The geodetic detrending(GD)methodology was introduced in the past decade and has opened the door to the global monitoring of ionospheric scintillation using global navigation satellite system(GNSS)receivers.The perfor...The geodetic detrending(GD)methodology was introduced in the past decade and has opened the door to the global monitoring of ionospheric scintillation using global navigation satellite system(GNSS)receivers.The performance of GD has been demonstrated in geodetic receivers.However,extending scintillation monitoring to low-cost commercial receivers remains a challenge.Low-cost devices could serve as valuable complements to specialised and much more expensive scintillation monitoring receivers.In this paper,first,a feasibility study was conducted using the GD technique,demonstrating that the scintillation indices derived from the observations of two lowcost receivers(Septentrio Mosaic X5 and UBLOX ZED-F9P)have a resolution similar to that achieved by geodetic receiver models,whose price is one order of magnitude higher.Second,measurements of GNSS signals at different frequencies from the Galileo and global positioning system(GPS)satellites were analysed in a specific experiment over six days of null scintillation.Next,the noise level in the scintillation parameters derived from the experiment was evaluated,which shows that for low-cost receivers,the minimum scintillation detection threshold increases only negligibly compared to geodetic-grade receivers.Moreover,the geometry-free(GF)combination of L1 with a second signal of different frequency was investigated as an alternative to detrending GNSS signals.Finally,for determining the ionospheric fluctuations produced by scintillation,the limitations of using the GF combination versus the uncombined measurements were highlighted.It is concluded that the minimum resolution of scintillation indices derived from low-cost receiver measurements makes it possible to distinguish values associated with periods of scintillation activity from those produced by residual noise from mismodeling.For both geodetic and low-cost receivers,the scintillation detection threshold obtained with uncombined carrier-phase measurements is smaller than that achieved with the classic GF combination.展开更多
The conversion of the cartesian coordinates of a point to its geodetic equivalent coordinates in reference to the geodetic ellipsoid is one of the main challenges in geodesy.The ellipse equation in the meridian plane ...The conversion of the cartesian coordinates of a point to its geodetic equivalent coordinates in reference to the geodetic ellipsoid is one of the main challenges in geodesy.The ellipse equation in the meridian plane significantly influences the value of the geodetic coordinates.This research analyzes this influence and how it can contribute to their solutions.The study investigates the mathematical relation between them and presents an exact formula relating to the geodetic height and the ellipse equation.In addition,a heuristic formula for the relation between the geodetic height and the ellipse equation is proposed,which is independent of the geodetic latitude and has a relative accuracy better than 99.9 %.The calculation is stable,and the cost is low.展开更多
While the geodetic excitationχ(t)of polar motion p(t)is essential to improve our understanding of global mass redistributions and relative motions with respect to the terrestrial frame,the widely adopted method to de...While the geodetic excitationχ(t)of polar motion p(t)is essential to improve our understanding of global mass redistributions and relative motions with respect to the terrestrial frame,the widely adopted method to deriveχ(t)from p(t)has biases in both amplitude and phase responses.This study has developed a new simple but more accurate method based on the combination of the frequency-and time-domain Liouville's equation(FTLE).The FTLE method has been validated not only with 6-h sampled synthetic excitation series but also with daily and 6-h sampled polar motion measurements as well asχ(t)produced by the interactive webpage tool of the International Earth Rotation and Reference Systems Service(IERS).Numerical comparisons demonstrate thatχ(t)derived from the FTLE method has superior performances in both the time and frequency domains with respect to that obtained from the widely adopted method or the IERS webpage tool,provided that the input p(t)series has a length around or more than 25 years,which presents no practical limitations since the necessary polar motion data are readily available.The FTLE code is provided in the form of Mat Lab function.展开更多
