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1. MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF MINING AND GEOLOGY BUI THI HONG THAM RESEARCH ON THE THEORETIC BASE FOR THE MODERNIZATION OF THE NATIONAL GEODETIC CONTROL NETWORK IN VIETNAM BY GLOBAL NAVIGATION SATELLITE SYSTEM GNSS Specialty: Geodesy and Mapping Code: 62520503 SUMMARY OF THE THESIS SUBMITTED FOR THE DEGREE OF DOCTOR HANOI – 2014
2. The thesis has been completed at the Department of Geodesy surveying, of Surveying Faculty, Hanoi University of Mining and Geology. Scientific Supervisors: 1. Prof. Dr.Sc. Dang Hung Vo Association of Geodesy, Maps and Remote Sensing of Vietnam 2. Dr. Vu Van Tri Hanoi university of Mining and Geology Examiner 1: Dr. Le Minh Association of Geodesy, Maps and Remote Sensing of Vietnam Examiner 2: Dr. Nguyen Dinh Thanh Defense Mapping Agency of Vietnam - Ministry of National Defense Examiner 3: Dr. Tran Hong Quang Association of Geodesy, Maps and Remote Sensing of Vietnam The dissertation will be defended at the University examination Council at the Hanoi University of Mining and Geology, at h, 2014 This dissertation is submitted to National library and library of Hanoi University of Mining and Geology.
3. 1 INTRODUCTION 1. The importance of dissertation The launching of global navigation satellite system (GNSS) opened a new era for sciences – technology, especially surveying - mapping. GNSS has changed basically in the conceptualization and methodology to position points on the ground due to its advantages. According to the national controling network, GNSS applications can be divided into two phases: - Authenticate, increase points, improve the traditional coordinate network; - Establish the national coordinate network under a new concept based on the ability of GNSS technologies. Currently, national coordinate network in the world are ordinarily built on GNSS continuously operating reference stations with consistent density, appropriated accuracy, reliability, safety and multi – purposes. This is called the GNSS CORS network. The name describes technologically "continuous observation to connect points in an online network system." Density and distribution of points varies from country to country. In Vietnam, the traditional network was upgraded preciseness, improved and modernized by GNSS technology to become national georeference system VN - 2000. This made a milestone of surveying and mapping science of our country. In face of the achievements in the world, it is essential to build continuously the geodetic coordinate network by GNSS technology to replace traditional geodetic network and meet the modern demands of the coordinates. GNSS technology applications are the most basic component of geographic information infrastructure and become a trend in the world, so we have to integrate without any other options. The Ministry of Defense has been executing the project of constructing the military georeference system GNSS CORS network (finished on 1/2 block workflows), Ministry of Natural Resources and Environment has built and implemented Strategy of measuring and mapping development, of which the modernization of coordinates and leveling network system is the main point (consideration to approval). Although there are scientific basis and practical studies to apply, there has been no thesis which does research in a systematical way of
4. 2 building modern geodetic coordinate network, multi-purposes to meet the demand and integrate development of geographic information in the world. "Research on the theoretic basis for the modernization of the national geodetic control network in Vietnam by global navigation satellite system GNSS" focuses on the issue. 2. Objective of the dissertation Provide scientific and practical foundations for the modernization of geodetic control network of Vietnam, serving multiple purposes (surveying - mapping, navigation, researching on modern crustal movements, international information integration, ) based on GNSS technology. 3. Subjective of the dissertation The subjective of the dissertation is the national control network in Vietnam and the applications of GNSS technology. 4. Scope of the dissertation In terms of science: Feasibilities of GNSS technology (global, continuous-time, methods of measurement, accuracy, reliability, achievements and international experience, ). Data processing of the actual stations continuously demonstrates how to connect coordinates, define and coordinate transformation, velocity of movements in the international coordinate systems ITRF. Solutions, methods to build the geodetic network are to establish a unified coordinate base in surveying and mapping, solve the problem of positioning reference system and scientific research to Earth. In terms of space: The national geodetic coordinate network can connect with the international coordinate network IGS. In terms of time: It is counted since Vietnam constructed the traditional geodetic network 5. Contents of dissertation To achieve this goal above, the dissertation must solve the following issues: - Evaluate overview of GNSS technology applied to build national geodetic network. - Study the ability of GNSS technology, new measurement methods, especially the group of methods to measure real time area. - The format (structure and density) GNSS CORS network serving the purpose of geodesy and mapping (basic terrain mapping,
5. 3 cadastral and construction), monitoring crustal movements, building the national reference system according to the dynamic point of view. - Process data of measurements of national GNSS CORS network simultaneously with IGS data to link international coordinates, update on coordinates according to the dynamic reference system point of view, and observation of modern crustal movements. 6. The methodology The dissertation using the following methodologies: - Methods of synthesis, analysis and inheritance: Collect the historic documents; update the information on the internet, synthesis, analysis of resources and research results, inherit selectively achievements related to the subject. - Methods of collection and processing GNSS data: static measurements, session 24/24 at the continuous measurement points. Processing of measurements and IGS data by Bernese 5.0 software, connect coordinates, velocities with IGS network, scalability coordinates, and velocities in the typical dynamic coordinates system ITRF. - Methods of comparisons: Compare the advantages and disadvantages of building geodetic control network according to the traditional method and the method using GNSS technology. - Methods of expert: Learn more knowledge and experience from experts. - Method of application of information technology: using programming languages; setting up spreadsheets to automate the calculation process. 7. Scientific and practical meaning of dissertation - The scientific meaning of dissertation: Approach a further step when to learn about the development of GNSS technology and provides reliable scientific foundations of GNSS technology applications in building modern geodetic coordinate network, multi - purpose consistent with the reality in Vietnam and connect with the world. - The practical meaning of dissertation: The results of the dissertation have contributed to the selection of the appropriate solution to modernization geodetic coordinate network, reference system in Vietnam.
