Relative navigation for autonomous aerial refueling rendezvous phase

A relative navigation system for autonomous aerial refueling (AAR) rendezvous phase is proposed in this paper. The system uses the inertial navigation system (INS), the Global Positioning System (GPS) and the infrared search and track system (IRST). It has both advantages of cooperative aircraft relative navigation and passive target location. A hybrid multistage fusion structure and corresponding algorithm are designed to estimate the high precision relative position, velocity and attitude information between the tanker and the UAV in real time. For the INS/GPS subsystem, a two-stage filtering algorithm based on extended Kalman filter is developed without any use of base-station, which helps to improve the accuracy of the filter model. Considering the requirement of reliability and robustness for aerial refueling, an independent IRST relative state tracker filter is set up in the system. It weakens the dependence of relative navigation system on data link, and makes the system highly reliable and fault-tolerant. The numerical simulation results indicate that the proposed algorithm can provide good performance in terms of accuracy and reliability.