A Kalman Filter Based Method for GPS Spoofing Detection

Abstract

It is well known that the GPS signals are weak, and therefore are vulnerable to various kinds of interference, intentional or unintentional. Spoofing is one form of intentional interference, or an attack. Unlike GPS signal jamming, GPS signal spoofing is an attack with a low profile, deceiving a given receiver silently. It is therefore much more difficult to detect than jamming. In this paper a new method of detecting a GPS spoofing attack is proposed. During a spoofing attack, the spoofer will use a stronger spoofing signal than the GPS signal to take over a target GPS receiver at some point in time. Since a spoofing signal will never be exactly the same as the authentic GPS signals in all aspects, the receiver carrier frequency tracking loop will react to such a spoofing attack during its takeover, which will produce a jitter in the receiver tracking loop that has its own characteristics. A Kalman Filter aided carrier frequency tracking loop in the GPS receiver is proposed to monitor the behavior of the tracked carrier frequency. A test function is proposed which is used to automatically decide if a spoofing attack does happen or not. Statistical simulation tests have been performed which show that this new method is effective and relatively reliable for spoofing detection.