It isn't surprising that the FCC has asked for additional testing of LightSquared's ancillary terrestrial component (ATC) using frequencies near the spectrum used by GPS and GPS accuracy augmentation systems. The potential impact of LightSquared's proposed operation has raised concerns about its impact on public safety, consumer GPS devices, aviation use of GPS and high precision GPS operations for science and industry.
In Public Notice DA 11-1537 the FCC stated, "LightSquared submitted proposed mitigation techniques to remedy the interference to GPS simultaneously with the technical working group final report. Notably, LightSquared proposed to revise its planned deployment to operate terrestrial transmitters only in the lower 10 MHz of its spectrum. The results thus far from the testing using the lower 10 MHz showed significant improvement compared to tests of the upper 10 MHz, although there continue to be interference concerns, e.g., with certain types of high precision GPS receivers, including devices used in national security and aviation applications. Additional tests are therefore necessary."
The FCC indicated the current process "is meeting our objective to fully understand the potential for harmful interference and develop solutions before LightSquared is permitted to deploy service."
The FCC is pushing for a "win-win" solution, stating that:
"We strongly encourage all parties to work in good faith and expeditiously towards a solution that serves our dual goals of facilitating the introduction of new wireless broadband services while protecting GPS against harmful interference."
It will be interesting to see if the new testing eases the concerns of GPS users and manufacturers, and if it doesn't, how the FCC will respond if both goals can't be met.