The Commerce Department's National Telecommunications and Information Administration (NTIA) said there is “no feasible solution to the interference problems posed by LightSquared Inc.'s proposed nationwide mobile broadband network.”

LightSquared proposed to offer high-speed wireless Internet service on a wholesale basis to as many as 260 million people on airwaves formerly reserved mainly for satellites. However, testing consistently has concluded that the proposed network could interfere with GPS operations.

In January 2010, the Federal Communications Commission (FCC) gave LightSquared preliminary approval to begin rolling out its network, but said it would withhold final approval until all interference issues are resolved. Since then, the company and the FCC have had intense criticism from Congressional members, GPS device manufacturers, government agencies and corporations that rely on GPS technology. Their primary concern is that LightSquared's network requires the company to deploy significantly more terrestrial base stations, which emit much higher power and create substantial interference with GPS operations.

LightSquared has proposed moving operations to a different set of frequencies and to lower the power levels of its network transmissions but the latest round of testing has concluded that the interference is not mitigated.

“No additional testing is warranted at this time,” the National Executive Committee for Space-Based Positioning, Navigation & Timing, an inter-agency body that advises federal departments and agencies on matters concerning GPS, said in a letter to NTIA, which manages the government's use of radio spectrum.

Testing requested by NTIA has found that LightSquared's transmissions caused harmful interference to the majority of GPS receivers, including those used for aviation. Rick Kaplan, the chief of the FCC’s Competition Bureau, said the agency will withhold final approval of LightSquared's network build-out until all testing is completed and the NTIA has reached its conclusions. The FCC manages all commercial and public radio spectrum in the United States, while the NTIA manages the federal government's use of the spectrum.

“We will do nothing to harm GPS in any way whatsoever,” Kaplan said. “It's obviously an essential service to our national defense and our economy.”

The NCC is an active participant in a coalition composed of commodity and general farm organizations working with farm equipment and GPS manufacturers to ensure GPS services and precision agriculture are not adversely affected by LightSquared.