The mutation of spaces observed in the Katangese Copper Belt(KCB)causes significant topographical changes.Some colonial geodetic markers are easily noticeable on many of the hills making up the KCB.These hills are sub...The mutation of spaces observed in the Katangese Copper Belt(KCB)causes significant topographical changes.Some colonial geodetic markers are easily noticeable on many of the hills making up the KCB.These hills are subject to mining which ruins the completeness of the network of triangulations:geometric and trigonometric Katangese.In order to keep control of the latter,the study shows on the one hand the possibility of using SRTM data(Shuttle Radar TopographyMission)in the monitoring of the macro-change of the reliefs,from 442 positions,and on the other hand,an indirect(remote)inventory method of the existing geodetic markers,by restoring the mapping of the said triangulation.Statistical and spatial analyses of paired samples of the 442 individuals allowed the study to observe the negative and positive altimetric variations at the locations of 79 geodetic markers,in an area of approximately two square degrees.In both cases,the research considers that the altimetric variations would exclude the physical existence of certain geodetic markers at their positions,and that we do not find the slightest information relating to their official relocations.展开更多
The third annual workshop of the International Geoscience Programme Project 565“Developing the Global Geodetic Observing System into a Monitoring System for the Global Water Cycle,”which was jointly organized by IGC...The third annual workshop of the International Geoscience Programme Project 565“Developing the Global Geodetic Observing System into a Monitoring System for the Global Water Cycle,”which was jointly organized by IGCP 565,the Group on Earth Observations(GEO)and the Global Geodetic Observing System(GGOS),was held on 11-13 October 2010 at the University of Nevada,Reno,in Reno,Nevada,USA.During the three days,a total of 57 participants from eleven countries in four continents discussed the status,science challenges and approach to addressing the challenge of utilizing geodetic observations for the monitoring of changes in terrestrial water storage.展开更多
A set <em>S ⊆ V (G)</em> is called a geodetic set if every vertex of <em>G</em> lies on a shortest <em>u-v</em> path for some <em>u, v ∈ S</em>, the minimum cardinality...A set <em>S ⊆ V (G)</em> is called a geodetic set if every vertex of <em>G</em> lies on a shortest <em>u-v</em> path for some <em>u, v ∈ S</em>, the minimum cardinality among all geodetic sets is called geodetic number and is denoted by <img src="Edit_82259359-0135-4a65-9378-b767f0405b48.png" alt="" />. A set <em>C ⊆ V (G)</em> is called a chromatic set if <em>C</em> contains all vertices of different colors in<em> G</em>, the minimum cardinality among all chromatic sets is called the chromatic number and is denoted by <img src="Edit_d849148d-5778-459b-abbb-ff25b5cd659b.png" alt="" />. A geo-chromatic set<em> S</em><sub><em>c</em></sub><em> ⊆ V (G</em><em>)</em> is both a geodetic set and a chromatic set. The geo-chromatic number <img src="Edit_505e203c-888c-471c-852d-4b9c2dd1a31c.png" alt="" /><em> </em>of<em> G</em> is the minimum cardinality among all geo-chromatic sets of<em> G</em>. In this paper, we determine the geodetic number and the geo-chromatic number of 2-cartesian product of some standard graphs like complete graphs, cycles and paths.展开更多
The meaning to research the potential of VLBI for geodetic applications is summarized. And the observation models and their related parameters of geodetic interest are investigated. Then, the principle and method of u...The meaning to research the potential of VLBI for geodetic applications is summarized. And the observation models and their related parameters of geodetic interest are investigated. Then, the principle and method of using the random model in VLBI data processing are investigated. With the world wide VLBI data from 2000-2004, the conditions to compute the parameters of geodetic interest are introduced, and so are the computing methods and processes. And the computed resuits of the parameters of geodetic interest are analyzed.展开更多
Determining the geodetic height of Mount Qomolangma was one of the very important missions in the 2005 Qomolangma height survey. There were three GPS networks in the survey: regional GPS crustal deformation network, g...Determining the geodetic height of Mount Qomolangma was one of the very important missions in the 2005 Qomolangma height survey. There were three GPS networks in the survey: regional GPS crustal deformation network, geodetic GPS control network, and GPS measurement on the mountain summit. Data collection and processing were introduced. The final data processing strategy and reasonable geodetic height were fairly determined based on careful data analysis.展开更多
