Maakoore liikumised riikliku geodeetilise võrgu GNSS kordusmõõtmistest
Laen...
Kuupäev
2019
Kättesaadav alates
12.09.2019
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Töö eesmärgiks oli välja selgitada maakoore postglatsiaalsed liikumised riikliku
geodeetilise võrgu (RGV) I klassi punktidel teostatud GNSS kordusmõõtmiste põhjal.
RGV I klassi punktide staatilisi GNSS mõõtmiskampaaniaid tehti kolmel aastal: 1995,
2008 ja 2017. Nende mõõtmiste tulemusi võrreldes saab tuvastada RGV deformeerimise
kiirust ja suunda. Töös kasutatavad GNSS mõõtmiste andmed on saadud Maa-ametilt.
RGV I klassi punktide koordinaadid arvutati referentsraamistikus ITRF2008 ning selleks
kasutati PPP-meetodit kasutavat teaduslikku tarkvara GIPSY-OASIS II (versioon 6.4).
Arvutuste tulemusena saadi kolmest ajaepohhist koosnev punktide koordinaatide aegrida.
Kiirused arvutati iga RGV I klassi punkti aegrea lineaarse trendi põhjal, kasutades
kaalutud vähimruutude regressiooni meetodit. Selleks kasutati programme TSAnalyzer
ning MS Excel. Leitud kiiruste valideerimiseks võrreldi neid uuematest postglatsiaalsete
maakoore liikumiste mudelitest NKG2016LU, NKG2016GIA, NKG_RF03vel, D1, ICE6G_C(VM5a), interpoleeritud kiirustega ja riikliku GNSS püsijaamade võrgu ESTREF
kiirustega. Lisaks arvutati kiirused kahe järjestikuse ajaepohhi (1997-2008 ja 2008-2017)
vahel eraldi, et selgitada välja kiiruste võimalikku muutust ajas.
Mõningad erinevused esinevad GNSS püsijaamade ning RGV I klassi punktide
MISSO97, MÄEBE97 ja PEETSU97 kiiruste vahel, kuid üldiselt sobivad kiirused
määramatuste piirides omavahel hästi. RGV I klassi punktide vertikaalkiiruste sobivus on
parem GIA mudeliga D1 (standardhälve ±0,36 mm/a). Horisontaalkiiruste on sobivus
parem mudeliga NKG_RF03vel (standardhälve N suunas ±0,19 mm/a ja E suunas ±0,27 mm/a). Selgus ka, et kahe järjestikuse ajaepohhi põhjal leitud kiiruste erinevused on
statistiliselt olulised, mis tähendab et RGV I klassi punktide liikumiskiirused ei ole läbi
aja olnud lineaarsed. Arvestades aegridade jääkhälbeid ja mudelitega sobivust hinnati
lõplikeks kiiruste määramatusteks horisontaalsuunas ±0,38 mm/a ja vertikaalsuunas ±0,41
mm/a.
The aim of this study was to determine postglacial movements of the Earth’s crust based on GNSS measurement campaigns on National Geodetic Reference Network. In 1995, 2008, and 2017, static GNSS measurements of National Geodetic Reference Network first order points were carried out. Comparison of these measurements allows to detect the size and direction of deformation of the National Geodetic Reference Network. GNSS observation data were received from the Estonian Land Board. Observations were processed in the ITRF2008 reference frame using GIPSY-OASIS II (version 6.4) software which employs the PPP method. Obtained coordinates were combined into a time series consisting of three epochs. The velocities of National Geodetic Reference Network first order points were calculated with TSAnalyzer and MS Excel based on the linear trend of each point, using weighted root mean squares regression method. To validate the results, they were compared with the velocities interpolated from postglacial land uplift (LU) and glacial isostatic adjustment (GIA) models NKG2016LU, NKG2016GIA, D1, ICE-6G_C(VM5a), and with the velocities of the national GNSS permanent station network ESTREF. In addition, velocities between two consecutive epochs (1997-2008 and 2008-2017) were calculated in order to establish possible change of the velocities in time. Although some differences exist between the velocities of the permanent GNSS stations and the National Geodetic Reference Network first order points MISSO97, MÄEBE97 and, PEETSU97, the velocities are generally consistent within the uncertainties. The vertical velocities of the first order points fit better with the GIA model D1 (standard deviation of the residuals is ±0,36 mm/yr). Horizontal velocities fit better with the model NKG_RF03vel (standard deviation in N direction is ±0,19 mm/yr and in E direction ±0,27 mm/yr). It was also found that differences between the velocities of successive epochs are statistically significant, meaning that the velocities of National Geodetic Reference Network first order points have not been linear over time. Taking into account the time series’ residuals and fit to the LU and GIA models, final velocity uncertainties in the horizontal direction ±0.38 mm/yr and in the vertical direction ±0.41 mm/yr were estimated.
The aim of this study was to determine postglacial movements of the Earth’s crust based on GNSS measurement campaigns on National Geodetic Reference Network. In 1995, 2008, and 2017, static GNSS measurements of National Geodetic Reference Network first order points were carried out. Comparison of these measurements allows to detect the size and direction of deformation of the National Geodetic Reference Network. GNSS observation data were received from the Estonian Land Board. Observations were processed in the ITRF2008 reference frame using GIPSY-OASIS II (version 6.4) software which employs the PPP method. Obtained coordinates were combined into a time series consisting of three epochs. The velocities of National Geodetic Reference Network first order points were calculated with TSAnalyzer and MS Excel based on the linear trend of each point, using weighted root mean squares regression method. To validate the results, they were compared with the velocities interpolated from postglacial land uplift (LU) and glacial isostatic adjustment (GIA) models NKG2016LU, NKG2016GIA, D1, ICE-6G_C(VM5a), and with the velocities of the national GNSS permanent station network ESTREF. In addition, velocities between two consecutive epochs (1997-2008 and 2008-2017) were calculated in order to establish possible change of the velocities in time. Although some differences exist between the velocities of the permanent GNSS stations and the National Geodetic Reference Network first order points MISSO97, MÄEBE97 and, PEETSU97, the velocities are generally consistent within the uncertainties. The vertical velocities of the first order points fit better with the GIA model D1 (standard deviation of the residuals is ±0,36 mm/yr). Horizontal velocities fit better with the model NKG_RF03vel (standard deviation in N direction is ±0,19 mm/yr and in E direction ±0,27 mm/yr). It was also found that differences between the velocities of successive epochs are statistically significant, meaning that the velocities of National Geodetic Reference Network first order points have not been linear over time. Taking into account the time series’ residuals and fit to the LU and GIA models, final velocity uncertainties in the horizontal direction ±0.38 mm/yr and in the vertical direction ±0.41 mm/yr were estimated.
Kirjeldus
Magistritöö
Geodeesia ja maakorralduse õppekaval
Märksõnad
magistritööd, geodeetilised süsteemid, geodeetilised mõõdistamised