Relay-Rover Differential Game

Guidance laws are developed to optimally position a relay Micro-UAV (MAV) to provide an operator at the base with real-time Intelligence, Surveillance, and Reconnaissance (ISR) by relaying communication and video signals when the rover MAV performing the ISR mission is out of radio contact range with the base. The ISR system is comprised of two MAVs, the Relay and the Rover, and a Base. The Relay strives to minimize the radio frequency (RF) power required for maintaining communications, while the Rover performs the ISR mission, which may maximize the required RF power. The optimal control of the Relay MAV entails the solution of a differential game. Suboptimal solutions are also analyzed to gain insight into the solution of the differential game. One suboptimal approach investigated envisages the Rover to momentarily remain stationary and solves for the optimal path for the Relay to minimize the RF power requirement during the planning horizon. The one - sided optimal control problem is solved. Another suboptimal approach is based upon the geometry of the system: The midpoint between the Rover and the Base is the location which minimizes the RF power required, so the Relay heads toward that point--assuming that the Rover is stationary. At the same time, to maximize the required RF power, the Rover runs away from the Relay.