Correlation-autofocusing-spectral 2-D ISAR image reconstruction from linear frequency modulated signals

In this paper, by applying an analytic geometric approach, a model of an ISAR (inverse synthetic aperture radar) signal with linear frequency modulation is developed. An ISAR scenario of the rectilinear movement of a 2D target in the 3D coordinate system is described. An image reconstruction procedure, independent of the trajectory parameters of the target is suggested. The image processing is performed over the time record of the ISAR signal. Range compression and azimuth compression are performed by correlation with an emitted LFM (linear frequency modulated) pulse, and fast Fourier transform, respectively. An autofocusing technique using a reference signal, reflected by the nearest (first) point scatterer from the target, is applied. Numerical experiments to prove the correctness of the ISAR image reconstruction procedure are performed.