用杂波子空间近似法实现机载相控阵雷达的自适应杂波抑制

在机载情况下，多普勒展宽的时变杂波可以由相控阵雷达中的空间－时间处理器得到最佳的抑制。然而对于大型阵列的实时应用却很困难，这是由于这种空间－时间最优处理要求很高的计算量（大约为每次迭代Ｏ｛（ＮＭ）＾２｝，其中Ｎ为阵元数，Ｍ为时间采样数）。在本文中，首先通过杂波子空间分析证明了杂波自由度小于Ｎ＋Ｍ，且单个多勒滤波器输出的杂波自由度很小，从而可以用一个仅有Ｎ＋Ｍ个自由度的低阶处理器来实现最佳的杂波抑制

ADAPTIVE CLUTTER SUPPRESSION FOR AIRBORNE PHASED ARRAY RADARS USING CLUTTER SUBSPACE APPROXIMATION

The Doppler broadened and time varying clutter can be optimumly suppressed by a space-time processor in a phased array PD radar,but the realtime application is difficult for large arrays because of its very high computational cost (about O{(NM)2} per iteration step, where N is the number of sensors and M is the number of pulses). By clutter subspace analysis the degree of freedom of clutter is proved to be less than N + M and the degree of freedom of clutter in the output of a Doppler filter is very small,so that optimum clutter suppression can be performed by a low-order processot with degree of freedom of only N+M. The clutter subspace can be well approximated by some Doppler-eigen beams,which are Doppler filters followed by spatial eigen beams,and the low-order processor using these beams efficiently realize near-optimum clutter suppression at a computational cost of only O{ (N + M)N+(N + M)2} per iteration step. As a result of the error compensation ability of the spatial eigen beams,in realistic situations it is not sensitive to the lack of degree of freedom of the processor.