Phase difference autofocus setting for imaging a radar with a synthetic aperture

摘要

An autofocusing method apparatus for Synthetic Aperture Radar (SAR) are disclosed which employ operation on two or three subarrays (X, Y) of the SAR compressed data to estimate quadratic and cubic phase errors in the data. Focusing of the SAR array may then be accomplished by removing the estimated phase error from the data to sharpen the image. Phase error is estimated by FFT filtering (44) product arrays (X, Y) formed by multiplying (34) the complex conjugate of one subarray (X) by another of the subarrays (Y) to form a correlation function. The correlation functions are integrated (54). A peak detection (56) of the integrated correlation functions yields a peak location in the filter which is proportional to the phase error which may then by calculated. IMAGE