数字相控阵雷达步进频合成宽带宽角扫描研究

A Study on Wideband and Wide-angle Scanning by Stepped Frequency Synthesis for Digital Phased Array Radar

数字相控阵雷达宽带宽角扫描存在波束指向偏差和孔径渡越问题,导致信噪比降低,脉压主瓣展宽,距离分辨率下降。频率步进信号在各脉冲周期内都是窄带信号,是常用的合成宽带信号,可以在获得距离高分辨率的同时降低对雷达瞬时带度的要求,从而降低了对雷达系统的要求。将步进频合成宽带技术应用到数字相控阵雷达,采用子脉冲移频移相方法可以消除波束指向偏差和孔径渡越影响,实现数字相控阵雷达宽带宽角扫描。并通过仿真计算,给出一些对工程实现有用的结论。

For wideband, wide-angle scanning of digital phased array radar there exists a problem of beam pointing deviation and aperture transit time, which leads to reduction of signal to noise ratio, widening of pulse compressed signal mainlobe, lowering of range resolution, etc. Frequency-stepped signal which is a narrow band signal at each pulse period, is often used in wide-band sig- nal synthesizing. It is possible to achieve high resolution while keeping radar instantaneous bandwidth low. As a result, radar system requirement is low. Application wideband technology of stepped frequency synthesis to digital phased array radar solves this problem. In this paper, we prove that adopting method of sub-pulse frequency shifting and phase shift eliminates beam pointing deviation and effect of aperture transit time, thus realizing wideband, wide-angle scanning of digital phased array radar. Through simulation and calculation, some useful for engineering conclusions were obtained and presented here.