Abstract: A system and method are described for mitigating the jamming or spoofing of information that is used in a Global Navigation Satellite System (GNSS) geolocation system, such as the Global Positioning System (GPS). In an area of interest where accurate geolocation information is critical—for example, at an airport, harbour, or other locations where accurate navigation is critical—several receiving stations having known and pre-determined geolocations are positioned. These receiving stations receive location signals from a constellation of geolocation satellites, and send the information about received signals to a central processing hub. The processing hub includes facilities to compare location information received by a particular receiving station and to determine whether the location information received by that receiving station from a particular satellite is consistent with known location information about that receiving station.