6. 4 8. Rational arguments and new contributions a. Rational arguments - First argument: According to a new point of view, National coordinate network in Vietnam is GNSS CORS network with appropriate infrastructure (receiver, antenna, augmentation systems, information infrastructure, network connectivity, ) meeting modern measuring methods; solving the task of defining and maintaining the coordinate reference system; the detailed measurement for setting up mapping; tracking and navigation; researching on modern crustal movements. - Second argument: because of the structure and density of the GNSS CORS network, methods of collecting and processing relevant data, the national network entirely meet the needs of the surveying and mapping, international connections of geographic information; carry out Earth scientific research in Vietnam according to global standards. - Third argument: The national geodetic coordinate network in Vietnam based on GNSS technology has high performance (advanced accuracy, extend technical scope, timely updates and automation). b. New contributions - To put forward a GNSS CORS network in Vietnam with full scientific and practical foundations. - To prove the necessity of building a dynamic reference system in Vietnam by specific data. - To propose the time to update the new coordinates for the GNSS CORS network in Vietnam. - To put forward the workflow of coordinate transformation, velocities of GNSS points between international terrestrial reference frames ITRF using 14 transformation parameters. - To establish the velocity diagram of GNSS points in Vietnam in a coordinate system. 9. Structure of dissertation The structure of dissertation includes three main parts: introduction, content as well as conclusions and recommendations, which is presented on 132 pages, 25 drawings and diagrams, 34 tables.
7. 5 Chapter 1 OVERVIEW OF APPLICATION OF GPS TECHNOLOGY IN BUILDING COORDINATE NETWORK SYSTEM 1.1. Application of GNSS technology in the construction of geodetic network in the world GNSS has become a major technology and has gradually replaced the traditional measurement technology in the construction of geodetic network. 1.2. Application of GNSS technology in the construction of geodetic network in Vietnam From the overview picture of the development of GNSS technology in the world and the process of applying GNSS technology in Vietnam, it can judge the trend of GNSS technology applications in Vietnam. Specifically, GNSS technology helps reduce working time with low cost and high-tech capabilities. Furthermore, it provides favorable conditions to change significantly the conceptions and forms of the national coordinate control network, specifically including: - Formatting many tiers with dense buried points of the traditional manner has been replaced by the form of the base GNSS CORS network with very little buried points, which creates a new method of determining the number and distribution of buried points at the last grade for measuring detailed topography, objects. This is a new form of national coordinate control network; we have not approached "The Concept of No - Network Geodesy" but access "low density geodetic network ". - It is possible to identify the local geoid model with high accuracy, the combination of coordinate and leveling network in a GNSS CORS network measured leveling is a new approach to unified coordinates - leveling control network. - The dynamic geodetic GNSS network depending on time is a new approach to the national georeference system, suites Earth observation associated with the new tectonics. The application of this approach in each country associated with the international reference system requires detailed studies. Therefore, the direction researching of the dissertation has been laid out and presented in section 5. Content of dissertation in the beginning of the dissertation.
8. 6 Chapter 2 STUDYING THE POSIBILITY OF GNSS TECHNOLOGY APPLICATIONS TO CHANGE THE NATIONAL HORIZONTAL NETWORK IN VIETNAM 2.1. The general problem 2.1.1. Conception changes of form, structure, precision of control network since the GNSS technology was born - Changes of the application structure of GNSS GNSS Basic system Augmentation system User segment Control Space SBAS GBAS receivers software segment segment GPS EGNOS EUPOS GLONASS WAAS SAPOS GALILEO MSAS COMPASS Figure 2.1. The application structure of GNSS technology [50] Currently, there have been fundamental changes in GNSS in terms of technology on promoting positioning under the new approach. With the present concept, the application structure of GNSS technology is expanded (Figure 2.1). - Development trends of measurement methods. The principle of measuring real-time NRTK starts with all reference stations in these network online observing satellites continuously with the software system installed on the master system of NRTK center.
