A sonar-based system for the detection of sharks

Abstract

This project is aimed to construct a shark detection system using active sonar to ultimately protect beaches and raise marine conservation. To this end, a reliable high-power ultrasound generator and a sensitive ultrasonic detector, suitable for long-range shark swimming pattern detection, has been constructed. PIC micro-controller was the core computer for this system. It controls all signal firing and reception sequences, including distance calculation and external communication to remote computer or FPGA via RS232. The scan feature is done by a stepper motor, controlled also by the PIC. The greatest challenge to date is matching the transducers’ impedance, and displaying the data on a monitor through the VGA port of the FPGA. The FPGA is still problematic due to inexperience in Verilog programming, but the matching problem has largely been tackled. Multiple target detection is not achievable at current stage due to limited transducers available. But as it stands, the system can perform basic object detection with acceptable distance and accurate calculations. Underwater ultrasound propagation and the inherit difficulties with object detections were better understood. In the future, the system can adopt phased-array active sonar and feature extraction to shed light in tackling the difficulties encountered.