Autofocusing-spectral 2-D ISAR image reconstruction from linear frequency modulated signal

This work is devoted to inverse synthetic aperture radar (ISAR) autofocus signal processing of linear frequency modulation (LFM) signals for image retrieving. The procedure consists of range compression and Fast Fourier Transform (FFT) azimuth compression. The image processing is accomplished over the time record of ISAR signal returns. The signal processing is performed assuming arbitrary rectilinear movement of a target in the 2-D coordinate system. By applying analytic geometric approach 2-D ISAR LFM signal model is developed. Autofocus technique based on tracking first echo signal is examined. The proposed autofocusing-spectral image reconstruction procedure is invariant to the trajectory parameters. Numerical experiment proving ability and accuracy of the spectral ISAR image reconstruction procedure is accomplished.