To improve the processing precision of phase unwrapping in interferometric synthetic aperture radar (InSAR), the phase difference was replaced by local frequency estimation. The local frequency estimation could reflect topographic change more accurately than phase difference. And to prevent the residues error spread all over the image, the mesh-less method was introduced to avoid error propagation effectively by dividing local support domain in interferogram. Both simulation and experimental results showed that the proposed method can reduce the influence of the error, and improves the precision of the phase unwrapping.
