New generation acoustic positioning systems

Underwater acoustics play a vital role in offshore applications including the positioning of underwater structures, ROV's, AUV's, and tracking of towed bodies for underwater surveying and mapping. Current operations are pushing traditional acoustic positioning systems to their limits. For the last 15 years Neutronix has been a pioneer in the field of acoustic signalling techniques. In the early 1990's this work was applied to a variety of applications for the Royal Australian Navy, to develop equipment which could be used in difficult noisy acoustic environments and be able to transmit information accurately, over very long ranges. Neutronix has developed a new signalling technology, ADS2 (Acoustic Digital Spread Spectrum) which overcomes many of the limitations (depth, range, accuracy, noise) of existing acoustic systems. Neutronix ADS2 systems are currently in use and are tested and proven to be accurate in both shallow and deep water, with proven high accuracy in ranges greater than 4,500m (14,000ft). In military applications the ranges up to 30km have been achieved. The new techniques allow a regular and fast position updates to the topside processing system, even in deep and ultra-deep waters, and reduces set up and calibration times considerably. The paper explains the ADS2 technology and its advantages then review particular applications for deep water, survey and DP positioning using LBL, SBL, USBL and multi-user systems.