Bias-corrected RPCs for QuickBird stereo satellite imagery: A case study in Shanghai

Along with a wide spread application of high resolution satellite imagery (HRSI) in urban mapping and change detection, the demand is increasing for higher accuracy metric products from HRSI. However, due to the inherent sensor orientation bias, the rational polynomial coefficients (RPCs) provided by the vendors can not produce accurate coordinates in ground point determination. Based on the QuickBird stereo HRSI, this paper has presented the performance of two schemes for bias elimination, including RPCs modification and RPCs regeneration. The experimental results show that, for the testing area, modified RPCs yields low positioning accuracy of 2 - 3 meters in planimetry and 3 meters in elevation since it is responsible for correcting only the shift bias. However, with minimal 2 control points, regenerated RPCs with shift and drift bias compensated produces accuracy of about 0.6 meters in planimetry and 1 meter in elevation. If more control points are available, RPCs regeneration with affine model bias compensation is more recommended. The bias-corrected RPCs provide a steady accuracy of half meter in planimetry. Furthermore, the bias-eliminated RPCs facilitate bias-free application. They can be used as replacements of the originals producing high accuracy in photogrammetric system for further processing such as ortho-rectification and DEM generation to provide cost advantage.