainwave entrainment for ultimate relaxation, stress reduction, pain management, improved sleep quality, super learning, enhanced creativity, out-of-body experience, and lucid dreaming (I kid you not); or
    • get sports updates and video highlights direct to your phone —

    Every time you do any one of these or myriad other activities on your handy pocket communications device, you, sir or madam, are contibuting to the problem that the GNSS community now struggles with.

    Society has developed a ravenous appetite for huge volumes of virtual data, and we are not at all content to wait until getting home or to the office for a wired connection to access it. We want it now! On the road or sidewalk, in the coffeeshop, in the mall, in the stadium, along the running path, yea, even unto in the wilderness.

    This appetite will only grow. LightSquared — mark my words, it will have plenty of company following — wants wider bandwidth to help you access online data faster. Sooner than you can say “traffic congestion,” even more data will be on offer, with even greater demand for wider bandwidth.

    As one webinar attendee e-mailed (he wrote in all caps to emphasize his feelings, but they are downsized here),
    “Do y’all think this has anything to do with the fact that mobile phone companies can make significantly more money streaming TV to cell phones than with GPS applications?”

    Technology is never a single-edged sword.