DRM外辐射源雷达多普勒扩展杂波抑制算法研究

数字调幅广播(DRM)外辐射源雷达面临严重的多径杂波问题,其中不仅包含静止地面散射物引起的无多普勒频移多径杂波,还有经运动海面等散射引起的具有多普勒频移扩展的多径杂波。扩展相消杂波抑制类(ECA)算法常被用于无源雷达杂波抑制,但均仅针对无多普勒频移的多径杂波。文中建立了考虑多普勒频移扩展杂波的该无源雷达信号模型,结合信号波形特点提出了载波域ECA算法(ECA-C)的扩展算法,深入分析了扩展ECA-C算法的多径杂波抑制机理。该方法通过对各载波信号组成进行分析,构造相应的杂波子空间,利用子空间正交投影可同时对静止的和具有多普勒频移的多径杂波进行抑制,提高了系统的杂波抑制能力,进而改善了弱目标检测能力。理论分析和实测数据处理结果表明了该算法的优越性。

Non-zero Doppler Shift Multipath Clutter Suppression in DRM-based Passive Bistatic Radar

DRM digital AM broadcasting-based passive radar faces serious multipath clutter problem, which not only contains zero Doppler-frequency-shift multipath clutter caused by static ground scattering objects, but also exists multipath clutter with doppler frequency shift caused by the moving sea surface or other scatters. The extensive cancellation algorithm ( ECA) is often used to suppress multipath clutter in passive radar, but only for the zero-doppler-frequency-shift multipath clutter. In this paper, the passive radar signal model considering multipath clutter with doppler shift is presented. Combining with the characteristics of the signal waveform, an extension algorithm of ECA in carrier domain is proposed. The multipath clutter suppression mechanism of the extended ECA-C is analyzed in-depth. The method firstly analyzes the component of each carrier signal, constructs the corresponding clutter subspace, and uses the subspace orthogonal projection for suppression of both the multipath clutter with zero and non-zero doppler frequency shift. It can improve the clutter suppression ability of the system, and thus improve the capability of weak target detection. Theoretical analysis and the measured data processing results show the superiority of the proposed algorithm.