The need for systems that can provide visibility in the world of underwater research is exploding. Many fields of study are expanding, with new missions and applications where underwater visibility is required multiplying every day. In the past, most of the general public had no idea what it took to do underwater rescue or research or what a complicated task working under the water is. It is now fairly routine for the general public to see images of the types of technology used in underwater search and research in the media. Terms like Autonomous Underwater Vehicle (AUV), Unmanned Underwater Vehicle (UUV), Remotely Operated Vehicle (ROV) and Side Scan Sonar are becoming more familiar after the horrific events of Flight 370 in Malaysia and other over-water tragedies. Over the last several months, as the search unfolds before our eyes on prime time television, it is hard not to pay attention as scientists proposed many “new” technologies and strategies to locate the Boeing 777.More
Abstract— Kraken Sonar Systems Ltd, based in St. John’s, Canada, produces an Interferometric Synthetic Aperture Sonar (InSAS) system, suitable for integration on a wide range of AUVs and towed platforms. In 2012, Kraken entered into a Cooperative Research and Development Agreement (CRADA) with the Naval Undersea Warfare Center (NUWC) in Newport, Rhode Island. This paper seeks to present a background of Kraken’s InSAS technology, and detail the results of the CRADA. The primary focus of the paper (and the CRADA) is the integration and testing of an AquaPix InSAS on NUWC’s medium-sized 12.75” diameter REMUS600 AUV, manufactured by Hydroid. Kraken designed a payload section for the R600, and assisted NUWC operators with integration onto the AUV. After a very short integration, the resulting integrated SAS-AUV was able to produce ultra-high resolution 3cm imagery and co-registered 25cm bathymetry with no vehicle re-tuning necessary. The main conclusion from this trial was objective evidence that SAS is achievable on medium sized AUVs without extensive tuning or additional control planes.More
This paper presents an architecture used to improve the navigation in UUVs by applying techniques that reduce vehicle position error growth during extended underwater operation. The techniques improve the navigation by reducing the horizontal vessel position error using navigation bottom fixes created from bottom objects detected in the overlapping
regions of side-scan sonar imagery. The architecture introduces a unique hybrid approach to feature detection and matching by combining both automated and manual methods. The details of a dynamic linear error model incorporating the drift in a typical INS\DVL navigation system are provided. The error model assigns a circular error to the horizontal position of the UUV using system specifications, in-field calibration measurements, or system provided error estimates. Results using real UUV navigation data from a REMUS 600 vehicle demonstrate the architecture's ability to significantly improve the navigation by reducing horizontal vessel position error using bottom fixes created from sidescan imagery.
Autonomous underwater vehicles (AUV) are used in a broad area of missions ranging from exploration over training to the destruction of moored and shoaled mines. A number of specialized AUVs distinguished in shape and dimension have been designed to meet the variety of requirements. Each of these AUVs has a need for a sonar system to execute its mission under all conditions. To meet this challenge of different scales, either various different special solutions of sonar systems or a few flexible solutions have to be used that can be adjusted quickly to the challenge of the day.
Over the last decades, L-3 ELAC Nautik has been involved in a number of programs requiring autonomous system and sonar operation and is now able to offer a sonar system architecture for AUVs, based on scalable, self-developed electronics. Several electronic boards can work in parallel if high resolution sonar data and a high number of signal channels are required. If instead small size is preferable, a small number of boards is enough to perform basic operation. This architecture can be used for example to perform detection of various objects or for bottom mapping. The system additionally includes simultaneous recording of broadband sonar data for offline processing.
L-3 ELAC Nautik explains the principles and applications of it’s proprietary architecture and gives an example of a realised sonar system with a conformal array configuration.More