GNSS Deformation Monitoring Solution Precision Influencing Factors In Caofeidian

By analyzing atmospheric refraction error,satellite ephemeris error,satellite elevation cut-off angle,the observation time that affect the high precision GNSS data processing,the method of improving the accuracy of GNSS baseline solution is studied.Based on this condition,an example is given to analyze and study the surface subsidence deformation monitoring by GNSS in Caofeidian.The main research contents are as follows:GNSS deformation monitoring theory is introduced systematically.Meanwhile GNSS measurement methods,error generation of GNSS deformation monitoring and GAMIT baseline solution and result analysis are discussed.For the atmospheric refraction,the errors caused by the ionosphere and the troposphere and the corresponding methods of attenuation are introduced respectively.The methods of dealing with tropospheric delay and tropospheric delay model are introduced in detail.The effects of different zenith delay parameters on the baseline solution are analyzed by examples,and the best parameters for eliminating the tropospheric delay error are obtained.In addition,the broadcast ephemeris and some parameters algorithm are described in detail,and the influence of broadcast ephemeris and precise ephemeris on different length baselines is compared with the measured data.The impact factors such as satellite elevation cut-off angle and observation duration are also analyzed with examples,and the value of each factor which is suitable for GNSS deformation monitoring data processing in Caofeidian area is obtained.The results of data processing of surface subsidence monitoring by GNSS in Caofeidian district is compared with the second-level leveling data.All GNSS monitoring points are within 5mm of the difference from the leveling.The accuracy and feasibility of GNSS surveying in Caofeidian settlement monitoring is illustrated.