Summary of doctor thesis le van hung

MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF MINING AND GEOLOGY The dissertation has been completed at the Department of Engineering surveying, of Surveying Faculty, Hanoi University of Mining and Geology Scientific Supervisors: Assoc Prof Dr Dang Nam Chinh LE VAN HUNG Hanoi university of Mining and Geology Assoc Prof Dr Nguyen Quang Phuc Hanoi university of Mining and Geology STUDY OF ADJUSTING COMBINATION OF GPS AND TERRESTRIAL OBSERVATIONS IN THE LOCAL TOPOCENTRIC COORDINATE SYSTEM APPLIED FOR ENGINEERING SURVEY NETWORK Examiner 1: Assoc Prof Dr Nguyen Quang Tac Hanoi Architectural University Examiner 2: Dr Dương Chi Cong VietNam Institute of Geodesy and cartography Study field: Geodesy and mapping Code: 62520503 SUMMARY OF DOCTORAL DISSERTATION Examiner 3: Dr Nguyen Van Van Military map service of general staff of Viet Nam army The dissertation will be defended at the University examination Council at the Hanoi University of Mining and Geology , at… h, ……………… 2014 This dissertation can be referenced at the National library Ha Noi – 2014 or at the library of the Hanoi University of Mining and Geology 1 INTRODUCTION The importance of dissertation For engineering survey (TðCT), we are likely to encounter cases where control networks are built in region not convenient for GPS observation due to limited satellite transmission signal; therefore, replying on only GPS technology for establishment of control network is not sufficient In such cases, it is essential for combination of GPS and terrestrial observations in order to enhance feasibility and effectiveness in establishment of engineering control network On the basis of the abovementioned practical requirements, it is prerequisite for studying means of adjusting combination of GPS and terrestrial observations and selecting the coordinate system which can be used in certain limitation as the basic coordinate system for engineering survey Using the local topocentric coordinate system whose datum point is established at the center of control network area can mitigate both abovementioned issues Objective, subjective and scope of the dissertation - Studying methods for establishment of the local topocentric coordinate system whose datum point is located at the center of the Works; completing procedures for transformation and conversion between the local topocentric coordinate system and other popular systems; - Determining the appropriate regions for local coordinate system to be used for civil and industrial engineering surveys; - Completing the theoretical basis and proposal of procedures for closely adjusting combination of GPS and terrestrial observations; - Establishing the software for adjusting combination of GPS observation and angular-side measurement, this has highly relevent application in the context of Viet Nam; - Evaluating the accuracy of software performance Content of dissertation - General study of GPS technology and total station (TððT) in order to establish engineering control network; - Study of the local topocentric coordinate system, conversion from the local topocentric coordinate system to geodetic coordinate system and to rectangular coordinate system in UTM projection; - Determination of usage limit of the local topocentric coordinate system in engineering survey; - Calculation of weight of relative measurement in adjustment of GPS network; - Study of adjusting GPS network in geocentric coordinates system (X,Y,Z) and the local topocentric coordinate system; - Study of adjusting combination of GPS observation and angular- side measurement in the local topocentric coordinate system; - Study of establishing computer programs to adjust combination of GPS observation and angular- side measurement Scientific and practical meaning of dissertation - Findings of the study provide the basis for adjusting combination of GPS and terrestrial observations in the local topocentric coordinate system applying for engineering high precision network - Proposal to use the local topocentric coordinate system as the basic coordinate system and replacement of rectangular coordinate system in UTM projection in civil and industrial engineering survey; - Algorithms and procedures are converted into combined adjustment softwares that are applicable to practical engineering survey in Viet Nam - Findings of the dissertation can be applicable in the field of education, teaching, scientific research and manufacturing Rational arguments: - First argument: It is significant for calculation of weight in GPS network and combination of GPS network and terrestrial observation Weight of GPS network should be standardized in accordance with two-step adjustment procedure - Second argument: It is required to calculate angle distort for adjusting the measured angle before adjustment combination of GPS and terrestrial observations Factors (i.e dimensions) of the network after adjustment ensure the best suitability with field factors These factors are necessary for the design works, construction of civil and industrial works that requires high accuracy - Third argument: The local topocentric coordinate system can be used as basic coordinate system, which is the replacement of rectangular coordinate system in UTM projection in order to serve for surveying 3 stage (large scale ratio), design, and construction works Scope (radius) of using the local topocentric coordinate system is estimated according to the requirements of angle distor and