对数正态纹理海杂波背景非相干CFAR检测方法

Non-coherent integration constant false alarm rate detectors against the log-normal textured sea clutter

在相参体系的雷达系统中,相比于相干积累检测方法,非相干积累检测方法具有快速检测的能力,能够满足雷达信号实时处理的需求,在实际应用中具有重大意义。然而,非相干积累检测方法对累积脉冲数、参考单元数、海杂波幅度分布模型的形状参数以及海杂波散斑协方差矩阵均是非恒虚警率的。为了实现对数正态纹理复合高斯海杂波背景下运动目标的快速检测,提出了一种累积前白化和非相干累积级联的检测方法,证明该方法对海杂波幅度分布的尺度参数以及散斑协方差矩阵均是恒虚警率的。此外,分析了功率累积和幅度累积方法对检测性能的影响。通过匹配于海杂波形状参数、累积脉冲数以及参考单元数的检测门限,可以确保所提出检测方法的恒虚警率特性,继而实现对海雷达在大场景下对目标的快速恒虚警率检测。实验结果表明,在检测性能上幅度累积优于功率累积,而且累积前白化总体上提高了运动目标的信杂比,同时对于位于主杂波区之外的高速运动目标也能带来明显的性能改善。

In a coherent radar system,compared with the coherent integration detectors,non-coherent integration detectors with fast implementation can meet the demand of real-time processing,and are of great significance in practical applications.However,these detectors do not have a constant false alarm rate(CFAR)with respect to the integrated pulse number,the number of reference cells,the shape parameter of the sea clutter model,and the speckle covariance matrix of the sea clutter.In order to realize fast CFAR detection of moving targets in sea clutter amplitude distribution with a log-normal texture,this paper proposes a detection method of speckle whitening followed by non-coherent integration,which is CFAR with respect to the scale parameter and speckle covariance matrix of the sea clutter.Moreover,it is also analyzed how the power integration and amplitude integration are to affect detection performance.By using the decision thresholds matching to the clutter shape parameter,the integrated pulse number,and the number of reference cells,the CFAR characteristic of the proposed detection method can be ensured,and then the proposed detector can implement a large-scene fast detection of maritime radars.Experiments show that the amplitude integration behaves better than the power integration and the speckle whitening before the integration wholly improves the signal-to-clutter ratios of moving targets,and that it can also bring a significant performance improvement for the high-speed moving target.