The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data

The merging of a gravimetric quasigeoid model with GPS-levelling data using second-generation wavelets is considered so as to provide better transformation of GPS ellipsoidal heights to normal heights. Since GPS-levelling data are irregular in the space domain and the classical wavelet transform rel...

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Main Authors: Soltanpour, A., Nahavandchi, H., Featherstone, Will
Format: Journal Article
Published: Springer - Verlag 2006
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/39267
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author Soltanpour, A.
Nahavandchi, H.
Featherstone, Will
author_facet Soltanpour, A.
Nahavandchi, H.
Featherstone, Will
author_sort Soltanpour, A.
building Curtin Institutional Repository
collection Online Access
description The merging of a gravimetric quasigeoid model with GPS-levelling data using second-generation wavelets is considered so as to provide better transformation of GPS ellipsoidal heights to normal heights. Since GPS-levelling data are irregular in the space domain and the classical wavelet transform relies on Fourier theory, which is unable to deal with irregular data sets without prior gridding, the classical wavelet transform is not directly applicable to this problem. Instead, second-generation wavelets and their associated lifting scheme, which do not require regularly spaced data, are used to combine gravimetric quasigeoid models and GPS-levelling data over Norway and Australia, and the results are cross-validated. Cross-validation means that GPS-levelling points not used in the merging are used to assess the results, where one point is omitted from the merging and used to test the merged surface, which is repeated for all points in the dataset. The wavelet-based results are also compared to those from least squares collocation (LSC) merging. This comparison shows that the second-generation wavelet method can be used instead of LSC with similar results, but the assumption of stationarity for LSC is not required in the wavelet method. Specifically, it is not necessary to (somewhat arbitrarily) remove trends from the data before applying the wavelet method, as is the case for LSC. It is also shown that the wavelet method is better at decreasing the maximum and minimum differences between the merged geoid and the cross-validating GPS-levelling data.
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institution Curtin University Malaysia
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spelling curtin-20.500.11937-392672019-02-19T05:35:17Z The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data Soltanpour, A. Nahavandchi, H. Featherstone, Will Second generation wavelets Quasigeoid Lifting scheme GPS-levelling Geoid Least squares collocation (LSC) Cross-validation The merging of a gravimetric quasigeoid model with GPS-levelling data using second-generation wavelets is considered so as to provide better transformation of GPS ellipsoidal heights to normal heights. Since GPS-levelling data are irregular in the space domain and the classical wavelet transform relies on Fourier theory, which is unable to deal with irregular data sets without prior gridding, the classical wavelet transform is not directly applicable to this problem. Instead, second-generation wavelets and their associated lifting scheme, which do not require regularly spaced data, are used to combine gravimetric quasigeoid models and GPS-levelling data over Norway and Australia, and the results are cross-validated. Cross-validation means that GPS-levelling points not used in the merging are used to assess the results, where one point is omitted from the merging and used to test the merged surface, which is repeated for all points in the dataset. The wavelet-based results are also compared to those from least squares collocation (LSC) merging. This comparison shows that the second-generation wavelet method can be used instead of LSC with similar results, but the assumption of stationarity for LSC is not required in the wavelet method. Specifically, it is not necessary to (somewhat arbitrarily) remove trends from the data before applying the wavelet method, as is the case for LSC. It is also shown that the wavelet method is better at decreasing the maximum and minimum differences between the merged geoid and the cross-validating GPS-levelling data. 2006 Journal Article http://hdl.handle.net/20.500.11937/39267 10.1007/s00190-006-0033-0 Springer - Verlag fulltext
spellingShingle Second generation wavelets
Quasigeoid
Lifting scheme
GPS-levelling
Geoid
Least squares collocation (LSC)
Cross-validation
Soltanpour, A.
Nahavandchi, H.
Featherstone, Will
The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data
title The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data
title_full The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data
title_fullStr The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data
title_full_unstemmed The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data
title_short The Use of Second-Generation Wavelets to Combine a Gravimetric Quasigeoid Model with GPS-Levelling Data
title_sort use of second-generation wavelets to combine a gravimetric quasigeoid model with gps-levelling data
topic Second generation wavelets
Quasigeoid
Lifting scheme
GPS-levelling
Geoid
Least squares collocation (LSC)
Cross-validation
url http://hdl.handle.net/20.500.11937/39267