Acta Geodaetica et Cartographica Sinica ›› 2025, Vol. 54 ›› Issue (10): 1786-1797.doi: 10.11947/j.AGCS.2025.20250124

• Geodesy and Navigation • Previous Articles     Next Articles

GNSS-assisted InSAR tropospheric delay correction model incorporating vertical stratification and turbulent components

Hailu CHEN(), Yunzhong SHEN()   

  1. College of Surveying and Geo-Informatics, Tongji University, Shanghai 200092, China
  • Received:2025-03-28 Revised:2025-07-09 Online:2025-11-14 Published:2025-11-14
  • Contact: Yunzhong SHEN E-mail:2210929@tongji.edu.cn;yzshen@tongji.edu.cn
  • About author:CHEN Hailu (1996—), male, PhD candidate, majors in InSAR data processing. E-mail: 2210929@tongji.edu.cn
  • Supported by:
    The National Natural Science Foundation of China(42274005)

Abstract:

GNSS reference station observed tropospheric delays are commonly employed to correct tropospheric delays in InSAR, which involves spatially interpolating the GNSS-observed delays to unmeasured locations. Traditional methods focus solely on the spatial correlation characteristics of turbulent components, achieve interferogram correction through functional or stochastic modeling while neglecting the stratified component. This study proposes a joint correction model that accounts for both stratified and turbulent delay components. Specifically, an elevation-dependent functional model and a stochastic model are adopted to absorb stratified and turbulent delay components, respectively. The deterministic parameters of stratified component and random turbulence at the GNSS-measured points are simultaneously resolved via least squares collocation. Finally, predict them to unmeasured points. Validation using 71 Sentinel-1 datasets over Southern California demonstrates that the proposed method reduces the average standard deviation (STD) of 70 short temporal baseline interferograms from 4.7 rad to 1.4 rad, outperforming both GACOS (average STD reduced to 2.7 rad), linear model (average STD reduced to 4.1 rad), GInSAR (average STD reduced to 2.9 rad) and LSC-GInSAR (average STD reduced to 1.8 rad) corrections. The derived deformation velocity reveals regional long-wavelength deformation pattern that agrees well with GNSS measurements (correlation coefficient is 0.67). These results confirm that the proposed approach can effectively correct medium-to-long-wavelength tropospheric delays in interferogram and is suitable for measuring large-scale deformation signals.

Key words: InSAR, global navigation satellite system, tropospheric delays, least squares collocation, variance component estimation

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