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Pre-analysis of GNSS water vapor tomography based on analysis of the models space resolution matrix with various combinations of GNSS satellites observations
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Elaheh Sadeghi *   , Masoud Mashhadi Hossainali , Abdolreza Safari |
| University of Tehran |
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Abstract: (334 Views) |
Water vapor has an obvious role in the hydrological cycle and plays a key role in energy transport. Therefore, monitoring and determining its changes and distribution is demanding. In voxel-based tropospheric tomography, water vapor is computed for a set of voxels, each covering a specific part of the troposphere. One of the fundamental flaws in GPS tomography is the absence or insufficiency of signals in some voxels. To evaluate the performance of tomography models, it is necessary to analysis the validity of the proposed model before implementing it. In this study, the efficacy of two elements has been investigated in tomography models: using the observed various GNSS combined strategies and changing the horizontal resolution of the tomography model had been investigated to improve the validation of tomography model. In this research, we use the resolution matrix and the spread of the resolution matrix to provide a quality measure without using the reference field as radiosonde data. The results show that all of GNSS observations can increase the quality of efficiency tomographic model but not as well as was expected. To give an instance, the design matrix rank deficiency of tomography model with 40 km horizontal resolution, has been improved just 7% on the study day, while the amount of observations 65% increased when we used all active satellites. Against, increasing the horizontal resolution caused to increase the quality of tomography models. So that, the values of spread decrease from 0.2 to 0.04, when just GPS observations were used. Therefore, increasing observations when using available techniques such as optimal horizontal resolution can be important for the tomography.
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| Keywords: GNSS tomography, design matrix, resolution matrix, spread function |
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Full-Text [PDF 826 kb]
(119 Downloads)
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Type of Study: Research |
Subject:
Geodesy
Received: 2022/09/13 | Accepted: 2022/12/26 | ePublished ahead of print: 2024/02/18 | Published: 2024/03/4
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