The phone conference was in response to a PNT EXCOM letter statement released Jan. 13, which stated that the 4G LTE network operator’s plan to use Inmarsat lower frequency signals would still affect spectrum utilized by the Global Positioning Satellite (GPS) system. “It is the unanimous conclusion of the test findings by the National Space-Based PNT EXCOM Agencies that both LightSquared’s original and modified plans for its proposed mobile network would cause harmful interference to many GPS receivers,” the letter said.

   According to Carlisle, some of the devices that PNT EXCOM tested have been out of production for more than a decade and that manufacturers of GPS receivers and government end-users rigged the process to produce bogus results. He also emphasized that many of the members on the PNT EXCOM board have professional ties to the GPS industry.

   “The GPS manufacturers cherry-picked the devices in secret without any independent oversight authority in place or input from LightSquared,” Carlisle said. “The testing protocol deliberately focused on obsolete and niche market devices that were least able to withstand potential interference … The PNT EXCOM selected an extremely conservative definition of failure — one dB of interference. Independent experts agree that a one dB threshold can only be detected in laboratory settings and has no impact on GPS positional accuracy or user experience.”

   Former U.S. Federal Communications Commission (FCC) Chief Engineer Edmond Thomas also spoke on the conference call and seconded Carlisle’s claims. “GPS and government end-users should have opened the process for transparent review, chosen a representative sample of devices that reflects the scope of general purpose GPS receivers in the marketplace today, applied best practice standards to the testing protocol and — most importantly — the tests should have been conducted by an independent laboratory rather than by the GPS manufacturers themselves,” Thomas said.

   LightSquared said it has called on the U.S. National Telecommunications and Information Administration (NTIA) to re-evaluate the initial round of testing and the mitigation proposals the company has proposed. The company also called on the FCC and the NTIA to conduct the second round of tests on high-precision devices at an independent laboratory.