中文摘要：

多输人多输出（MIMO）雷达是近年来出现的一种新体制雷达，针对MIMO体制的机载雷达开展空时自适应处理（STAP）技术研究是值得进一步努力的方向。本文研究了机载MIMO雷达STAP技术的降维算法，通过对STAP技术杂波抑制原理进行分析，推导并得到一种基于杂波子空间的降维算法。结合扁长椭球波函数（PSWF）的特点，提出了一种基于杂波子空间估计的降维算法，并与若干降维算法的杂波抑制性能进行比较。结果表明，当存在阵元幅相误差时，该算法在保持杂波抑制性能的同时能够有效地降低STAP算法的运算量。

英文摘要：

Multiple input multiple output （MIMO） radar is a new radar system developed recently and space time adaptive processing （STAP） for airborne MIMO radar systems deserves further research. This article mainly studies a reduced-rank STAP algorithm in an airborne MIMO radar system. According to an analysis of the clutter suppression principle of STAP, a reduced-rank algorithm based on clutter subspace is derived. On the basis of the reduced-rank algorithm, and combined with the feature of prolate spheroidal wave functions （PSWF）, the article proposes a new reduced-rank algorithm based on the estimation of clutter subspace and compares its performance with several other reduced-rank algorithms. The results show that when there exist amplitude and phase errors in the array elements, the new algorithm can effectively reduce computational complexity at the same time keep thc clutter suppression performance of the STAP algorithm.