Research On The Application Of Precise Point Positioning In Gps-supported Aerial Triangulation

In traditional GPS-supported aerotriangulation, differential GPS (DGPS) positioning technology is used to determine the 3-dimensional coordinates of the perspective centers. However, the establishment of GPS reference stations for DGPS positioning is not only labor-intensive and costly, but also increases the implementation difficulty of aerial photography. This paper mainly studis aerial triangulation supported with Precise Point Positioning (PPP) , in order to achieve the same accuracy with DGPS and simplify the work of aerial photography.This Paper first introduced the the basic principles of GPS-supported aero triangulation, In turn leads to the mathematical model of GPS-supported Bundle Block Adjustment, then focuses on the the method of obtaining the coordinates of the perspective centers and the measurements of ground-photo-control. Last, three sets of actual aerial images taken from surveying and mapping projects, different in both terrain and photographic scale, are given as experimental models. In these experiments, the PPP results were compared with results obtained by DGPS positioning and traditional bundle block adjustment, and the impact of errors with PPP on the adjusted results is analyzed. Finally, the results of GPS supported bundle block adjustment with different ground controls are analyzed in detail.The empirical results show that PPP applied in aerial triangulation has a systematic error within a few decimeters on the same route. However, the two results of PPP and DGPS are used in GPS-supported bundle block adjustment can be achieved almost identical results, This shows that PPP can be effectively applied to GPS-supported aerial triangulation. the adjustment results of different ground control show that, with the increasement of GCPs, adjustment results can be effectively improved. If two rows of control points are measured,. and a systematic error compensation model is adopted strip-by-strip,the result of bundle block adjustment supported by PPP Can achieve a higher accuracy. In the situation of no ground control, increasing the weights of coordinates of GPS camera stations can improve the accuracy of the results of adjustment to meet the precision of small and medium scale mapping needs.