Autonomous Surface Craft
Innovative Remote Navigation Design for the Defense Industry
The U.S. Department of Defense’s Defense Advanced Research Projects Agency, or DARPA, often requests design innovation from private companies. DARPA challenged American engineers to re-imagine our nation’s sonobuoy system, a network of static buoys that used sonar pings to detect oceanic vessels and radio technology to send data back to a command ship station. To modernize the system, DARPA requested development of mobile sonobuoys that could either remain unanchored in one place or move to new coordinates using remote navigation. McGilvra Engineering partnered with two other engineering consultancies on the project; one firm designed the hardware, another the communications and McGilvra designed the remote navigation software.
The lightweight, collapsible, solar-powered mobile sonobuoys are covered in solar panels and have a low profile, so they are difficult to see in the open water. Their low-voltage, rechargeable batteries and small thrusters create very little noise for radars to detect. Despite their stealthy design, nature still buffets the little vessels, knocking them off course. The mobile sonobuoys can be deployed all at once from the air or sea. Once deployed, the McGilvra-engineered software on each craft directs the thrusters to slowly motor that craft to its assigned GPS location. Each craft maintains its position, with a margin of acceptable deviation to account for wind and waves. Once a mobile sonobuoy strays too far from its coordinates, it motors back into place. The software system’s remote navigation allows the military team to tweak its performance in response to a low battery charge, to ensure energy efficiency and to maintain strategic effectiveness.
Should the command team need the mobile sonobuoys in another location or in a different formation, they can reposition the mobile sonobuoys on the fly by sending each craft new GPS coordinates. The remote navigation software sends each craft to its new location, where the mobile sonobuoys again maintain their position and sonar vigil.
The ocean has both seafaring vessels and aquatic life, so the mobile sonobuoy software can distinguish between the two. The software detects the sound signature for surface and submarine traffic as well as migrating whale pods or schools of fish. It filters the sound signatures and sends just the relevant data to the command center. Though the sonobuoys’ development was for military defense, this same technology could be used to further oceanic and zoologic research. DARPA awarded McGilvra and its two engineering partners the contract for this autonomous surface craft and this technology, including the remote navigation software, is in use today to report potential threats to the homeland.
A small autonomous surface craft was developed to monitor sub-surface activity as part of a Defense Advanced Research Agency (DARPA) program. Our responsibility was the communications and control systems. A five-processor board was developed with each processor responsible for a key subsystem of the craft. The craft is required to motor to its specified deployment location and maintains it’s position using thrusters and an inertial navigation system with GPS. A sub-surface microphone monitors underwater activity while a satellite data connection relays the information to a land-based station. The unit is powered by lithium-ion batteries which are recharged by a solar power system and a wave driven generator.