基于波束域分块RDLMS的机载外辐射源雷达杂波对消算法

Clutter Cancellation Algorithm for Airborne Passive Radar Based on Block RDLMS in Beam Domain

针对机载外辐射源雷达多普勒展宽的杂波对消问题,该文首先从降低计算量的角度出发,提出了波束域分块RDLMS算法。通过波束形成降低了多普勒维对消阶数,通过分块减小了迭代次数并可以利用FFT快速实现。分析表明,所提算法能够大幅降低杂波对消的计算量,为实时处理提供了支撑。其次,在处理性能方面,由于算法对所有滤波器系数采用相同的步长,当杂噪比较高时会有较大的对消残余;根据系数比例自适应算法的思想,该文提出了改进算法,对不同的滤波器系数采用不同的步长,步长的大小与滤波器系数的对数成正比。仿真表明,改进算法使杂波对消残余降低了1.3dB,对消性能接近理想。

For the cancellation of Doppler-spreading clutters of airborne passive radar, firstly, Block RDLMS in beam domain is proposed in order to reduce computational load. In the proposed algorithm, the order of cancellation in Doppler dimension is reduced by beamforming, and the iteration of adaptive processing is reduced by data segmenting, while FFT can be employed. It is verified that the proposed algorithm can reduce computational load substantially, which is valuable for real-time cancellation. Secondly, the improved algorithm is developed based on the idea of proportionate adaptation. Because the same step is assigned to all weights in the proposed algorithm, there will be relatively more residual clutter when the Clutter to Noise Ratio （CNR） is higher. The improved algorithm will assign different steps proportional to the logarithm of corresponding weights. Simulations show that by using the improved algorithm the residual is reduced 1.3dB and the performance of clutter cancellation approaches the ideal case.