9. 7 The aim of NRTK is to minimize the impact of the error depended on the distance and location calculated within the network. Minimizing sources of error in the measurement process is different when the technology used NRTK in is different (MAC, FKP, VRS, ). Each technology will lead to significant differences in performance, reliability and accuracy for rover stations. - Geodetic control network under the new perspective is integrated geodetic points, based on the existing geodetic infrastructure of each country and GNSS technology to exploit efficiently for practice and scientific research. The network is based on the following principles: + The network must be durable and long lasting; + Reasonable density, data in the plane reference, leveling and gravity system; + To be the basis for national geodetic reference system; + To meet the applications when using of modern surveying technology. As a result, geodetic control network under standpoint ensures the capacity to provide data about the shape, size, gravity field of the Earth, as well as the volatility of quantities over time. This network has the following tasks: - Navigation and tracking: error millimeters. - Surveying and mapping: error position about centimeters. - Research and identify crustal movements: error millimeters. - Supporting research atmosphere, 2.1.2. The method of construction GNSS CORS network playing basic geodetic plane network in the world and Southeast Asia Today, so many GNSS CORS networks have been established in the world, which are the major infrastructure to provide the necessary applications with high accuracy in surveying, mapping, navigation and the Earth science applications. The countries which have set GNSS CORS network have to follow the legal and the rules of the countries. Moreover, the countries with great potential of sharing the network also cooperate to form GNSS CORS networks of the region.
10. 8 2.1.3. Some features when building GNSS CORS network The main advantages of the GNSS CORS network: reducing depended error sources due to the connection of the permanent stations to produce the network, the longer distances of points in the GNSS CORS network results in decreasing the number and density of the points, and automating the GNSS measurements referencing , calculation results to unified reference frame. 2.2. The ability to change the horizontal control network in Vietnam by the method of construction GNSS CORS network The control plane network in Vietnam in the future will be the GNSS CORS network (NRTK CORS), which has distance and appropriate accuracy to satisfy most missions. Table 2.1. The number of GNSS CORS stations in Vietnam Distance of a GNSS Control area of a GNSS The number N0 CORS (km) CORS (km2) GNSS CORS 1 20 346 959 2 40 1386 239 3 50 2165 153 4 60 3118 106 5 70 4244 78 6 80 5543 60 7 90 7015 47 8 100 8660 38 9 150 19486 17 10 200 34641 10 11 250 54127 6 2.3. Construction GNSS CORS network in Vietnam 2.3.1. The idea of the tier the national GNSS CORS network, structure, density and accuracy The idea of construction GNSS CORS network in Vietnam must be multi-purposes network service, and satisfy most missions presented in Table 2.2.
11. 9 Table 2.2. Mission and accuracy requirements of the national GNSS CORS network The accuracy N0 Mission requirements To satisfy the requirements of measurement 1 ≤ 10 cm basic maps as terrain mapping 2 To satisfy the requirements of cadastral ≤ 4 cm To satisfy the requirements of navigation and 3 ≤ 3 m tracking To satisfy the requirements of researching 4 about mm modern crustal movements To satisfy the requirements of establish the 5 about mm national geodetic reference To connect with IGS, the network has some 6 points of attributes IGS to resolve international about mm scientific tasks regionally and globally To form the national GNSS CORS network serving multi- purposes, the ideas of designing network are proposed: - Calculation 0f number of points in the GNSS CORS network bases on missions and accuracy requirements of each tier in the network. - The sum of the national GNSS CORS network is calculated when this network satisfies the requirements of measurement basic maps - the third GNSS CORS stations. - Some of the third GNSS CORS stations will be selected to meet the mission of the first and the second GNSS CORS stations. - Some of the second and the third GNSS CORS stations will be selected to meet the mission of the first stations. - One GNSS CORS station is able to satisfy many different tasks. Table 2.3. Recommended the number of GNSS CORS stations Control area of a The number Area Distance Vietnam GNSS CORS GNSS (km2) (km) (km2) CORS The key economic 67150.2 50 2165 39 region other areas 264547.8 80 5543 48 The total number of GNSS CORS stations 79
