LightSquared either knew or should have known about apparent interference between its proposed LTE (Long-Term Evolution) network and receivers for GPS (Global Positioning System) before it requested a waiver from the U.S. Federal Communications Commission (FCC) to operate the network, the Coalition to Save Our GPS said in a paper released late Friday. After LightSquared received a conditional waiver in January, a mandatory series of tests revealed serious interference.

The fledgling carrier plans to offer wholesale mobile services over satellites and a land-based LTE network. But the LTE system would operate in radio spectrum near to that used by GPS, raising concerns about degraded navigation capabilities. In January, the FCC said LightSquared could build and operate the network if it didn't interfere with GPS receivers. The carrier was required to form a working group to test the technologies together, and that group filed its findings last week.

After the tests showed significant interference to GPS from transmissions in the upper band of LightSquared's spectrum, the company devised a new plan in which it would start out by launching services on a lower band. On Friday, the GPS group jumped on that change of direction with strong criticism.

"The utter failure of LightSquared's initial deployment plans to pass interference tests raises fundamental questions about the representations LightSquared made to the FCC," the Coalition said. "The current strong indication is that whatever LightSquared told the FCC prior to January 2011 was highly inaccurate, to a degree that verges on negligence."

Based on the outcome of its earlier plan, the Coalition also questioned LightSquared's assessment that operating only in the lower band would spare 99.5 percent of GPS receivers from interference. The group then picked apart the carrier's 37-page proposal, challenging specific statements made by LightSquared.