A metric for defining low probability of detection based on gain differences

A metric for defining low probability of detection of a communication signal by a radiometer is described. The metric is based on the gain difference G between the communication receiver and the radiometer, which includes their path losses, antenna gains, etc., plus two "mismatch" losses incurred by the radiometer. The probability of detection P/sub D/ is computed as a function of the gain G, and the detectability gain (DG) is defined as the gain for which P/sub D/ has some acceptable value. Results are given for a "generic" communication system, and methods for comparing existing or proposed systems by using the DG as a metric are presented.