In this paper, unit moving trihedron is first constructed for a point on the surface of a revolution ellipsoid. Via translation, the origin of the trihedron coincides with that of Cartesian coordinates established at ...In this paper, unit moving trihedron is first constructed for a point on the surface of a revolution ellipsoid. Via translation, the origin of the trihedron coincides with that of Cartesian coordinates established at the center of the ellipsoid, and then through two coordinate rotations, the trihedron completely coincides with the Cartesian coordinates. Transformation formulae between the moving trihedron and unit Cartesian coordinate frameworks as well as transformation of point displacement between two unit coordinate frameworks are presented. Based on the above transformation formulae between two different coordinate frameworks, due to the fact that the displacement and moving trihedron of the point are both functions of the geodetic coordinates, components in the corresponding axis for differential of displacement vector and geodetic curves arc differential at the point in geodetic system can be obtained through complicated derivation. Displacement gradient matrix at the point in geodetic system is also given. Finally, expressions of strain and rotation tensor in geodetic coordinates are presented. Geometric meanings of the rotation tensor are explained in detail. The intrinsic relationship between strain tensors of sphere and ellipsoid are also discussed.展开更多
A singularity-free perturbation solution is presented for inverting the Cartesian to Geodetic transformation.Conventional approaches for inverting the transformation use the natural ellipsoidal coordinates,this work e...A singularity-free perturbation solution is presented for inverting the Cartesian to Geodetic transformation.Conventional approaches for inverting the transformation use the natural ellipsoidal coordinates,this work explores the use of the satellite ground-track vector as the differential correction variable.The geodetic latitude is recovered by well-known elementary means.A high-accuracy highperformance 3D vector-valued continued fraction iteration is constructed.Rapid convergence is achieved because the starting guess for the ground-track vector provides a maximum error of 30 m for the satellite height above the Earth’s surface,throughout the LEO-GEO range of applications.As a result,a single iteration of the continued fraction iteration yields a maximum error for the satellite height of 10??11 km.and maximum error for the geodetic anomaly of 10??9 rad.The coordinate transformation is completed by non-iteratively recovering the satellite height and the geodetic anomaly.No Taylor expansions are introduced and no Jacobian sensitivity calculations are required.For all practical applications the new algorithm provides a closed-form solution.The accuracy and algorithmic performance of the proposed approach is compared with other state of the art algorithms.展开更多
The fast slewing rate and wide band of the VLBI2010 Global Observing System(VGOS) telescopes are beneficial to procure more observations and to obtain VLBI reference points(RPs) of high precisions.Meanwhile, with the ...The fast slewing rate and wide band of the VLBI2010 Global Observing System(VGOS) telescopes are beneficial to procure more observations and to obtain VLBI reference points(RPs) of high precisions.Meanwhile, with the development of synchronous tracking of fixed targets on telescopes during the observing, the RPs also can be determined in near real time based on a frame defined by other techniques. These opportunities provide us a possibility to explore the high geodetic resolution of VGOS telescopes. We design a thermal variation in RP as true values, and schedule a synchronous session of VGOS and target point(TP) series observing. Then VGOS delays and TP series are simulated and solved via piecewise functions. The results show that the accuracy of vertical component of the RP could be determined at an accuracy of 0.5 ± 0.3 mm in an hour using TP series, whereas the vertical components of RP solved by using VGOS delay measurements have a greater uncertainty due to the random error in the simulated atmosphere and bad radio source sky coverage in a shorter time interval. Some details in the data processing and accuracy evaluation are also introduced.展开更多
With the wide application of GPS technology, the application of the system of space rectangular coordinates is more and more extensive. Transformation of space rectangular coordinates into geodetic coordinates becomes...With the wide application of GPS technology, the application of the system of space rectangular coordinates is more and more extensive. Transformation of space rectangular coordinates into geodetic coordinates becomes a very popular problem. In order to evaluate various kinds of algorithms existing for solving the problem, three evaluation criteria of the algorithm were put forward at first, that is, precision, calculation speed and algorithm regional suitability. After given some basic formula, three kinds of representative algorithms, classics iteration algorithm, ellipsoidal parameter transformation algorithm and rational polynomials approximation algorithm were introduced. Through a test program made by MATLAB, these three kinds of algorithms were compared. Some helpful conclusions were drawn.展开更多
