Tracking Bias of Navigation Signal on Performance of Post-correlation MMSE Anti-jamming Algorithm

Adaptive antenna array technique is an effective method for interference mitigation in Global Navigation Satellite Systems (GNSS) receivers. Among which, minimum mean square error (MMSE) algorithm could maximize the GNSS signal and reject interference, by minimizing the mean-square-error between the array output and a reference signal. Its performance depends on the reference signal that used. In practice, an ideal reference signal is difficult to obtain directly due to the low power of satellite signals. Thus MMSE algorithm is usually performed after code correlation when a local reference signal could be recovered from tracking results. However, due to the existence of tracking bias, the recovered local reference signal will deviate from an ideal one, resulting in performance deterioration. This paper analyzes the impact of tracking bias including code phase bias, carrier phase bias and carrier frequency bias, on performance of the post-correlation MMSE algorithm. The results show that, the loss of the array output SINR (signal to interference plus noise ratio) caused by tracking bias is ignorable considering the precision of the current tracking loops techniques. The performance of the post-MMSE algorithm approaches to that of an optimal beamformer.