{mosads}“Had the GPS industry complied with DoD’s recommended filtering standards for GPS receivers, there would be no issue with LightSquared’s operations in the lower portion of its downlink band,” Carlisle wrote. 

He also said GPS makers ignored the receiver design recommendations of a United Nations agency that sets international standards for radio and satellite spectrum.

In a press release, LightSquared accused GPS makers of “simply trying to formalize squatting for free on someone else’s licensed spectrum.”

LightSquared is planning a hybrid service that relies on both satellite and land-based cell towers. It will sell access to its network to other companies for use with their devices.

The company’s land-based network will provide 4G speeds, while its satellite network will provide reception nearly everywhere in the country.

But tests earlier this year showed that LightSquared’s land-based network interferes with GPS devices. GPS is considered critical to public safety because it is used by emergency responders, airplane navigators and the military.

In response to the interference concerns, LightSquared agreed to only use the lower half of its spectrum for its land-based network. 

The FCC is currently reviewing LightSquared’s proposal, and FCC officials have said they will not allow the company to move forward until the GPS interference issues are resolved.

The United States GPS Industry Council declined to comment.