A New Method for Continuous Wave Interference Mitigation in Single-Frequency GPS Receivers

Abstract

This paper proposes a new method for jamming suppression in the global positioning system (GPS) receivers. The proposed mitigation technique is based on cascading the adaptive finite impulse response (FIR) filter and the approximate conditional mean (ACM) filter. Adaptive FIR filter puts a notch at the interference frequency, but it causes self-noise in presence of high power jammers. ACM filter is an effective filter for estimating the jamming with known autoregressive process model parameters. However, its performance is degraded in the cases of high power interferences. Cascading these two filters has two advantages: first, collaboration of these two filters can help removing high power jammers. Second, the depth of notch can be limited by a threshold in presence of high power jammers to prevent self-noise effect. In such a case, the ACM filter can help to remove the remaining jamming effects on GPS signal. The performance of proposed method is analyzed in presence of single and multiple continuous wave interferences. Experimental results show the benefits of proposed method on terms of signal to noise power ratio improvement and mean square error compared to previous methods.