This report supplements SPANN Laboratory Technical Report TR-94-02. A NeymanPearson likelihood ratio test (LRT) is derived to allow the multi-aperture SAR hidden Markov model (HMM) automatic target detection (ATD) algorithm to achieve different false alarm rates by varying a single threshold parameter. The computational requirements of the HMM ATD algorithm and two alternative algorithms are analyzed. (The alternative algorithms are two-parameter CFAR detection and split-aperture change detection.) For simulated MASAR imagery, the HMM ATD algorithm and two-parameter CFAR detection have similar computational requirements, while splitaperture change detection requires almost two orders of magnitude more calculations. y This research was supported by Wright Laboratory. z The SPANN Lab's WWW URL is http://eewww.eng.ohio-state.edu/research/spann/. I. INTRODUCTION As a supplement to SPANN Laboratory Technical Report TR-94-02 [1], this report presents our current research results on the ...