GPS Spoofing Mitigation using Adaptive Estimator in Tracking Loop

The attacks such as spoofing is one of the main sources of error in tracking of Global Positioning System (GPS) receivers. The aim of these attacks is to calculate fake time and position. The spoofer sends the counterfeit signal and causes to spoof. This counterfeit signal is generated in different ways. In this paper, the studied interference is the delay spoof. Indeed, the aim is introducing a new approach in tracking loop of the GPS receiver in order to decrease the generated delay by spoof attack. The suggested algorithm has two main steps. The first step estimates the amount of delay spoof. Subsequently, through an innovative approach, the effect of spoofing signal is extracted and then subtracted from the total measured correlation function. To achieve that, the effect of spoofing signal is estimated and the estimated spoofing signal is generated separately. For this purpose, two estimator based on multi-correlator and adaptive approach is introduced. Correlation of this signal with the digital IF signal is calculated and entered into the spoof mitigation part. In this part, correlation of this signal is added to auto-correlation of received signal and correlation of authentic signal is achieved. These techniques provide easy-to-implement and quality assurance tools for anti-spoofing. Applying the proposed algorithm decreases the average spoofing error by 88%.