12. 10 The national geodetic control network will be modernized by GNSS CORS network with minimum and reasonable density of points, consistent and sustainable, including 79 points, in which: - 4 points join to IGS - tier 1; - 8 satisfy the requirements of setting up the national geodetic reference Reward - tier 2; - 11 satisfy the requirements of researching modern crustal movements - tier 2; - 4 points has DGPS service functions that satisfy the requirements of navigation and tracking - tier 3; - 79 points satisfy the requirements of measurement basic maps - tier 3. * Comment Figure 2.2 shows that the application of GNSS technology has changed the traditional network in both structure and density. The new one is multi-purpose network; satisfies the requirements of modern surveying; guarantees for solving the task of verifying and maintaining the reference frame, coordinate system; satisfies the requirements of measurement basic mapping; navigation and tracking; researching modern crustal movements. 79 points in the national GNSS CORS network are designed on the base map of Vietnam. Some points in the network serve many objectives when building the GNSS CORS (eg. points in MongCai cover five functions: join IGS, build the national geodetic reference frame, research modern crustal movements, navigation and tracking and serves basic mapping). In the process of building the national modern geodetic network, some points in VN - 2000 satisfying the requirements will be selected as the points of the national GNSS CORS. These points in two networks will serve for the determination of coordinate transformation parameters. This will ensure that close link between the old and new network as well as the unified use of two networks. The above analysis proves the capacity and accuracy of GNSS technology in the current period, shows technical efficiency (improves
13. 11 the accuracy and expands the technical scope, timely updates, automation, ) indisputable of this technology when applied for the construction of the national geodetic network in Vietnam. 1040 1080 1120 1160 TRUNGQUOC 200 Hainam HoangSa Islands (Vietnam) 160 CAMPUCHIA THAILAN 120 TruongSa Islands (Vietnam) 80 MALAYSIA Figure 2.2. The GNSS CORS network in Vietnam Note: : Function set up the national reference frame; : Research function geodynamics; : DGPS function; : Joined on IGS. The green area indicates three main economic Northern, Central, Southern. The green lines separate territorial Vietnam into blocks according to the documents [6]. 2.3.2. Principles of organization, construction and operation of GNSS CORS network Each GNSS CORS station has minimum requirements on many aspects of the construction process and operation.
14. 12 Chapter 3 THE NATIONAL HORIZONTAL NETWORK FOR MORDEN CRUSTAL MOVEMENTS RESEARCH 3.1. Scientific and practical significance of researching modern crustal movements in intercontinental and global scale Over time, GNSS technology is growing and perfect, problems of geometry and physics of the Earth is resolved. Until now, this technology has completely satisfying scale of studies, the accuracy required for the job posting. This is the basis to take form concepts of dynamic geodetic. 3.2. The network monitors modern crustal movements and achievements when applying GNSS technology The determination of the Earth's crustal movements requires the highest accuracy and compliances with rigorous technical process at any scale. Presently, the realities have demonstrated that this technology can fully satisfy the accuracy requirements. 3.3. Monitoring modern crustal movements in Vietnam In Vietnam, the monitoring system using GNSS technology has been implemented to create a database growing richer. These findings have contributed to geodynamic map of the region in more detailed, accurate and reliable way. 3.4. Adjustment DGPS/CORS on the international reference system 3.4.1. Measurement data Table 3.1. Synthetic measurement data N0 Day DOY Name of points MCRS DNRS PQRS TSRS KUNM NTUS PIMO WUHN 1 1/12/2010 335 x x x x x x x 2 2/12/2010 336 x x x x x x x 3 3/12/2010 337 x x x x x x x 4 4/12/2010 338 x x x x x x x 5 1/6/2011 152 x x x x x x x x 6 2/6/2011 153 x x x x x x x x
15. 13 7 3/6/2011 154 x x x x x x x x 8 4/6/2011 155 x x x x x x x x 9 5/6/2011 156 x x x x x x x x 10 1/3/2012 61 x x x x x x x 11 2/3/2012 62 x x x x x x x 12 3/3/2012 63 x x x x x x x 13 4/3/2012 64 x x x x x x x 14 5/3/2012 65 x x x x x x x 3.4.2. Download international support information and data All the support information and data: Precise ephemerides of satellite’s internal orbital model, Earth’s rotation axis data, and global ionosphere model, etc. are exploited from IGS. 3.4.3. Processing software DGPS/CORS data collected will be processed by the Bernese 5.0 software processes closely follow the menu. 3.4.4. Steps Results for the network computing processor were synthesized following tables. Table 3.2. Coordinate of points N0 Point X (m) Y (m) Z (m) 1 DNRS -1915754.4967 5824431.0548 1750989.0477 2 MCRS -1831172.4798 5646418.0114 2325703.8077 3 PQRS -1521499.8762 6094084.7056 1104443.9268 4 TSRS -2354092.2732 5850302.4095 952491.9085 Table 3.3. Absolute velocity of points DGPS/CORS V V V V Azimuth N0 Point B L H (mm/y) (mm/y) (mm/y) (mm/y) (0) 1 DNRS 34.7 -20.5 44.9 40.3 120.6 2 MCRS 30.8 -7.8 -1.8 31.8 104.2 3 PQRS 21.1 -12.2 11.7 24.4 120.0 4 TSRS 20.2 -13.5 -6.0 24.3 123.8
