无源双基地雷达直达波脉冲丢失与相位突变影响分析

摘要

The amplitude and phase modulation caused by the rotating transmit antenna pattern results in pulses loss and phase reversal within the direct-path pulse train. The loss mechanisms of signal to noise ratio (SNR) were discussed for these modulation phenomena. With respect to the ordinal number of pulses loss or/and phase reversal happened, the analytical expressions for the peak output of CAF were derived.Simulation results show that the maximum loss in SNR is less than 4 dB,and the SNR loss curves of different Doppler frequencies and number of pulse loss are conformed to the analysis in theory. The maximum error of Doppler frequency estimation is about 0.75 of the frequency resolution cell.%针对利用天线在方位上机械扫描的脉冲雷达为外辐射源的特殊性,首先分析了发射天线主波束在目标驻留时间内,从其副瓣波束截获的直达波存在脉冲丢失或/和180°相位突变的现象,然后分别推导了互模糊函数峰值输出与脉冲丢失总数、相位突变及其对应脉冲序数间的理论关系,并仿真分析了脉冲丢失或/和相位突变对信噪比损失和多普勒频率估计的影响.由仿真结果发现,脉冲丢失或/和相位突变引入的最大信噪比损失约为4dB,对应的最大多普勒频率估计误差约为频率分辨单元的0.75倍,且其变化规律与理论分析结果相同.