LightSquared is fighting back on the controversial topic of GPS interference by sending a formal letter to the Federal Communications Commission asserting the entire problem is the fault of the GPS industry.

This is a life or death matter for LightSquared, which is building out a 4G LTE mobile network using satellite bands. Sprint is a believer, as evidenced by a major deal LightSquared and Sprint signed to provide 4G LTE and work toward universally available broadband.

Lined up against them are a group called Coalition to Save Our GPS that includes FedEx Corp., United Parcel Service Inc., the Air Transport Association, and GPS unit makers Trimble and Garmin.

“Had the GPS industry complied with [the Department of Defense’s] recommended filtering standards for GPS receivers, there would be no issue with LightSquared’s operations in the lower portion of its downlink band,” wrote LightSquared executive vice president for Regulatory Affairs & Public Policy Jeffrey Carlisle.

LightSquared has permission from the FCC to use its frequencies for a 4G network, even though when they were purchased it was with a caveat that they could only be used with satellites. The problem is, GPS systems are not coloring between their designated lines, so the LightSquared system interferes with GPS data  that isn’t strictly where it’s supposed to be.

LightSquared wants a filter of some kind, and the GPS industry counters that the required technology doesn’t exist.

LightSquared’s letter read, “Given the DoD’s clear recommendations and the long-standing ITU warnings, it is not credible for the GPS industry to now claim that it is not responsible for the flawed design of its receivers. By demanding that LightSquared be prevented from building a ground service that has been authorized for years, the GPS manufacturers are simply trying to formalize squatting for free on someone else’s licensed spectrum.”

The GPS industry, meanwhile, contends that its systems are too well integrated into the very fabric of society to be changed now, and that LightSquared should have thought about that before they bought the frequencies they then got a waiver on.

Related Links:

The Hill –

LightSquared background information –