Polar format algorithm of synthetic aperture radar imaging on spiral trajectory

A novel polar format algorithm is proposed for spiral trajectory. The synthetic aperture radar (SAR) signal model of spiral trajectory platform is firstly established, then the sector-by-sector phase compensation method of spiral trajectory SAR is proposed. With the descending of the flight platform, the slant range also decreases, thus the sector-by-sector phase compensation is required to correct the quadratic terms of the Range Cell Migration to expand the effective imaging range and eliminate the defocus of the target at the edge of the scene. The 2D-NUFFT is used to transform the 2D wavenumber domain instead of the traditional nearest interpolation method, which decreases the calculation. Finally, the algorithm is validated by simulation.