LightSquared claims interference tests were rigged

Posted by Emma Woollacott

LightSquared, currently seeking final FCC approval to build a nationwide 4G wireless wholesale network, is complaining that tests which appear to show its service interferes with GPS signals were rigged.

The tests, carried out by Air Force Space Command on behalf of the Space-Based Positioning, Navigation, and Timing Executive Committee (PNT EXCOM), concluded that the company's proposed service - which uses the Mobile Satellite Services (MSS) frequency band adjacent to Global Positioning System (GPS) frequencies, raised serious concerns.

"It is the unanimous conclusion of the test findings by the National Space-Based PNT EXCOM Agencies that both LightSquared's original and modified plans for its proposed mobile network would cause harmful interference to many GPS receivers," EXCOM co-chairs Ashton Carter and John Porcari wrote to the Department of Commerce.

"Additionally, an analysis by the Federal Aviation Administration (FAA) has concluded that the LightSquared proposals are not compatible with several GPS-dependent aircraft safety-of-flight systems."

But the tests were a fiddle on the part of GPS manufacturers and government end users, claims a furious LightSquared.

"The GPS manufacturers cherry-picked the devices in secret without any independent oversight authority in place or input from LightSquared," it says.

"The testing protocol deliberately focused on obsolete and niche market devices that were least able to withstand potential interference."

In any case, claims LightSquared, the testing standard was unreasonably harsh, defining failure as a single decibel of interference.

"Independent experts agree that a one dB threshold can only be detected in laboratory settings and has no impact on GPS positional accuracy or user experience," says the company.

"In fact, GPS devices are designed with the ability to withstand eight dB or more of loss of sensitivity due to man-caused and natural interference. By setting the definition of interference at one dB, the testing was rigged to ensure that most receivers would fail."

It's calling for further testing from the National Telecommunications and Information Administration (NTIA). If it doesn't succeed, though, the project appears to be doomed.