Multiple targets resolving using time range Doppler image

As targets flying in groups may spread over several range cells and their Doppler frequencies are time-varying, a scheme of target number detection in groups using a conventional low-resolution radar is proposed based on a time-range-Doppler image cube which is constructed by substituting a time-frequency transform for the Fourier transform in the conventional range-Doppler imaging. The image cube provides not only a clear range-Doppler image with superior resolution at each time instant but also the time-varying history of the images, hence a good solution to the problem of range spread and image blunting. The experimental results of actual target echoes demonstrate the validity of the scheme with successful detection of four targets flying in groups.