Compiled information on this page regarding the LightSquared GPS / Space-Based Navigation positioning & timing issue.
Background Information
What is LightSquared? LightSquared Subsidiary LLC is a company that plans to provide a wholesale, nationwide 4G-LTE wireless broadband network integrated with satellite coverage. LightSquared will combine existing mobile satellite communications services (formerly known as SkyTerra) with a ground-based wireless communications network that uses the same L-band radio spectrum as the satellites. On January 26, 2011, the Federal Communications Commission (FCC) issued an Order and Authorization giving LightSquared conditional approval to build out its ground-based wireless network (referred to as an ancillary terrestrial component, ATC) by reusing its authorized mobile satellite service (MSS) spectrum. The approval is subject to further testing and FCC review (see below).
Why is the GPS community concerned? The base stations of the LightSquared network will transmit signals in a radio band immediately adjacent to the GPS frequencies. The GPS community is concerned because testing has shown that LightSquared's ground-based transmissions overpower the relatively weak GPS signal from space. Although LightSquared will operate in its own radio band, that band is so close to the GPS signals that most GPS devices pick up the stronger LightSquared signal and become overloaded or jammed. There is also concern that the FCC may approve a technical solution to the problem that requires millions of existing GPS users to upgrade or replace their devices.
What is being done to address the concerns? In its Order and Authorization, the FCC required that LightSquared create a working group with the GPS community "to address interference concerns regarding GPS and, further, that this [working group] process must be completed to the Commission’s satisfaction before LightSquared commences offering commercial service." LightSquared committed $20 million to the working group and worked closely with the U.S. GPS Industry Council and other participants to complete interference testing. The FCC ordered LightSquared to file monthly progress reports and a final report due June 15, 2011. On June 15, LightSquared requested and the FCC approved an extension of the deadline to July 1, 2011. They submitted their final report on June 30, 2011, along with a separate document providing their recommendation to the FCC. The FCC opened a 30-day public comment period on the report and recommendations, with a comment deadline of July 30, 2011. LightSquared cannot commence commercial operations of its terrestrial network until the FCC, "after consultation with NTIA [National Telecommunications and Information Administration], concludes that harmful interference concerns have been resolved and sends a letter to LightSquared stating that the process is complete." Independent of the FCC-ordered study, the government's National Space-Based PNT Systems Engineering Forum (NPEF) conducted its own testing of the potential interference to military and civilian GPS users from LightSquared's terrestrial network. The NPEF completed its report on June 1, 2011; the unclassified public version was released July 6, 2011.
Recent News & related Web Links
http://www.pnt.gov/interference/lightsquared/
http://en.wikipedia.org/wiki/LightSquared
GPS World Magazine: http://www.gpsworld.com/content/search?keywords=lightsquared
Thrust, Parry, Riposte: Desperate LightSquared Fencing August 16, 2011 |
News Both comment and reply periods on Federal Communications Commission (FCC) Proceeding Number 11-109 have closed, and the agency may render a decision at any time regarding LightSquared’s rights — or not — to interfere with the GPS signal from coast to coast. The company marked the closing of the reply period with a letter to the FCC claiming that GPS receivers do not comply with U.S. Department of Defense guidelines issued in 2008. Meanwhile, a key participant in FCC and GPS discussions with preceding holders of the LightSquared spectrum confirmed that recent statements by the current owners of rights to the Mobile Subscriber Service (MSS) band are “not an accurate perception” of the creation of an ancillary terrestrial component within the MSS space-to-earth band. Finally, the FCC has requested more specific and presumably more verifiable data on the number and lifespan of GPS receivers that will be interfered with, and the number of terrestrial base stations LightSquared plans to deploy. Confused? Ill at ease? Out of sorts?
Tune in to GPS World’s Thursday, August 18, webinar with two Washington D.C. experts on the subject, to sort out the tangled skein. Jules McNeff, a member of the U.S. GPS Industry Council from the late 1990s to early 2000s, and a participant in discussions with LightSquared predecessor companies during that period, filed an FCC comment regarding the history and creation of an ancillary terrestrial component (ATC) within the MSS band. McNeff is now vice president of strategy and programs for Overlook Systems Technologies, and a speaker on GPS World’s “LightSquared Watch” webinar this Thursday at 1 p.m. Eastern time, 10 a.m. Pacific. Register free here for the webinar. Joining him on the air will be Scott Pace, director of the Space Policy Institute, Elliott School of International Affairs, George Washington University. McNeff writes in his comment to the FCC that “I have noted statements [by LightSquared] regarding the perceived unwillingness of the GPS industry and GPS users to hurry and modify their equipment and applications because they should have known of LightSquared plans “ten years ago.” This is not an accurate perception, as both the FCC and MSS providers took pains from the beginning to assure the GPS industry that the ATC would remain just that (“Ancillary”) and thus the service providers in the MSS band would not be allowed to operate a terrestrial component independently from the MSS satellite transmissions. That assurance of MSS linkage was only removed by FCC action within the last year, which led to the current urgent situation, highly threatening to the continued viability of the myriad civil GPS applications based upon the GPS L1 signal.“ He goes on to state, as did many others in their FCC comments, that “There are millions of GPS receivers now in use across the U.S. Many are obvious, in aircraft and boats, cell phone systems, precision agriculture, construction, and many more. However, many are not obvious, as they are designed to service applications within systems and infrastructures on which we rely for commerce and safety, and interference effects resulting from concentrated and proliferated LightSquared transmissions on those receivers are unknown, untested and largely unpredictable in advance. “Given the circumstances I have described above, I believe it is inappropriate for LightSquared to be authorized by the FCC to proceed with its plan to transmit at either location within this band.”
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Posted to WiGICC forum on 18 Aug 2011 by KJ Parsons