Yesterday the US House of Representatives' Committee on Transportation and Infrastructure heard from a number of bodies, including the Air Transport Association and the Air Line Pilots Association, that LightSquared's proposed LTE network would directly interfere with the safe running of flights. The hearing was told that the network would not be compatible with safety-of-flight systems that rely on GPS to improve their ability to prevent in-air collisions.
John D. Porcari, the Deputy Secretary for the US Department of Transportation, asked the committee to introduce standards that regulate the usage of GPS' neighboring spectrum. He told the hearing that precise GPS systems like those found in aircrafts need to utilize wide-band receivers that also pickup signals outside the regulated spectrum. When asked why LightSquared's proposed network interferes with GPS, Porcari told the committee:
"GPS by its very nature is a very weak space-based signal received by GPS receivers in the atmosphere or in terrestrial applications… The recent [neighboring] pieces of spectrum were for mobile satellite service, which was [a] quiet use. What has happened with this specific proposal is essentially, you went from a mobile satellite proposal with limited ground augmentation to a ground-based service with limited satellite augmentation, and that really changed the fundamental nature of signals and how they would be received. It's really important to point out that GPS was put in a quiet piece of the spectrum on purpose, because fundamentally, it has to have quiet neighbors."
Yesterday LightSquared publicly asked the FCC to regulate GPS receivers to prevent them from using the spectrum that the company's LTE network relies upon. Porcari was asked why he proposes that spectrum use be regulated rather than, as LightSquared suggests, the receivers themselves. He stated that "the idea of spectrum interference standards would be to give everyone involved, the industry and others, a confidence in the long-term as they build more and more precise GPS devices." He wants the Government to run tests to identify what uses of the neighboring spectrum would be compatible with GPS standards before another company puts major capital or products at risk.
LightSquared continues to maintain that the tests carried out on GPS interference were not accurate, as "the government relied on the GPS industry to devise the tests and conduct them in secret using a standard that does not reflect real-life conditions. The company had its request to testify at yesterday's hearing denied.