UACE2017 Proceedings: Adaptive equalisation for continuous active sonar?

Session:
Large Time-Bandwidth acoustic signals for target detection and tracking
Paper:
Adaptive equalisation for continuous active sonar?
Author(s):
Konstantinos Pelekanakis, Jeffrey Bates, Alessandra Tesei
Abstract:
Underwater acoustic environments exhibit long and time-varying multipath propagation conditions that severely limit the spatio-temporal coherence of any continuous active sonar (CAS) pulse. Due to this issue, traditional matched filter processing at the receiver does not always achieve the desired processing gains leading to poor target tracking. Hence, a major effort in the field of active sonar is steered towards the design of novel receivers that emphasize on efficient Doppler target tracking while maintaining good range resolution. This paper represents the first attempt to process the target’s echoes based on an adaptive decision-feedback equaliser (DFE), a well-known technique applied in underwater acoustic communications. The performance of the proposed signal is tested through a simple experimental setup during a sea trial off the coast of Portugal in 2016. The transmitted binary phase shift keying (BPSK) signal occupied the 1500 - 2500 Hz band and lasted for 7.7 seconds. Our results demonstrate a high-precision Doppler measurement with an update rate of 1 ms for a target moving at 6 knots.
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