STAP中直接数据域算法的一种改进

An improved direct data domain algorithm in STAP

Sarkar等人提出的直接数据域算法中,利用时域两脉冲(或空域两阵元等)加权对消实现对感兴趣信号(SOI)的去除,得到不含感兴趣信号(SOI)只含有干扰信号的样本,进而估计滤波权。但由于预处理使用的是一维滤波,在SOI去除的同时,也对消了一部分杂波,使得估计的杂波能量不足,引起改善因子损失,因此对消滤波器阻带带宽应尽量小。而由于实际应用中一般不可能精确已知SOI方向,过窄的滤波带宽往往又不能完全对消SOI。为了提高SOI的误差鲁棒性,同时改善杂波抑制性能,提出了一种改进的算法,先用MTI(三脉冲对消)抑制主瓣杂波,再用一种改进的直接数据域方法抑制其它杂波。仿真结果验证了该算法的有效性。

In the traditional direct data domain algorithm proposed by Sarkar, signal of interest（SOI） is canceled by weighted cancellation using two consecutive pulses at the same antenna （or two consecutive antennas at the same time）, and then one can get signal without SOI, which only possesses samples of disturbing signal. Furthermore the filtering weight can be estimated. Due to this preprocessing,weighted vector trained from the processed data can extract the SOI from the original sample snapshot. Due to that the preprocessing is operated only in one dimension, not only the SOI but also part of clutter are canceled, which is unexpected and results in the inadequacy of the estimated clutter energy and the loss of the improvement factor. Therefore, the stopband of the preprocessing filter should be as narrow as possible. However, in the real application, it is impossible to know the direction of the SOI accurately, if the stopband is too narrow, the SOl would not be canceled completely. To enhance the robustness of the SOI error, and improve the capability of the clutter suppression, this paper proposes an improved method, which uses a MTI （three pulse canceller） to suppress the mainlobe clutter, following uses a modified direct data domain approach to suppress other clutter. The simulation results proved the validation and the effectivity of this method.