Leaked government test results show LightSquared interferes with 75% of GPS receivers

LightSquared's proposed satellite/terrestrial service reportedly caused interference to 75 percent of GPS receivers studied in U.S. government tests, according to a draft summary of the results obtained by Bloomberg.

According to the leaked draft, results from testing conducted between Oct. 31 and Nov. 4 revealed that "millions of fielded GPS units are not compatible" with the planned nationwide service.

"LightSquared signals caused harmful interference to a majority of GPS receivers tested," according to the draft prepared for a meeting next week of U.S. officials reviewing the LightSquared proposal. "No additional testing is required to confirm harmful interference exists."

In a blog post, Tim Farrar, principal with TMF Associates, said that assuming this conclusion is endorsed by the NTIA at its meeting this week, the FCC would be "perfectly within its rights to deem that no further testing is required to confirm that the conditions of the January 2011 waiver cannot be met and it must be revoked."

LightSquared has been under fire since its June report to the FCC showed that its proposed LTE network posed an interference problem to existing GPS devices. LightSquared can't operate in the band until the FCC is satisfied that interference won't be a problem. LightSquared in recent months has made a number of concessions, including agreeing to temporarily stay out of the upper part of the spectrum that is adjacent to the GPS bands and limiting the power of its base stations.

In response to the leak of the testing results, Martin Harriman, executive vice president of Ecosystem Development and Satellite Business with LightSquared, said "We are outraged by the illegal leak of incomplete government data to news organizations. This breach attempts to draw an inaccurate conclusion to negatively influence the future of LightSquared and narrowly serve the business interests of the GPS industry."

Harriman called the statement that most GPS devices would be disrupted by LightSquared's operations "patently false." He said "there is no way that such a conclusion could be drawn without deliberately ignoring a critical element in LightSquared's mitigation proposal to manage the power from its network that GPS devices will be able to receive. By ignoring this commitment by LightSquared, this conclusion is erroneously based on estimated power levels that are up to 15 times the levels guaranteed by LightSquared."

Harriman told Bloomberg that LightSquared's proposal to operate at a lower power level than what was used during the tests would impact about 10 percent of GPS devices.  

LightSquared is proposing to operate at a lower power than the level used during the tests, and believes that its operations would affect about 10 percent of devices, Harriman said.

The laboratory testing was performed for the National Space-Based Positioning, Navigation, and Timing (PNT) Systems Engineering Forum, an executive branch body that helps advise policy makers on issues around GPS. The forum will present its results on Dec. 14.

Wholesale LTE provider LightSquared said GPS interference test results showed that high-precision GPS receivers from three GPS device makers are compatible with LightSquared's L-band spectrum. LightSquared pressed regulators to approve the commercial operation of its network, but doubts remain from some in the GPS community that the issue is resolved.

LightSquared CEO Sanjiv Ahuja held a press conference last week to trumpet new test results that were conducted by an Alcatel-Lucent (NYSE:ALU) lab. He said GPS interference test results showed that high-precision GPS receivers from three GPS device makers are compatible with LightSquared's L-band spectrum, demonstrating that LightSquared is making progress on the interference issue.

For more:
- see this Bloomberg article
- see this TMF Associates blog post
- see this LightSquared release

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