Combined Solution And Plate Motion Simulation Based On Conformal Geometric Algebra Station Technology

In the process of constructing and maintaining the International Terrestrial Reference Frame(ITRF),space geodetic technology has gradually become a key technology for the construction of the terrestrial reference frame.The current method of maintaining the International Earth Reference Frame is based on the premise that the observation site performs linear motion,but in fact,due to the influence of the earth's structure and plate movement,the motion of the observation site is nonlinear,so the speed provided by ITRF cannot truly reflect the measurement.The position of the station changes;as the high-precision reference frame becomes more and more important in the national infrastructure construction,it is necessary to consider the real motion state of the station,rather than express it in pure linear motion.In the construction of the epoch reference frame,it is necessary to use the Helmert transformation multiple times to realize the conversion of different reference frames.This conversion is based on multiple matrix calculations,which makes the epoch reference frame conversion more cumbersome and cannot take into account the measurement site.Three-dimensional motion direction motion state description.Therefore,this paper studies the operator expression method of the versor unified motion equation based on the conformal geometric algebra,realizes the unity of transformation and formal expression in the reference frame,simplifies the conversion process between the reference frames,and takes into account the description of the three-dimensional direction motion state of the measuring station.At the same time,the versor unified motion equation intuitively reflects the geometric meaning of the reference frame conversion.In this paper,by solving the combined solutions of the four spatial geodesy technologies,constructing an epoch reference frame,introducing conformal geometric algebra,and realizing plate motion simulation based on conformal geometric algebra,the research work of this paper mainly includes the following contents:(1)In-depth research on the theory and algorithm of spatial geodetic data combination based on the superposition of normal equations,and construct an epoch reference frame based on this.(2)Using the epoch reference frame to combine related algorithms,realize the combined related programs in the four spatial geodetic technologies of GNSS,SLR,DORIS and VLBI based on python,and compare and analyze the combined results to verify the reliability and combined accuracy of the program Analyzed the difference between the combined results and ITRF2014 coordinate points.The results show that GNSS has the highest accuracy in the process of describing the location of the survey site,and the difference between the coordinates of the survey site and ITRF2014 is basically maintained at the millimeter level.(3)Based on the conformal geometric algebra,the unified expression method of the motion of the station is studied,and the conversion of the station under different epochs and different reference frames is realized.The results show that the conversion accuracy of the unified motion equation based on the conformal geometric algebra versor is basic Keeping in the vicinity of millimeters verifies that the conformal geometric algebraic versor unified motion equation is concise and has clear geometric meaning when expressing the motion of the station.(4)Using the similar transformation method,using the monthly solution combination results of the four spatial geodetic data from 2014 to 2016 to construct the global plate horizontal and vertical velocity fields,the results show the movement speed of the stations in the border areas of the North American and Eurasian plates Larger,the movement speed of the stations within the plate is relatively small,and the movement trend of the stations in the respective plates is basically the same.(5)Based on the conformal geometric algebra,the plate expression method is studied,and the versor unified motion equation is used to realize the plate motion simulation based on the conformal geometric algebra under different epochs;and the Prophet algorithm is used to compare the period of GNSS epoch reference frame The motion feature extraction of term and trend term shows that the periodic term motion characteristics of the station site displayed in the weekly solution epoch reference frame are more obvious.The periodic term motion in the monthly solution epoch reference frame is more stable,but it may also be due to the combination process of the epoch reference frame Mask some of the movement characteristics of the station.