  Wild-land fire fighting is a hazardous job. A key task for firefighters is to
observe the "fire front" to chart the progress of the fire and areas that will
likely spread next. Lack of information of the fire front causes many
accidents. Using Unmanned Aerial Vehicles (UAVs) to cover wildfire is promising
because it can replace humans in hazardous fire tracking and significantly
reduce operation costs. In this paper we propose a distributed control
framework designed for a team of UAVs that can closely monitor a wildfire in
open space, and precisely track its development. The UAV team, designed for
flexible deployment, can effectively avoid in-flight collisions and cooperate
well with neighbors. They can maintain a certain height level to the ground for
safe flight above fire. Experimental results are conducted to demonstrate the
capabilities of the UAV team in covering a spreading wildfire.
