Abstract:Multipath, signal diffraction and electromagnetic signal interference are the main factors to decrease the quality of GNSS data. All of these factors are related to the environment of the station. To know more about the relationship between the environment and data, the GNSS data collected from 7 stations in different environments are analyzed by using TEQC software and baseline solutions. The results show the following problems.1) Cycle slip, signal diffraction and multipath effect are the most serious when the GNSS antenna under trees.2) There is a certainextent of electromagnetic signal interference near wireless communication base station and radar station, but less under high voltage transmission line.3) Modern geodetic antenna is immune to the reflected signal when the antenna is above the water surface, but powerless to the reflected signal from the glass curtain wall.