GPS World reports that Lightsquared's network of 40,000 transmitters will interfere with GPS signals.

Initial technical analyses have shown that the distant, low-powered GPS signals would receive substantial interference from high-powered, close-proximity transmissions from a network of ground stations. The consequences of disruption to the GPS signals are far reaching, likely to affect large portions of the population and the federal government.

Does anyone know what sort of "technical analyses" were done?


There are many news articles mentioning a report to the FCC submitted recently by LightSquared. There is a strong spatial dimension to this problem. It appears GPS in rural areas will be harmed most - and will also benefit most from wireless broadband. Why is it so hard to find maps illustrating the analyses?

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    This only affects signal in the US? - on 1.57542 GHz (L1 signal) and 1.2276 GHz (L2 signal). The 1.17645 GHZ (aeronautical navigation) is unaffected. – Mapperz Apr 7 '11 at 14:55
  • LightSquared Waiver - scribd.com/doc/47633036/LightSquared-Waiver – Mapperz Apr 11 '11 at 15:03
  • Here is URL of PDF for the Garmin (Burgett & Hokuf) report filing quoted by Zachary below. It is posted up by the Save our GPS folks--at saveourgps.org/pdf/… – V Stuart Foote Apr 13 '11 at 14:08
  • I'd just like to point out that in spite of the many pages of text and tables of numbers now available on this issue, I've yet to see any maps or other meaningful graphic illustrations (Edward Tufte of the GIS world, where are you?) – matt wilkie Jul 28 '11 at 20:07
  • there are 2 days left for public comment (July 30th) - chat.stackexchange.com/rooms/939/gis – matt wilkie Jul 28 '11 at 20:19

I found this report via Free Geography Tools. The GPS units test results shown here are near the end of the report.

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    Thanks for posting, It would be interesting to see polygons created by buffering transmitter locations shown on a web map. – Kirk Kuykendall Apr 7 '11 at 17:02

As @Mapperz has rightly pointed out this phenomena effects only US. There has been widespread concerns on this issue and a Coalition to Save Our GPS has been formed with a mission - Uniting to Protect GPS - A National Utility for More Than 30 Years. The site contains wide variety of resources on the issue in the form of White Papers, Studies and Reports, Testimonies and FCC filings. The Coalition has members from all industries - GPS manufacturers, Aeronautical industry bodies, Geomatics software makers etc.


This may be slanted but I would hope that someone from these panelists would have a direct answer to your question.

LightSquared and GPS: Our Story So Far "GPS has become a key component of the U.S. national infrastructure, the driver of a significant part of the civilian economies of the world, and the enabler of millions of professional precision uses and consumer benefits. The viability of the GPS signal is now threatened - ironically by what appears to be a misguided attempt to increase accessibility to broadband by creating a needless zero-sum result for customers who want both services." - Joe Paiva "Act Now to Protect GPS Signal," GPS World, March 2011

Date: Thursday, April 21, 2011 Time: 10:00 a.m. Pacific / 1:00 p.m. Eastern / 5:00 p.m. GMT Moderator: Alan Cameron, Editor-In-Chief, GPS World Panelists: Captain Joe Burns, Managing Director of Technology and Flight Test, United Airlines Eric Gakstatter, Editor, Geospatial Solutions and GPS World's Survey Scene Newsletters Bill Klepczynski, Owner, Global Timing Services, LLC. Logan Scott, Principal, Logan Scott Consulting Platinum Sponsor: Hemisphere GPS Duration: 60 minutes

  • what's the 2nd para in this quote about? From the dates it appears to be advance notice (at the time you posted) of an upcoming debate, but the location and type (conference? radio? tv? ___?) is unspecified. – matt wilkie Jul 28 '11 at 20:28
  • apologies @matt - I would have thought I would post the link with it. Perhaps I got called away during the process. Here is where I found that to begin with on the okgis list... gis.ou.edu/sympa/arc/okgis/2011-04/msg00008.html – Brad Nesom Jul 28 '11 at 22:17

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