Model-based source localization in the 8–16 kHz band using the channel impulse response function

Abstract

SignalEx tests have been conducted in a variety of shallow water coastal environments to relate the performance of acoustic communications systems to the prevailing oceanographic conditions. These tests have typically consisted of using a fixed receiver (one to four elements, spaced for diversity) and a transmitter drifting out to ranges beyond the minimum detectable level. During these tests, waveforms to probe the channel in the 8 to 16 kHz band were transmitted at regular intervals. These probe signals were used to test source localization algorithms at these high frequencies. Model-based source localization at these very high frequencies requires either very accurate modeling or algorithms inherently robust against model mismatch. Although the first couple of multipath arrivals can be stabilized from ping to ping, the later arrivals exhibit rapidly fluctuating amplitudes and times of arrival, due to the motion of the ocean surface, water column variability, and the varying bathymetry as the transmitter drifts in range. Measurements of the time-varying channel response and source localization results using the 8–16 kHz band SignalEx channel probes will be presented from sites at the New England Front and the Coronado Bank off San Diego.