Passive synthetic arrays

Abstract

This article develops the concept of the passive synthetic array, including its design and implementation, its response to signal and noise, and its overall performance. The only case considered is the ideal case of a constant velocity receiver, a constant bearing narrow-band source, stationary signal and noise statistics, and single-path propagation in the plane of the source and receiving synthetic array. It is shown that, in this ideal case, the passive synthetic array is identical to the narrow-band spectrum analyzer in both implementation and performance, with the total gain determined to a close approximation by the bandwidth of the signal. Considering the processor to be a synthetic array beamformer, however, yields additional information about a detected narrow-band source because the bearing of the source can be determined if a course or speed change is made by the sensor.