The Pop-Up Buoy (PUB)
CHARLES STARK DRAPER LAB INC CAMBRIDGE MA
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The Pop-Up Buoy PUB was conceived as a practical means to implement a real-time telemetry link between a satellite and instruments beneath the ocean surface. It is a self-contained module, tethered to a moored subsurface buoy, and capable of propelling itself up and down between the ocean surface and a submerged rest station. Most of its life is spent submerged, secure from storms and surface traffic, while storing data sent from remote sensors via an acoustic link. At pre-determined times of satellite passage, it rises to the surface for a brief transmission. If a storm is sensed by pressure fluctuations the transmission can be postponed or cancelled. Typical low data rates, e.g., only 3000 bits every 3 days in the acoustic tomography application, can be handled with infrequent transmissions. Energy for propulsion is then so small that a two-year life system may be packaged in a compact unit. A PUB sized for tomography has the form of a 56 cm sphere with small appendages and weighs 104 Kg 230 lbs. The design of this unit is described.
- Marine Engineering