Xueping Zhang and Xiuxiao Yuan
_{School of Remote Sensing and Information Engineering, Wuhan University,  
129 Luoyu Road, Wuhan 430079, China}

Abstract. Direct georeferencing has become more and more important in aerial photogrammetry, but the accuracy can’t satisfy the requirements at small mapping scales in practical projects. The main reason is that he accuracy of exterior orientation elements determined by the POS is not high enough. According to the heory of space intersection and error propagation law, mathematical model of exterior orientation elements’ effects on direct georeferencing based on space intersection proposed firstly. Afterwards, mathematical model of exterior orientation elements’ effects on direct georeferencing based on collinearity equations are proposed according to collinearity equations and least  square adjustment. The mathematical models are experimented using three sets of actual data at different photographic scales and terrains. Based on the empirical results, the effect rules of exterior orientation elements’ errors on direct georeferencing in theory and in practice are analyzed respectively. Finally, effects of different combinations of same accuracies of exterior orientation elements on direct Georeferencing are discussed.

Keywords: Position and Orientation System, exterior orientation elements, direct georeferencing, error

In: Wan, Y. et al. (eds) Proceeding of the 8th international symposium on spatial accuracy assessment in natural resources and environmental sciences, World Academic Union (Press).