基于简化差分相干积累的北斗B1频点信号精捕获算法

北斗卫星信号的捕获速度、灵敏度及精度将直接影响接收机的性能指标.本文提出了一种提高北斗导航卫星B1频点信号检测信噪比的精捕获算法,该算法基于简化差分相干积累（SDCI）的短时匹配滤波器（STMF）和快速傅里叶变换（FFT）运算（STMF-FFT）.为了保证在降低FFT运算量和提高信号检测概率的条件下,获得更精确的多普勒频率估计,采用逼近效果较好的切比雪夫线性最小二乘曲线拟合法得到多普勒频移的精确化估计值.理论分析和仿真验证表明：本文提出的SDCI算法比非相干积累算法获得的检测信噪比高约3.2 dB.

BeiDou B1 signals fine acquisition algorithm based on simplified differentially coherent integration

The speed, sensitivity and accuracy of acquiring BeiDou satellite signals are critical perfor mance index for a BeiDou receiver. In this paper, a fine acquisition algorithm is proposed, which has improved the detection signal-to-noise ratio （SNR） of BeiDou B1 signals. This algorithm is on the ba sis of short time matched filter （STMF） and fast Fourier transform （FFT） of simplified differentially coherent integration （SDCI）. To obtain accurate estimation of the Doppler shift with low amount of FFT calculation and high probability of signal detection, Chebyshev linear least squares curve fitting is adopted. Theoretical analysis and simulation results show that the SDCI algorithm allows an approximate 3.2 dB improvement in the detection SNR compared to non-coherent integration method.