Effects of nonredundance on a synthetic-aperture imaging system

Abstract

The analysis of signal-to-noise ratio (SNR) and associated imaging properties of an integrative synthetic-aperture imaging technique is extended to include the effects of an explicitly nonredundant aperture. This requires modification of the image estimator that has been used previously. In the case of a nonredundant transmitter and point receiver, which corresponds to a coherently illuminated object in an analogous optical system, no useful image is formed. As the receiver size increases, the system is capable of forming an image of increasing fidelity to an object that in the counterpart analogous system is illuminated with light of decreasing spatial coherence. As the receiver aperture enlarges, the image should become independent of coherent artifacts just as in the case of imaging with a redundant transmitter. Curves of SNR versus receiver-to-transmitter diameter ratio are given that compare the redundant and the nonredundant cases. The SNR is somewhat lower at all receiver sizes for the nonredundant transmitter aperture.