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In this paper, a novel approach to provide full autonomy in the control and synchronization of multiple payload sonar systems is described, facilitating the close-proximity integration and concurrent operation of multiple high-frequency acoustic sensors on an unmanned underwater vehicle. Recent advances in computational technology and real-time programming techniques afford the ability to process bathymetric data in situ to react to real-time environment data. The novel approach presented interrogates real-time bathymetric data to predict the transmission-reception timing of payload sensor acoustic pulses, thus permitting the ability to synchronize the trigger of the instruments such that neighboring return signals of other sonar are not saturated by sensor crosstalk.Index Terms-Acoustic interference, adaptive control, autonomous sensor control, robot sensing systems, seabed mapping, sonar signal analysis.

AUTHORS' BIOGRAPHIES Edward Thurman received his BEng (1 st Class Hons) in Computer Engineering at the University of Limerick (UL) in 2005 and is a member of its Mobile & Marine Robotics Research Centre (MMRRC). His research interests are in acoustics, realtime control and sensor integration. He is currently pursuing a PhD in the area of autonomous sensor strategies for use on underwater vehicles. James Riordan received his BEng in Electronic Engineering in 2002 at UL. He was awarded the PhD degree in Computational Ocean Acoustics in 2006 for research conducted with the MMRRC, where he is currently a Postdoctoral Research Fellow. His research interests include marine survey operations, realtime imaging-sonar simulation, fractal modelling, multi-resolution model abstraction, mesh optimisation, sonar data processing and visualisation. Daniel Toal received his BSc(Eng) in Electrical Engineering from the Dublin University, his MSc in Manufacturing Systems Engineering from Cranfield University, UK, and his PhD from UL. From 1991 to the present he has been lecturing variously on electronics, automation, CAD/CAM/CIM, robotics, electronics manufacture and avionics. His research interests include autonomous mobile robotics, marine robotics, automation, sensor integration and motion control. He is Director of the MMRRC.

This paper describes in detail a novel multi-sonar controller developed at the University of Limerick and tested on the new smart, remotely operated vehicle (ROV) Latis at sea in March 2009. The multi-sonar controller allows the simultaneous operation of similarfrequency imaging and mapping sonar by interrogating the sonar returns of the multi-beam sonar in real time and adaptively triggering the pings of each sonar in a terrain-adaptive manner to avoid cross-talk and interference in sonar returns. The technique has benefits in hydrographic mapping and in payload sonar management on unmanned underwater vehicles. Detailed results on the testing of the sonar controller system are reported. The paper also describes the smart ROV Latis, designed and built at the University of Limerick, on which the sonar systems have been tested. With its advanced control systems and high-bandwidth networking capabilities, the ROV Latis is an ideal platform for experimentation of new techniques such as the multi-sonar controller, which can be ported to other ROVs and autonomous underwater vehicle platforms once proven.

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