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GPS Industry's Failure to Comply With Department of Defense and International Standards for GPS

 

 

August 11, 2011

 

The GPS industry’s failure to comply with the Department of Defense’s (DoD) filtering standards is the root cause of potential interference issues involving LightSquared’s proposed broadband wireless network, LightSquared Executive Vice President for Regulatory Affairs & Public Policy Jeffrey Carlisle wrote in a letter filed today at the Federal Communications Commission (FCC).

“Had the GPS industry complied with DoD’s recommended filtering standards for GPS receivers, there would be no issue with LightSquared’s operations in the lower portion of its downlink band,” Carlisle stated in the FCC filing.

The DoD’s Global Positioning System Standard Positioning Service Performance Standard, issued in September 2008, calls for GPS receivers to filter out transmissions from adjacent bands in order to achieve the performance intended to be provided by the GPS system. 

In addition to ignoring the DoD standard, the GPS industry also has spurned international recommendations for GPS receiver design. Since 2000, the International Telecommunication Union (ITU), the United Nations agency that sets international standards for radio and satellite spectrum, has cautioned that “a more stringent pre-correlator filter may be needed to protect [GPS] receiver operations from adjacent band RF emissions.”

The DoD standard, in effect, grants GPS a 4 MHz “guard band.” Now, however, the GPS manufacturers are rejecting LightSquared’s offer of a 23 MHz guard band that would be created by LightSquared’s decision to begin its terrestrial operations in the lower half of the downlink band.

Instead, the GPS industry unreasonably insists on a 34 MHz guard band – 8.5 times as wide as the DoD recommendation.

“If all spectrum users demanded the irrational guard band solutions that GPS manufacturers are demanding, we would not have broadband in this country and efficient spectrum use would take a backseat to the squeakiest wheel,” Carlisle said. “This type of precedent would set back the United States' competitiveness by decades. The GPS industry turned a blind eye to the Department of Defense’s recommendations regarding the manufacturing of commercial GPS receivers and a blind eye to the ITU’s long-standing recommendations regarding GPS receiver performance.”

Given the DoD’s clear recommendations and the long-standing ITU warnings, it is not credible for the GPS industry to now claim that it is not responsible for the flawed design of its receivers. By demanding that LightSquared be prevented from building a ground service that has been authorized for years, the GPS manufacturers are simply trying to formalize squatting for free on someone else’s licensed spectrum.

The GPS industry has a responsibility to use its licensed spectrum in accordance with international and federal government standards – not for LightSquared’s sake, but for the sake of the American people who own the public airwaves and who fund the GPS satellite system.

"The GPS industry benefits from an estimated $18 billion taxpayer subsidy to offer a commercial service that is completely dependent on a government satellite system.  Despite the federal handout, they have deliberately ignored Defense Department criteria for using the restricted system,” Carlisle said. “LightSquared remains committed to working in partnership with responsible members of the GPS industry and for the benefit of the public by creating good-paying jobs and economic opportunity at a time when America desperately needs both.”