An Aircraft-Centered Multi-Frame TBD Method for Airborne Radar Systems

It is widely verified that the multi-frame track-before-detect (MF-TBD) is effective for the detection and tracking of weak targets. This paper considers the extension of MF-TBD to moving surveillance platform, specifically, the airborne radar system. For static radars, MF-TBD needs to first map the received raw data to an absolute coordinate, mostly the WGS-84 coordinate, and then perform the raw data integration between multi-frame to accumulate target energy along physically feasible states. The time-varying surveillance space and biased complex coordinate system conversion, caused by the aircraft motion, produce the unaligned multi-frame mapping. It brings the cell misalignment and dislocation error that contribute to the challenge of the tracking accuracy in the absolute coordinate. To address these limitations, the proposed aircraft-centered multi-frame TBD (AC-MF-TBD) method adopts the concept of relative kinematics making the aircraft as the center of each measurement frame and doing raw data integration in this relative coordinate, namely the inertial coordinate. It makes the mapping no longer time-varying and develops the tracking accuracy on the airborne radar. AC-MF-TBD essentially avoids the errors introduced by the aircraft motion in the absolute coordinate. In addition, the coordinate conversion using the attitude information of the aircraft is still a necessary process for AC-MF-TBD. The attitude angle calibration is used to improve the conversion accuracy. The simulation shows the performance of the proposed algorithm.