Geodetic deformation severely affects the development of the oilfield and probably causes casing damage or abandonment of injection wells and producers. Therefore, it is meaningful to survey and study three-dimensiona...Geodetic deformation severely affects the development of the oilfield and probably causes casing damage or abandonment of injection wells and producers. Therefore, it is meaningful to survey and study three-dimensional geodetic deformation in the process of the oilfield development. In order to study this issue, 11-year long term surveying of three-dimensional geodetic deformation has been carried out while developing Naner area in Daqing oilfield. Basic rules of 3-D geodetic deformation have been obtained through surveying. Results show that production and injection under high pressure may cause the changes of surface elevation, and geodetic deformation correlates with simultaneous formation pressure. Precautions and relative technological measurements have been put forward in the waterflood development in Naner region and provide theoretical guidelines for the production and casing preservation of the oilfield. Finally, surveying results are interpreted by porous elastic theory. Mathematical model to calculate 3-D geodetic deformation is put forward in the course of the oilfield development.展开更多
The statistical testing models of the plate tectonic units and the hypothesis of their rigidity is presented by using the dense geodetic data, and to a certain extent the established statistic value c...The statistical testing models of the plate tectonic units and the hypothesis of their rigidity is presented by using the dense geodetic data, and to a certain extent the established statistic value can be regarded as a quantitative index to compare the rigidity degrees of different blocks. The several conclusions about the global megaplates and the regional tectonics of China are tested and verified by actual calculations, which testifies the effectiveness of this method in testing the rigidity degree and delineating their boundaries.展开更多
This paper discusses theoretically the stability of solutions for dynamic geodetic network adjustment,Kalman filtering and sequence adjustment,and two examples are given.The solution for dynamic geodetic network adjus...This paper discusses theoretically the stability of solutions for dynamic geodetic network adjustment,Kalman filtering and sequence adjustment,and two examples are given.The solution for dynamic geodetic network adjustment is stable if the dynamic geodetic network is a classical network.There is not rank deficit in datum,or else the solution is not stable,which will depend on the initial value.展开更多
Current situations of geodetic coordinate datum development procedures and management methods in China were presented. The precisions of astronomic geodetic network and space geodetic network were introduced. Geodetic...Current situations of geodetic coordinate datum development procedures and management methods in China were presented. The precisions of astronomic geodetic network and space geodetic network were introduced. Geodetic datum requirements under the current and future new surveying technologies and their applications were discussed. The necessity for upgrading national astronomic geodetic network and development of a new open coordinate geodetic datum management method was investigated.展开更多
In this paper authors have obtained a new necessary and sufficient condition for a graph G to be a geodetic graph. Let g : E --> Z(+) be a function from the set of edges of a graph G to the set of nonnegative integ...In this paper authors have obtained a new necessary and sufficient condition for a graph G to be a geodetic graph. Let g : E --> Z(+) be a function from the set of edges of a graph G to the set of nonnegative integers and let g(G) denote the graph obtained from G by replacing each edge e is an element of E by a suspended are (path) P-g(e+2) of length g(e) + 1. and by using this condition, established a criterion for a function g to be a function which can generate a new geodetic block g(G) from a given geodetic block G.展开更多
