On the statistical tests over Fennoscandian GNSS/levelling networks
In Geodesy and Surveying we work with a large amount of observations which alwayscontains different types of errors. The errors decrease the quality of the observations andpropagate to the results. Therefore, detection and removing the gross errors are of vitalimportance. The Global Navigation Satel...
Main Author: | |
---|---|
Format: | Bachelor Thesis |
Language: | English |
Published: |
KTH, Geodesi och satellitpositionering
2015
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173643 |
id |
ftkthstockholm:oai:DiVA.org:kth-173643 |
---|---|
record_format |
openpolar |
spelling |
ftkthstockholm:oai:DiVA.org:kth-173643 2023-05-15T16:12:14+02:00 On the statistical tests over Fennoscandian GNSS/levelling networks Zoghi, Sedigheh 2015 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173643 eng eng KTH, Geodesi och satellitpositionering TRITA-GIT EX 15-012 http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173643 info:eu-repo/semantics/openAccess Other Civil Engineering Annan samhällsbyggnadsteknik Student thesis info:eu-repo/semantics/bachelorThesis text 2015 ftkthstockholm 2022-08-11T12:28:35Z In Geodesy and Surveying we work with a large amount of observations which alwayscontains different types of errors. The errors decrease the quality of the observations andpropagate to the results. Therefore, detection and removing the gross errors are of vitalimportance. The Global Navigation Satellite Systems (GNSS) can be used to measure theellipsoidal height and by subtracting an existing geoid height from that, the orthometric heightcan be determined. There is a simple linear relation amongst these triple heights, whichcannot be fulfilled due to the presence of different types of error. One of the important sort ofthese errors is gross errors.This study concerns about investigation and detection of blunders or gross errors on the 4346GNSS/levelling points over Fennoscandia. Each country has its own data set with specificprecision. The well-known gravity model EGM08 is used to compute the geoid heights withrespect to WGS84 reference ellipsoid. We have a large amount of data and we expect thattheir errors follow the normal distribution. The main aim of this thesis is to apply some datascreening methods both before and after adjustment process in such a way that the normaldistribution of the data set is achieved by eliminating the erroneous data. This will be done byperforming the pre- and post-adjustment data screening. For the pre-adjustment we performeddata filtering, test of normality of observations and test of their variances for theGNSS/levelling data over Sweden, Denmark, Norway and Finland. We used the 4-, 5- and 7-parameter corrective surfaces for modelling the systematic trends of the differences betweenthe EGM08 geoid model and the ellipsoidal and orthometric height differences. The test ofnormality of residuals, global test of variance, Baarda’s data snooping and Tau test will beperformed after the removal of the trends. Numerical studies show that the GNSS/levellingdata of Sweden, Denmark and Finland are of good qualities, but the claimed errors for thedata are rather optimistic. The situation ... Bachelor Thesis Fennoscandia Fennoscandian Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA Norway |
institution |
Open Polar |
collection |
Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
op_collection_id |
ftkthstockholm |
language |
English |
topic |
Other Civil Engineering Annan samhällsbyggnadsteknik |
spellingShingle |
Other Civil Engineering Annan samhällsbyggnadsteknik Zoghi, Sedigheh On the statistical tests over Fennoscandian GNSS/levelling networks |
topic_facet |
Other Civil Engineering Annan samhällsbyggnadsteknik |
description |
In Geodesy and Surveying we work with a large amount of observations which alwayscontains different types of errors. The errors decrease the quality of the observations andpropagate to the results. Therefore, detection and removing the gross errors are of vitalimportance. The Global Navigation Satellite Systems (GNSS) can be used to measure theellipsoidal height and by subtracting an existing geoid height from that, the orthometric heightcan be determined. There is a simple linear relation amongst these triple heights, whichcannot be fulfilled due to the presence of different types of error. One of the important sort ofthese errors is gross errors.This study concerns about investigation and detection of blunders or gross errors on the 4346GNSS/levelling points over Fennoscandia. Each country has its own data set with specificprecision. The well-known gravity model EGM08 is used to compute the geoid heights withrespect to WGS84 reference ellipsoid. We have a large amount of data and we expect thattheir errors follow the normal distribution. The main aim of this thesis is to apply some datascreening methods both before and after adjustment process in such a way that the normaldistribution of the data set is achieved by eliminating the erroneous data. This will be done byperforming the pre- and post-adjustment data screening. For the pre-adjustment we performeddata filtering, test of normality of observations and test of their variances for theGNSS/levelling data over Sweden, Denmark, Norway and Finland. We used the 4-, 5- and 7-parameter corrective surfaces for modelling the systematic trends of the differences betweenthe EGM08 geoid model and the ellipsoidal and orthometric height differences. The test ofnormality of residuals, global test of variance, Baarda’s data snooping and Tau test will beperformed after the removal of the trends. Numerical studies show that the GNSS/levellingdata of Sweden, Denmark and Finland are of good qualities, but the claimed errors for thedata are rather optimistic. The situation ... |
format |
Bachelor Thesis |
author |
Zoghi, Sedigheh |
author_facet |
Zoghi, Sedigheh |
author_sort |
Zoghi, Sedigheh |
title |
On the statistical tests over Fennoscandian GNSS/levelling networks |
title_short |
On the statistical tests over Fennoscandian GNSS/levelling networks |
title_full |
On the statistical tests over Fennoscandian GNSS/levelling networks |
title_fullStr |
On the statistical tests over Fennoscandian GNSS/levelling networks |
title_full_unstemmed |
On the statistical tests over Fennoscandian GNSS/levelling networks |
title_sort |
on the statistical tests over fennoscandian gnss/levelling networks |
publisher |
KTH, Geodesi och satellitpositionering |
publishDate |
2015 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173643 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Fennoscandia Fennoscandian |
genre_facet |
Fennoscandia Fennoscandian |
op_relation |
TRITA-GIT EX 15-012 http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173643 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1765997499075526656 |