The Effect of Bottom Attenuation on High Frequency Source Localization Using the Frequency Difference MFP

Abstract

High frequency signals are more difficult to model due to sound scattering by the random media and rough surface, consequently source localization using matched filed processing (MFP) becomes more and more difficult as the frequency increases. Frequency difference MFP uses the frequency difference signals generated by multiplying one signal at one frequency by the conjugate of another signal at another frequency shifted by a frequency difference, thereby effectively downshifting the signal and compensating the random medium effect which is assumed to be the same for both signals. It is noted that the frequency-difference signal is not exactly the same as a low frequency signal at the difference frequency. The mismatch between them and the effect of bottom on the signal modal distribution and consequently the goodness of source localization are studied in this paper.