Research On Techniques Of Synthetic Aperture Side-scan Bathymetric System

Synthetic aperture sonar (SAS) technique uses a small array and can get a high resolution by dealing with the data ,which are collected when the array moves . So a high resolution map of the seabed could be gained. As a consequence, the SAS becomes one of the highlights in the sonar field .The cost of sonar can be reduced by using the SAS technique .Besides ,installing of the sonar array becomes easier .In this thesis ,the synthetic aperture technique is combined with the side-scan sonar based on study of synthetic aperture sonar technique .In other words , several key techniques of synthetic aperture side-scan system are researched in this paper .For example ,adaptive Notch filter is used to detect the phase difference .And in the process of studying motion compensation ,an available method-Displaced Phase Center(DPC) is used .In this paper, the task is divided into the following several aspects : synthetic aperture technique is studied ,including its history ,basic theory and the future ;And a map which can reflect ability of the seabed echoing signal is simulated by the computer in the different situations .In the process of estimating depth of the seafloor by using the combination of the synthetic aperture and side-looking sonar, the phase difference between two signals is needed to be detected ,and adaptive Notch filter is used to deal with it .Motion compensation is a very important part of the SAS .In order to study the technique, displaced phase center is researched ,which is compared with Phase Gradient Algorithm(PGA).In the end ,computer simulations of the theories are carried out.