Autonomous Underwater Vehicle, Seaglider
Seagliders are a range of autonomous underwater vehicles (AUV) or underwater gliders developed for continuous, long term measurement of oceanographic parameters. Rather than an electrically driven propeller, these vehicles uses small changes in buoyancy and wings to achieve forward motion. The system's pitch and roll are controlled using adjustable ballast (the vehicle battery).
Seaglider® Autonomous Underwater Vehicles have revolutionized the collection of ocean data. Their change in buoyancy make them move through the water column in a saw-tooth pattern, surfacing often to determine its position while continuously collecting data. This results in very low power consumption and long endurance of up to 10 months depending on configuration and payloads. Navigation is accomplished using a combination of GPS fixes while on the surface and internal sensors that monitor the vehicle heading, depth and attitude during dives. External sensors are constantly scanning the ocean to determine environmental properties.
Presently three different versions are available - see data sheets (below) for details:
- Seaglider C2 - Max depth: 200 m
- Seaglider - Max depth: 1000 m
The Seaglider® Advantage
Seaglider® has revolutionised the way that oceanographic data is collected. Its novel method of propulsion uses very little energy. In addition, the vehicle has been meticulously designed to be as efficient as possible.
The outcome is a data collection tool that can be deployed for months at a time rather than the hours or days associated with traditional AUV systems. While its top speed is low, the vehicle's extremely long endurance allows it to traverse thousands of kilometers in a single deployment. The vehicle is relatively small and lightweight, enabling deployment via small vessels of opportunity.
Using the AUV you can collect data with excellent temporal and spatial characteristics at a fraction of the cost of traditional collection methods.
Constant Contact and Data Retrieval
In typical operational scenarios, the vehicle will surface after each dive to transmit collected data and receive commands via satellite telemetry. In this way the system pilot can continually monitor flight performance and vehicle health, making adjustments as necessary to improve efficiency and the quality of the collected data. In addition, the end user(s) can obtain the collected data in near real time.
- Chemical Oceanography
- Environmental Monitoring
- Climate Change Studies
- Ocean Observatories
- Storm Monitoring
- Ecosystem Assessment
- Fisheries Research
- Anti-Submarine Warfare (ASW)
- Intelligence, Surveillance & Reconnaissance (ISR)
- Baseline Environmental Assessment
- Acoustic Monitoring of Marine Mammals
- Operate from Anywhere in the World: Vehicle is piloted remotely via the internet and satellite link. Data is retrieved in near real-time via satellite telemetry. Robust design allows remote deployment.
- Long-Endurance Data Collection: Low drag, flooded fiberglass composite fairing. Extended duration deployment, up to 10 months. Ultra-lower power ARM processor.
- Low Cost: Low capital cost – a fraction of traditional methods for collected the same data. Can be launched from small vessels of opportunity, reducing deployment costs.
- Versatile Payload Capability: Versatile payload capability for collection of a wide range of high-quality ocean data. Sensors can be integrated into dry or wet payload volumes. Simple and versatile sensor interface.
- Vehicle dimensions:
- Length: 1.8 - 2 meters (configuration dependent)
- Wing span: 1 - 1.5 meter (configuration dependent)
- Antenna mast: 43 cm – 1 meter (configuration dependent)
- Maximum diameter: 30 cm
- Weight in air: Less than 80 kg (configuration dependent)
- Maximum operating depth: 1000 meters
- Energy: Lithium sulfuryl chloride primary batteries 17 MJ
- Endurance: Up to 10 Months (dependent upon configuration, sampling rate and operational area)
- Speed: Typical speed 25 cm/s (0.5 kt)
- Control: Small changes in buoyancy and wings are used to achieve forward motion. The system's pitch and roll are controlled using adjustable ballast (the vehicle battery).
- Navigation methods: Navigation is accomplished using a combination of GPS fixes while on the surface and internal sensors that monitor the vehicle heading, depth, an attitude during dives. Dead reckoning between surface GPS fixes using a 3-axis digital compass. Acoustic altimeter and bathymetry map system for near-bottom dives.
- Communication: Iridium satellite telemetry
- Software: Piloting tools software included with standard system. Optional subscription-based cloud user interface for mission planning, monitoring and control.
Water density plot
Disolved oxygen plot
Temperature salinity plot
Seaglider auxiliary support equipment/vehicle safety features
When sending data via Iridium, Seaglider also sends health status information including:
- Internal Pressure
- Internal Humidity
- Hydraulic System Status
- Mass Shifter Status
- Battery Level
Critical system faults will result in mission abort and notification sent via satellite telemetry.
Communication and Tracking
Operators can monitor the Seaglider’s progress and status via Iridium. GPS coordinates are sent via Iridium to pinpoint location and allow you to track the vehicle throughout the mission. You can also use Iridium to communicate with the vehicle, redirecting the mission or changing mission parameters.
If the mission aborts and the vehicle surfaces, it will send an alert via Iridium. There is additional optional equipment available for purchase for emergency localization, including:
- ARGOS tag as a backup to Iridium & GPS
- Acoustic Deck Box for Emergency Recovery Underwater
The AUV was developed in the 1990s in a collaborative effort between the Applied Physics Laboratory at University of Washington and the University of Washington's School of Oceanography. Funding for the development was provided by the U.S. Navy's Office of Naval Research. As of 2018, more than 350 Seaglider AUVs have been delivered to research institutions, naval organizations and commercial operators around the world.