Swarming Driftcams: a Novel Platform for Locating and Tracking Pelagic Scattering Layers

This paper presents the design, development, and field results of novel depth-controlled sensor platforms. Called the “Swarming Driftcams,” these platforms travel passively in horizontal direction with ocean currents while controlling and profiling depth. These platforms use integrated depth, acceleration, attitude, temperature, and camera sensors to collect data from water column ecosystems. A novel buoyancy engine, using an electrically actuated reciprocating pump, facilitates active depth correction to a maximum depth of 700 m. Embedded computers control data collection, camera, lighting, and depth control. The vehicle contains a combination USBL and acoustic modem for bidirectional communication and surface tracking as well as intervehicle communications. A radio beacon and an Iridium GPS satellite beacon aid in surface location and recovery. In addition, the system has a small form factor, measuring 1 m in total height with a mass of 48 kg. Multiple vehicles can be deployed and tracked enabling increased data collection and the possibility for cooperative sampling strategies within the water column. All aspects of the vehicle hardware are discussed. Preliminary results are also presented for recent deployments into scattering layers in the Gulf of Mexico.