A Novel Efficient Spaceborne SAR Geolocation Method Based on Recursion Formulae

A novel efficient geolocation method for spaceborne Synthetic Aperture Radar (SAR) is proposed based on recursion formulae in this paper. In this method, three groups of recursion formulae are utilized to compute the three-axis position increments between the position-unknown pixel and the adjacent position-determined pixel, i.e. the reference pixel, with the input increments of the height, slant range and azimuth time between the two pixels. Subsequently, these increments are added to the position of the reference pixel to obtain the position of the position-unknown pixel. Regarding respectively the height, slant range and azimuth time as the variables, these recursion formulae are acquired by differentiating the geolocation equations. Consequently, the construction of three-dimensional grid, coefficients fitting and interpolation are avoided in this method. The geolocation results of simulated and real data validate the accuracy and effectiveness of this method.