应答机对称天线干涉对雷达信号影响分析

针对测速雷达在目标旋转时,由对称天线导致的下行信号干涉问题,通过理论分析远场条件下信号干涉合成方向图变化情况和双基微多普勒计算方法,提出了一种分析干涉区前后多普勒阶跃的方法。通过分析测速雷达记录数据中AGC(Automatic Gain Control,自动增益控制)电平、多普勒和综合误差电压,再利用小波变换和自相关方法,可以提取微多普勒信息和微多普勒周期。理论分析和数据验证可知,信号干涉区出现在对称天线中间±20°左右,雷达接收AGC电平在干涉区下降10~20dB,多普勒差分出现峰值,微多普勒在干涉区前后出现正负峰值,综合误差电压会显著增大。这些结论有利于认识干涉现象对测速设备接收信号的影响。

Analysis of Radar Signals Induced by Symmetric Antenna Interference Region of Transponders

For research on the effect of signal interference induced by symmetric antennas of rotating target with the Velocity Measurement Radar (VMR),factors including Automatic Gain Control (AGC),Doppler,micro-Doppler and error voltage of VMR were analyzed in theory,and a method for computing the difference of Doppler before and after the interference region was proposed.Then we processed radar data to find secrets about the factors of AGC,Doppler and error voltage when radar antennas are in interference region,obtained the micro-Doppler and its period using the method of wavelet transform and auto-correlation.There was a conclusion through theoretical analysis and data validation,that is,the AGC value fluctuated greatly with a descending range of 10～20 dB,the Doppler jumped greatly,and the error of voltage enlarged obviously when radar antennas were in interference region,and there appeared two peak values of micro-Doppler (positive and negative) at the moment before and after the interference region.