一种可用于预白化类空时自适应处理中的阵元误差校正算法

Array Error Calibration Algorithm Pre-whitened Space-Time Adaptive Processing

在非均匀杂波环境中,预白化类空时自适应处理(STAP)具有较高的收敛速度,可显著提高雷达的杂波抑制性能。但在实际阵列接收系统中,阵元误差的存在会使预白化类STAP性能严重下降。针对此问题,提出了一种基于杂波回波的阵元误差校正算法。该算法首先将阵元误差表示为方位依赖的幅相误差;然后将空间各个方位的主瓣杂波作为校正源,利用其阵列输出协方差矩阵的Toeplitz结构会在阵元误差影响下发生改变的特性,估计相应方位的阵元幅相误差;最后利用估计的幅相误差校正先验协方差矩阵和假定目标的导向矢量。仿真结果表明:当阵列接收系统存在阵元误差时,阵元误差校正算法可明显改善预白化类STAP算法的杂波抑制性能。

Pre-whitened space-time adaptive processing(STAP)can obtain fast convergence rate and achieve better clutter suppression performance in heterogeneous clutter environment.However,pre-whitened STAP shows significantly performance degradation in the presence of array errors.To solve this problem,we propose a novel algorithm based on clutter echo to calibrate the array errors online.Firstly,the array errors are represented as orientation-dependent gain-phase errors.Then,the main-lobe clutter in every direction will be used as calibration source,and the gain-phase errors in the corresponding direction can be estimated on the basis of the property that its covariance matrix of the array output does not preserve the Toeplitz structure due to the effect of the array errors.Finally,the estimated gain-phase errors are used to calibrate the prior covariance matrix and the assumed target steering vector.The simulation results show that the proposed algorithm can improve the clutter suppression performance of the pre-whitened STAP.