LightSquared says new tests prove it has fixed the GPS interference problem that has held up the deployment of its hybrid satellite-terrestrial LTE network.

The company claimed Wednesday that an independent laboratory has found that "several" high-precision receivers are compatible with its network, including those outfitted with filters developed by GPS expert Javad GNSS.

"Preliminary results show that GPS devices tested in the lab easily surpass performance standards thanks to these newly developed solutions," LightSquared CEO Sanjiv Ahuja said. "We are confident that this independent testing will mirror testing being done by the federal government."

LightSquared's proposed network sits in spectrum adjacent to airwaves used by GPS. It was forced to scrap its first deployment plan because its signal knocked out GPS receivers, and it has since been trying to prove that it has addressed the problem by moving its network to a different band and developing special filters that protect GPS receivers from interference.

LightSquared hired an independent lab to test solutions to the GPS interference problem developed by Javad GNSS, PCTel, Partron, Hemisphere GPS and other companies. Initial testing of Hemisphere's solution "has gone very well," LightSquared said.

The government is currently testing LightSquared's purported fix. It is not clear when results will be made public. The FCC will not allow LightSquared to turn on its network until the GPS interference issue has been resolved.

High-precision receivers have been problematic for LightSquared because they are more sensitive than other GPS receivers and particularly susceptible to interference. High-precision receivers are used in aviation, agriculture, the military and other industries for critical applications such as landing planes and guiding missiles.

Some in the GPS industry, notably the members of the Save Our GPS Coalition, say LightSquared's interference issue is an unsolvable physics problem.

The group maintains that the issue remains unresolved despite LightSquared's latest claims.

"It is obviously extremely premature to claim at this point that these latest tests demonstrate that LightSquared's proposed repurposing of the mobile satellite band for terrestrial operations is 'compatible' with high-precision GPS," Trimble president and coalition founder Jim Kirkland said. "In fact, we know that the results announced today do not address proven interference to hundreds of thousands of existing high-precision GPS receivers in a wide variety of critical uses."