The Design of Radar Corner Reflectors for the Australian Geophysical Observing System: a single design suitable for InSAR deformation monitoring and SAR calibration at multiple microwave frequency bands.

Garthwaite, Matthew C.; Nancarrow, S.; Hislop, A.; Thankappan, Medhavy; Dawson, John; Lawrie, Sarah

doi:10.11636/record.2015.003

Cited by 30 publications

(40 citation statements)

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“…The Surat Basin (Figure 3b), a topographically flat (height differences of~320 to 480 m AHD) dryland agricultural area in eastern Australia. This site is also used for radiometric and geometric calibration of SAR satellites including the Sentinel-1 constellation, through a permanent corner reflector array deployed there [32].…”

Section: Assessment Of Suitability Of Snap Toolbox For Australian Sarmentioning

confidence: 99%

“…Note that all Sentinel-1 scenes are VV, with the exception of a scene in the Surat Basin, which is HH. This is a Sentinel-1B scene in ascending mode, which was selected to assess the γ 0 image's absolute geometric accuracy due to the availability of an accurately characterized corner reflector within this scene [32]. GAMMA and SNAP software were used to produce radiometrically terrain corrected Sentinel-1 γ 0 backscatter products for Lake Eucumbene and Surat Basin study sites, both using the same input parameters and the same DEM (the refined GA_DEM).…”

Section: Assessment Of Suitability Of Snap Toolbox For Australian Sarmentioning

confidence: 99%

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Building a SAR-Enabled Data Cube Capability in Australia Using SAR Analysis Ready Data

Ticehurst

Zhou

Lehmann

et al. 2019

Data

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A research alliance between the Commonwealth Scientific and Industrial Research Organization and Geoscience Australia was established in relation to Digital Earth Australia, to develop a Synthetic Aperture Radar (SAR)-enabled Data Cube capability for Australia. This project has been developing SAR analysis ready data (ARD) products, including normalized radar backscatter (gamma nought, γ0), eigenvector-based dual-polarization decomposition and interferometric coherence, all generated from the European Space Agency (ESA) Sentinel-1 interferometric wide swath mode data available on the Copernicus Australasia Regional Data Hub. These are produced using the open source ESA SNAP toolbox. The processing workflows are described, along with a comparison of the γ0 backscatter and interferometric coherence ARD produced using SNAP and the proprietary software GAMMA. This comparison also evaluates the effects on γ0 backscatter due to variations related to: Near- and far-range look angles; SNAP’s default Shuttle Radar Topography Mission (SRTM) DEM and a refined Australia-wide DEM; as well as terrain. The agreement between SNAP and GAMMA is generally good, but also presents some systematic geometric and radiometric differences. The difference between SNAP’s default SRTM DEM and the refined DEM showed a small geometric shift along the radar view direction. The systematic geometric and radiometric issues detected can however be expected to have negligible effects on analysis, provided products from the two processors and two DEMs are used separately and not mixed within the same analysis. The results lead to the conclusion that the SNAP toolbox is suitable for producing the Sentinel-1 ARD products.

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Section: Assessment Of Suitability Of Snap Toolbox For Australian Sarmentioning

confidence: 99%

Section: Assessment Of Suitability Of Snap Toolbox For Australian Sarmentioning

confidence: 99%

Building a SAR-Enabled Data Cube Capability in Australia Using SAR Analysis Ready Data

Ticehurst

Zhou

Lehmann

et al. 2019

Data

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“…When deployed, the CR must be orientated such that the azimuth and elevation of the boresight vector (originating from the intersection of the three triangular plates) is directed in the SAR satellite’s LoS. This can be achieved using the freely available, physics-based Systems Tool Kit modelling environment [ 60 ], and the procedures described in [ 61 ], to account for the orbit and look angle of the SAR sensor, and the location of CR deployment. Orientation parameters were initially calculated for descending (north to south) passes of TSX, which was the only SAR satellite operating over Perth at the beginning of this study.…”

Section: Practical Considerations For Installing Geodetic Infrastrmentioning

confidence: 99%

“…Orientation parameters were initially calculated for descending (north to south) passes of TSX, which was the only SAR satellite operating over Perth at the beginning of this study. However, TSX and Sentinel-1B, which became available in September 2016, have a similar orbital configuration (i.e., right-looking SAR instrument in a descending pass) and look angles (~32° to ~36°), therefore the orientation parameters are within the alignment accuracy (few degrees [ 61 ]) and are applicable to descending passes of both missions.…”

Section: Practical Considerations For Installing Geodetic Infrastrmentioning

confidence: 99%

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

Parker

Featherstone

Penna

et al. 2017

Sensors

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Abstract: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.

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“…Previous studies [3][4][5][6], primarily consider the effect of reflections, and/or the characteristics of target limitations in disturbance analysis. Previous studies [3][4][5][6] do not consider the whole effect of interference because the tests were conducted in the controlled conditions at good test facilities, such as the 'St. Kilda ground reflection range' , or at other sites, such as 'an area in the north Canberra in the Australian Capital Territory' [4].…”

Section: Introductionmentioning

confidence: 99%

Interference Analysis for Synthetic Aperture Radar Calibration Sites with Triangular Trihedral Corner Reflectors

Shin¹,

Ra²

2016

International Journal of Aeronautical and Space Sciences

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The typical method for performing an absolute radiometric calibration of a Synthetic Aperture Radar (SAR) System is to analyze its response, without interference, to a target with a known Radar Cross Section (RCS). To minimize interference, an error-free calibration site for a Corner Reflector (CR) is required on a wide and flat plain or on an area without disturbance sources (such as ground objects). However, in reality, due to expense and lack of availability for long periods, it is difficult to identify such a site. An alternative solution is the use of a Triangular Trihedral Corner Reflector (TTCR) site, with a surrounding protection wall consisting of berms and a hollow. It is possible in this scenario, to create the minimum criteria for an effectively error-free site involving a conventional object-tip reflection applied to all beams. Sidelobe interference by the berm is considered to be the major disturbance factor. Total interference, including an object-tip reflection and a sidelobe interference, is analyzed experimentally with SAR images. The results provide a new guideline for the minimum criteria of TTCR site design that require, at least, the removal of all ground objects within the fifth sidelobe.

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The Design of Radar Corner Reflectors for the Australian Geophysical Observing System: a single design suitable for InSAR deformation monitoring and SAR calibration at multiple microwave frequency bands.

Cited by 30 publications

References 0 publications

Building a SAR-Enabled Data Cube Capability in Australia Using SAR Analysis Ready Data

Building a SAR-Enabled Data Cube Capability in Australia Using SAR Analysis Ready Data

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

Interference Analysis for Synthetic Aperture Radar Calibration Sites with Triangular Trihedral Corner Reflectors

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