HUGIN 3000 AUV for Deepwater Surveying

Abstract The existing HUGIN vehicles have been used for seabed surveying in water depths down to 500 meters, both in tests and commercial work. This has provided an invaluable amount of user experience and a confirmation of expected advantages. The primary requirements are:detailed acoustic measurementsprecise positioning of the measurementssurvey efficiency AUV/UUV technology has the inherent capability to improve all three requirements, compared to other existing tools. The next vehicle, HUGIN 3000, is designed for operation down to 3000 meters. The design is a further development of the basic principles of the existing vehicles - a highly manoeuvrable, stable and low drag body shape, battery and navigation principles. Significant extensions are made in depth capability, diving endurance, payload sensor flexibility and navigation sensor suite. Of primary importance is a friendly co-functioning of the large number of acoustic systems in operation simultaneously, i.e. multibeam echo sounder, side scan sonar, sub-bottom profiler, acoustic command and data links, acoustic positioning. The paper is addressing the existing experience and the basic principles for HUGIN 3000. Introduction The trend in energy exploration and development is towards deepwater development (with great potential for larger finds), subsea and floating production systems. Deepwater field developments beyond the continental shelf will require the same level of survey data quality and intervention access as established for shallower water. In this scenario, there is an increasing understanding that underwater robotics and in particular Autonomous Underwater Vehicles/ Untethered Underwater Vehicles (AUV/UUV) will play an important role in future survey and subsea engineering. This paper describes the application of the HUGIN AUV/UUV in seabed surveying, based on practical experience and future development plans. The HUGIN vehicle development started in 1995. Partners were Statoil, the Norwegian Defence Research Establishment (FFI), Norwegian Underwater Intervention AS (NUI), and Kongsberg Simrad AS (KS). The objective was to design an untethered vehicle to be used for high-resolution seabed mapping, [1][2][3]. Two models, HUGIN I and HUGIN II, have been built, tested and used in, commercial and scientific applications. Both vehicles are depth rated to 600m. A 3000 meter version is under development and the first vehicle is contracted for delivery to C&C Technology, Lafayette, early autumn year 2000. The vehicles, and in particular HUGIN 3000, can be looked at as a general sensor carrier with flexibility in selecting the appropriate sensor/sensor suite for the actual survey application as described in the following. Requirements and operational advantages. High payload sensor data quality. The properties making an AUV/UUV to an ideal payload sensor carrier platform coincide with the requirements crucial to obtaining high quality survey data, i.e. low acoustic self noise, hydrodynamic stability and effective control of optimal height above the seafloor. High positioning accuracy. The freedom in positioning an AUV/UUV relative to the support vessel allows the support vessel being directly above the vehicle during survey operations. Consequently, this will minimise the effects of acoustic ray-bending errors on the acoustic positioning accuracy.