16. 14 1040 1080 1120 1160 MCRS TRUNGQUOC (MT ) (ĐB ) 200 LAO (TB-BTB) Hainam DNRS HoangSa Islands 0 16 (Vietnam) CAMPUCHIA (BIENDONG) 120 THAILAN (NTB-NB) TrươngSa Islands (Vietnam) PQRS TSRS 80 MALAYSIA 30 mm/year 100 km MALAYSIA Figure 3.1. Diagram velocity vectors movements of points DGPS/CORS * Comments - Thus, the national DGPS CORS network has been computed processed and connected to IGS. Measurement and support data were selected to fully satisfy the task of establishing geodetic reference frame and identify modern crustal movements during the processing. - The process was carried out according to strict procedures. - The velocity of points: MCRS (MongCai), DNRS (DaNang), PQRS (PhuQuoc) and TSRS (TruongSa) determined by the integration of standard equations is about 3 cm/year. Error of the vertical and latitude, longitude velocities are approximately 3 mm/year and 1 mm/year, respectively. The result is high accuracy in comparing to the 3 cm velocity. - Movements in the different regions of the territory are various: 40.3 mm/year in the Central region (the largest value), and the velocity movement in the MongCai is faster than PhuQuoc and TruongSa 31.8
17. 15 mm/year. The modern crustal movements are similar in PhuQuoc area and TruongSa Islands. - The velocity vectors indicated the study area tends to movement towards Northwest – Southeast connecting to the other published results both in direction and value. - In addition, the results also give the coordinates of the points in the ITRF05 reference frame related to international time 2010 - 03-04 00:00:00. The software also allows determining coordinates in relation to any selected point. - The velocity vector obtained through the processing practically of the dissertation is recognized as a scientific contribution to research modern crustal movement map on the territory of our country. Chapter 4 CONSTRUCTION OF THE NATIONAL HORIZONTAL REFERENCE SYSTEM ACCORDING TO DYNAMIC POINT OF VIEW 4.1. The process of forming the dynamic geodetic reference system in the world The implementation of the ITRS is to determine International Terrestrial Reference Frame (ITRF) with 7 parameters including 3 parameters of original geocentric, 3 of axis orientation angle parameters and 1 parameter of the difference in length. These parameters are updated base on the observation data every year. It is necessary to consider the rate of change of the 7 parameters because they are always in a state of dynamic (Earth exists in the dynamic) .Thus, a number of parameters is 14. 4.2. The necessity of the construction of the dynamic reference system in Vietnam 4.2.1. Overview of the national horizontal reference system VN - 2000 The reference system and the national horizontal system VN - 2000 is the initial result steps of the modernization of the national the horizontal network and the national horizontal system in Vietnam. 4.2.2. The necessity of the construction of the dynamic reference system in Vietnam The GNSS CORS network being basic elements to create the dynamic coordinate system will be built in our country. The
18. 16 national coordinate system changes over time; however, coordinates of points in the national GNSS CORS network serving on measurement basic maps must be published at the time of determined. Over time, coordinates of GNSS CORS have changed. When coordinates of these points in new time compared with its coordinates at time published that beyond a limit will so the GNSS CORS network does not satisfy accuracy for the measurement basic map. As a result, coordinates of points in the national GNSS CORS network used must be updated - coordinates at the new time. Therefore, to study the need to build the national dynamic coordinate system in Vietnam by measurement data, velocity deviation movements of tectonic blocks will be calculated, its consequences is recommended reasonable time to update the national GNSS CORS network. Table 4.1. Velocity deviations between tectonic blocks Velocity deviation movements of tectonic blocks (mm) Year DB and TB - BTB TB - BTB and NTB - NB TB - BTB and BĐ dmax 1 8.5 15.9 16 16 2 17 31.8 32 32 3 25.5 47.7 48 48 4 34 63.6 64 64 5 42.5 79.5 80 80 6 51 95.4 96 96 7 59.5 111.3 112 112 8 68 127.2 128 128 9 76.5 143.1 144 144 10 85 159 160 160 Note: North East (DB); North West - North Central (TB - BTB); Sea East (BD), South Central - South (NTB - NB). Indeed, coordinates of GNSS points are significantly affected by the deformation of the crust or plate tectonic movement. Calculation results are evidence to the need to build the reference system in Vietnam.
