Tracking Error Analysis and Performance Evaluation Method for GNSS Non-coherent Vector Tracking Loop

Abstract

It is hard to accurately analyze the performance of non-coherent (NC) Global Navigation Satellite System (GNSS) vector tracking loop (VTL) according to tracking error because of tracking error propagation between tracking channels and the non-linear nature of NC-VTL. To solve this problem, this paper first analyzes NC-VTL algorithms and proposes a vector code loop control algorithm, which can be easily implemented in both hardware and software GNSS receiver. Secondly, the tracking error propagation of NC-VTL is analyzed in detail. The mathematic formula, that describes the relationship between tracking error and navigation error, timing error, ephemeris error, satellite clock bias error, atmospheric correction error, ionosphere correction error is deduced. Thirdly, according to these equations, the performance evaluation method based on semi-analytic framework for NC-VTL is established. This method can flexibly set simulation scene, NC-VTL parameters and accurately calculate the signal tracking error and navigation error. The mixing and correlation operation are discarded in this method with realistic simulation for NC-VTL’s running reserved. Thus this method provides a flexible, fast way to accurately and reliably access the performance of NC-VTL. In the end, a sample evaluation result is displayed to verify the effectiveness of this evaluation method.