The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community
Issue link: http://sea-technology.epubxp.com/i/99539
(Top) Spatial map of the velocity feld in the Kootenai River measured for the Naval Postgraduate School by the station-keeping USV-2600. (Right) USV transects of the Kootenai River, Idaho. suites can be integrated during the design process or by the end user's reconfguration of the payload deck to satisfy mission objectives. USV missions range from simple bathymetric surveys, volume fow rate measurements in rivers or stream gauging to more challenging missions that involve cast sensor suites, towed sensors, ROV operations, or mine countermeasures (MCM) and autonomous mine neutralization. Riverine and Coastal Surveys Numerous systems are in use to quantify estuary, riverine and coastal environments. The Naval Postgraduate School has conducted riverine and coastal surveys to study the environment and quantify the statistical accuracy for USVdeployed sensors and the effcacy of USV operations. 24 st / DECEMBER 2012 These surveys deployed a SeaRobotics USV2600, outftted with a Teledyne RDI (Poway, California) 1,200-kilohertz acoustic Doppler current profler (ADCP), a Tritech International Ltd. (Westhill, Scotland) PA200 altimeter, an AQUAscat (Hartley Wintney, England) 1000 acoustic backscatter sensor and a WetLabs (Philomath, Oregon) spectrophotometer. The system incorporated an Ashtech (Santa Clara, California) real-time kinematic GPS. The payload sensors acquired water quality, sediment transport and volume fow rate data in the Kootenai River of Idaho and the Elkhorn Slough in California. Extensive missions were performed to quantify data taken with both USVs and a YSI Inc. (Yellow Springs, Ohio) EcoMapper AUV. The USV-2600 performed successfully due to its ability to station keep for extended periods within 1 meter of the desired location. The study used a station-keeping period of 10 minutes, but post-processing with Kalman algorithms indicated a four-minute dwell would have been suffcient. The operation concluded that the USV's ability to precisely hold station in both time and space exceeded the ability of humans, showing it could effectively study parameters associated with the riverine fow environment. Similarly, USVs used in studies performed by the U.S. Geological Survey and others in shallow waters have quantifed oyster beds and gathered water quality data. The agency utilized EdgeTech (West Wareham, Massachusetts) FS-4200 dual-frequency side scan sonar (120 and 410 kilohertz) and sub-bottom profler, Teledyne RDI 600-kilohertz Workhorse Rio Grande ADCP and Ashtech RTK GPS from Thales (Paris, France) to map current and acquire side scan sonar data and sub-bottom profles to locate current and ancient oyster beds to track bed health and migration over time in Apalachicoloa Bay, Florida. CSA International Inc. (Stuart, Florida) www.sea-technology.com