Javad has developed a filter that, in conjunction with other changes to GPS receiver antennas, could prevent interference on effectively all precision GPS receivers, according to the companies. The filter would cost only $6, they said. There are approximately 50 of the Javad filters available now for carrying out tests, said Javad Ashjaee, president and CEO of Javad GNSS.

LightSquared said GPS manufacturers, not users, should bear the cost of upgrading GPS gear to prevent interference with the new network. The company has pledged to spend as much as $50 million to cover the cost of modifying all federal government receivers. There are believed to be upwards of 1 million precision GPS receivers in use in the U.S., said Martin Harriman, executive vice president of ecosystem development and satellite business at LightSquared.

As they did last month, the companies held up Javad's solution as proof that the interference is not an unsolvable problem as many GPS backers have claimed. Instead, efforts to block LightSquared are aimed at protecting the interests of the GPS industry, they said.

"This is not a law of physics issue," Harriman said. All the components of Javad's solution are available off the shelf today, the companies said. "Smart engineering is what is needed to attack this problem quickly," he said. Javad said the idea that the interference problem can't be solved stems from a misunderstanding of a solution that he presented several years ago.

The Coalition to Save Our GPS, which represents GPS vendors and users, downplayed the potential value of the new technology.