Synthetic aperture sonar

Synthetic aperture sonar (SAS) is a form of sonar in which sophisticated post-processing of sonar data are used in ways closely analogous to synthetic aperture radar. Synthetic aperture sonars combine a number of acoustic pings to form an image with much higher resolution than conventional sonars, typically 10 times higher. The principle of synthetic aperture sonar is to move a sonar along a line and illuminate the same spot on the sea floor with several pings. This produces a synthetic array equal to the distance traveled. By coherent reorganization of the data from all the pings, a synthetic aperture image is produced with improved along-track resolution. In contrast to conventional side-scan sonar, SAS processing provides range-independent along-track resolution. At maximum range the resolution can be magnitudes better than that of side-scan sonars.

For further reading, the Open Access Article: Introduction to Synthetic Aperture Sonar can be recommended as introduction for people familiar with Sonar Systems. For academics, the IEEE Journal of Oceanic Engineering article: Synthetic Aperture Sonar, A Review of Current Status gives an overview of the history and an extensive list of references for the community achievements up to 2009.