GPS的码跟踪误差检测器与伪距测量的预处理

On Suitable Relaxation of Limitation of ±1 Chip for GPS Utilization in China

本文讨论了采用扩大范围码跟踪误差检测器的延时锁定环的设计方法。

In the case of GPS (Global Positioning System) state 3, the tracking of C/ A signals available to China is very difficult if not impossible and, as is well known, requires aiding from INS (Inertial Navigahon System). INS available in China is of low accuracy. In order to make such INS to be effective as aiding to GPS and to improve the robustness of the whole GPS/ INS system, it is, in the authors' opinion, necessary to relax the limitation of ±1 chip (such limitation is dcemed quite acceptable in developed countries) on the code tracking error detector.In order to relax the above-mentioned limitation, the authors form a drive signal of the loop from cross correlation operations of many shifted signals of the input and local code. This relaxation brings in increased noise, which the authors consider can be eliminated by very narrow bandwidth. The correlated noise of pseudorange measured by narrow bandwidth code tracking loop can be compensated for with an adaptive code tracking error estimator. Simulation results indicate preliminarily that authors' proposal is effective.