A fast order method on OS-CFAR detector in SAR images

Radar fast threshold constant false alarm rate (CFAR) detector, which keeps CFAR by estimating background and adjusting adaptive threshold, is widely used for detecting targets in synthetic aperture radar images. Two typical CFAR detectors based on sliding windows, the cell-averaged CFAR (CA-CFAR) detector and the order-statistics CFAR (OS-CFAR) detector are compared in this paper firstly. The results show the OS-CFAR detector has a better performance at high resolution, but it suffers from the computation burden. This paper proposes a fast algorithm to reduce the computational intensiveness of the OS-CFAR detector and the corresponding analysis of computational savings are given. According to the experimental results of real SAR data, the experiment result is in good agreement with the theory.