Research On The Technology Of Precise Point Positioning Applying In The IMU/GPS-Supported Photogrammetry

IMU/GPS (Inertial Measurement Unit / Global Position System)-supported photogrammetry technology could acquire the photo's six parameters of exterior orientation directly, including the three position parameters and three angle parameters. It needs no or few ground control points in photogrammetry using this technology, and could void aerotriangulation in medium- small scale surveying and mapping (only just need automatic aerotriangulation in large scale surveying and mapping). Thus, it makes photogrammetry speedy and cheaper.At present, it mainly uses DGPS processing technology in the IMU/GPS-supported photogrammetry. DGPS technology needn't consider complex error model and calculates few parameters and high position accuracy, so that it is widely used in IMU/GPS-supported photogrammetry. But following the IMU/GPS-supported photogrammetry matures, its shortcomings also increasingly appear. The deficiencies are listed: it needs at least one base station receiver on the continuous observation which not only affects the operational efficiency, but also greatly increases the human, material and financial; with the distance of users and base station increasing, the relativity of the troposphere and ionosphere error will be weakened, consequently reducing its position accuracy.Precise point positioning technology provides a new solution for the IMU/GPS-supported photogrammetry. The accuracy of precision ephemeris and precision clock errors has been very high which provided by GPS service organization-IGS. With improvement of the performance of receiver, enhancing of the carrier phase accuracy continuously and in-depth of the atmospheric correction model and ways continuously, it is possible that the precise point positioning applying in the IMU/GPS-supported photogrammetry.In this paper, it systematically introduces the principles of the precise point positioning and the IMU/GPS-supported photogrammetry technology, and through combined with the specific aerial area, analyzes the accuracy of the precise point positioning, IMU/PPP integrated filter and IMU/GPS -supported aerotriangulation. At last, it systematically analyzes the result and sums up technical processing scheme of the IMU/GPS-supported photogrammetry. The main research includes:1. Analyze the accuracy of PPP combining with the result of conventional aerotriangulation by GrafNav 7.8 software (GPS data processing software) which calculates PPP and DGPS solution;2. Analyze the accuracy of IMU/PPP integrated filter combining with the result of conventional aerotriangulation by AEROoffice software (IMU/GPS integrated filter data processing software) which calculates elements of exterior orientation which have been corrected through the calibration field;3. Analyze the accuracy of IMU/PPP-supported aerial photogrammetric point determination comparing with the result of the IMU/DGPS-supported aerial photogrammetric point determination by Geolord-AT (PBBA) software (photogrammetric point determination software);4. Generalize the technical processing scheme and the implementation of the flow of IMU/PPP-supported photogrammetry.Through the above research, this article reaches the following production:The internal accordant accuracy of PPP is slightly lower than the DGPS. Compared with the DGPS, the plan and elevation accuracy of PPP has the systematic error which is different in each flying and in three directions.The coordinate value which IMU/PPP subtracted from IMU/DGPS is nearly same with the coordinate value which the PPP subtracted from the DGPS without the correction of field calibration, so that the error of them also is systematic. After the coordinate corrected by field calibration, the accuracy of IMU/PPP and IMU/DGPS in three direction is nearly same.IMU/PPP-supported aerotriangulation without ground control points could not fit the specifications of the scale of 1:10000 map of the hilly, which need join the corner ground control pointsAt the same time the article indicates that the research on advancement of precision ephemeris and clock error is the one of direction in future; because the un-differential ambiguity of precise point positioning no longer has the characteristics of an integer, the quality control of precise point positioning is particularly important, which also needs to be researched in future; The method of dynamic conditions zenith troposphere correction needs to be explored.The organization of this paper is as follows:The first chapter is the introduction part. Introduce the significance of this paper and expatiate the development of the IMU/GPS-supported photogrammetry technology and the PPP. Narrate the situation that precise point positioning applying on the IMU / GPS-supported photogrammetry. And describe the content of this paper.The second chapter systemically expatiates the technology of precise point positioning. Based on the analysis of domestic and international information, it shows the reference system of PPP, including the time systems and coordinate systems. Than introduces the International GPS Service Agencies which analyzes and processes precision ephemeris and precision clock error. Finally, it focuses on the error sources of PPP which combined with the principle of the precise point positioning.The third chapter has discussed the IMU/GPS-supported photogrammetry. Introduce the method, related terms, the rotation system and coordinate system of IMU/GPS-supported photogrammetry. Analyze conversion between different coordinates and obtain the necessary attitude angle Phi, Omega and Kappa. Finally, expatiate the principle of IMU/GPS-supported photogrammetry and IMU/GPS -supported aerotriangulation.The fourth chapter researches the accuracy of the PPP, IMU/PPP integrated filter and IMU/PPP -supported photogrammetic point determination without ground control points and using corner ground control points. Finally, it sums up technical processing scheme of IMU/PPP-supported photogrammetry.The fifth chapter has summarized the full research in the article, and proposes some opinion and advices for the further research. Finally, it forecasts the development of this technical.