Research Summaries

Back Cooperative Underwater Sensing with Aqua-Quad

Fiscal Year 2015
Division Research & Sponsored Programs
Department Consortium for Robotics & Unmanned Systems Education & Research
Investigator(s) Buettner, Jr., Raymond R.
Jones, Kevin D.
Sponsor Office of Naval Research (Navy)
Summary There are a multitude of tasks, in all branches of the armed forces as well as the scientific community and private sectors that require persistent, wide-area sensing in virtually all environments – air, sea and land. On the ocean surface, buoys and disposable floaters are frequently used, but are subject to ocean currents, providing mobility, but not necessarily mobility in the desired direction. They typically provide limited sensing at or near the surface, and are usually limited to low-bandwidth satellite communications or data storage until they are retrieved. Underwater there are a few solutions. For example, sea gliders provide long endurance and at least some mobility beyond ocean currents. However they are limited to undersea and surface sensing, and are typically out of communications most of the time, again limited to low-bandwidth communications when they are on the surface. Wide area, long endurance coverage in the air is also challenging. One ongoing study, TaLEUAS proposes to utilize a flock of networked airborne gliders that use a combination of natural, convective lift in the environment and photovoltaic cells coupled to high specific energy rechargeable batteries to provide 24/7 aerial coverage. While this concept is promising for aerial missions, ISR, communications-relay, etc., it is not of much use for sensing at the ocean surface, underwater, or ground sensing where severe proximity limitations exist, such as looking for mines buried in the beach. None of these schemes are able to cover all environments, air/sea/ground, and each includes constraints for communications, mobility and/or survivability in harsh weather. In 2014 CRUSER funded a concept that is a true hybrid platform, capable of use in all these environments, with both air and surface mobility, 24/7 sensing and high bandwidth communications - the Aqua-Quad.
The work proposed for FY15 builds on the FY14 developments by adding a passive acoustic sensor (Acousonde from, and expanding the fleet to 4 or 5 units which can work cooperatively to locate and track underwater targets. Student thesis work (LT Chase Dillard) is currently underway to simulate a flock of 4 Aqua-Quads which act as drifters most of the time, but that can expend energy to move against the current when needed and when stored energy is available. Most targets of interest will be below the thermal layer, so the Aqua-Quad will need to “deploy” the sensor by releasing a reel that lets the sensor drop on a tether that provides power and data to/from the sensor. Once deployed, the Aqua-Quad will not need to retrieve the sensor, but will leave it hanging on the tether, some 30m deep. For communication hops where the Aqua-Quad doesn’t need to relocate, it will leave the sensor underwater, but rise high enough to achieve communications with other members of the flock or a command center. To relocate, the Aqua-Quad will need to fly a bit higher and lift the sensor out of the water (an additional 250g + 100g tether), reducing flight times to about 20 minutes at a time.
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal