Results of the development of a long-range acoustic homing system for autonomous underwater vehicles

Abstract

Modified international submarine engineering (ISE) explorer AUVs with an endurance of over 400 km are being used to aid in the mapping of the under-ice Arctic seafloor. The explorers are equipped with a DRDC-developed acoustic homing system built into the AUV nose cone. The acoustic receiver consists of seven digital hydrophones arranged in a tri-axis cross-dipole array. A controller/data processor located within the AUV pressure hull handles the real-time acoustic arrival azimuth and elevation estimation, as well as the control and calculations for an on-demand short-range three dimensional (3-D) localization system, and the control of vehicle telemetry data flow. The processor and array consume less than 2 W. A small, easily transportable, DRDC-designed acoustic transducer provides a powerful acoustic homing signal. Using the homing system, the vehicles were able to locate an acoustic beacon at a randomly drifting Ice Camp from a range in excess of 50 km (100-km ranges possible). The design, development, and use of the homing system are described in this paper. In addition, on-going software improvements providing enhanced capabilities and system miniaturization are described.