New applications for autonomous aerial vehicles in coastal oceanographic research

Libe Washburn1, Eduardo Romero2, Cyril Johnson2 and Brian M Emery3, (1)University of California Santa Barbara, Marine Science Institute and Department of Geography, Santa Barbara, CA, United States, (2)University of California, Marine Science Institute, Santa Barbara, CA, United States, (3)University of California Santa Barbara, Santa Barbara, CA, United States
Abstract:
We describe the use of small, autonomous aerial vehicles (AAVs) for two applications to improve observations of the coastal ocean. Two types of aerial vehicles are used in these applications: small, fixed-wing airplanes and quad-rotor vehicles constructed in our laboratory. A key characteristic of these vehicles is their ability to accurately follow prescribed flight trajectories.

The first application is a new method using AAVs for antenna pattern measurements (APMs) of high frequency (HF), oceanographic radars. HF radar is arguably the best observational approach for mapping coastal surface currents. Accurate surface current measurements by HF radar require APMs and these are typically made from small vessels carrying radio transponders in arcs around individual radar sites. This is costly because it requires sea-going technicians, a vessel, and other equipment for small boat operations. Adverse sea conditions often limit small vessels in conducting APMs. AAVs can conduct APMs at much lower cost and in a broader range of sea states with comparable accuracy. The AAVs carry small radio-frequency signal sources designed and fabricated in our laboratory. AAV-based patterns extend farther shoreward through the surf zone. This increases the range of bearings over which APMs are determined. Use of AAVs also allows more frequent APMs.

The second application is water sample collection by AAVs for calibrating time series obtained from newly available pH sensors. Influx of low pH waters into subtidal and intertidal habitats is an emerging threat to coastal ecosystems. Acquisition of bottle samples for calibrating these sensors is important for accurate pH measurement. We have developed a lightweight sampling bottle as a payload for quad-rotor AAVs to collect water samples near moored pH sensors. The use of quad-rotor AAVs allows collection of numerous samples during sensor deployments so the effects of sensor drift and bio-fouling can be quantified.

Back to: Autonomous Systems for Study of Coastal and Estuarine Processes Posters