19. 17 The dynamic reference frame is always changing over time, so the period of updating the coordinates of the GNSS CORS network is reasonable by calculation specifically. There are two reasons for this; firstly, if the update of coordinate is not done, the GNSS network will be deformed and do not guarantee the accuracy of the measurement of basic maps; secondly, if its updating is always done so difficult for measurement mapping, economically costly. To propose the updating time for the new national coordinate GNSS CORS network guaranteeing for surveying terrain mapping 1:500 in all conditions (barren or bushy area), the dissertation choices maximum error 100 mm. The deviation presented on table 4.1 shows that movement velocity of the largest annual tectonic blocks in the 6th and 7th years are 96 mm and 112 mm, respectively; meaning the velocity in 7th year (dmax ) is greater than 100 mm. Therefore, the interval of time required to update the new coordinate for the national GNSS CORS network is recommended 7 years. 4.3. Construction of the dynamic reference system in Vietnam The GNSS CORS network is the realization of the national coordinate system according to the dynamic view. This network will maintain the national geocentric coordinate frame 3D and support for in real-time positioning, navigation and monitoring applications. In addition, measuring precision leveling, measuring gravity points in its network will form a unified the national network on plane, leveling and gravity, which is the basis for building the precise accuracy geoid model in Vietnam. 4.4. The way uses the geodetic reference system in the practice 4.4.1. transformation Formula system 4.4.2. Build flowchart of coordinates and velocities transformation of GNSS points between two dynamic coordinate systems
20. 18 (V ,V ,V ) B L H ITRF(1) (t - t0) 14 parameters ITRF(t0)(1) ITRF(t)(2) (V ,V ,V ) X Y Z ITRF(1) X(t0)(1) X(t)(1) X(t)(1) X(t)(2) Figure 4.1. Process coordinates transformation from ITRF(1) at time t0 to ITRF(2) at time t (V ,V ,V ) B L H ITRF(1) (t - t0) 14 parameters ITRF(t0)(1) ITRF(t)(2) (V ,V ,V ) X Y Z ITRF(2) X(t0)(1) X(t)(1) (V ,V ,V ) X Y Z ITRF(2) (V ,V ,V ) B L H ITRF(2) Figure 4.2. Process transfer velocity from ITRF(1) to ITRF(2)
21. 19 4.4.3. Empirical calculations Table 4.2. Coordinates of GNSS points in ITRF08 at 18/07/2012 N0 Point X (m) Y (m) Z (m) 1 XUYO -1606525.3107 5700807.4794 2358910.3445 2 OAN0 -1566459.7943 5711793.1162 2359391.0194 3 DOI0 -1554911.1281 5722287.9981 2341248.9526 4 SOC1 -1621267.4901 5719456.3583 2303158.3259 5 TAM2 -1601083.2914 5719707.1284 2318672.4007 6 HUN1 -1571100.2652 5731225.1349 2308717.3752 7 NTHO -1555548.8832 5730756.5177 2320416.1883 8 SON1 -1557982.9310 5741852.5798 2291130.9723 9 LAP1 -1541103.3835 5738426.8455 2311048.3542 10 BAVI -1578207.2652 5740266.8121 2281398.4277 11 HOA1 -1561203.3469 5754853.9430 2257478.9710 12 NAM0 -1480436.1083 5741958.4656 2342822.2803 13 NGA1 -1353072.7825 5749668.0049 2402462.2895 14 HAM1 -1355321.3541 5762376.1094 2367436.5756 15 DON1 -1334851.1103 5758491.9047 2387972.1199 16 LEM1 -1335854.0006 5773067.2098 2353215.1336 17 MON1 -1464209.0062 5767238.2661 2291232.1061 18 NOI1 -1457371.9564 5771322.4579 2285116.1053 19 LOT1 -1445752.0185 5771190.8986 2292523.2300 20 QTA2 -1432563.6411 5770244.6106 2303209.1292 21 NAD2 -1458337.9705 5777358.5267 2270039.5502 22 DIEB -1336842.3829 5787988.4739 2315702.2299 23 DOSN -1724757.3380 5714523.9160 2239792.0393 24 NT01 -1726969.5917 5714864.9568 2237081.3908 25 NT03 -1844373.6094 5997105.5965 1142317.0439 26 NT04 -1575936.5479 6075089.2127 1132070.0742 27 QT01 -1339440.8883 5788398.0139 2313170.2549
22. 20 28 QT03 -1916791.4419 5822974.9368 1754668.6848 29 VUNT -1849617.0276 5995299.9136 1143372.7201 30 CAMP -1772774.5625 5687232.9039 2271331.8300 31 NONN -1921866.9957 5823665.8416 1747139.7398 32 DNRS -1915754.6080 5824431.1345 1750989.0334 33 MCRS -1831172.5471 5646417.9871 2325703.7915 34 PQRS -1521499.9300 6094084.7200 1104443.9070 35 TSRS -2354092.3105 5850302.3783 952491.8786 Table 4.3. Absolute movement velocities of the GNSS points in ITRF08 0 VL VB VH V Azimuth N Point 0 (mm/y) (mm/y) (mm/y) (mm/y) ( ) 1 XUYO -10.8 35.1 0.6 36.7 107.1 2 OAN0 -10.2 33.6 -13.9 35.1 106.9 3 DOI0 -10.1 33.8 -10.4 35.3 106.6 4 SOC1 -10.2 33.0 -1.7 34.6 107.2 5 TAM2 -10.5 32.5 -0.5 34.2 107.9 6 HUN1 -10.0 33.2 -5.1 34.7 106.8 7 NTHO -10.5 33.4 -10.6 35.0 107.4 8 SON1 -10.4 32.9 -3.6 34.5 107.5 9 LAP1 -10.9 33.0 -4.7 34.8 108.3 10 BAVI -9.4 32.2 -1.2 33.6 106.3 11 HOA1 -9.6 34.0 -2.7 35.3 105.8 12 NAM0 -10.3 35.2 3.3 36.7 106.3 13 NGA1 -8.0 39.2 12.2 40.0 101.5 14 HAM1 -8.8 33.0 15.4 34.2 104.9 15 DON1 -10.4 35.3 15.3 36.8 106.4 16 LEM1 -9.4 34.9 12.0 36.2 105.1 17 MON1 -11.7 32.5 -1.0 34.6 109.8 18 NOI1 -10.4 33.1 -4.3 34.7 107.4
