直射通道辅助的北斗弱反射信号捕获算法

针对利用北斗卫星信号进行海面非协同探测系统中微弱反射信号的捕获问题，提出了一种利用直射通道辅助反射通道进行信号捕获的算法。在短时匹配滤波器-快速傅里叶变换（STMF-FFT,Short-Term Matched filtering-Fast Fourier Transform）和差分相干积累（SDCI,Simplified Differentially Coherent Integration）的信号捕获算法的基础上加入直射通道辅助信息，缩短搜星时间和频移-码相位二维搜索范围，提高了反射信号捕获灵敏度，缩短了信号捕获时间。仿真结果表明，基于直射通道辅助的北斗弱反射信号捕获算法能够捕获-151.3dBm的弱反射信号，相较无辅助算法，捕获灵敏度提高3.1dB，平均捕获时间缩短39.5s。 

BeiDou Weak Reflected Signal Acquisition Algorithm Assisted by the Direct Channel

Aimed at the problem which takes advantage of Beidou Satellite Signal to test weak reflected signal within Non-cooperative Detection, this article comes up with the algorithm by utilizing the auxiliary of direct channel reflected channel to achieve signal acquisition. The article adds the auxiliary of direct channel information to the algorithm which combines with Short-term matched filtering-Fast Fourier Transform Algorithm(STMF-FFT) and Simplified Differentially Coherent Integration(SDCI) , in order to shorten the satellite search time,narrow the scope in two-dimension of frequency and code phase and improve the sensitivity of testing weak reflected signal and time of signal acquisition simultaneously. In the end, the simulations reveal that the acquisition sensitivity of this kind of algorithm can acquire the weak reflected signal power reduced to 151.3dBm and increased by 3.1dB compared with non-auxiliary algorithm.The average acquisition time shorts 39.5s.