LightSquared has now claimed that the tests carried out to determine that its 4G network will interfere with GPS signals is ‘bogus’, or ‘rigged’. These tests were carried out by Air Force Space Command and were on the behalf of Space-Based Positioning, Navigation and Timing Executive Committee (PNT EXCOM). The tests results showed that the frequency band used by the the 4G network (Mobile Satellite Services or MSS in short) lies next to the GPS frequencies on the spectrum.
EXCOM’s co-chairs Ashton Carter and John Porcari wrote to the Department of Commerce their findings, “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. 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.”
LightSquared claims that these tests were bogus and ‘fiddled with’. They say, “The GPS manufacturers cherry-picked the devices in secret without any independent oversight authority in place or input from LightSquared. The testing protocol deliberately focused on obsolete and niche market devices that were least able to withstand potential interference.”
LightSquared also claims that the tests were placed on a harsh standard and even 1dB (decibel) of interference was deemed as ‘failure’. They argue, “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. 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.”
LightSquared wants another round of tests to take place and with more practical considerations in mind. It wants the National Telecommunications and Information Administration (NTIA) to carry out the tests.