Submersible pop-up buoy for RF communication

Buoy geometries for ocean applications are as varied and diverse as the programs that give rise to their needs. NRaD is designing for ONR an autonomous, battery-powered, pop-up buoy system to provide RF communications between the sea surface and a remote ship or shore terminus, or an airborne or spaceborne repeater. This buoy system will act as a communication relay, sending and receiving data over an RF link, and shuttling that information, via fiber-optic link, to and from a sensor system on the ocean floor. Unique design features include an inherently positive, variable-displacement spar; a variable-ballast chamber to regulate surface exposure; and a self-compensating tether-management/counterbalance system. Four micro-controllers distributed throughout the buoy system control all buoy parameters. An innovative antenna configuration combines several transmit and receive antennas in a smooth mast, which will reduce drag and snagging. Onboard engineering sensors will collect and store voltages, currents, pitch, roll, temperature, and other buoy performance data on a regular basis while the spar is submerged, and will send that information to the user when RF communication is established. Safety features include backup acoustic commands to the buoy and a GPS locator/beacon that will detect and report the spar´s position should it break away from its mooring