A low-cost method for measuring surface currents and modeling drifting objects

The ability to measure and model water currents is essential to ensure the safety and correct operations of many water surface activities. For example, the complex currents in harbors seriously affect the safety of vessels, while river turbulence and vortices cause safety hazards for people participating in white-water rafting, swimming, and other sports activities. In this paper, we demonstrate a low-cost method to measure and model surface currents. Specially designed GPS sensors are dropped into the water to record their drifting trajectories, which are then transformed into a current map to show the characteristics of the currents, including their velocity and direction. A proof-of-concept experiment shows the feasibility of the proposed method and how turbulence locations can be identified. We further demonstrate that the derived current map can be used to construct a mobility model of a drifting object and generate its virtual drifting trajectories. Our analyses show that the generated virtual trajectories closely fit the collected trajectories.