LightSquared Test Plan Focused on 'Real World Levels'

LightSquared and Roberson finalized how they will gauge the scope and degree of L-band LTE network interference to GPS, if at all, they said. In a 42-page GPS sensitivity measurement plan to be filed in FCC docket 12-340, the two spell out the key performance indicators to be looked at, as well as signal-to-noise ratios and other GPS receiver data. "Emphasis is on real world expected LTE signal levels," with GPS devices being tested by Roberson for accuracy and sensitivity in the presence of LTE downlink and uplink signals, LightSquared said. The key performance indicators include 2D and 3D position errors, loss of real time kinematics and timing errors. The testing is underway now. In a statement Tuesday, the company said it expects to have results this fall. Being tested are nearly four dozen different GPS devices, ranging from high precision and aviation -- both certified and non-certified -- units to general location and navigation models and some smartphones and tablets. The LTE signals to be used in the key performance indicators testing will be 1526-1536 MHz, 1670-1680 and -- schedule permitting -- 1545-1555 downlinks, and 1627.5-1637.5 and 1646.7-1656.7 uplinks, LightSquared said. It and a variety of GPS makers have been at loggerheads over interference worries stemming from the satellite company's satellite LTE plans (see 1507020056). The GPS Innovation Alliance has criticized the test as redundant to similar efforts in the planning stages at the Department of Transportation, as well as containing questionable methodology (see 1508180019). "After years of indecision and inaction, it is time to move forward," LightSquared said in its statement.