GNSS 信号捕获的包络损耗及其补偿方法

摘要

In order to decrease the influence of GNSS ( global navigation satellite system) signal′s envelope loss on detection probability, the cause of this phenomenon is analyzed theoretically for serial/parallel acquisition.Increas-ing frequency search domain or zero-padding technique can improve signal′s average gain, but increase more search time or computation augment.Interpolation between adjacent frequency points can reduce the envelope loss obvious-ly with low computation load.The compensation on the main/subject envelope which is easy to perform can recover signal energy by 3 dB.Simulations and FPGA test demonstrated the effectiveness of this approach, which is espe-cially beneficial to weak signal acquisition.%为了减小GNSS（ global navigation satellite system）信号包络损失对发现概率的影响，理论分析了串行捕获和并行捕获下包络损失的形成原因。采用增加频域搜索范围或者补零等传统方法可以改善信号平均增益，但是会增加搜索时间或者增加运算量。采用频点间内插的方法可以在运算量增加不大的情况下大幅改善包络损失的影响。通过子包络补偿和主包络补偿2种方法可以改善信号增益达3 dB，其运算简单、易于实现。仿真与FPGA测试证明了内插方法的有效性，其有利于GNSS弱信号的捕获。