GPS Interference Concerns Revived
An attempt to launch a high-speed cellular network that raised alarm over GPS interference was squelched by federal regulators back in 2012, but now the same company is proposing a new network, and GA advocacy groups have banded together to oppose it. Ligado Networks, formerly known as LightSquared, claims its technology has improved, and will disrupt GPS signals only within 500 feet of its transmission towers. That’s not good enough, says the GA coalition in a letter (PDF) sent to the FAA on Wednesday. Plenty of aircraft, including drones, on a variety of missions, operate in close proximity to flight obstructions, the letter states, and therefore a loss of navigational accuracy in those areas would have “adverse impacts on the ability to safely navigate.”
The coalition asks the FAA to support further testing and evaluation of the proposed system, to be conducted by an impartial third-party organization, so “we may fully understand the impacts to GPS-dependent systems and to ensure no degradation of safety within the NAS.” The letter is signed by 11 groups representing GA interests, including AOPA, NBAA, ALPA, Helicopter Association International, National Agricultural Aviation Association and National EMS Pilots Association. Ligado said in a statement last month that it will protect certified aviation GPS devices by reducing the power level at which certain of its downlink connections operate. “This change reflects our collaboration with the Federal Aviation Administration and honors our pledge to find consensus with government and industry actors,” the company said.
An industry newsletter, Inside GNSS [Global Navigation Satellite Systems], reported on Monday that key federal regulators met three months ago to discuss the issue with Ligado but have not yet released their recommendation on whether or not to allow the development of the service. Subsequently, Ligado modified its license request, making a frequency change the company said would avoid interference with certified aviation GPS receivers. However, testing by the Transportation Department found that the limits set for certified aviation receivers did not protect receivers in all other categories, according to Inside GNSS.