Air-to-Air Tracking of a Maneuvering Target with Gimbaled Radar

This paper is concerned with the steering of an antenna beam for an air-to-air tracking system where an airborne radar antenna senses an airborne maneuvering target. A mechanical gimbal-mounted airborne radar is used to steer the antenna beam. The difficulty with a gimbaled radar is that the radar measurement becomes inaccurate if the target is outside the antenna beam width, which is usually less than 2deg. An extended Kalman filter is developed to estimate the relative position, relative velocity, and absolute acceleration of the target in Cartesian coordinates, which are further used to drive the antenna beam. Realistic noise models of sensors are incorporated in the measurements. A high-fidelity model is developed to accommodate the sensors operating at different frequencies. The mathematical formulation of initializing the state vector and process noise matrix using measurements, the measurement sensitivity matrix, and the process noise covariance matrix are presented. The flight dynamics of two fighter aircraft, both executing 3g, maneuvers is simulated to validate the proposed model. The accuracy achieved in the line-of-sight rate and line-of-sight angle estimation are deemed to be adequate for the tracking scenario. Furthermore, a MonteCarlo analysis of 50 runs is provided to validate the extended Kalman filter.