Study On The Regularity Of Crustal Movement And Deformation In Anhui Province Based On CORS Data

The continuous and stable GNSS(Global Navigation Satellite System)observation data accumulated by the Continuous Operating Reference System(Continuous Operating Reference System,CORS)provides important data support for the crustal deformation of the study area.In addition,the combination of satellite positioning technology and modern communication technology enables its applications in monitoring regional tectonic movements,satellite orbit determination,and studying post-ice rebound.After the data obtained from continuous GNSS observations are accurately calculated,a set of reference station coordinate sequences arranged in chronological order can be obtained,which includes the structural movement of the area where the station is located and nonlinear changes caused by geophysical effects.By modeling the GNSS time series,on the one hand,the position and movement rate of the station can be accurately obtained,so as to establish and maintain a regional reference frame.On the other hand,by studying the characteristics of non-linear changes in the time series,the accuracy of the station coordinates and motion speed can be further improved.The main work of this paper is to use GAMIT/GLOBK software to calculate the observation data of the Anhui Province Satellite Positioning Integrated Service System(AHCORS)from January 2013 to June 2018 for nearly 5.5 years,and use the GNSS coordinate time series analysis method.The common mode errors of the AHCORS coordinate time series and the velocity field in this area are also analyzed respectively.The main research contents are as follows:1.Using GAMIT/GLOBK software to calculate the AHCORS observation file from January 2013 to June 2018.In order to improve the accuracy of calculation,simultaneous observation data of 5 IGS stations in China and surrounding areas are introduced it.Use GLOBK to obtain the coordinate time series of the station relative to the ITRF(International Terrestrial Reference Frame)2008 frame.2.Using the method of principal component analysis to perform regional spatial filtering on the AHCORS time series to determine the common mode error.Interpolation calculations are used to obtain the time series of Hydrological loading,Non-tidal atmospheric loading and Non-tidal oceanic loading at the CORS site in Anhui Province.Through the analysis of annual and semi-annual characteristic of the common mode error sequence and the average mass loading sequence characteristics,the source of common mode error cannot be explained to a large extent.Through the analysis of RMS reduction rate of noise sequences before and after spatial filtering,it is found that filtering has obvious effect on the reduction of RMS in N,E and U directions,and the reduction effect in N and E directions is obviously better than that in U direction.After noise analysis of the coordinate time series before and after filtering,it is found that white noise + flicker noise(WN+FN)noise is dominant before and after common mode error extraction in this region.3.Using the periodogram method to analyze the power spectral density of the noise sequence of each coordinate component of AHCORS,the results show that the best noise model of the CORS station in Anhui Province is the WN+FN model.The threedimensional velocity field in the framework of ITRF2008 is estimated when considering the colored noise.The results show that the average velocity in the horizontal direction of AHCORS is 31.72 mm/a and the direction is E22.76°S.In order to further obtain the internal relative motion of the ACORS station,the horizontal motion velocity was converted from the ITRF2008 framework to the Eurasian plate.The results showed that the average horizontal velocity was 6.28 mm/a and the direction was E2.65°N,taking the Eurasian plate as a reference.In the vertical direction,as the boundary of Huaihe River shows a trend of uplift in the south and subsidence in the north.The subsidence is obvious in Huaibei area,and the maximum subsidence rate is 32.82mm/a,which occurred in SZDS station.The obvious subsidence in this area may be caused by the exploitation of groundwater and mineral resources in recent years.