Effects of instable propagation medium on the coherence of high frequency synthetic aperture sonar

In order to investigate the effects of the temporal instability and spatial non-uniform of the sonar propagation medium on the imaging of synthetic aperture sonar (SAS), the dynamic variation of sonar propagation medium is studied through measuring the phase stability of SAS signals in this paper. At the same time, the effects of the instable sonar propagation medium on the SAS signal coherence as well as its limitation to the size of synthetic aperture are analyzed.