A New Research Direction: Underwater Acoustic Signal Combined Processing Based on Multi-Field Coherence

The low-cost and highly-reliable underwater acoustic network is an effective means of monitoring the marine environment, detecting seabed resources, searching in marine rescue operations, etc. [1,2]. There are many acoustic field effects distributed in the Pacific, Atlantic, Indian Ocean, etc., including convergence zones, shadow zones, deep sea acoustic channels and so on. The different sensor nodes of the network may be deployed in different acoustic field zones while adopting suitable working modes; for example, sensor nodes deployed in convergence zones adopt the “convergence zone working mode”, while those deployed in the deep-sea acoustic channels adopt the “deep sea acoustic waveguide working mode”. With the increase in the bandwidth and rate of underwater communication, it has become possible to carry out the combined processing of the acoustic signals of distributed nodes. Therefore, achieving processing gain of multi-field coherence and correlation through combined processing of different sensor node signals will become a new research direction.