This paper presents experiment results of the measurement conducted at the Roznew Dam power plant. For a course of starting and operating of turbo-plants, downstream face of the dam was monitored in relation to its ev...This paper presents experiment results of the measurement conducted at the Roznew Dam power plant. For a course of starting and operating of turbo-plants, downstream face of the dam was monitored in relation to its eventual displacements on direction parallel to the construction axis. For the purpose of the experiment, geodetic measurement techniques and 2D DIC （digital image correlation） method （utilizing photographs of the object recorded with digital camera） were compared with regard to credibility, efficiency and accuracy. The vertical and horizontal displacements were monitored by tachometers measurements. The deformations in x-axis and y-axis on the wall surface was monitored by 2D DIC. It has been noticed that 2D DIC method is a surface method, continuous--not discreet. It allows for continuous observations of surface deformations, which is not possible in case of tachemetric measurements. Despite many advantages, the 2D DIC method lacks unambiguous evaluation of precision and relevance of designated displacements, which is rather significant for possibilities of utilization in technical control of large engineered objects. It should be also marked that the tachometric method is more reliable but is more laborious. Research of this type might comprise additional element for the assessment of the influence of dynamic loads, such as activating turbine water flow, onto the overall condition of the surveyed structure.展开更多
The factual data on error of positioning in VRS GPS networks have been analyzed, where the mobile receiver is provided with VRS. The method of highly informative zone is suggested for removal of initial vagueness in s...The factual data on error of positioning in VRS GPS networks have been analyzed, where the mobile receiver is provided with VRS. The method of highly informative zone is suggested for removal of initial vagueness in selection of reference stations for purposes of development of VRS on the basis of minimum GPS network, composed of three reference stations. The recommendations on use of suggested method are given.展开更多
基金funding from European Union(MCIN/AEI/10.13039/501100011033/FEDER)(Nos.PID2022-138485OB-I00 and CNS2022-135383)European Space Agency(RT-WMIS)(No.4000137762/22/NL/GLC/ov)funding support from the China Scholarship Council(No.202006020025)。
文摘The geodetic detrending(GD)methodology was introduced in the past decade and has opened the door to the global monitoring of ionospheric scintillation using global navigation satellite system(GNSS)receivers.The performance of GD has been demonstrated in geodetic receivers.However,extending scintillation monitoring to low-cost commercial receivers remains a challenge.Low-cost devices could serve as valuable complements to specialised and much more expensive scintillation monitoring receivers.In this paper,first,a feasibility study was conducted using the GD technique,demonstrating that the scintillation indices derived from the observations of two lowcost receivers(Septentrio Mosaic X5 and UBLOX ZED-F9P)have a resolution similar to that achieved by geodetic receiver models,whose price is one order of magnitude higher.Second,measurements of GNSS signals at different frequencies from the Galileo and global positioning system(GPS)satellites were analysed in a specific experiment over six days of null scintillation.Next,the noise level in the scintillation parameters derived from the experiment was evaluated,which shows that for low-cost receivers,the minimum scintillation detection threshold increases only negligibly compared to geodetic-grade receivers.Moreover,the geometry-free(GF)combination of L1 with a second signal of different frequency was investigated as an alternative to detrending GNSS signals.Finally,for determining the ionospheric fluctuations produced by scintillation,the limitations of using the GF combination versus the uncombined measurements were highlighted.It is concluded that the minimum resolution of scintillation indices derived from low-cost receiver measurements makes it possible to distinguish values associated with periods of scintillation activity from those produced by residual noise from mismodeling.For both geodetic and low-cost receivers,the scintillation detection threshold obtained with uncombined carrier-phase measurements is smaller than that achieved with the classic GF combination.
文摘The conversion of the cartesian coordinates of a point to its geodetic equivalent coordinates in reference to the geodetic ellipsoid is one of the main challenges in geodesy.The ellipse equation in the meridian plane significantly influences the value of the geodetic coordinates.This research analyzes this influence and how it can contribute to their solutions.The study investigates the mathematical relation between them and presents an exact formula relating to the geodetic height and the ellipse equation.In addition,a heuristic formula for the relation between the geodetic height and the ellipse equation is proposed,which is independent of the geodetic latitude and has a relative accuracy better than 99.9 %.The calculation is stable,and the cost is low.
