GNSS Spoofing Detection Based on Decomposition of the Complex Cross Ambiguity Function

In this paper, we describe, implement, and validate a new method to decompose the Complex Cross Ambiguity Function (CCAF) of spoofed Global Navigation Satellite System (GNSS) signals into their constitutive components. The method is applicable to spoofing scenarios that can lead to Hazardous Misleading information (HMI) and are difficult to detect by other means, including previously proposed methods that rely on observation of the magnitude of the CCAF alone [1]. The method can identify spoofing in the presence of multipath and when the spoofing signal is power matched and offsets in code delay and Doppler frequency are relatively close to the true signal. Spoofing can be identified at an early stage within the receiver and there is no need for any additional hardware.