SAR Imaging of a Moving Target

In the proposed work new synthetic aperture radar geometry named generalized inverse synthetic aperture radar (GISAR) geometry is addressed. A new three-dimensional (3D) model of deterministic components of GISAR trajectory signals with stepped frequency modulation is suggested. 3D GISAR geometry is described by means of the analytical geometry. The geometry and kinematics of the object and GISAR observation system are described in separate 3-D Cartesian coordinate system. The stationary objects are presented in 3-D regular grid of isotropic point scatterers, relatively moving with respect to GISAR system at the velocity of the SAR carrier. The SAR carrier is considered unmoving placed in the origin of the coordinate system of observation. The stationary targets are moving at the complex velocity equal to the geometrical sum of the target velocity and SAR carrier velocity. The analytical expressions to compute the range distance to point scatterers of the stationary scene and moving targets are derived. The image reconstruction procedure includes both range and azimuth compression: cross correlation technique to GISAR signal to realize range compression and short time frequency transform to realize azimuth compression. A range alignment and an autofocusing technique are applied to GISAR signal. To illustrate the capability of the 3D ISAR signal model numerical experiment is implemented.