基金supported by the National Natural Science Foundation of China(grant numbers 41874025 and 41474022)。
文摘While the geodetic excitationχ(t)of polar motion p(t)is essential to improve our understanding of global mass redistributions and relative motions with respect to the terrestrial frame,the widely adopted method to deriveχ(t)from p(t)has biases in both amplitude and phase responses.This study has developed a new simple but more accurate method based on the combination of the frequency-and time-domain Liouville's equation(FTLE).The FTLE method has been validated not only with 6-h sampled synthetic excitation series but also with daily and 6-h sampled polar motion measurements as well asχ(t)produced by the interactive webpage tool of the International Earth Rotation and Reference Systems Service(IERS).Numerical comparisons demonstrate thatχ(t)derived from the FTLE method has superior performances in both the time and frequency domains with respect to that obtained from the widely adopted method or the IERS webpage tool,provided that the input p(t)series has a length around or more than 25 years,which presents no practical limitations since the necessary polar motion data are readily available.The FTLE code is provided in the form of Mat Lab function.
文摘The mutation of spaces observed in the Katangese Copper Belt(KCB)causes significant topographical changes.Some colonial geodetic markers are easily noticeable on many of the hills making up the KCB.These hills are subject to mining which ruins the completeness of the network of triangulations:geometric and trigonometric Katangese.In order to keep control of the latter,the study shows on the one hand the possibility of using SRTM data(Shuttle Radar TopographyMission)in the monitoring of the macro-change of the reliefs,from 442 positions,and on the other hand,an indirect(remote)inventory method of the existing geodetic markers,by restoring the mapping of the said triangulation.Statistical and spatial analyses of paired samples of the 442 individuals allowed the study to observe the negative and positive altimetric variations at the locations of 79 geodetic markers,in an area of approximately two square degrees.In both cases,the research considers that the altimetric variations would exclude the physical existence of certain geodetic markers at their positions,and that we do not find the slightest information relating to their official relocations.
文摘The third annual workshop of the International Geoscience Programme Project 565“Developing the Global Geodetic Observing System into a Monitoring System for the Global Water Cycle,”which was jointly organized by IGCP 565,the Group on Earth Observations(GEO)and the Global Geodetic Observing System(GGOS),was held on 11-13 October 2010 at the University of Nevada,Reno,in Reno,Nevada,USA.During the three days,a total of 57 participants from eleven countries in four continents discussed the status,science challenges and approach to addressing the challenge of utilizing geodetic observations for the monitoring of changes in terrestrial water storage.
文摘A set <em>S ⊆ V (G)</em> is called a geodetic set if every vertex of <em>G</em> lies on a shortest <em>u-v</em> path for some <em>u, v ∈ S</em>, the minimum cardinality among all geodetic sets is called geodetic number and is denoted by <img src="Edit_82259359-0135-4a65-9378-b767f0405b48.png" alt="" />. A set <em>C ⊆ V (G)</em> is called a chromatic set if <em>C</em> contains all vertices of different colors in<em> G</em>, the minimum cardinality among all chromatic sets is called the chromatic number and is denoted by <img src="Edit_d849148d-5778-459b-abbb-ff25b5cd659b.png" alt="" />. A geo-chromatic set<em> S</em><sub><em>c</em></sub><em> ⊆ V (G</em><em>)</em> is both a geodetic set and a chromatic set. The geo-chromatic number <img src="Edit_505e203c-888c-471c-852d-4b9c2dd1a31c.png" alt="" /><em> </em>of<em> G</em> is the minimum cardinality among all geo-chromatic sets of<em> G</em>. In this paper, we determine the geodetic number and the geo-chromatic number of 2-cartesian product of some standard graphs like complete graphs, cycles and paths.
基金Funded by the National 973 Program of China (No.2006CB701301)the Project of University Education and Research of HubeiProvince (No.20053039).
文摘The meaning to research the potential of VLBI for geodetic applications is summarized. And the observation models and their related parameters of geodetic interest are investigated. Then, the principle and method of using the random model in VLBI data processing are investigated. With the world wide VLBI data from 2000-2004, the conditions to compute the parameters of geodetic interest are introduced, and so are the computing methods and processes. And the computed resuits of the parameters of geodetic interest are analyzed.
