Controlling mobile sensors for monitoring events with coverage constraints

Sensor networks are systems of many small units that work together to monitor a given environment. Endowing such sensor units with mobility can allow them to reactively converge on more interesting portions of their environment. This enables the concentration of sensing resources where they are most useful and provides robustness by delivering redundancy at the point of interest. However, when converging, in general the sensors should not leave any portion of the environment unsensed. In this paper, we review distributed methods for controlling the sensors and describe a family of distributed methods for retaining coverage while allowing the convergence to proceed where possible. The coverage methods are based on the Voronoi diagram of the sensors' positions, and can use different amounts of communication and computation to produce complete coverage of the environment. We also describe extensions that serve to make coverage more uniform or allow specific areas to be left uncovered. We present implementations of these algorithms in simulation and describe results and avenues of future work.