Target tracking using television-based bistatic radar

The use of a non-co-operative television transmitter as the illuminator for a bistatic radar system is investigated. A signal processing scheme is developed that allows airborne targets to be detected and tracked using only the vision or sound carrier of the television broadcast. This scheme requires no synchronisation with the television transmitter, and uses the Doppler shift and bearing of target echoes to estimate the target's track. The signal processing scheme consists of a two-channel fast Fourier transform, to determine the Doppler and phase characteristics of the received signal, followed by time and frequency acting constant false alarm rate detection schemes to detect the target echoes. These echoes are corrected for phase errors arising from antenna element mutual coupling, and the corresponding bearings are calculated. A Kalman filter based tracking scheme is used to associate the individual Doppler and bearing returns belonging to different targets, resulting in Doppler and bearing profiles for each target. These are used to estimate the Cartesian co-ordinates and velocity of each target using an extended Kalman filter, initialised using a genetic algorithm and Levenberg–Marquardt optimiser. It is shown that targets can be detected and tracked over a large area, at ranges of up to 260 km.