Range estimation of a moving source using interference patterns in deep water

The frequency-range interference patterns of the acoustic field in the shadow zone of deep water correlate with the source location. However, extraction of such interference structure requires a broadband source and fails for narrowband signals. In this work, the narrowband depth-time interference patterns of the acoustic field from a moving source are investigated. Two types of time intervals in the observed patterns are derived based on the ray theory. These time intervals are correlated with the multipath arrival angles, which in turn imply the source range. The simulations and the experimental results demonstrate stable range estimations using the interference patterns.