MIMU/GPS嵌入式组合导航中GPS信号非相干搜索算法分析

对于GPS信号的搜索捕获采用长积分时间相干搜索算法,会导致频率的搜索范围增加,而采用非相干积分搜索算法将增加平方损失．针对非相干搜索算法中由于多普勒频移估计偏差和码移估计偏差的影响而导致的平方损失,提出了基于微惯性测量单元MIMU／GPS嵌入式组合导航辅助的时域非相干搜索算法来提高对卫星信号的捕获能力,并对其捕获性进行仿真分析研究．结果表明,采用MIMU辅助的时域非相干搜索算法可以提高对GPS信号的捕获能力．

Analysis on Algorithm of GPS Signal Non-Coherent Acquisition Scheme in MIMU/GPS Embedded Integrated Navigation

The signal processing for a GPS receiver is composed of the signal acquisition, the tracking, and the navigation. The goal of the acquisition is to synchronize the code phase and a carrier frequency with the income signal for a particular satellite. For the algorithm of GPS signal acquisition, the previous GPS acquisition scheme adopted not only the coherent integration acquisition technique, but also the non-coherent integration technique. Since the long coherent integration time increases the number of frequency search cells, while the non-coherent integration technique causes the squaring loss. Because of the effect of estimated Doppler frequency error and estimated code phase error on the non-coherent integration technique, this paper proposed an efficient MIMU/GPS embedded integrated navigation system to aid GPS signal non-coherent integration acquisition scheme. Expressions of detection probability and false alarm probability about GPS signal acquisition were gained in this paper. And the method of MIMU to aid GPS signal non-coherent acquisition was presented. Finally, the paper analyzed the performance of MIMU/GPS aiding GPS signal non-coherent integration acquisition. The simulated result shows the precision of the estimated doppler frequency is better than 4 Hz. The result also shows based on MIMU/GPS integrated navigation aiding, the performance of GPS signal non-coherent integration acquisition can be improved greatly.