Target Tracking in Time-Division-Multifrequency-Based Passive Radar

Passive bistatic radars have been reported to detect and track drones, general aviation aircraft, and civil aviation aircraft extensively. However, localization performance is limited by the poor azimuth estimation. On the other hand, lots of digital television broadcasting transmitters have sprung up, and they work at different frequencies. In order to utilize the spatial diversity of the transmitters with one receiver, the time-division-multifrequency(TDMF)-based passive radar is constructed. The TDMF system reports the target observations from different transmitters sequentially like an asynchronous system. We proposed a target tracking method to make full use of the spatial diversity. The method is divided into two stages, namely extrapolated bistatic tracking and Cartesian tracking. Extrapolated bistatic tracking is designed to solve the asynchronous problem and guarantees a high-accuracy initial track. Then, the measurements from different transmitters are utilized to update the Cartesian tracks sequentially. This spatial diversity leads to a high-accuracy track. The posterior Cramer-Rao bound for the TDMF system is also derived. Simulation and experimental results show close performance to the simultaneous multifrequency passive radar. Furthermore, field experimental data verifies the feasibility of the proposed approach.