A Real Time Experimental Synthetic Aperture Sonar and a Study on Autofocus in Sonar Environment

Synthetic Aperture. and Autofocus Techniques have been used in radar for many years and have given excellent results (Ref. 1, 2, 3, 4), but unfortunately the-adverse environment'of Sonar i. e. , the variability ofₜhe medium, the slow speed of propagation and difficulty of maintaining a Smooth path for the sensor, has restricted the application of the techniques in Sonar CRef. 5, 6, 7) JThis paper will describe a study of implementations of a time domain synthetic aperture algorithm and the performance ofₐn autofocus algorithm in a Sonar environment. THE IMPLEMENTATION OF A SYNTHETIC APERTURE' ALGORITHMA time domain algorithm has been implemented on an experimental synthetic aperture sonar system in a large tank available in the Department (Ref. 8). The basic principle is that for each image point the signals received at each element point are summed with appropriate delays depending on the position of the image point being reconstructed.