Repeated sorting on the sliding window for OS-CFAR

An algorithm is suggested for repeated sorting of a sliding window of n consecutive reference cells, required in order statistics-constant false alarm rate radar detection. The sliding window surrounds a central cell under test with guard cells on its sides, which are excluded from the sorted reference cells. The algorithm's computational complexity is smaller by a factor of n/4 compared with performing a new independent sorting after each slide. That factor does not depend on the number of guard cells. The advantage of the new algorithm was confirmed by theoretical and numerical comparison with respect to two other recently reported approaches.