Detection of Weak Signals with Unknown Coherence Time.
TECHNOLOGY SERVICE CORP SANTA MONICA CALIF
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The problem of detecting a signal whose coherence time is short compared to the total time of observation is examined. Further, the signals coherence time is regarded as unknown. The signal itself is assumed to have a constant amplitude, and its phase and frequency may change in an arbitrary fashion from one coherence interval to the next. Though no assumption is made regarding the signal-to-noise ratio per coherence interval, it is assumed that the integrated signal-to-noise ratio over the the total processing time is large enough for useful detection probabilities to result. This is to be distinguished from an assumption of large signal-to-noise per coherence interval, in which case there is little motivation to process the entire data record before detection. The structure of the maximum-likelihood detector for this signal in white, zero mean, Gaussian noise is derived and the detection performance is numerically evaluated for specific cases. Author