GPS Interference

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Federal Tests Show 'No Practical Solutions' to LightSquared Interference with GPS

January 20, 2012

In what could be a significant set-back for upstart telecommunications provider LightSquared, and its plans to deploy a nationwide 4G wireless network, a joint panel of representatives from nine federal agencies has determined there are “no practical solutions” that would allow LightSquared’s proposed broadband service to operate “without significantly interfering with GPS.”

“Over the past year we have closely worked with LightSquared to evaluate its original deployment plan, and subsequent modifications, to address interference concerns,” read a letter sent January 13 by the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT) to the National Telecommunications and Information Administration (NTIA). “Substantial federal resources have been expended and diverted from other programs in testing and analyzing LightSquared's proposals.” The PNT added that no further tests are warranted, as LightSquared has not demonstrated any means that would prevent such interference from occurring.

As NBAA has reported, numerous tests over the past year showed signals from LightSquared's proposed 4G LTE network would drown out the weaker signals used by global positioning system receivers. In December, the company offered to limit its signal to lower frequency bands farthest away from the bandwidth used by GPS, in exchange for immediate access to that spectrum – but one week later, LightSquared lashed out at the GPS industry in a Federal Communications Commission filing, claiming poor design of the units is solely to blame for the problem.

Not surprisingly, LightSquared immediately issued a release calling for the FCC and NTIA to “retake the lead” on conducting tests of its network, claiming the PNT report demonstrated “bias and inappropriate collusion with the private sector.” LightSquared noted a director for Trimble GPS, an outspoken LightSquared opponent, served as Director of the PNT Advisory Board. “Government testing has become unfair and shrouded from the public eye,” LightSquared stated.

The GPS industry countered those tests were intended to be independent from any influence from the company. “LightSquared has been afforded every possible opportunity to make its technical case, and has failed to demonstrate that it can avoid interference to many critical GPS based activities,” stated Dale Leibach, spokesman for the Coalition to Save Our GPS (of which NBAA is a member), in a January 13 release. “Over the last year, it has proposed numerous modifications to its existing proposals, which it claimed would solve the interference problem. Each of these proposals has been extensively evaluated and none have been found adequate to eliminate widespread interference to GPS.

“Every set of independent technical studies has confirmed that LightSquared's proposed operations would create widespread interference to critical GPS uses,” Leibach added.

With the PNT decision now on the books, a final ruling from the FCC on whether LightSquared will be allowed to go ahead with its plans may come at any time. A reported $9 billion deal for LightSquared with telecommunications giant Sprint hinges on the outcome of that decision; last month, Sprint extended LightSquared's deadline to receive that approval until January 31.