DIGITAL ULTRASONIC-SCANNING SYSTEM FOR POSITIONING UNDERWATER REMOTELY OPERATED VEHICLES

The design of a digital ultrasonic scanning system for positioning und erwater remotely operated vehicles (UROVs) is presented in this paper. Its principle of operation is based on ultrasonic distance measuremen ts (by determining the time of flight) and mechanical scanning. Ultras onic imaging is used to construct the 3-D image of the environment sur rounding the vehicle. The image is then used, in combination with sign als coming from a gyroscope, to estimate the actual distances of the v ehicle from the objects in the vicinity of the vehicle. The system con sists of a 200 KHz point transducer, a scanning transmitter-receiver u nit and a computer for image reconstruction and control of the UROV. T he main advantages of this system are its simplicity and its accurate large scale measurement capability. The design of the system was carri ed out in order to conform directly with the computer controlling the UROV, and its operation was experimentally demonstrated.