23. 21 19 LOT1 -11.9 33.6 -6.1 35.7 109.5 20 QTA2 -10.8 34.0 -9.5 35.7 107.6 21 NAD2 -10.4 32.5 -10.1 34.1 107.7 22 DIEB -9.6 27.3 4.0 28.9 109.4 23 DOSN -8.0 27.6 16.7 28.8 106.2 24 NT01 -11.7 36.3 7.6 38.1 107.9 25 NT03 -11.7 27.1 18.8 29.5 113.4 26 NT04 -9.8 15.9 -14.5 18.6 121.6 27 QT01 -10.3 30.2 -19.9 31.9 108.8 28 QT03 -15.0 26.9 -2.6 30.8 119.1 29 VUNT -11.1 22.8 1.0 25.4 116.0 30 BDE1 -14.1 22.6 0.5 26.6 122.0 31 DTE1 -11.6 24.1 3.1 26.8 115.7 32 BLO1 -14.1 24.1 2.6 27.9 120.3 33 ALO1 -15.4 29.5 19.5 33.2 117.6 34 LNI1 -13.5 26.1 3.9 29.4 117.3 35 THN1 -13.2 25.5 2.7 28.7 117.4 36 BLV1 -14.7 27.7 -0.3 31.4 118.0 37 LANG -12.5 38.3 -22.6 40.3 108.1 38 DOHO -9.1 24.9 -15.1 26.5 110.1 39 HUES -19.8 30.0 10.2 35.9 123.4 40 STT1 -10.3 21.9 -7.5 24.2 115.2 41 CDA1 -7.4 20.7 -9.6 22.0 109.7 42 HOCM -11.5 22.0 -3.0 24.8 117.6 43 CAMP -4.4 47.7 28.1 47.9 95.3 44 NONN -0.2 44.5 24.6 44.5 90.3 45 DNRS -20.5 35.0 45.0 40.6 120.4 46 MCRS -7.8 31.0 -1.8 32.0 104.1 47 PQRS -12.1 21.4 11.8 24.6 119.5 48 TSRS -13.5 20.4 -5.9 24.5 123.5
24. 22 * Establish diagram the absolute movement velocities on the territory of Vietnam coordinates and velocity of some GNSS points on the territory of Vietnam transferred from ITRF94, ITRF00, ITRF05 to ITRF08 on 18th, july7, 2012 base on Vietnam and international data. The results are shown in Figure 4.3. The transformation method allows applying to coordinate and velocity between the dynamic national reference frame (eg. tied to ITRF). This result is not only theoretical but also practical contribution to the study of modern crustal movements and construction of the dynamic coordinates system in future in our country. 1040 1080 1120 1160 TRUNGQUOC 200 LAO HoangSa Island (Vietnam) CAMPUCHIA 160 THAILAN 120 TruongSa Islands (Vietnam) 80 MALAYSIA 30 mm/year 100 km Figure 4.1. The diagram of movement velocities of GNSS points
25. 23 CONCLUSIONS AND RECOMMENDATIONS A. Conclusion Based on the study of the theory and results of infrastructure processing data presented in the dissertation, the PhD student has some remarks: (1) The dissertation gives overview of infrastructure development process of geodetic engineering in the world and Vietnam. Construction of the GNSS CORS network and the support techniques is a vital trend of all countries to reach the real-time kinematic and multi- purposed network in the way of the dynamic geodetic network 4D without datum points. (2) It is necessary to modernize the geodetic control network of Vietnam according to new trends (GNSS CORS network) to satisfy multi-purposes: requirements of measurement of basic maps, navigation and tracking, modern crustal movements, setting up the national geodetic reference and connect to IGS. (3) The GNSS CORS network includes 3 tiers with total 79 points: 4 points on IGS participation; 8 point setting up the national geodetic reference; 11 points serves for research modern crustal movements, 4 points function navigation and tracking and 79 points serves for measurement basic maps. A point can satisfy many different tasks. (4) The data at 4 points in the national GNSS CORS network located on 4 plate blocks: North East, North West - North Central, South Central - South and South Sea are adjusted in the international coordinate system. The results showed that movements of points on the plate blocks in Vietnam are uneven. The analysis and calculation based on the real data prove necessity of build the dynamic coordinate reference frame in our country. (5) Coordinates of the national GNSS CORS network will be published each term to serve for surveying basic maps. If the difference of coordinates between the new date and the published date is greater than allowed threshold, coordinates of GNSS CORS points used will be the later value. The dissertation researched a case and recommended updated interval of time the new coordinate for the national GNSS CORS network.
