Motion estimation for Synthetic Aperture Sonars

Inhalt:
The advantage of a synthetic aperture sonar (SAS) image compared to an image of a side scan sonar is an almost constant cross range resolution. To achieve an improvement by coherent processing the motion of the vehicle has to be known on the order of a tenth of the sonar signal wavelength for the number of pings contributing to the synthetic aperture. This challenging task holds also for SAR, but under different environmental conditions. The velocity of propagation (light / sound) within the different media is different by orders of magnitudes and also the speed of the vehicles. Also the stability of the platforms with respect to the wavelength differ due to the influence of the media on the motion. The media typically has a larger impact on SAS systems. In this paper we show results for motion estimation based on the displaced phase centre antenna (DPCA) approach and present a comparison of SAS images.