RESTORATION OF SIGNAL TO NOISE AND SPATIAL APERTURE IN SQUINT ANGLES RANGE MIGRATION ALGORITHM FOR SAR

A moving radar generates a search mode synthetic aperture image of a patch having a principal scatterer. The boundaries of the patch are from R0 to R1 slant range and θ0 to θ1 azimuth angle. A computer motion compensates digital samples to obtain a motion compensated digital array. The motion compensated digital array is converted to a frequency array in the frequency domain Kx, Ky The frequency array has a rectangular aperture extending ΔKx and ΔKy. Available samples from the frequency array are computed using a Range Migration Algorithm including a Stolt interpolation. Usable samples are identified from the available samples using one or more criteria. Usable samples are removed from available samples to obtain incomplete samples. Features related to the patch having a principal scatterer are extracted from the usable samples. The features are used to extrapolate extrapolated samples from the usable samples. The extrapolated samples, the usable samples and the incomplete samples are combined to compute the image of the patch and principal scatterer. Incomplete samples are substituted where they overlap interpolated samples.