大入射余角CFAR检测器

Large-grazing-angle CFAR detector

雷达在大入射余角高分辨率海杂波背景下检测时,等效后向散射面积增大,大部分海杂波能量投射到少数距离单元,能量分布不均,出现功率突然增大的杂波"异常单元",导致检测器参考窗口所处的背景环境复杂多变,传统检测器检测概率降低,虚警率及误检率增加。为解决此问题,通过参考滑窗单元的协方差矩阵构造正定矩阵,求解其矩阵范数用以估计杂波功率水平,并采用支持向量机改进传统恒虚警率(constant false-alarm rate,CFAR)检测器,得到基于正定矩阵杂波功率估计训练支持向量机的改进CFAR检测器。实验结果表明,新检测器在均匀杂波、多目标环境下检测性能稳定,在杂波边缘的虚警控制能力良好。

When detecting in high resolution and large-grazing-angle situation, radar has a larger equivalent backscattering area. Thus, most of the sea clutter energy is projected to a few of distance units, which leads to inhomogeneity of the energy distribution. Therefore, the “abnormal unit” with a sudden increase in power appears, which makes the background environment of the reference window of a detector complex and variable. Consequently, the detection probability is reduced and the false alarm rate is increased. In order to solve this problem, positive definite matrices are constructed by referring to the covariance matrix of the sliding window and its matrix norm is solved to estimate the clutter power intensity. The support vector machine is used to improve the traditional constant false-alarm rate (CFAR) detector. An improved CFAR detector based on support vector machine which is trained by the reference widow power estimated by positive definite matrices is obtained. The experimental results show that the new detector has stable detection performance in the uniform clutter and multi-target environment, and the performance of false alarm control at the clutter edge is good.