Transient localization in shallow water environments with a vertical line array

Abstract

Several algorithms based on autocorrelation matching of multiple hydrophone elements in a vertical line array have been developed to localize a broadband transient signal. An earlier developed frequency-domain autocorrelation matching (FACM) algorithm was based on autocorrelation matching of only a single hydrophone. The success and robustness of this algorithm in the presence of environmental mismatch was the motivation to adapt it to include the additional information of multiple hydrophones. The new algorithms developed were based on joint autocorrelation matching, specifically depth- and frequency- domain autocorrelation matching ((KzFACM)), wavenumber- and frequency-domain autocorrelation matching (kzFACM), and an incoherent summation of the FACM results of all the elements in a vertical line array (lFACM). These algorithms were tested in simple, shallow water environments with and without mismatch in the specification of acoustic parameters (e.g., bathymetry and sound speed). The results suggest that the use of the additional information from multiple elements does improve both the accuracy and robustness of the localizations. All of the algorithms produced similar results, although the lFACM and the KzFACM algorithms appeared to perform slightly better than the (KZFACM) algorithm in the presence of mismatch. However, the relative performance of the algorithms appeared to be sensitive to the environment and placement of the source and receivers in the waveguide.