The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay
Global navigation satellite systems (GNSSs) have become an important tool for remotely sensing water vapor in the atmosphere. In GNSS data processing, mapping functions and gradient models are needed to map the zenith tropospheric delay (ZTD) to the slant total tropospheric delay (STD) along a signa...
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ftmdpi:oai:mdpi.com:/2072-4292/12/1/130/ 2023-08-20T04:08:38+02:00 The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan agris 2020-01-01 application/pdf https://doi.org/10.3390/rs12010130 EN eng Multidisciplinary Digital Publishing Institute Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs12010130 https://creativecommons.org/licenses/by/4.0/ Remote Sensing; Volume 12; Issue 1; Pages: 130 tropospheric delay mapping function gradient models bending effect Text 2020 ftmdpi https://doi.org/10.3390/rs12010130 2023-07-31T22:57:21Z Global navigation satellite systems (GNSSs) have become an important tool for remotely sensing water vapor in the atmosphere. In GNSS data processing, mapping functions and gradient models are needed to map the zenith tropospheric delay (ZTD) to the slant total tropospheric delay (STD) along a signal path. Therefore, it is essential to investigate the spatial–temporal performance of various mapping functions and gradient models in the determination of STD. In this study, the STDs at nine elevations were first calculated by applying the ray-tracing method to the atmospheric European Reanalysis-Interim (ERA—Interim) dataset. These STDs were then used as the reference to study the accuracy of the STDs that determined the ZTD together with mapping functions and gradient models. The performance of three mapping functions (i.e., Niell mapping function (NMF), global mapping function (GMF), and Vienna mapping function (VMF1)) and three gradient models (i.e., Chen, MacMillan, and Meindl) in six regions (the temperate zone, Qinghai–Tibet Plateau, Equator, Sahara Desert, Amazon Rainforest, and North Pole) in determining slant tropospheric delay was investigated in this study. The results indicate that the three mapping functions have relatively similar performance above a 15° elevation, but below a 15° elevation, VMF1 clearly performed better than the GMF and NMF. The results also show that, if no gradient model is included, the root-mean-square (RMS) of the STD is smaller than 2 mm above the 30° elevation and smaller than 9 mm above the 15° elevation but shows a significant increase below the 15° elevation. For example, in the temperate zone, the RMS increases from approximately 35 mm at the 10° elevation to approximately 160 mm at the 3° elevation. The inclusion of gradient models can significantly improve the accuracy of STDs by 50%. All three gradient models performed similarly at all elevations and in all regions. The bending effect was also investigated, and the results indicate that the tropospheric delay caused by ... Text North Pole MDPI Open Access Publishing North Pole Remote Sensing 12 1 130 |
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English |
topic |
tropospheric delay mapping function gradient models bending effect |
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tropospheric delay mapping function gradient models bending effect Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
topic_facet |
tropospheric delay mapping function gradient models bending effect |
description |
Global navigation satellite systems (GNSSs) have become an important tool for remotely sensing water vapor in the atmosphere. In GNSS data processing, mapping functions and gradient models are needed to map the zenith tropospheric delay (ZTD) to the slant total tropospheric delay (STD) along a signal path. Therefore, it is essential to investigate the spatial–temporal performance of various mapping functions and gradient models in the determination of STD. In this study, the STDs at nine elevations were first calculated by applying the ray-tracing method to the atmospheric European Reanalysis-Interim (ERA—Interim) dataset. These STDs were then used as the reference to study the accuracy of the STDs that determined the ZTD together with mapping functions and gradient models. The performance of three mapping functions (i.e., Niell mapping function (NMF), global mapping function (GMF), and Vienna mapping function (VMF1)) and three gradient models (i.e., Chen, MacMillan, and Meindl) in six regions (the temperate zone, Qinghai–Tibet Plateau, Equator, Sahara Desert, Amazon Rainforest, and North Pole) in determining slant tropospheric delay was investigated in this study. The results indicate that the three mapping functions have relatively similar performance above a 15° elevation, but below a 15° elevation, VMF1 clearly performed better than the GMF and NMF. The results also show that, if no gradient model is included, the root-mean-square (RMS) of the STD is smaller than 2 mm above the 30° elevation and smaller than 9 mm above the 15° elevation but shows a significant increase below the 15° elevation. For example, in the temperate zone, the RMS increases from approximately 35 mm at the 10° elevation to approximately 160 mm at the 3° elevation. The inclusion of gradient models can significantly improve the accuracy of STDs by 50%. All three gradient models performed similarly at all elevations and in all regions. The bending effect was also investigated, and the results indicate that the tropospheric delay caused by ... |
format |
Text |
author |
Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan |
author_facet |
Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan |
author_sort |
Cong Qiu |
title |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_short |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_full |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_fullStr |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_full_unstemmed |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_sort |
performance of different mapping functions and gradient models in the determination of slant tropospheric delay |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2020 |
url |
https://doi.org/10.3390/rs12010130 |
op_coverage |
agris |
geographic |
North Pole |
geographic_facet |
North Pole |
genre |
North Pole |
genre_facet |
North Pole |
op_source |
Remote Sensing; Volume 12; Issue 1; Pages: 130 |
op_relation |
Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs12010130 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/rs12010130 |
container_title |
Remote Sensing |
container_volume |
12 |
container_issue |
1 |
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130 |
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1774721005879558144 |