LightSquared Claims Solution to GPS Interference
LightSquared said Wednesday it has an affordable solution to interference between its 4G network and GPS systems and will have working units available for tests planned by the U.S. government in the coming months.
The hybrid satellite and LTE (Long Term Evolution) carrier said the technology was developed by Javad GNSS, an established maker of GPS equipment, and would all be available on the market by March. LightSquared wants it to be available as a retrofit to existing GPS receivers where possible, but some users might need to replace their existing receivers. On a conference call Wednesday, the companies did not forecast the cost of the solutions.
Tests have shown LightSquared's proposed LTE network, which would operate in a spectrum band now devoted to satellite services, would run into interference with most GPS products in the upper part of its band and with some high-precision units in the lower part of its band. The solution would work only in the lower band, and LightSquared said it does not plan to use the upper band for some time, according to Martin Harriman, executive vice president of ecosystem development and satellite business.
Many GPS proponents have said no practical filter can be built that would solve the interference problem. But the solution developed by Javad proves that the problem in the lower block can be solved with technology that is already available, Harriman said.
"It dispels the myth that this can't be done," Harriman said. "We've done it, we've tested it, it works."
LightSquared's plan for a hybrid satellite and LTE network across the U.S. has faced strong opposition from users and makers of GPS, who have said the company should not be allowed to use the satellite band for the land-based network. The controversy has grown into a political firestorm because of allegations that the Obama administration has favored LightSquared because of contributions to Democrats by LightSquared executives.
Javad has built and tested prototypes of GPS receivers for high-precision positioning and for high-precision timing, LightSquared said. Preproduction units of both will be available for public tests beginning next month. The positioning products are expected to hit the market in November and the timing devices next March. The units would be available in time for testing by the NTIA (National Telecommunications and Information Administration) that is expected to conclude by the end of November, Harriman said.
These types of devices, which use an augmented form of GPS, are used for specialized applications in agriculture, surveying and other areas, not for consumer uses of GPS.
On the conference call, Harriman pushed back his forecast for when the U.S. Federal Communications Commission would give LightSquared the go-ahead to operate its LTE network. Because of the NTIA tests, he now does not expect an approval until after the end of November, rather than by the end of this month as he had recently predicted.