Fractional Fourier transform based target number detection

Due to the drawback that a conventional radar can not directly resolve the targets flying in a group in both range and azimuth, a method of target number detection is proposed by using the fractional Fourier transform based on the fact that the targets may be resolved in the Doppler frequency domain. The combination of coarse and fine search steps adopted effectively resolves the contradiction between the computation time and the search accuracy. In addition, being a 1-D linear transform and without the influence of the cross-term as in other time-frequency transforms, the method performs well under either higher SNR or lower SNR. The experimental results of actual target echoes demonstrate the performance of the method