Who's Afraid of the Spoofer? GPS/GNSS Spoofing Detection via Automatic Gain Control (AGC)

The idea of Global Positioning System (GPS)/Global Navigation Satellite System (GNSS) "spoofing," or the ability to mislead a satellite navigation receiver into establishing a position or time fix which is incorrect, has been gaining attention as spoofing has become more sophisticated. Various techniques have been proposed to enable detection if a receiver is being spoofed - with varying degrees of success and computational complexity. In this paper, a monitor in the Radio Frequency (RF) front end using the automatic gain control (AGC) mechanism is outlined. It has low computational complexity and is an extremely powerful means to detect spoofing, making spoofing no more of a threat than the much less sophisticated radio frequency interference/ jamming. The technique is validated using live testing. Copyright (C) 2012 Institute of Navigation.