A dimension-reduced modal space detector in deep-sea environment

The matched correlation detector (MCD), combining the received data with the sound transfer function (namely the replica field) is theoretically optimal for underwater passive detection. However, it suffers from the model mismatch problem caused by environmental uncertainties. And furthermore, when applied to the deep-sea environment, it encounters the large search range problem. In this paper, we focus on the source detection problem in deep-sea environment. To overcome the disadvantages of MCD, we choose the modal space detector (MSD) which uses a vertical linear array (VLA). We derive the expression of the deep-sea MSD and further, to improve the signal-to-noise ratio (SNR) of the test statistic, we propose a dimension-reduced form of MSD, which is termed as DR-MSD for short. By numerical simulation, we discuss that how source frequency, array depth and array aperture influence the dimension reduction. And we point out that the dimension-reduced number in DR-MSD decreases when the source frequency and the VLA aperture increase. The numerical results also indicate that DR-MSD can alleviate the search burden and obtain a better detection performance when compared to traditional MSD.