IMU/DGPS Supported ADS40 Imagery Direct Georeferencing and Its Error Analysis

The theory of the direct georeferencing(DG) of ADS40 imagery supported by IMU/DGPS system is introduced.According to the situation that different local space rectangular coordinates system have been adopted for different ADS40 strips,the equations to transform the exterior orientation elements of all strips to one ground frame are derived.Test results show that the DG error of ADS40 images is systematic,so bundle adjustment with the help of some control points is necessary in actual task.The method to unite exterior orientation elements of different strips and the conclusions from test will lay a foundation for the triangulation of ADS40 imagery.