Experimental results of Autonomous Underwater Vehicle 'AQUA EXPLORER 2' for inspection of underwater cables

This paper describes the results of sea tests of an Autonomous Underwater Vehicle named AQUA EXPLORER 2 (AE-2). The experimental results of the acoustic video-signal transmission system are also be presented. AE-2 can find and trace buried underwater cables by using a cable tracking sensor and can measure the burial depth of cables. Two sea tests were successfully performed. The purposes of these sea tests were to evaluate the performance of the vertical and horizontal motion, cable tracking, and video image transmission system. In the first sea test, AE-2 succeeded in tracking the electric cable which was laid in a calm bay. In the second sea test, AE-2 succeeded in tracking a real telecommunication cable which was laid in the Pacific Ocean. The image of the seabed can be sent in real time to a mother vessel via an acoustic data transmission system, and digitally recorded on a hard-disk on the vehicle simultaneously. Its transmission speed is 16-32 Kbits/sec and it can transmit two pictures of 160 by 120 pixels per second.