Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter
Radiometric Terrain Corrected (RTC) gamma nought backscatter, which was introduced around a decade ago, has evolved into the standard for analysis-ready Synthetic Aperture Radar (SAR) data. While working with RTC backscatter data is particularly advantageous over undulated terrain, it requires subst...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-07-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/23/13/6072 |
| _version_ | 1797435969952022528 |
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| author | Claudio Navacchi Senmao Cao Bernhard Bauer-Marschallinger Paul Snoeij David Small Wolfgang Wagner |
| author_facet | Claudio Navacchi Senmao Cao Bernhard Bauer-Marschallinger Paul Snoeij David Small Wolfgang Wagner |
| author_sort | Claudio Navacchi |
| collection | DOAJ |
| description | Radiometric Terrain Corrected (RTC) gamma nought backscatter, which was introduced around a decade ago, has evolved into the standard for analysis-ready Synthetic Aperture Radar (SAR) data. While working with RTC backscatter data is particularly advantageous over undulated terrain, it requires substantial computing resources given that the terrain flattening is more computationally demanding than simple orthorectification. The extra computation may become problematic when working with large SAR datasets such as the one provided by the Sentinel-1 mission. In this study, we examine existing Sentinel-1 RTC pre-processing workflows and assess ways to reduce processing and storage overheads by considering the satellite’s high orbital stability. By propagating Sentinel-1’s orbital deviations through the complete pre-processing chain, we show that the local contributing area and the shadow mask can be assumed to be static for each relative orbit. Providing them as a combined external static layer to the pre-processing workflow, and streamlining the transformations between ground and orbit geometry, reduces the overall processing times by half. We conducted our experiments with our in-house developed toolbox named <i>wizsard</i>, which allowed us to analyse various aspects of RTC, specifically run time performance, oversampling, and radiometric quality. Compared to the Sentinel Application Platform (SNAP) this implementation allowed speeding up processing by factors of 10–50. The findings of this study are not just relevant for Sentinel-1 but for all SAR missions with high spatio-temporal coverage and orbital stability. |
| first_indexed | 2024-03-09T10:55:56Z |
| format | Article |
| id | doaj.art-11ec266c65dd4821808c62f0782e0392 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-09T10:55:56Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-11ec266c65dd4821808c62f0782e03922023-12-01T01:36:14ZengMDPI AGSensors1424-82202023-07-012313607210.3390/s23136072Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought BackscatterClaudio Navacchi0Senmao Cao1Bernhard Bauer-Marschallinger2Paul Snoeij3David Small4Wolfgang Wagner5Department of Geodesy and Geoinformation, TU Wien, 1040 Vienna, AustriaEarth Observation Data Centre for Water Resources Monitoring (EODC), 1030 Vienna, AustriaDepartment of Geodesy and Geoinformation, TU Wien, 1040 Vienna, AustriaV.O.F. APSS, 4725 SJ Wouwse Plantage, The NetherlandsDepartment of Geography, University of Zurich, CH-8057 Zurich, SwitzerlandDepartment of Geodesy and Geoinformation, TU Wien, 1040 Vienna, AustriaRadiometric Terrain Corrected (RTC) gamma nought backscatter, which was introduced around a decade ago, has evolved into the standard for analysis-ready Synthetic Aperture Radar (SAR) data. While working with RTC backscatter data is particularly advantageous over undulated terrain, it requires substantial computing resources given that the terrain flattening is more computationally demanding than simple orthorectification. The extra computation may become problematic when working with large SAR datasets such as the one provided by the Sentinel-1 mission. In this study, we examine existing Sentinel-1 RTC pre-processing workflows and assess ways to reduce processing and storage overheads by considering the satellite’s high orbital stability. By propagating Sentinel-1’s orbital deviations through the complete pre-processing chain, we show that the local contributing area and the shadow mask can be assumed to be static for each relative orbit. Providing them as a combined external static layer to the pre-processing workflow, and streamlining the transformations between ground and orbit geometry, reduces the overall processing times by half. We conducted our experiments with our in-house developed toolbox named <i>wizsard</i>, which allowed us to analyse various aspects of RTC, specifically run time performance, oversampling, and radiometric quality. Compared to the Sentinel Application Platform (SNAP) this implementation allowed speeding up processing by factors of 10–50. The findings of this study are not just relevant for Sentinel-1 but for all SAR missions with high spatio-temporal coverage and orbital stability.https://www.mdpi.com/1424-8220/23/13/6072Sentinel-1Synthetic Aperture Radar (SAR)Ground Range Detected (GRD)georeferencingorbital tuberadiometric terrain correction (RTC) |
| spellingShingle | Claudio Navacchi Senmao Cao Bernhard Bauer-Marschallinger Paul Snoeij David Small Wolfgang Wagner Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter Sensors Sentinel-1 Synthetic Aperture Radar (SAR) Ground Range Detected (GRD) georeferencing orbital tube radiometric terrain correction (RTC) |
| title | Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter |
| title_full | Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter |
| title_fullStr | Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter |
| title_full_unstemmed | Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter |
| title_short | Utilising Sentinel-1’s Orbital Stability for Efficient Pre-Processing of Radiometric Terrain Corrected Gamma Nought Backscatter |
| title_sort | utilising sentinel 1 s orbital stability for efficient pre processing of radiometric terrain corrected gamma nought backscatter |
| topic | Sentinel-1 Synthetic Aperture Radar (SAR) Ground Range Detected (GRD) georeferencing orbital tube radiometric terrain correction (RTC) |
| url | https://www.mdpi.com/1424-8220/23/13/6072 |
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