26. 24 (6) Process of coordinates transformation and velocities of GNSS points between two dynamic coordinate systems by formula systems being function of time have been studied and recommended. This is foundation to build the picture of the coordinate and absolute velocity of GNSS points in Vietnam in the one coordinate system at the same time. B. Recommendations On the basis of results achieved, PhD student has some recommendations: (1) Making effort to implement the GNSS CORS network: technical advances, economic efficiency of GNSS technology have been confirmed; the new measurement method has been established and developed. The coordinate system by the control GNSS CORS points is an inevitable trend today. Therefore, support systems (continuous stations network, processing centers, information infrastructure, etc.) should be established as soon as possible. This creates favorable condition to execute task of positioning by modern technology, satisfy requirements of accuracy, bring about high economic efficiency and promote the comprehensive integration with the world. (2) Strengthening the research and application of multi - GNSS systems: One of the most important characteristics of the GNSS CORS network is stable, continuous and reliable operation with high automation and computerization. Basically, we have just used GPS while GLONASS system has returned the entire operation mode, and GALILEO system launched satellites and sent signals in demo format. Therefore, it is necessary to identify approaches and prepare (receiver, software, user rights, ) in order to apply multiple systems, improve the safety factor and the reliability of overall system and cope with unfavorable circumstances actively. (3) Construction of the infrastructure toward GNSS CORS stations is complex and costly. This requires operation of interdisciplinary and human resources of the whole nation. It is difficult to catch up technological innovation in the world if the research process and implementation are slow.
27. LIST OF PUBLICATIONS RELATED TO THE DISSERTATION 1. Bui Thi Hong Tham (2009), "Converting raster data between two coordinate systems by software Global Mapper", Hanoi College of Natural Resources and Environment, Collection of scientific works (2008-2009) fields of environmental resources, tr . 94-101. 2. Msc. Bui Thi Hong Tham (2009), "Applied research repeat adjustment method to find the raw measurements", Journal of Geodesy and and Cartography, No. 1, p. 37-41. 3. Bui Thi Hong Tham (2010), "The need of modernization the geodetic control network in Vietnam and basic advantages of continuous operating reference stations CORS", Natural Resources and Environment Magazine, No. 14 (100), p. 52-53. 4. Bui Thi Hong Tham, Cao Minh Thuy (2011), "Navigation satellite systems and the future of GNSS receivers", Natural Resources and Environment Magazine, No. 15 (125), p. 18-20. 5. Bui Thi Hong Tham, Cao Minh Thuy (2011), "Using software to convert raster data between two coordinates systems", Natural Resources and Environment Magazine, No. 15 (125), p. 27-29. 6. Msc. Bui Thi Hong Tham (2011), "Frames of reference and the Earth System", Journal of Geodesy and Cartography, No. 9, p. 43 to 47, 53. 7. Bui Thi Hong Tham (2012), "Adjustment several stages with the geodetic horizontal control network", Natural Resources and Environment Magazine, No. 21 (155), p. 30-32. 8. Msc. Bui Thi Hong Tham (2012), "Research adjustment method with several stages for processing datas of geodetic horizontal and
28. vertical control networks", Hanoi University for Natural Resources and Environment, scientific research project. 9. Dr. Vy Quoc Hai, Msc. Bui Thi Hong Tham, Dr. Duong Chi Cong (2012), “Velocity transformation between international terrestrial reference frames", Scientific Conference 20th, Hanoi University of Mining and Geology. 10. Assoc. Prof. Dang Nam Chinh, Msc. Bui Thi Hong Tham (2012), "Curriculum geodetic data processing", Hanoi University for Natural Resources and Environment. 11. Msc. Bui Thi Hong Tham (2013), "The coordinate transformation between international terrestrial reference frames", Journal of Engineering Science Mining - Geology, No. 41, p. 52-56. 12. Bui Thi Hong Tham (2013), "The time needed to update the new coordinates for the national GNSS CORS network in Vietnam", The first scientific and technology workshop of Hanoi University for Natural Resources and Environment - 2013, p. 118-123. 13. Bui Thi Hong Tham (2013), "Apply extended adjustment theory to geodetic control networks", The first scientific and technology workshop of Hanoi University for Natural Resources and Environment - 2013, p. 223-228. 14. Bui Thi Hong Tham, "Determination of absolute crustal movements from data of Differential Global Navigation Satellite System (DGNSS)", Journal of Geology (the article was reviewed. It will be published).