Abstract: What is disclosed is a GNSS based navigation operations monitoring system and method. Reports are received from a number of stations that indicate: locations of the station by a GNSS receiver; reported locations of a vehicle determined by a GNSS receiver and communicated in a location reporting signal transmitted by the vehicle; and received signal strength of the location reporting signal. GNSS navigation abnormalities are determined based on inconsistencies between reported locations of the vehicle and the received signal strengths. A geographic location of the abnormality is reported based on determining the GNSS navigation abnormality.