Effects of input power fluctuations on passive sonar receiver performance

Passive sonar receivers operate in environments producing signals and noise with fluctuating power envelopes. The effect of these fluctuations on receiver performance was investigated by a combination of analysis and a Monte Carlo simulation in which signals and noise were represented by members of compound random processes. The receiver was represented by a multichannel analog with an adaptive detection threshold. It was determined that both detection and false alarm probability depend on the relationship of the relaxation times of the input power envelopes and the post-rectification averaging time of the receiver, as well as on the degree of fluctuation.