无源双基地雷达系统直达波抑制算法

Research on Direct Signal Cancellation Algorithm of Passive Bistatic Radar

无源双基地雷达系统目标时延和多普勒频移估计,一般采用直达波通道信号与目标回波通道信号作互模糊函数处理,通过搜索互模糊函数的峰值来检测目标。虽然直达波干扰信号的互模糊函数峰值出现在零时延和零多普勒频移处,但其能量远大于目标回波信号,导致信号检测噪声门限增高,旁瓣电平增大,从而淹没目标信号。利用矢量空间的最小二乘算法抑制目标通道中的直达波信号,针对计算速度问题,提出了改进算法。仿真结果表明,该算法能够明显抑制直达波信号,同时该算法也可以完成弱目标的检测,因而具有重要的应用意义。

The target parameters estimation of the delay-Doppler of passive bistatic radar is based on the Cross-Ambiguity Function（CAF） between the target echo and the direct signal channel.Although the interference signal CAF peak is located at the zero range and Doppler bin,its side lobe is still higher than the target CAF peak,so the target will be masked by the higher noise floor.In order to detect target echoes,it is necessary to cancel the direct signal in the target echo channel.The LS algorithm based vector space is proposed to resolve the problem.The result shows that the algorithm can significantly depress the direct signal;it can also detect the weak target which is masked by strong target echoes.