Analysis Of Time Series And Research Of Velocity Field Model Of CORS Reference Station

It provides the data basis for the study of surface movement that long-term accumulation of GNSS observation data,but the influence caused by various errors can not be ignored,and the exploration of crustal movement law can not leave the high-precision velocity and velocity field model,so it is very important to analysis ti me series and research velocity field model.The details are as follows:(1)Theory basis.The positioning reference system and GAMIT / GLOBK process are introduced;The principles of discontinuous signal and gross error processing,regional superposition filtering,maximum likelihood,wavelet decomposition and univariate linear fitting method are described;The principles of inverse distance weighting,Ordinary Kriging,improved original Kriging model considering the influence of U direction and K-means-Ordinary Kriging combination model are introduced.(2)Time series achievement and analysis.The results of CORS calculation of North America plate and Hong Kong show that: horizontally,the boundary point of North America plate moves to the northwest,and the inland point moves to the southwest,and the movement trend is larger than that of U direction;The horizontal direction of Hong Kong survey area is southeast,while the U direction is nearly horizontal.Taking SOL1,VCIO,HKKT and HKWS of the as examples,taking the discontinuous term and gross error processing,common mode error elimination,noise analysis,seasonal term reconstruction and trend term extraction.The results show that the time series is smoother after analysis,and the overall annual p eriodicity is more obvious,and the WN + FN noise model is the main noise model in the three directions,and the trend term results are more consistent with the data movement trend,The horizontal velocity of SOL1,VCIO,HKKT and HKWS changed by 2.62 mm,1.07 mm,2.52 mm and 2.99 mm,respectively,and the vertical velocity changed by 0.91 mm,0.60 mm,0.08 mm and 0.06 mm.And the horizontal velocity of most points produces 10°.The internal deflection angle,a few points change more than 10°.(3)Basic model analysis of velocity field.The results of velocity field modeling by the inverse distance weighting method and the Ordinary Kriging method show that the accuracy difference between the two models is small for the points with large distribution density and relatively uniform distribution,while the Ordinary Kriging method has more advantages for the points with sparse distribution or boundary points.(4)Improved single model.Aiming at the problem that Ordinary Kriging does not consider the influence of space,an improved model considering the influence of U direction is proposed.Compared with the basic model,the improved model modeling accuracy of HKTK and SHK5 is improved by 3.29mm/a and 8.66mm/a,and the improvement of North America plate is larger than that of Hong Kong survey area,It is closely related to the survey area span feature and CORS point distribution.This improved method provides a modeling research direction for considering multi factor influence.(5)Improved combination model.In order to solve the problem that the contribution rate of modeling is not considered by the Ordinary Kriging,a K-means-Ordinary Kriging combination model is proposed.The resul ts show that the improvements of HKSL,HKLM and HKTK are 3.22 mm/a,3.04 mm /a and 4.41 mm/a,respectively;However,the improvement of SHK5,NLIB,HKLO,SOL1 and VCIO points in North America plate is relatively large,and the maximum improvement range is 8.22 mm/a,which is NLIB point.On the whole,the combination model has more advantages than the first three models.The combination model provides a basis for the study of attribute similarity modeling of measurement points.This thesis contains 41 figures,7 tables and 86 references.