The Potential for Unifying Global‐Scale Satellite Measurements of Ground Displacements Using Radio Telescopes

Parker, Amy; McCallum, Lucia; Featherstone, Will; McCallum, Jamie; Haas, Rüdiger

doi:10.1029/2019gl084915

Cited by 4 publications

(2 citation statements)

References 43 publications

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“…In light of the increased use of InSAR as a geodetic tool to monitor anthropogenic activities, networks of artificial corner reflectors have been installed to act as persistent high-amplitude reflections in SAR imagery and ties to Australia's growing ground-based GNSS infrastructure (e.g., Surat Basin: [60]; Perth: [15]; southwest Sydney: [81]). Combining InSAR with absolute geodetic techniques acts to validate the measurements and enable the integration of relative InSAR displacement maps into absolute reference frames defined by the GNSS sites (e.g., [82]), with proposed extensions of this approach to the Australian (and global) network of Very Long Baseline Interferometry telescopes [83].…”

Section: Discussion: Future Opportunities For Developing the Role Of Sar For Hazard Monitoring In Australiamentioning

confidence: 99%

Applications of Satellite Radar Imagery for Hazard Monitoring: Insights from Australia

et al. 2021

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Earth observation (EO) satellites facilitate hazard monitoring and mapping over large-scale and remote areas. Despite Synthetic Aperture Radar (SAR) satellites being well-documented as a hazard monitoring tool, the uptake of these data is geographically variable, with the Australian continent being one example where the use of SAR data is limited. Consequently, less is known about how these data apply in the Australian context, how they could aid national hazard monitoring and assessment, and what new insights could be gleaned for the benefit of the international disaster risk reduction community. The European Space Agency Sentinel-1 satellite mission now provides the first spatially and temporally complete global SAR dataset and the first opportunity to use these data to systematically assess hazards in new locations. Using the example of Australia, where floods and uncontrolled bushfires, earthquakes, resource extraction (groundwater, mining, hydrocarbons) and geomorphological changes each pose potential risks to communities, we review past usage of EO for hazard monitoring and present a suite of new case studies that demonstrate the potential added benefits of SAR. The outcomes provide a baseline understanding of the potential role of SAR in national hazard monitoring and assessment in an Australian context. Future opportunities to improve national hazard identification will arise from: new SAR sensing capabilities, which for Australia includes a first-ever civilian EO capability, NovaSAR-1; the integration of Sentinel-1 SAR with other EO datasets; and the provision of standardised SAR products via Analysis Ready Data and Open Data Cubes to support operational applications.

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Section: Discussion: Future Opportunities For Developing the Role Of Sar For Hazard Monitoring In Australiamentioning

confidence: 99%

Applications of Satellite Radar Imagery for Hazard Monitoring: Insights from Australia

et al. 2021

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“…However, transponders have not been widely used due to limited availability and costs, and the installation of CRs can be problematic given their size and shape and a potential need for monitoring by repeat ground survey. A method for InSAR connection to a global TRF was suggested by Parker et al (2019) where ties could be made to very long baseline interferometry (VLBI) antenna across land masses separated by ocean. However, this is not practical for local or regional studies because global distribution of VLBI antennas is sparse (e.g., there are only three VLBI stations in Australia).…”

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confidence: 99%

Evaluation of methods for connecting InSAR to a terrestrial reference frame in the Latrobe Valley, Australia

Johnston

Filmer

Fuhrmann

2021

J Geod

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Deformation measurements from satellite-borne synthetic aperture radar interferometry (InSAR) are usually measured relative to an arbitrary reference point (RP) of assumed stability over time. For InSAR rates to be reliably interpreted as uplift or subsidence, they must be connected to a defined Earth-centred terrestrial reference frame (TRF), usually made through GNSS continuously operating reference stations (CORS). We adapt and compare three methods of TRF connection proposed by different studies which we term the single CORS RP (SCRP), plane-fit multiple CORS (PFMC), and the multiple CORS RP (MCRP). We generalise equations for these methods, and importantly, develop equations to propagate InSAR and GNSS uncertainties through the transformation process. This is significant, because it is important to not only estimate the InSAR uncertainties, but also to account for the uncertainties that are introduced when connecting to the CORS to better inform our interpretation of the deformation field and the limitation of the measurements. We then test these methods using Sentinel-1 data in the Latrobe Valley, Australia. These results indicate that differences among the three TRF connection methods may be greater than their estimated uncertainties. MCRP appears the most reliable method, although it may be limited in large study areas with sparse CORS due to long wavelength errors and that gaps and/or steps may appear at the spatial limit from the CORS. SCRP relies on the quality of the single CORS connection, but can be validated by unconnected CORS in the study area. The PFMC method is suited to larger areas undergoing slow, constant deformation covering large spatial extents where there are evenly distributed CORS across the study area. Selecting an optimal method of TRF connection is dependent on local site conditions, CORS network geometry and the characteristics of the deformation field. Hence, the choice of TRF connection method should be carefully considered, because different methods may result in significantly different transformed deformation rates. We confirm slow subsidence across the Latrobe Valley relative to the vertical component of the ITRF2014, with localised high subsidence rates near open cut mining activities. Subsidence of ~ -6mm/yr is observed in the adjacent coastal region which may exacerbate relative sea level rise along the coastline, increasing future risks of coastal inundation.

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Practical Considerations of VLBI Observations to the GENESIS Mission

Schunck,

McCallum,

Molera Calvés

2024

International Association of Geodesy Symposia

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With the GENESIS proposal accepted, this study reevaluates the implementability of incorporating VLBI observations of satellites into geodetic VLBI experiments. Observations of NavIC system satellites were carried out using the 12-m AuScope radio telescopes in Hobart and Katherine. The primary focus is on scrutinizing the necessary efforts within the VLBI community aimed at effectively supporting the GENESIS satellite mission. Our investigation identifies limitations in the existing processing pipelines, particularly in the generation of station-specific procedure and local control files, as well as in satellite tracking support within the antenna control units, resulting in step-wise tracking rather than continuous tracking. Additionally, we have conducted an analysis to ascertain the effective visibility of the GENESIS satellite within both current and future VLBI networks. Our findings align with the envisioned visibility criteria of GENESIS when more VGOS-type stations are integrated into the current network. In this case, the satellite becomes visible from at least two stations with long baselines for approximately 75.6% of the time during experiments and 21.5% of the time in a year.

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The Potential for Unifying Global‐Scale Satellite Measurements of Ground Displacements Using Radio Telescopes

Cited by 4 publications

References 43 publications

Applications of Satellite Radar Imagery for Hazard Monitoring: Insights from Australia

Applications of Satellite Radar Imagery for Hazard Monitoring: Insights from Australia

Evaluation of methods for connecting InSAR to a terrestrial reference frame in the Latrobe Valley, Australia

Practical Considerations of VLBI Observations to the GENESIS Mission

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