length distort New contributions - Completing the formulation system in order to determine appropriate region for the local topocentric coordinate system to be used in engineering surveying; - Introducing the formula for calculation of the horizontal angle distort when adjusting combination of GPS and terrestrial observations in the local topocentric coordinate system - Establishing Data Processing Software called ADGT (ADjustment GPS Topography) including transformation module, conversion module, module for analyzing side processing data, module for adjusting combination of GPS and terrestrial observations in the local topocentric coordinate system applying for engineering surveying Quantity and structure of dissertation Content of dissertation is presented on 118 pages, 39 drawings and diagrams, 21 tables in order to avoid the impact of weather conditions and meteorology on the measurement result 1.1.2 GPS observation method Based on specific parameters a, b of GPS satellite and total station, draw the diagram (Figure 1.1) to compare visually the accuracy of side length measurement by GPS ( mD-GPS) and accuracy of side measurement by total station (mD-TD) According to the diagram, at the distance of D 1 Establishment of common standard equation Establishment and solution of common standard equation NOTE: LTCS: local topocentric coordinate system 4.1 PROGRAME FOR COMBINATION ADJUSMENT Procedures for adjusting combination of GPS observation and angular-side measurement in the local topocentric coordinate system is performed in the following procedures: Assessment of accuracy END Figure 4.1 - A block diagram for computer program 21 22 4.2 ESTABLISHMENT OF SOFTWARE FOR ADJUSTMENT COMBINATION OF GPS AND TERRESTRIAL OBSERVATIONS IN LOCAL TOPOCENTRIC COORDINATE SYSTEM 4.3.2.Field claculation of adjusment combination of GPS and terrestrial observations for Thai Nguyen Cement Plant Engineering control network of Thai Nguyen Cement Plant includes 21 points to be determined, 04 outer control points called from GPS-01 to GPS-04, 13 control points on the construction plane called TN-01 to TN-13, 51 basesides measured by GPS, 26 sides and 19 angles measured by electric total station
Result on adjustment of GPS network by softwares including ADGT, TBC, GPSurvey 2.35 indicates that: • Difference in the geodetic coordinates between software ADGT and TBC, GPSurvey 2.35 is similar to that between software TBC and GPSurvey 2.35 • Mean square error of position between software ADGT and GPSurvey 2.35 is about 0,1mm Besides, difference in plane is about 1,5mm between software ADGT and TBC;
Adjustment combination of GPS and terrestrial observations by software ADGT: • Combination of GPS and terrestrial observation enhances the accuracy of the network; • Compatibility of two technologies is proved and reliability of results is enhanced 4.3.3 General comments Covariance matrix of GPS vectors received from side solutions only reflects error of each separated vectors, but not present the quality of whole measurement of GPS network; therefore, adjustment combination of GPS observation and angular-side measurement should be carried out two-step processing procedures After the first step, For processing geodetic data, the most significant requirement is to ensure the accuracy of results; therefore it is required to select the appropriate algorithm and proper processing procedures Based on the algorithm and procedures at section 4.1, for adjustment combination of GPS and terrestrial observations in the topocentric coordinate system, these steps should be followed sequentially: Step 1: Use a software with GPS receiver to import and process GPS observation value such as GPSurvey 2.35, TGO, TTC, TBC, etc Step 2: Establish the adjustment software in combination with ADGT.EXE “ADGT (ADjustment GPS Topography) software: includes modules with an user-friendly design, Vietnamese language, simplicity, direct data imported on Windows platform, good operation on Windows-8 operating system with fast processor speed and results are exported in Vietnamese forms 4.3 FIELD CALCULATION 4.3.1 Field claculation of adjusment combination of GPS and terrestrial observations for Dung Quat Oil Refinery Plant Engineering control network of Dung Quat Oil Refinery Plant includes 01 datum point, 14 points to be determined, 34 baselines, 04 angles and 08 sides
Result on adjustment of GPS network by softwares including ADGT, TBC, GPSurvey 2.35 indicates that: • Difference in the geodetic coordinates between softwares ADGT and TBC, GPSurvey 2.35 is similar to that between softwares TBC and GPSurvey 2.35 • Mean square error of position between softwa re ADGT and GPSurvey 2.35 is all the same Besides, difference in plane is about 3mm between software ADGT and GPSurvey 2.35;
