Signal direction-of-arrival and amplitude estimation for multiple-row bathymetric sidescan sonars
In practical applications with bathymetric sidescan sonars, the multipath reflections and other directional interferences are the key limiting factors for a better performance. This thesis proposes a new scheme to deal with the interferences using a multiple-row bathymetric sidescan sonar. Instead of smoothing the measurements over some time or angle intervals, which was previously widely investigated, we resolve the multipath interferences from the direct signal. Two approaches on signal direction-of-arrival DOA and amplitude estimation are developed, the correlated signal direction estimate CSDE for three-row systems and the ESPRIT-based method. These approaches are compared using different sonar data models, including a stochastic model from the statistical analysis on bottom scattering and a coherent model from the analysis on interference field; the simulations show the ESPRIT-based approach is quite robust at the angular separation of 100 between two sources and at the signal-to-noise ratio above 10dB except for highly coherent or temporally correlated signals, for which CSDE works very well. The computer simulation results and the discussions on practical algorithm implementation indicate the proposed scheme can be applied to a real multiple-row bathymetric sidescan sonar. With the capability to simultaneously resolve two or more directional signals, the new sonar model should work better for a wider variety of practical situations in shallow water with out significant increase of the system cost.
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 1998
Showing items related by title, author, creator and subject.
Briggs, Michael Jeffrey (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1981-06)The multichannel Maximum Entropy Method (MEM) of spectral analysis is developed and applied in the dynamic analysis of offshore structures. Two different algorithms are implemented and compared with the conventional ...
Eggen, Trym H. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-06)This work is concerned with coherent communication by means of acoustic signals over underwater communication channels. The estimated scattering functions of real data ranging from the Arctic environment to tropical ...
Wage, Kathleen E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1994-09)Normal mode theory provides an efficient description of signals which propagate axially in the SOFAR channel and are detectable at long ranges. Mode amplitudes and their second order statistics are useful in studies of ...