LightSquared, GPS Group Joust on Interference Claims

LightSquared and the GPS Innovation Alliance continue to spar over interference issues, with LightSquared criticizing multiple assertions in a presentation the GPS industry group gave to the FCC last month. Worries about its proposed satellite-based broadband network interfering with GPS signal reception is overblown and points more to GPS receiver design problems, LightSquared said in an ex parte filing posted Thursday in docket 12-340. In its presentation, the GPS Innovation Alliance said that Global Navigation Satellite System equipment can better tolerate signal interference than many other commercial devices, but the power difference between GNSS and LTE signals is huge and the spacing between the signals is slim, meaning GNSS must tolerate what wireless systems do not. That presentation had "several significant errors," LightSquared said in its rebuttal. Receive-only devices such as GPS units don't need wide gaps of spectrum spacing from other operations, and the band gap the industry group talked about is at times less than what exists between LightSquared and GNSS, it said. "If GNSS devices are particularly vulnerable to interference, then high levels of resiliency should be a primary consideration in responsible receiver design," LightSquared said. "The tools to prevent [interference] lie in the hands of the GNSS receiver designers themselves."