基于子空间变换的机载宽带杂波抑制与扩展目标检测方法

The project will investigate on detection of weak targets using airborne wideband array radar. The signal bandwidth is increased to reduce the clutter power and the integration time is increased to improve target integration gain. The detection performance of weak target can be increased using these above technique. Unfortunately, increased bandwidth and accumulation time will cause the target range walking across range cells. In this case, the space-slow time-fast time three-dimensional processing is needed to suppress the ground clutter. Since it is very difficult to obtain the clutter covariance matrix and three-dimensional steering vector, original three-dimensional processing can not be achieved. The project intends to transform observational data into multiple independent subspaces . We will design adaptive clutter suppression algorithms in each subspace and guidelines for subspace synthesis.Finally, robust target detection algorithm is designed to detect range spread target.The research includes: (1) wideband clutter suppression algorithm based on the subspace decomposition and synthesis; (2) wideband adaptive interference suppression by steering vector space-frequency parameter decoupling and wideband focused method; (3) to design robust wideband radar range spread target detection algorithm. Finally, the measured data obtained through laboratory experimental system will be used to verify the performance of the proposed algorithm. In summary, these research results are of great important both theoretical guidance and application value in detecting weak targets under heavy clutter.

本项目针对机载平台宽带阵列雷达探测微弱目标展开研究。采用增加信号带宽降低杂波功率、增加积累时间提高目标积累增益，以提高强杂波中的微弱目标探测能力。但带宽和积累时间的增加会使得目标跨越距离单元，需要进行空间－慢时间－快时间三维处理抑制杂波。由于难以获得杂波协方差矩阵和三维导向矢量，直接进行三维处理无法实现。本项目拟采用基于子空间变换的思路把观测数据变换到多个独立子空间里，在各子空间进行自适应杂波抑制，并优化设计准则将子空间结果进行综合，最后设计稳健的检测器检测距离扩展目标。研究内容包括：（1）基于子空间分解和综合的宽带杂波抑制方法；（2）设计导向矢量空频参数去耦与宽带聚焦思想相结合的宽带干扰抑制方法；（3）宽带雷达距离扩展目标的稳健检测算法设计。最后通过实验室现有的实验系统获得实测数据来验证算法的性能。项目研究成果对强杂波下探测微弱目标具有理论指导和应用价值。

本基金项目主要针对运动平台宽带阵列雷达探测微弱目标展开相关研究。为了在强杂波中探测微弱目标，采用增加信号带宽降低杂波功率，增加积累时间提高目标积累增益，但带宽和积累时间的增加会使得目标跨越距离单元，需要进行空间－慢时间－快时间三维处理抑制杂波。由于难以获得杂波协方差矩阵和三维导向矢量，直接进行三维处理无法实现。本项目采用基于子空间变换的思路把观测数据变换到多个独立子空间里，在各子空间进行自适应杂波抑制，并优化设计准则将子空间结果进行综合。获得主要结果如下：（1）提出基于循环前缀的多输入多输出频分多址综合孔径雷达系统方案，该方法可以使得每个发射天线在同样带宽下保持很好地波形正交，并最终得到低副瓣距离像。（2）提出基于超高速飞行器多通道综合孔径雷达的模糊杂波抑制和动目标成像方法，在距离频域和方位频域对杂波进行抑制。（3）提出基于杂波的先验知识分布的距离扩展目标自适应检测算法，结合广义似然比检验设计了不依赖辅助数据的距离扩展目标自适应检测器。（4）提出一种宽带数字阵列雷达干扰自适应抑制方法，可在子阵和子带内实现，降低了算法的计算量和增强干扰抑制的稳健性。项目研究成果对强杂波下探测微弱目标具有理论指导和应用价值。经过本项目的研究，已在国内外期刊和国际会议上发表论文36篇，受理授权专利10篇。