高动态弱信号环境下基于INS的GNSS捕获方法分析

为保证GNSS在挑战环境下的捕获性能,分析了高动态弱信号捕获存在的问题,提出了一种新的INS辅助并行码相位捕获方法,在频域利用INS辅助信息卫星星历/历书数据估计多普勒,缩小频率搜索范围,在码域利用码相位估计及并行码相位搜索的方法,减少码相位搜索时间,最后结合差分相干累积提高捕获灵敏度,实现高动态弱信号的快速捕获。仿真结果表明,该算法能显著提升高动态、弱信号环境下GNSS接收机的捕获性能。

Analysis of GNSS Acquisition Method Based on INS in High Dynamic and Weak Signal Environment

In order to ensure the acquisition performance of GNSS in challenging environment, the problems existing in high dynamic weak signal acquisition are analyzed and a new ins assisted parallel code phase acquisition method is proposed, which uses ins assisted information and satellite ephemeris/almanac to estimate doppler in frequency domain to reduce the frequency search range, and uses code phase estimation and parallel code phase search in code domain to reduce the code phase search time. This method improved the acquisition sensitivity combined with differential coherent accumulation to realize the fast acquisition of high dynamic weak signals. Simulation results showed that the algorithm can significantly improve the acquisition speed and performance of GNSS receiver in high dynamic and weak signal environment.