Order Statistic Filters as Postdetection Processors

Abstract-The performance of a radar detection system can be im-proved through postdetection processing. Two popular postdetection processors are the n-pulse and binary integrators. This paper examines the performance of the binary integrator from the viewpoint of order statistics and describes the binary integrator as an order statistic (OS) filter. A general analysis is developed for OS filters in detection systems and is used to show the OS filter is a consistent and biased estimator of the quantities of the received signal distributions. The features of the OS filter and n-pulse integrator that are critical to detection per-formance are compared to determine the proper application of each processor. It is shown that the OS filter can be used to emphasize se-lective regions of the input distributions where good statistical separ-ability between the classes of input signals exist. The results from this analysis are useful for the development of optimization procedures over a variety of input signals and are applicable to any detection system where the sampled signals can be modeled statistically, such as in sonar and ultrasonic detection systems. A computer simulation is performed to illustrate the performance of binary and n-pulse integration for the detection of a white chi distributed target in white Weibull clutter and of a white Rayleigh distributed target in white Rayleigh clutter. I