A proposal to launch a high-speed cellular communications network, which could potentially interfere with GPS, is once again raising red flags for aviation groups, including AOPA. The proposal comes from Ligado Networks, formerly known as LightSquared, which in 2011 and 2012 became embattled with the FCC and the aviation industry over potential GPS interference issues. Ultimately the FCC revoked the company’s conditional approval to begin construction of a network, forcing LightSquared into bankruptcy in 2012.
In the latest round, AOPA and 10 other industry groups sent a letter on June 15 to the FAA calling on the agency to conduct further testing by an impartial third party to ensure the cellular signals, which are in a satellite frequency band very near GPS frequencies, won’t cause any disruption for GPS systems including for aircraft operating near the towers.
As stated in the letter, “There remain outstanding issues that call into question the impacts such a system would have on airspace safety, specifically as it relates to both certified and uncertified GPS systems, continuity of navigational accuracy at low levels, and effects on other safety of flight systems to include satellite communications.”
Ligado claims its technology has improved since 2012 and it will only disrupt GPS signals within 500 feet of the transmission towers, but GA organizations aren’t convinced.
“Interference issues that have the potential to negatively impact the operational aviation environment remain unresolved, and require definitive testing and evaluation before any system deployment,” the letter stated. Since 2012, the number of unmanned aircraft, which are especially reliant on GPS, has ballooned, and many such aircraft fly at low altitudes and would be particularly likely to operate within 500 feet of Ligado cell towers.
Along with AOPA, the letter was signed by the National Business Aviation Association, Air Line Pilots Association, Airborne Public Safety Association, Airlines for America, Association of Air Medical Services, Helicopter Association International, Helicopter Safety Advisory Conference, National Agricultural Aviation Association, National EMS Pilots Association, and Professional Helicopter Pilots Association.