Research On Airborne Inar DEM Block Adjustment With Independent Model

InSAR technology can acquire high precision ground 3D information, and it is one of the key technologies of SAR topographic mapping. DEM obtained by Interferometric processing without geocoding (slant-range DEM) has high precise relative elevation, but due to the slant-range expression, it can't be used directly. At the same time, the inaccuracy of interferometric geometry calibration would bring some errors to the slant-range DEM. Firstly, convert slant-range DEM to ground-range DEM, then propose an absolute orientation model according to spatial similarity transformation method. Based on this model, a block adjustment method with independent model is put forward for slant-range DEM. At last, calculat the model orientation parameters and pass points'coordinates, gain the high precision 3D information.The main work of this paper is as below:1. Slant-range DEM absolute orientation model. According to the character of side looking SAR and its imaging models, with relative elevation information, it views ground-range DEM generated by slant to ground-range transformation as rigid body, by using of spatial similarity transformation, convert model rectangular space coordinates to photogrammetric coordinates then to geographic coordinates, thus it established the function of model point and its geographic coordinates.2. Block adjustment with independent model on the basis of absolute orientation model. Use the mathematical model of absolute orientation model, regard every ground-range DEM in every strip as unit model, and link all unit models with tie points, then calculated unit models'orientation parameters and pass points'coordinates, finally realize strip combined block adjustment.3. Experiments on absolute orientation and block adjustment. The absolute orientation is tested with slant-DEM taken from Weinan area in Shaanxi province, the results show it meets the 1:10000 mapping requirement, and the block adjustment is tested with the data site taken from Maqu area in Gansu province, the results show it meets the 1:50000 mapping requirement.