基金Funded by the National Natural Science Foundation of China (No.40504003).
文摘Determining the geodetic height of Mount Qomolangma was one of the very important missions in the 2005 Qomolangma height survey. There were three GPS networks in the survey: regional GPS crustal deformation network, geodetic GPS control network, and GPS measurement on the mountain summit. Data collection and processing were introduced. The final data processing strategy and reasonable geodetic height were fairly determined based on careful data analysis.
文摘In this paper, unit moving trihedron is first constructed for a point on the surface of a revolution ellipsoid. Via translation, the origin of the trihedron coincides with that of Cartesian coordinates established at the center of the ellipsoid, and then through two coordinate rotations, the trihedron completely coincides with the Cartesian coordinates. Transformation formulae between the moving trihedron and unit Cartesian coordinate frameworks as well as transformation of point displacement between two unit coordinate frameworks are presented. Based on the above transformation formulae between two different coordinate frameworks, due to the fact that the displacement and moving trihedron of the point are both functions of the geodetic coordinates, components in the corresponding axis for differential of displacement vector and geodetic curves arc differential at the point in geodetic system can be obtained through complicated derivation. Displacement gradient matrix at the point in geodetic system is also given. Finally, expressions of strain and rotation tensor in geodetic coordinates are presented. Geometric meanings of the rotation tensor are explained in detail. The intrinsic relationship between strain tensors of sphere and ellipsoid are also discussed.
文摘A singularity-free perturbation solution is presented for inverting the Cartesian to Geodetic transformation.Conventional approaches for inverting the transformation use the natural ellipsoidal coordinates,this work explores the use of the satellite ground-track vector as the differential correction variable.The geodetic latitude is recovered by well-known elementary means.A high-accuracy highperformance 3D vector-valued continued fraction iteration is constructed.Rapid convergence is achieved because the starting guess for the ground-track vector provides a maximum error of 30 m for the satellite height above the Earth’s surface,throughout the LEO-GEO range of applications.As a result,a single iteration of the continued fraction iteration yields a maximum error for the satellite height of 10??11 km.and maximum error for the geodetic anomaly of 10??9 rad.The coordinate transformation is completed by non-iteratively recovering the satellite height and the geodetic anomaly.No Taylor expansions are introduced and no Jacobian sensitivity calculations are required.For all practical applications the new algorithm provides a closed-form solution.The accuracy and algorithmic performance of the proposed approach is compared with other state of the art algorithms.
基金supported by National Natural Science Foundation of China (1703067)
文摘The fast slewing rate and wide band of the VLBI2010 Global Observing System(VGOS) telescopes are beneficial to procure more observations and to obtain VLBI reference points(RPs) of high precisions.Meanwhile, with the development of synchronous tracking of fixed targets on telescopes during the observing, the RPs also can be determined in near real time based on a frame defined by other techniques. These opportunities provide us a possibility to explore the high geodetic resolution of VGOS telescopes. We design a thermal variation in RP as true values, and schedule a synchronous session of VGOS and target point(TP) series observing. Then VGOS delays and TP series are simulated and solved via piecewise functions. The results show that the accuracy of vertical component of the RP could be determined at an accuracy of 0.5 ± 0.3 mm in an hour using TP series, whereas the vertical components of RP solved by using VGOS delay measurements have a greater uncertainty due to the random error in the simulated atmosphere and bad radio source sky coverage in a shorter time interval. Some details in the data processing and accuracy evaluation are also introduced.
文摘With the wide application of GPS technology, the application of the system of space rectangular coordinates is more and more extensive. Transformation of space rectangular coordinates into geodetic coordinates becomes a very popular problem. In order to evaluate various kinds of algorithms existing for solving the problem, three evaluation criteria of the algorithm were put forward at first, that is, precision, calculation speed and algorithm regional suitability. After given some basic formula, three kinds of representative algorithms, classics iteration algorithm, ellipsoidal parameter transformation algorithm and rational polynomials approximation algorithm were introduced. Through a test program made by MATLAB, these three kinds of algorithms were compared. Some helpful conclusions were drawn.
