Distributed Estimation of the Pelagic Scattering Layer Using a Buoyancy Controlled Robotic System

This paper formulates a strategy for Driftcam, an ocean-going robot system, to observe and track the motion of an ocean biological phenomenon called the pelagic scattering layer, which consists of organisms that migrate vertically in the water column once per day. Driftcam’s horizontal motion is determined by the flow field and the vertical motion is regulated by onboard buoyancy control. In order to observe the evolution of the scattering layer, an ensemble Kalman filter is applied to estimate organism density; the density dynamics are propagated using the Perron-Frobenius operator. Multiple Driftcam are subject to depth regulation by open-loop and closed-loop controllers; a control strategy is proposed to track the peak of the density. Numerical simulations illustrate the efficacy of this strategy and motivate ongoing and future efforts to design a coordination formation algorithm for multi-agent Driftcam system to track the motion of the scattering layer, with implications for ocean monitoring.