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CHANGING THE NATIONAL HEIGHT SYSTEM AND GEOID MODEL IN LATVIA

Authors :
Janis Balodis
Katerina Morozova
Maris Kalinka
Gunars Silabriedis
Irina Baltmane
Krišs Balodis
Ingus Mitrofanovs
Izolde Jumare
Source :
Geodesy and Cartography; Vol 42 No 1 (2016); 20-24, Geodesy and Cartography, Vol 42, Iss 1 (2016)
Publication Year :
2016
Publisher :
Vilnius Gediminas Technical University, 2016.

Abstract

According to the decision of IAG Reference Frame Sub-commission for Europe (EUREF) the EVRF2007 solution as the vertical reference has to be deployed in EU countries.The new height system LAS-2000,5 had been enacted as the European Vertical Reference System‘s EVRF2007 realization in Latvia and the new geoid model LV‘14 had been introduced by Latvian authority Latvian Geospatial Information Agency. However, the appreciation of the quality of quasi-geoid model LV‘14 is rather contradictious among the users in Latvia. The independent estimate and comparison of the two Latvian geoid models developed till now has been performed by the Institute of Geodesy and Geoinformatics. Previous geoid model LV98 which was developed for Baltic-1977 height system almost 20 years ago is outdated now. Preparatory actions described in order to fulfil the task of comparison the geoids in two different height systems. The equations and transformation parameters are presented in this article for the normal height conversion from Baltic-1977 height system to the Latvian realization named LAS-2000,5. The comparison is performed of both Latvian quasigeoid models – the new one LV‘14 and previous LV98. The quality of both models estimated by controlling the geoid heights at the properly densified GNSS/levelling network sites. The distribution of discrepancies in comparison with normal distribution N(x,μ,s) is depicted in corresponding figures. For LV‘14 quasi-geoid model the standard deviation of discrepancies is 3.2 cm, 75% of discrepancies x ≤ 3.2 cm. For LV98 quasigeoid model the standard deviation of discrepancies is 4.7 cm, 80% of discrepancies x ≤ 6 cm. Without doubt, the newly developed LV‘14 quasi-geoid model is of higher quality.

Details

ISSN :
20297009 and 20296991
Volume :
42
Database :
OpenAIRE
Journal :
Geodesy and cartography
Accession number :
edsair.doi.dedup.....4673fcdca5dd9a7d8950fee8b52360f4
Full Text :
https://doi.org/10.3846/20296991.2016.1168009