文摘Geodetic deformation severely affects the development of the oilfield and probably causes casing damage or abandonment of injection wells and producers. Therefore, it is meaningful to survey and study three-dimensional geodetic deformation in the process of the oilfield development. In order to study this issue, 11-year long term surveying of three-dimensional geodetic deformation has been carried out while developing Naner area in Daqing oilfield. Basic rules of 3-D geodetic deformation have been obtained through surveying. Results show that production and injection under high pressure may cause the changes of surface elevation, and geodetic deformation correlates with simultaneous formation pressure. Precautions and relative technological measurements have been put forward in the waterflood development in Naner region and provide theoretical guidelines for the production and casing preservation of the oilfield. Finally, surveying results are interpreted by porous elastic theory. Mathematical model to calculate 3-D geodetic deformation is put forward in the course of the oilfield development.
文摘The statistical testing models of the plate tectonic units and the hypothesis of their rigidity is presented by using the dense geodetic data, and to a certain extent the established statistic value can be regarded as a quantitative index to compare the rigidity degrees of different blocks. The several conclusions about the global megaplates and the regional tectonics of China are tested and verified by actual calculations, which testifies the effectiveness of this method in testing the rigidity degree and delineating their boundaries.
文摘This paper discusses theoretically the stability of solutions for dynamic geodetic network adjustment,Kalman filtering and sequence adjustment,and two examples are given.The solution for dynamic geodetic network adjustment is stable if the dynamic geodetic network is a classical network.There is not rank deficit in datum,or else the solution is not stable,which will depend on the initial value.
文摘Current situations of geodetic coordinate datum development procedures and management methods in China were presented. The precisions of astronomic geodetic network and space geodetic network were introduced. Geodetic datum requirements under the current and future new surveying technologies and their applications were discussed. The necessity for upgrading national astronomic geodetic network and development of a new open coordinate geodetic datum management method was investigated.
文摘In this paper authors have obtained a new necessary and sufficient condition for a graph G to be a geodetic graph. Let g : E --> Z(+) be a function from the set of edges of a graph G to the set of nonnegative integers and let g(G) denote the graph obtained from G by replacing each edge e is an element of E by a suspended are (path) P-g(e+2) of length g(e) + 1. and by using this condition, established a criterion for a function g to be a function which can generate a new geodetic block g(G) from a given geodetic block G.
文摘This paper presents experiment results of the measurement conducted at the Roznew Dam power plant. For a course of starting and operating of turbo-plants, downstream face of the dam was monitored in relation to its eventual displacements on direction parallel to the construction axis. For the purpose of the experiment, geodetic measurement techniques and 2D DIC （digital image correlation） method （utilizing photographs of the object recorded with digital camera） were compared with regard to credibility, efficiency and accuracy. The vertical and horizontal displacements were monitored by tachometers measurements. The deformations in x-axis and y-axis on the wall surface was monitored by 2D DIC. It has been noticed that 2D DIC method is a surface method, continuous--not discreet. It allows for continuous observations of surface deformations, which is not possible in case of tachemetric measurements. Despite many advantages, the 2D DIC method lacks unambiguous evaluation of precision and relevance of designated displacements, which is rather significant for possibilities of utilization in technical control of large engineered objects. It should be also marked that the tachometric method is more reliable but is more laborious. Research of this type might comprise additional element for the assessment of the influence of dynamic loads, such as activating turbine water flow, onto the overall condition of the surveyed structure.
文摘The factual data on error of positioning in VRS GPS networks have been analyzed, where the mobile receiver is provided with VRS. The method of highly informative zone is suggested for removal of initial vagueness in selection of reference stations for purposes of development of VRS on the basis of minimum GPS network, composed of three reference stations. The recommendations on use of suggested method are given.
