Applying the Delay-Curve Hough Transform To Shallow-Water Environments

摘要

The Delay-Curve Hough Transform (DCHT) has been proposed to detect the correlation traces produced by constant velocity targets in broadband correlograms and to estimate target track parameters. The derivation of the DCHT assumed that the sound velocity profile (SVP) is a constant and the correlation trace is due to the direct propagation path. These assumptions are not true in the shallow-water environments. This study investigates the use of the DCHT in these environments by examining the effects of the SVP on the correlation traces appearing in broadband correlograms for three different shallow-water environments. The GAMARAY model, an eigenray-based sound propagation model, was used to produce the sound field. Even though beyond some short ranges the direct propagation path disappears and the dominant eigenrays are due to multipath, the correlation traces still maintain the shape of the analytic delay curves, and the DCHT successfully detects the targets. The estimates of target heading, speed factor, and closest point of approach (CPA) time by the DCHT proved to be accurate. However, in most cases, estimates of the depth factor were incorrect. A theoretical explanation for the unreliability of the estimation of the depth factor is also given.