通信辅助卫星导航接收机最优捕获灵敏度分析

Optimum Acquisition Sensitivity Analysis of Communication Assisted GNSS Receivers

通信辅助有助于降低卫星导航信号捕获的搜索模糊度,因此接收机可通过改进捕获算法以提高捕获灵敏度。但是,目前在同等条件下捕获灵敏度提升量与通信辅助精度的量化关系尚不明确。通过约束平均捕获时间和捕获算法计算复杂度两项指标的门限值,对接收机辅助信息精度与捕获灵敏度提升量之间的关系进行量化分析,得出相应条件下的最优捕获算法参数。分析表明,在频率搜索范围以1/2的幂次进行逐渐压缩的过程中,捕获灵敏度提升量最高约为4dB,且随频率搜索范围压缩程度的提高而逐渐缩小。根据评估方法得到的最优捕获算法参数受捕获概率指标、虚警概率指标等影响较小,可预置于接收机中,根据具体情况进行选择。

Assistance information is helpful for GNSS receivers to reduce the search ambiguity,therefore receivers are able to improve acquisition sensitivity by optimizing the acquisition algorithm.However,the quantitative relationship between acquisition sensitivity increment and the accuracy of assistance information is not clear.This paper analyzes the relation between the accuracy of assistance information and the acquisition sensitivity increment through constraining the thresholds of mean acquisition time and the algorithm calculation complexity.And the optimized parameters for acquisition algorithm are obtained for different conditions.The analysis shows that when the search range of frequency compresses by the order of 1/2,the highest acquisition sensitivity increment is about 4dB and the increment decreases with the compression of the frequency range.The optimized parameters for acquisition algorithm are barely affected by the index of probability of acquisition and false alarm.Therefore,the optimized parameters can be preset in the receiver and adopted according to specific conditions.