TAILIEUCHUNG - Improvement of the accuracy of the quasigeoid model VIGAC2017

This scientific article will introduce a first research result for improvement of accuracy of the quasigeoid model VIGAC2017 on the base of it’s fitting to 194 national quasigeoid heights by the least squares collocation. Research results show that accuracy of the quasigeoid model VIGAC2017 will be obtained at level of ±0,058 m and increased to 20,69 % | Vietnam Journal of Earth Sciences, 40(1), 39-46, Doi: Vietnam Academy of Science and Technology Vietnam Journal of Earth Sciences (VAST) Improvement of the accuracy of the quasigeoid model VIGAC2017 Ha Minh Hoa Vietnam Institute of Geodesy and Cartography (VIGAC) Received 14 June 2017; Received in revised form 25 October 2017; Accepted 10 November 2017 ABSTRACT A national spatial reference system will be constructed based on a highly accurate national quasigeoid model with accuracy more than 4 cm. In Vietnam at the present stage there isn’t a detailed gravimetric measurement in mountainous regions and marine area. So with the purpose of improvement of accuracy of the national quasigeoid model VIGAC2017, we only can solve the task of fitting this model to national quasigeoid heights obtained from heights GPS/first, second orders levelling quasigeoid heights through least squares collocation. This scientific article will introduce a first research result for improvement of accuracy of the quasigeoid model VIGAC2017 on the base of it’s fitting to 194 national quasigeoid heights by the least squares collocation. Research results show that accuracy of the quasigeoid model VIGAC2017 will be obtained at level of ±0,058 m and increased to 20,69 %. Keywords: National spatial reference system; national quasigeoid height; least squares collocation; covariance matrix; semivariogram; semivariance function. ©2018 Vietnam Academy of Science and Technology 1. Introduction 1 A wide application of GNSS technology with GNSS data processing in ITRF and a combined usage of detailed gravimetric data and more accurate with every passing day Earth Gravity Model (EGM) for the construction of a highly accurate national quasigeoid model naturely lead to a bulding of a national spatial reference system. Ha Minh Hoa, 2017 had found that the most impotant base for the bulding of the national spatial reference system is the .

• Địa Lý
• Vietnam Journal of Earth Sciences
• Improvement of the accuracy of the quasigeoid model VIGAC2017
• The accuracy of the quasigeoid model VIGAC2017
• The quasigeoid model VIGAC2017
• The least squares collocation
• General characteristics of rare earth
• Radioactive elements in Dong Pao deposit
• The natural tap and thermal waters
• Liquid scintillation counter
• Probabilistic seismic hazard assessment for the South Central Vietnam
• Probabilistic seismic hazard assessment
• The South Central Vietnam
• Recent seismotectonic and geodynamic
• Prediction of maximum earthquake magnitude for northern Vietnam region
• The gev distribution
• Maximum earthquake magnitude
• Generalized extreme value distribution
• The earthquake catalog of Northern Vietnam
• Continuous GPS network in Vietnam
• The total electron
• The South East Asian region
• The continuous GPS network
• The South East Asian equatorial ionization anomaly
• Upper Permian lower Triassic volcanic sequences
• The Hoa Binh area
• northwest Vietnam
• Insignificant cumulative displacement
• Oriented core samples
• An analysis of forest biomass changes
• Geospatial tools and ground survey data
• Yok Don national park
• Central Highlands of Vietnam
• SPOT HRV satellite
• The autumn precipitation
• Tropical cyclone activity
• Central Vietnam and its East Sea
• Sea surface temperature
• Adaptation plans anticipated
• Construction of initial national quasi geoid model VIGAC2017
• First step to national spatial reference system in Vietnam
• Coordinate transformation parameters
• The WGS 84 ellipsoid
• Abnormal features of oceanographic characteristics
• Upwelling Vietnam waters under impact of El Niño events
• Deeper water layers during
• El Niño phase
• The relation between fault movement potential
• Seismic activity of major faults in Northwestern Vietnam
• Fault Movement Potential
• The nearly horizontal trend
• U Pb detrital zircon geochronology
• Sedimentary rocks in NE Vietnam
• Implication for Early and Middle Devoni an Palaeogeography
• LA SF ICP MS techniques
• The western Himalaya
• Preliminary study on phytogeography
• Dipterocarpaceae Blume family in Vietnam
• Dipterocarpaceae Blume family
• Tropical and or slightly passing
• The Mekong River deltas
• Impacts of climate change on erosion and water flow
• The soil and water assessment tool and gis
• Cau river basin in Vietnam
• oil and Water Assessment Tool
• Errors in determination of main parameters of earthquake hypocenter
• The national seismic network of Vietnam
• Main parameters of earthquake hypocenter
• The seismic stations
• The previous studies
• Sea level rise and resilience in Vietnam
• Sea level rise and resilience in the AsiaPacific
• Sea level rise and resilience
• Climate change induced sea level rise
• Spatial distribution of hot days in north central region
• Vietnam in the period of 1980 2013
• Hot days in north central region
• North Center Region
• Debris flow hazard in relation
• Geological environment changes in mountainous regions
• Geological environment changes
• Debris flows in Vietnam
• High arsenic concentration in groundwater related to sedimentary facies
• The Mekong River Delta
• High arsenic concentration
• AOAC laboratory Vietnamese standard
• Assessment of geomorphic processes and active tectonics
• Con Voi mountain range area
• The hypsometric curve analysis method
• The hypsometric curve
• Uptake capacity of metals by Vetiveria zizanioides
• Uptake capacity of metals
• Dong Xam metal production trade village
• Thai Binh province
• Metal production trade village
• Coralline Ba Ca ratios
• Luminescent line records
• Con Dao island
• Mekong river runoff
• Bright luminescent lines
• Simulation of long term variations
• The F2 layercritical frequency f0F2
• The northern tropical crest of ionization at Phu Thuy
• The thermosphere ionosphere electrodynamicsgeneral circulation model
• Long term variations
• Methodology of determining effective porosity
• Longitudinal dispersivity of aquifer
• The application to field tracer injection test in Southern Hanoi
• The groundwater flow
• New discovery of late early ordovician graptolites
• Discussion on stratigraphic sequence of paleozoic sediments
• The Dinh Ca Trang Xa section
• Vo Nhai disctrict
• A digital shoreline analysis system
• Mangrove shoreline changes along
• The Giao Thuy coastal area
• Mangrove shoreline changes and mangrove zoning