在分析基于非合作脉冲雷达的机会探测系统特殊性的基础上,重点研究了发射天线在方位上机械扫描时,其天线波瓣图调制效应对系统相参处理输出信噪比的影响。为描述天线周期扫描对系统接收信号的调制规律,引入天线归一化场波瓣图的一般表达式,建立了直达波和目标回波信号的数学模型。然后,以理想条件下匹配滤波输出的最大信噪比为参考,推导了系统互相关处理后峰值输出的信噪比损失。最后,仿真分析了直达波和目标回波的信噪比变化对系统相参处理输出的影响,并给出了关于距离单元选择和接收机中频带宽设计的建议。
The effect of transmit antenna scanning modulation on the output signal to noise ratio(SNR)loss in a noncooperative illuminator based bistatic radar is analyzed,which is mechanically scanned in azimuth.The rotating transmit antenna modulated direct-path signal and target echo are described.The general expression of normalized filed pattern for widely used antennas is analyzed.Mathematical representations for direct-path signal and target echo are proposed.Then,with respect to the match filter,the analytical expression for SNR loss of cross-ambiguity processing is derived.The relationship between SNR loss and SNRs of direct-path channel and target echo channel is discussed by simulation.Some suggestions on range bins selection for target detection and the receivers' intermediate frequency bandwidth are presented.