A beam pattern design procedure for multidimensional sonar arrays empolying minimum variance beamforming
Richards, Randall G.
MetadataShow full item record
This paper develops a beam pattern design procedure for general multidimensional irregular sonar arrays that incorporates the not well understood effects of array geometry into the design process. The procedure is implemented by generating a "penalty function" in a spectral covariance function form. Processing the penalty function causes beam pattern high sidelobes to be penalized and the main lobe to be emphasized. This is accomplished by forming the penalty function in terms of an isotropic noise field of specified strength modified with a finite sector of low coherent energy and stabilized with incoherent sensor noise. By inputting the penalty function into a minimum variance beamformer, the beam pattern and aperture weights are calculated based on the given array geometry. The beamformer used is Capon's Maximum Likelihood Method. The array used to test the procedure is located on a sixty degree sector of a cylindrical surface. The procedure is implemented by two different methods, each with some desirable characteristics. One method suppresses sidelobes directly by the placement of nulls. The other method suppresses sidelobes indirectly by the enhancement of the main lobe with anti-nulls. Both methods are evaluated in terms of a sensitivity factor which constrains the maximum white noise array gain. Results show that both methods result in sidelobe levels that range from 20 to 35 dB lower compared to a conventional beam pattern with uniform aperture weighting and that the design procedure is applicable to beam patterns steered to both true broadside and to off-broadside directions.
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1990
Showing items related by title, author, creator and subject.
Bennett, Sara L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1988-09)The highly energetic Agulhas Retroflection region south of the African continent lies at the junction of the South Indian, South Atlantic, and Circumpolar Oceans. A new survey of the Agulhas Retroflection taken in March ...
Kading, Tristan (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-02)Thiol substances can form stable complexes with metals (especially copper and mercury) in the surface ocean that can impact cycling and bioavailability of those elements. In this study, I present seven concentration ...
Sanford, Lawrence P. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1984-08)Intermittent, shoreward propagating packets of high frequency first mode internal waves are common on the continental shelf when the water column is stratified and may induce large fluctuations in near bottom velocity. ...