LightSquared hasn't provided GPS filters for federal testing

Startup wireless carrier LightSquared has claimed since September that it has developed filters that will mitigate interference with high-precision Global Positioning System receivers used in farming and surveying, but the company has not yet delivered the filters to federal agencies for tests, said a spokeswoman for the National Telecommunications and Information Administration.

The Federal Communications Commission directed LightSquared and the GPS industry working group to conduct tests this January in partnership with federal agencies, including the Defense and Transportation departments, to determine if the company's network, which uses frequencies adjacent to the GPS band, would interfere with GPS receivers.

In the June 30 working group report, LightSquared acknowledged its base stations could overload high-precision GPS receivers. The GPS industry said in the report that "we know of nothing feasible that can be done to make currently fielded wide-band high-precision, timing and network receivers and augmentation systems operate properly when in the vicinity of a LightSquared base station."

In September, in a letter to the deputy secretaries of Defense and Transportation, NTIA administrator Lawrence Strickling said the GPS industry and LightSquared agreed that operation of its network in the lower frequency band allocated to the company would cause "unacceptable interference" to high-precision GPS receivers.

LightSquared, Strickling said, agreed to procure a signal filter to mitigate these problems. The company also agreed it would not begin operation until tests could determine the filter had eliminated signal overload without degrading precision GPS receiver performance.

On Sept. 21, LightSquared said it had reached an agreement with receiver manufacturer Javad GNSS Inc. to develop a system that will eliminate related interference issues for high-precision GPS devices. On Oct. 13, LightSquared said

network engineering firm PCTEL had developed an antenna to help reduce GPS interference and tech company Partron America had developed a $6 signal filter.

This Wednesday, LightSquared held a press conference to highlight test results by Alcatel-Lucent that showed the Javad receivers can operate without interference from the company's cellular network.

Jim Kirkland, vice president and general counsel of GPS manufacturer Trimble, said in a statement, "it's important to keep in mind that these are LightSquared-sponsored tests separate from the ongoing, independent testing being conducted under the auspices of the NTIA, and are simply one input into an overall analysis of the effect of LightSquared's planned operations on critical GPS uses."

But LightSquared still needs to submit its filters for tests by federal agencies, and has not yet done so, said NTIA spokeswoman Moira Vahey. She said those tests cannot begin until LightSquared provides the filters. LightSquared did not respond to queries about when it will provide the filters for testing by federal agencies.

Tests by the working group earlier this year revealed that the LightSquared network also could interfere with personal GPS receivers and cellphones equipped with GPS chips.

To reduce interference, LightSquared proposed using only the lower 10 MHz of bandwidth allocated to it by FCC, which required a new round of tests that ended Nov. 30.

Vahey said NTIA has received the results of separate tests conducted by evaluators at White Sands Missile Range, N.M., and by an independent lab she declined to name. NTIA has not completed analysis of that test data, and Vahey could not estimate when that analysis will be made public.

Kirkland predicted that NTIA will release the results of the personal receiver and cellphone test by the middle of December and said he does not expect the high-precision receiver tests to begin until 2012.