Practical Considerations before Installing Ground-Based Geodetic Infrastructure for Integrated InSAR and cGNSS Monitoring of Vertical Land Motion

Sensors

Will E. Featherstone¹  Amy L. Parker¹  Mick S. Filmer¹  Matthew C. Garthwaite²  Nigel T. Penna³ 

[1] Department of Spatial Sciences and the Institute for Geoscience Research, Curtin University of Technology, GPO Box U1987, Perth 6845, Australia;Geodesy Section, Community Safety and Earth Monitoring Division, Geoscience Australia, GPO Box 378, Canberra 2601, Australia;School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK;

关键词: vertical land motion;    InSAR;    corner reflectors;    continuous GNSS;    TerraSAR-X;    sentinel-1;    geodetic networks;    displacement monitoring;   

DOI  :  10.3390/s17081753

来源: DOAJ

【 摘 要 】

Continuously operating Global Navigation Satellite Systems (cGNSS) can be used to convert relative values of vertical land motion (VLM) derived from Interferometric Synthetic Aperture Radar (InSAR) to absolute values in a global or regional reference frame. Artificial trihedral corner reflectors (CRs) provide high-intensity and temporally stable reflections in SAR time series imagery, more so than naturally occurring permanent scatterers. Therefore, it is logical to co-locate CRs with cGNSS as ground-based geodetic infrastructure for the integrated monitoring of VLM. We describe the practical considerations for such co-locations using four case-study examples from Perth, Australia. After basic initial considerations such as land access, sky visibility and security, temporary test deployments of co-located CRs with cGNSS should be analysed together to determine site suitability. Signal to clutter ratios from SAR imagery are used to determine potential sites for placement of the CR. A significant concern is whether the co-location of a deliberately designed reflecting object generates unwanted multipath (reflected signals) in the cGNSS data. To mitigate against this, we located CRs >30 m from the cGNSS with no inter-visibility. Daily RMS values of the zero-difference ionosphere-free carrier-phase residuals, and ellipsoidal heights from static precise point positioning GNSS processing at each co-located site were then used to ascertain that the CR did not generate unwanted cGNSS multipath. These steps form a set of recommendations for the installation of such geodetic ground-infrastructure, which may be of use to others wishing to establish integrated InSAR-cGNSS monitoring of VLM elsewhere.

【 授权许可】

Unknown