In recent years the underwater navigation industry has expanded into more diverse and unique applications requiring a greater capability from its platform sensor set. Teledyne RD Instruments has answered the demand with a new patented Phased Array technology to be used as part of the growing Doppler Velocity Log and Acoustic Doppler Current Profiler Product Lines. This new technology derives a fundamental set of advantages over the standard Piston Array. It exhibits how the new Phased Array utilizes a single array transducer composed of multiple elements where four individual acoustic beams are electronically formed at their defined angles. In contrast the existing piston transducer technology utilizes the four individual ceramics where each beam is projected at its respective mounting angle. This yields the opportunity to increase the size of the single array while reducing the overall transducer size giving way for the characteristics which provide for operational improvement.More
The development of a magnetometry system for an underwater glider is detailed in this paper. The system is designed for low noise, low sampling rates and high accuracy measurements. The integration progress into a 200 m Slocum Electric glider is presented in addition to an evaluation of the electrical and system noise levels. A calibration algorithm is evaluated for correcting sensor errors as well as hard and soft magnetic effects due to the glider.More
This paper presents a summary of the current state-of-the-art in INS-based navigation systems in AUVs manufactured by Bluefin Robotics Corporation. A detailed description of the successful integrations of the Kearfott T-24 Ring Laser Gyro and the IXSEA PHINS III Fiber Optic Gyro into recent Bluefin Robotics AUVs is presented. Both systems provide excellent navigation accuracy for high quality data acquisition. This paper provides a comprehensive assessment of the primary advantages and disadvantages of each INS, paying particular attention to navigation accuracy, power draw, physical size, and acoustic radiated noise. Additionally, a brief presentation of a recently integrated Synthetic Aperture Sonar system will be used to highlight how critical a high-performance INS is to hydrographic, mine countermeasures, and other SAS applications.More
Why current profiling from gliders?
There are really good reasons for making current velocity measurements on a glider. Simply using profiles of current velocity structure and shear as a reference to interpret contour plots of other physical variables is reason enough for many researchers. Measuring higher velocity in one location compared to another could provide evidence of upwelling. Observing variation in the velocity shear at different locations can provide insight to the formation and dissipation of phytoplankton thin layers. Or simply use the acoustic backscatter to map and quantify zooplankton in an effort to understand zooplankton in a effort to understand zooplankton distribution, dynamics, and relationship to whale or fish feeding.
Prediction of the substantial biologically mediated carbon flows in a rapidly changing and acidifying ocean requires model simulations informed by observations of key carbon cycle processes on the appropriate spatial and temporal scales. From 2000 to 2004, the National Oceanographic Partnership Program (NOPP) supported the development of the first low-cost, fully autonomous ocean profiling Carbon Explorers, which demonstrated that year-round, real-time observations of particulate organic carbon (POC) concentration and sedimentation could be achieved in the world’s ocean. NOPP also initiated the development of a particulate inorganic carbon (PIC) sensor suitable for operational deployment across all oceanographic platforms. As a result, PIC profile characterization that once required shipboard sample collection and shipboard or shore-based laboratory analysis is now possible to full ocean depth in real time using a 0.2-W sensor operating at 24 Hz. NOPP developments further spawned US Department of Energy support to develop the Carbon Flux Explorer, a free vehicle capable of following hourly variations of PIC and POC sedimentation from the near surface to kilometer depths for seasons to years and capable of relaying contemporaneous observations via satellite. We have demonstrated the feasibility of real-time, low-cost carbon observations that are of fundamental value to carbon prediction and that, when further developed, will lead to a fully enhanced global carbon observatory capable of real-time assessment of the ocean carbon sink, a needed constraint for assessment of carbon management
policies on a global scale.
Identification and tracking of hydrocarbons in the marine environment is challenging. State of the art systems typically rely on surface slicks to identify hydrocarbon contamination such as oil spills. Subsurface detection remains challenging. This paper describes the TETHYS in-situ mass spectrometer and results of real-world deployments.
TETHYS is a small, self contained mass spectrometer capable of operation to 5000 meters depth. The TETHYS instrument can quantitatively identify a wide range of hydrocarbons at trace concentrations (minimum limits of detection typically 500 parts-per-trillion) in the subsurface environment.
TETHYS has been successfully deployed on AUVs, ROVs, towfish, manned submersibles, and with divers for a variety of purposes, including deep ocean scientific exploration and mapping missions as well as commercial offshore oil and gas leak detection and cleanup.More
A unique cycloidal mass spectrometer, called TETHYS1, has been developed to explore dissolved hydrocarbon and atmospheric gases at ocean depths to 5,000 meters.More