Applicability of Null-Steering for Spoofing Mitigation in Civilian GPS

Civilian GPS signals are currently used in many critical applications, such as precise timing for power grids and telecommunication networks. Spoofing may cause their improper functioning. It is a threat which emerges with the growing availability of GPS constellation simulators and other devices which may be used to perform such attack. Development of the effective countermeasures, covering detection and mitigation, is necessary to provide the appropriate level of protection. In this article the authors present a GPS spoofing mitigation method which uses spatial filtering (null-steering) for excision of undesired signals. The performance of this method is analyzed in various conditions. The attenuation of undesired signals, in presence of noise, is estimated. Furthermore, the statistical analysis ofthe influence of spatial filtering on the availability of true signals is provided.