Time Series Analysis Of ShanDong Area CORS Station Based On Environmental Load

Continuous operation reference station system is a product of satellite positioning technology,computer network technology,digital communication technology and other high and new technologies.It is an important infrastructure of modern surveying and mapping system.CORS station can provide users with high-precision navigation and positioning services,and plays an important role in establishing and maintaining the stability of the regional coordinate reference framework.With the progress of science and technology,CORS is playing an important role The observation accuracy of the station has been greatly improved.The accuracy in the horizontal direction has reached 3mm,and the accuracy in the elevation direction is relatively low in the horizontal direction,but it has also reached about 6mm.According to a large number of research data,it can be seen that under the global framework,the annual horizontal movement speed of China's land can reach tens of millimeters,and the annual change in the vertical direction The amplitude can also reach centimeter level.By analyzing the characteristics of the time series of CORS station,we can get the characteristics of the crustal deformation in a certain region.However,there are various errors in the coordinate time series of CORS station.The environmental load(air load,sea level change load,land water load)is one of the important factors affecting the nonlinear change of CORS station.According to the research,we can find that the environmental load The influence of crustal deformation has reached cm level,which has become an important factor in the study of high-precision regional crustal deformation.In addition,there are common mode errors and colored noises in the regional CORS network.Therefore,if high-precision regional crustal deformation research and CORS station coordinate time series analysis are to be carried out,these errors must be accurately calculated and eliminated.A large amount of GNSS observation data has been accumulated at CORS station in Shandong Province,which provides a solid data base for the study of the crustal deformation characteristics in Shandong Province.In this paper,the coordinate time series is obtained by using the data of 21 CORS stations in Shandong Province from June 2015 to August 2019 for 4 years,and the following research is carried out on this basis.(1)Firstly,it introduces the research background of this paper,the construction of CORS station at home and abroad,as well as the current research status of time series with CORS station and the research status of environmental load.(2)The mathematical methods and principles used in this paper are explained and derived.Firstly,the earth model used at present is introduced,and the formula of spherical harmonic function is derived according to Farrell load theory,then the methods and theories used in time series analysis of CORS station are introduced.(3)Using power spectrum and wavelet analysis,the u-direction time series of CORS station is analyzed periodically.It can be seen that the CORS station in Shandong Province has obvious annual cycle,half year cycle,seasonal cycle and two-year long cycle.The common mode error of GPS network composed of regional CORS station is extracted by principal component analysis and deducted from the original time series To a higher precision time series,for the following analysis laid the foundation.(4)Based on the global atmospheric model,regional meteorological station data,global soil water assimilation data model and sea level change model,three kinds of non structural loads are calculated by using the removal recovery method,spherical harmonic function and Green function integral,and the influence of non structural loads on regional crustal deformation is obtained.(5)After deducting the influence of environmental load from the filtered time series,the standard deviation of time series before and after deducting and the spectral index model were observed to analyze the influence of environmental load on the time series of CORS station.