In a recent AW&ST viewpoint, former NASA Administrator Dan Goldin argued in defense of the FCC’s flawed decision to allow high-power terrestrial transmitters in the quiet band of frequencies that includes GPS (AW&ST July 13-26, p. 74). Sadly, Goldin missed the whole point of the intense outcry against the FCC’s grave error: The FCC has failed to protect GPS, an incredibly valuable national treasure. The commission’s ruling benefits investors in one company but would do irreparable harm to millions of American GPS users. This is a sad replay of Ligado’s previous incarnation, LightSquared.
Extensive U.S. Transportation Department testing demonstrated that virtually all civil GPS applications would be threatened, not only by the new 10-watt transmitters located on every other street corner, but potentially by millions of Ligado’s mobile devices. Both segments raise the GPS signal noise floor.
Their transmitters would be 2 billion times more powerful than the GPS signals for a GPS user—equivalent to trying to hear a whisper with 100 jets taking off. Of particular concern is the impact on aviation (including UAVs, helicopters, automatic dependent surveillance-broadcast, terrain avoidance and warning systems and commercial aircraft communications/air traffic control). This degradation could markedly increase the risk of midair collisions and controlled flight into terrain.
