Developing a Control Architecture for Multiple Unmanned Aerial Vehicles to Search and Localize RF Time-Varying Mobile Targets: Part I

In this paper, we present a control architecture that allows multiple Unmanned Aerial Vehicles (UAVs) to cooperatively detect mobile RF (Radio Frequency) emitting ground targets. The architecture is developed under the premise that UAVs are controlled as a distributed system. The distributed system-based technique maximizes the search and detection capabilities of multiple UAVs. We use a hybrid approach that combines a set of intentional cooperative rules with emerging properties of a swarm to accomplish the objective. The UAVs are equipped only with low-precision RF direction finding sensors and we assume the targets may emit signals randomly with variable duration. Once a target is detected, each UAV optimizes a cost function to determine whether to participate in a cooperative localization task. The cost function balances between the completion of detecting all targets (global search) in the search space and increasing the precision of cooperatively locating already detected targets. A search function for each UAV determines the collective search patterns of collaborating UAVs. Two functions used by each UAV determine (1) the optimal number of UAVs involved in locating targets, (2) the search pattern to detect all targets, and (3) the UAV flight path for an individual UAV. We show the validity of our algorithm using simulation results. Hardware implementation of the strategies is planned for this coming year.