Adjustment combination of GPS and terrestrial observations by software ADGT: • Angular-side measurement is well performed in additional area; • Compatibility of two technologies is proved and reliability of results is enhanced µ mean square error of unit weight GPS , will be determined, which is the basis for estimating the covariance matrix of a priori weight to standardize GPS observation in the second step Adjustment combination of GPS and angular-side measurement in the local topocentric coordinate system whose datum is established in 23 24 the center of network with proper control scope will simplify procedures of adjustment calculation, ensure coherence and meet the requirement of network deformation The factors (i.e dimension) of network after adjustment ensure the best conformity to field factors This is critical to design work, construction of civil and industrial works requiring high accuracy level 3.In the local topocentric coordinate system, it is possible to adjust combination of GPS network (3D) and terrestrial network (2D) if GPS receiver cannot be placed in some network points, but angular-side measurement are carried out by classical observations stages of survey (large scale), design and construction The scope (radius) of using the topocentric coordinate system is calculated by required deformation and by the formula L≤ 2,45.R 1/T Within the scale of defined area, the elements (dimension) of network after adjustment ensure the best suitability for field factors This is necessary for the design, construction of civil and industrial works which requires high accuracy ADGT software is reliable enough to use for the adjusting combination of GPS and terrestrial observations in engineering survey in Vietnam B Recomendations In the actual engineering survey for civil and industrial works, it is able to combine GPS technology and electric total station to establish geodetic network and process adjustment in the local topocentric coordinate system in order to meet technical requirements and improve the reliability of network In the local topocentric coordinate system, it is possible to adjust GPS network (3D) and terrestrial network (2D) if some points are not in good conditions for placing GPS receiver When establishing the local topocentric coordinate system, it is necessary to select the datum suitable for a receiver to be placed on and adjacent to network centre This coordinate system utilizes orthogonal projection; therefore, if elevation of points are significantly different, angle distort must be calculated in the formula (2.1) to adjust the measured angle before adjustment To determine exactly the weight of GPS observation when adjusting combination with angular- side measurement, it is required to apply two-step adjustment procedure In the first step, the adjustment of only GPS observation value is defined in order to determine approximate CONCLUSION AND RECOMMENDATIONS A Conclusion 1.In fact, adjustment combination of GPS network and terrestrial observations in the local topocentric coordinate system is the adjustment in the three-dimensional coordinate system (3D) with rigorous algorithm and adjustment procedures The coordinate components z of topocentric coordinate system enables calculation and determination of geodetic height H of network points after adjustment Covariance matrix CXYZ of GPS vectors only represents the correlative relationship of measurement value, but the increments of their variance and covariance; mean square error of unit weight µ GPS after adjustment of only GPS network is much greater than The value µ GPS is required to be determined in order to re-estimate covariance matrix of GPS vectors when adjusting combination of GPS and terrestrial observations It is required to calculate angle distort in order to correct the angles before the adjustment combination with GPS observation value This is critical for measured angles between points of significantly different elevation The topocentric coordinate system may be used as a basis instead of plane rectangular coordinate system in UTM projection, serving for coordinates and mean sqaure error of unit weight µ GPS , which is the basis for re-estimate covariance matrix of GPS observation value in the second step of adjustment When calculating weight of measurement value, Constant C=1 is taken LIST OF PUBLICATIONS RELATED TO THE DISSERTATION Le Van Hung (2008), “ Economic efficiency - the use of the technique combined Trimble5602 electronic total station and Trimble R3 GPS monitoring in shift work”, Building science and technology journal, (No 2), Ha Noi Le Van Hung (2008), “ Reasonable solution to the axis moving high in the construction of tall buildings”, Building science and technology journal, (No 3), Ha Noi Ngo Xuan The, Nguyen Xuan Hoa, Le Van Hung (2010), “ Establishment of software systems for transformation from GPS coordinates to the coordinate system works”, Building science and technology journal, (No 3), Ha Noi Dang Nam Chinh, Le Van Hung (2011),“ Adjustment in multiple phases and approach to Kalman filter” Science - technical journal of mining and geology, (No 35), Ha Noi Le Van Hung (2012), “ Difference between the UTM plane rectangular coordinates system and local topocentric coordinate system”, Building science and technology journal, (No 3), Ha Noi Dang Nam Chinh, Le Van Hung (2013), “ Determination of the limit when using of local topocentric coordinate system for engineering surveying”, Science - technical journal of mining and geology, (No 41), Special issue for 40 years of Department of Geodesy, Ha Noi Nguyen Xuan Hoa, Le Van Hung (2013), “ Establishment of interpolation formula for the elevation anomalous in the local topocentric coordinate system” Building science and technology journal, (No 2), Ha Noi Dang Nam Chinh, Nguyen Quang Phuc, Le Van Hung (2013), “Adjustment combination of GPS observables and measurements by electronic total station in the local topocentric coordinate system”, Proceeding of conference on the 50th anniversary of establishment of Viet Nam institute for Building science and technology, Geotechnical – Surveying engineering, (ISBN 978-604-82-0021-3), Construction Publishing House, Ha Noi