Open Access

ARTICLE

Atmospheric Delay Correction Using GNSS and GACOS Data in InSAR Land Subsidence Monitoring over Banting, Selangor

Mohd Hakimi Abdul Rahman¹, Amir Sharifuddin Ab Latip^1,*, Zulkiflee Abd Latif^1,2, Siti Balqis Mohd Tun¹, Nur Azlina Hariffin¹, Mohd Fikri Razali³

1 Centre of Studies for Surveying Science and Geomatics, Faculty of Built Environment, Universiti Teknologi Mara (UiTM), Shah Alam, 40450, Selangor, Malaysia
2 Institute for Biodiversity and Sustainable Development (IBSD), Universiti Teknologi Mara (UiTM), Shah Alam, 40450, Selangor, Malaysia
3 Malaysian Space Agency (MYSA), No. 13 Jalan Tun Ismail, Kuala Lumpur, 50480, Malaysia

* Corresponding Author: Amir Sharifuddin Ab Latip. Email:

(This article belongs to the Special Issue: Innovative Applications and Developments in Geomatics Technology)

Revue Internationale de Géomatique 2025, 34, 959-972. https://doi.org/10.32604/rig.2025.071109

Received 31 July 2025; Accepted 17 November 2025; Issue published 12 December 2025

Abstract

Atmospheric phase delay, primarily caused by water vapor in the troposphere, is a major source of error in InSAR measurements, especially for land subsidence monitoring. This study integrates GNSS and GACOS data to correct tropospheric delay and enhance InSAR accuracy in Banting, Selangor. A total of 27 Sentinel-1A images, 14 GNSS stations, and 27 corresponding GACOS ZTD maps were used to monitor subsidence between 2023 and 2025. The InSAR data were processed using SNAP, StaMPS, and the TRAIN toolbox, incorporating both GNSS- and GACOS-derived ZTD corrections. The results show that applying atmospheric correction improved the estimated deformation range from −14.9 mm/year (min) and 9.1 mm/year (max) to −14.7 and 9.2 mm/year using GACOS ZTD. Further enhancement was achieved by integrating GNSS and GACOS ZTD, resulting in deformation estimates ranging from −15.4 to 9.3 mm/year. Validation against reference GNSS data from the MERU MyRTKnet station revealed that the integrated correction yielded the lowest RMSE of 0.025, compared to 0.029 with GACOS-only correction and 0.03 without any correction. Overall, the integration of GNSS- and GACOS-derived atmospheric corrections significantly improved the accuracy of InSAR-based subsidence measurements, offering a promising approach for precise ground deformation monitoring in humid, tropical environments.

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Keywords

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