An Improved Design Method of Code Tracking Loop for BOC Modulation Signals

As the multi-peaks features exist in the high order Binary Offset Carrier( BOC) modulation signals' self-correlation functions,the span of correlation peaks after de-spreading is often affected by the noise with a low Signal-to-noise Ratio( SNR),it makes a strong impact on the performance of the code tracking loop and the accuracy of the pseudo-range. This paper introduces the classic tracking loop called Non-correlation Very Early Late Processing( VNELP) for the BOC modulation signals,evaluates the tracking performance of loop in low level SNR,and puts forward a delay accuracy branch method based on VNELP code tracking loop to make the loop processing performance for high order BOC modulation signals get better with a low SNR. The computer simulation results show that this method is feasible and can effectively improve the performance of VNELP loop.