Detection of Spoofing using Differential GNSS

One of the main problems in modern navigation of both manned and unmanned transport systems is that of transport safety. Differential GNSS technology has been used to improve the accuracy of transport positioning, in which position is calculated relative to a fixed reference station with a known position XYZ. Unfortunately, GNSS is vulnerable to malicious intrusion. GNSS signals and/or correction signals from the reference station can be spoofed by false signals, and special receivers have been used to provide defenses against such attacks. But how can the roving receiver (i.e. the user) be sure that the information they receive is authentic? Spoofing is the transmission of a matched-GNSS-signal-structure and/or signals to a reference station in order to cause interference and attempt to commandeer the tracking loops of a victim receiver, thereby allowing manipulation of the receiver’s timing or navigation solution. A spoofer can transmit its counterfeit signals from a stand-off distance of several hundred meters, or it can be co-located with its victim. In this article we consider the principles of spoofing detection using Differential GNSS, in which a correction signal from the reference station is used for the detection of spoofing.