The Model 115 Autonomous GPS Drifter is a current following (Lagrangian) drifting buoy. It is released in a body of water and moves with the currents over a period of days to months. As the drifter moves, onboard electronics acquire a time series of positions using GPS plus optional sensor data. This data is sent to the end user via the worldwide Argos satellite network.
The Model 115 is a lower cost adaptation of the Model 104 GPS/Argos drifter that provides functionality adequate for many applications while remaining compatible with software, deployment logistics, data format, and drifter characteristics of its more advanced sibling. Additionally, the Model 115 is optimized for simple deployment, allowing drifter launches from ships of opportunity by minimally-trained personnel.
Precision Lagrangian current data provided by the Model 115 is useful in current measurement, larval fish studies, oil spill or floating debris tracking, discharge dispersement calculations, and similar studies.
Physical characteristicsPhysical drifter design is similar to the Coastal Ocean Dynamics Experiment (CODE) drifter developed at the Scripps Institute of Oceanography. This design (also known as a Davis or SCULP drifter) provides excellent coupling to the surface layer and exhibits little wave rectification. An optional conversion kit allows the drifter to be changed in the field to a deep drogued configuration. The drifters are small and light (14 kg / 30 pounds) and are easily hand-deployed and retrieved by one person.
The Model 115 features a 12 channel GPS receiver that records position to 0.01 minute of latitude and longitude (18 meters).
Temperature: -10 to +40C, resolution 0.01C. Stock accuracy is better than +/-0.5C. Typical postprocessed accuracy with optional individual calibration 0.05C.
Conductivity / temperature: -10 to +40C, resolution 0.01C. 0-60 mmho/cm, resolution 0.01 mmho/cm. Full digital sensor with individual calibration yields typical postprocessed accuracy of 0.05C and 0.05 mmho/cm.
The Mode 115 is shipped from the factory with the desired customer setup saved in EEPROM, where it persists through battery changes. The drifter can be operated using a magnet applied to two marked areas of the drifter hull. A "beep code" audible through the case allows personnel without a computer to monitor and confirm proper drifter operation before deployments. If desired, an internal RS-232 interface port allows the end user to alter the operational setup and save the changes to EEPROM.
|Click for sample graphics screen from real time tracking software.|
Decoding and tracking software is included with all GPS/Argos drifters at no charge:
Brightwaters Instrument Corporation has been building autonomous drifting buoys since 1991, with the current Model 115 representing a sixth generation of design. Innovations developed at Brightwaters have been adopted across the drifter industry. Continuous design improvements reflect Brightwaters' commitment to offer the most technically advanced drifters in the world.
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