Design of nonparametric truncated sequential detectors withparallel linear boundaries

A design method is proposed for a class of nonparametric truncated sequential detectors. These detectors test nonparametric statistics against two parallel linear boundaries with an abrupt truncation at some sample size. The proposed method obtains the asymptotic relative efficiencies (ARE) of these tests with respect to their corresponding fixed-sample-size (FSS) tests in terms of some parameters of the tests. There parameters are then chosen to optimize the ARE. This (asymptotically) optimal set of parameters is used to design the thresholds of the sequential tests. Numerical results are obtained and design examples are presented, using the sum of the signs of the observations as the test statistic. The method can be used for nonparametric sequential detectors and for robust and parametric sequential detectors as well     

Two-Stage CFAR Detectors for Multiple-Range-Bin Radars

Two-stage detectors using generalized sign and four-level conditional statistics for signal detection in multiple-range-bin radars are described. The resulting detectors are of constant false-alarm rate (CFAR). Performances are evaluated and compared with singlestage versions. If the a priori probability of either the no-target case or the target-presence case is large (close to 1), a two-stage test can be designed to have the advantage of reducing the average number of samples required without sacrificing detection probability. With the proper choices of parameters, significant improvement in the efficiency can be achieved. Asymptotic relative efficiency of two-stage detectors with respect to single-stage detectors is derived and some numerical results are evaluated.