分布式目标的子空间双门限GLRT CFAR检测

Dual-Threshold CFAR Detection for Distributed Targets

研究了分布式目标在球不变随机变量杂波中的检测问题,提出了一种具有恒虚警特性的双门限广义似然比检测器。分布式目标建模为子空间信号,在距离维和多普勒频率维同时扩展.第一门限的作用是筛选信杂比高的待检测距离单元.将选出的距离单元进行能量积累并与第二门限进行比较做出判决.假设杂波协方差矩阵已知,构造了双门限检测器,并通过推导检测器虚警概率说明其具有恒虚警特性.将基于辅助通道数据的杂波协方差矩阵的估计值替换假设已知的杂波协方差矩阵,得到一个自适应检测器.通过Monte Carlo仿真进行性能分析,说明检测器的有效性和鲁棒性.

For the distributed target in spherically invariant random vector clutter,a dual-threshold GLRT detector with constant false alarm rate（CFAR） property is derived.The distributed target,which is modeled as a subspace random signal,may be distributed both in range and in Doppler frequency axes.The cell whose signalto-clutter ratio is higher is selected by the first threshold.Then the accumulation of energy is implemented in these selected cells,and it makes a final decision according to the second threshold.Assuming that the normalized clutter covariance matrix is known,the dual-threshold GLRT is devised.The probability of false alarm of dual-threshold GLRT is derived and it ensures CFAR property.And then according to a secondary data set to estimate the clutter normalized clutter covariance matrix,the adaptive detector is obtained.The performance assessment conducted by Monte Carlo simulation confirms the effectiveness and robustness of the proposed detector.