A simplified signal analysis algorithm for the development of a low cost underwater echo-sounder

In the literature survey, most of the signal analysis techniques for underwater acoustic information rely on complex mathematical models, which are impractical for a small real time application such as an underwater echo sounder. The purpose of this work is to introduce a modified signal process algorithm which can be easily implemented into a microprocessor and to determine the distance an obstacle from a moving underwater vehicle. This simplified acoustic signal analyzer uses a series of ‘mask shading’, ‘3-time majority’ and ‘echo-duration threshold’ signal process steps to increase the accuracy of distance measurement for the self-developed underwater echo sounder. Experiment result shows that the proposed algorithm can ignore the erroneous signal cased by environment noise at sea and transient noise from the circuit board. This work has been proven valuable when used with an auxiliary solar-powered boat to measure the slurry accumulation at a local An-Ping Harbor in southern Taiwan.

► A modified signal process algorithm for underwater application.
► Low cost underwater echo-sounder developed.
► Experiment shows that it can ignore the erroneous signal from the environment.