Geometrical fusion of multitrack PS point clouds

Recent radar satellites like TerraSAR-X and COSMO-SkyMed deliver very high resolution synthetic aperture radar images at a spatial resolution of less than 1 m. Persistent scatterer (PS) positions obtained from stacks of high-resolution spotlight data show very much details of buildings and other structures in 3-D due to the enormous amount of PS obtainable from data of this resolution class. As soon as more than one stack covering the same area is available, a combination of the results is eligible. However, geocoded PSs cannot be simply united due to residual offsets in their absolute positions which stem from unknown absolute height values of the different reference points chosen when processing the individual stacks independently. In this letter, two different methods for a geometrical fusion of geocoded PSs from stacks acquired at different aspect and incidence angles are presented. The algorithms are applied to PS interferometry results of both urban and nonurban areas.