Training and hands-on SNAP Sentinel-1 IW SLC Interferogram and Displacement
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The document provides an overview of the ESA Research and Service Support (RSS) and its Sentinel-1 interferometry processing service integrated into the Geohazards Exploitation Platform (GEP). The service performs interferometry on Sentinel-1 imagery pairs using the Sentinel Application Platform (SNAP) with predefined parameters. It splits processing across sub-swaths in parallel to generate interferograms, coherence maps, and displacements in about 4 hours. Future improvements may add phase unwrapping and allow customizing DEM and projection settings. Hands-on demonstrations and Q&A were also provided to help users access and understand the service.
![ESA Sentinel 1 mission
• Sentinel-1 [1] is an ESA mission which comprises a constellation of
two polar-orbiting satellites, operating day and night performing C-
band synthetic aperture radar imaging, enabling them to acquire
imagery regardless of the weather.](https://image.slidesharecdn.com/crl-gepmeeting31stmarch2017-170403084045/85/Training-and-hands-on-SNAP-Sentinel-1-IW-SLC-Interferogram-and-Displacement-7-320.jpg)
![TOPSAR
Interferometric Wide Swath
• The Interferometric Wide Swath [2] mode is the main acquisition mode
over land and satisfies the majority of service requirements. It acquires data
with a 250 km swath at 5 m by 20 m spatial resolution (single look). IW mode
captures three sub-swaths using Terrain Observation with Progressive Scans
SAR (TOPSAR).
• With the TOPSAR technique [3], in addition to steering the beam in range as
in ScanSAR, the beam is also electronically steered from backward to forward
in the azimuth direction for each burst, avoiding scalloping and resulting in
homogeneous image quality throughout the swath.](https://image.slidesharecdn.com/crl-gepmeeting31stmarch2017-170403084045/85/Training-and-hands-on-SNAP-Sentinel-1-IW-SLC-Interferogram-and-Displacement-8-320.jpg)
![SAR Interferometry
• Interferometric synthetic aperture radar (InSAR) [4] exploits
the phase difference between two complex radar SAR observations
taken from slightly different sensor positions and extracts
information about the earth‟s surface.
SAR signal‟s phase SAR interferometric phase](https://image.slidesharecdn.com/crl-gepmeeting31stmarch2017-170403084045/85/Training-and-hands-on-SNAP-Sentinel-1-IW-SLC-Interferogram-and-Displacement-9-320.jpg)
![SNAP
• A common architecture for all Sentinel Toolboxes is being jointly developed by
Brockmann Consult, Array Systems Computing and C-S called the Sentinel
Application Platform (SNAP) [5].
• The Sentinel-1 Toolbox (S1TBX) consists of a collection of processing tools,
data product readers and writers and a display and analysis application to
support the large archive of data from ESA SAR missions. The Sentinel-1
Toolbox is being developed for ESA by Array Systems Computing in
partnership with DLR, Brockmann Consult and OceanDataLab.](https://image.slidesharecdn.com/crl-gepmeeting31stmarch2017-170403084045/85/Training-and-hands-on-SNAP-Sentinel-1-IW-SLC-Interferogram-and-Displacement-10-320.jpg)
Training and hands-on SNAP Sentinel-1 IW SLC Interferogram and Displacement
- 1. Training and hands-on SNAP Sentinel-1 IW SLC Interferogram and Displacement CRL - GEP meeting 31st March 2017 Michele Caccia michele.caccia@cgi.com rss_team@esa.int
- 2. • Research Service Support (RSS) introduction • GEP “SNAP Sentinel-1 IW SLC Interferogram and Displacements” service: • Framework introduction • Algorithm overview • Hands on the integrated service in GEP • Examples of obtained results • Overview of the integrated GEP SNAP COIN service • Future improvements • Questions and answers OUTLINE
- 3. RSS Overview: Challenge • How to provide support to the Earth Observation community? • Since 2007, the ESA Research and Service Support (RSS) provides support to the Earth Observation community
- 4. RSS Overview: purpose • ESA Research and Service Support (RSS) provides resources to support Earth Observation data exploitation: • data access/processing by bringing users algorithm close to data • development of new applications and services to generate value- added products
- 5. How RSS helps G-TEP: • GEP processing services integration and maintenance • Support to GEP data sourcing and provisioning • Assistance for EO data results publishing • SBAS S1 GEP service demonstrator operation RSS support to G-TEP
- 6. GEP S-1 interferometry processing service through SNAP • The “SNAP Sentinel-1 IW SLC Interferogram and Displacements” service: • performs SAR interferometry on a pair of Sentinel-1 images (TOPSAR Interferometric Wideswath, Single Look Complex); • has integrated SNAP (SeNtinel Application Platform) to implement the interferometric processing chain; • provides a set of parameters representing a good trade-off between tool customization and configuration complexity. • Thank to this service, GEP users can easily handle the interferometric processing performed through SNAP: • manually creation of processing graphs in SNAP is avoided • no need to download data and run processing on a local (and powerful) machine • parallel processing on a cluster environment is embedded, providing results in about 4 hours (instead of about 7/8 hours with a single local machine)
- 7. ESA Sentinel 1 mission • Sentinel-1 [1] is an ESA mission which comprises a constellation of two polar-orbiting satellites, operating day and night performing C- band synthetic aperture radar imaging, enabling them to acquire imagery regardless of the weather.
- 8. TOPSAR Interferometric Wide Swath • The Interferometric Wide Swath [2] mode is the main acquisition mode over land and satisfies the majority of service requirements. It acquires data with a 250 km swath at 5 m by 20 m spatial resolution (single look). IW mode captures three sub-swaths using Terrain Observation with Progressive Scans SAR (TOPSAR). • With the TOPSAR technique [3], in addition to steering the beam in range as in ScanSAR, the beam is also electronically steered from backward to forward in the azimuth direction for each burst, avoiding scalloping and resulting in homogeneous image quality throughout the swath.
- 9. SAR Interferometry • Interferometric synthetic aperture radar (InSAR) [4] exploits the phase difference between two complex radar SAR observations taken from slightly different sensor positions and extracts information about the earth‟s surface. SAR signal‟s phase SAR interferometric phase
- 10. SNAP • A common architecture for all Sentinel Toolboxes is being jointly developed by Brockmann Consult, Array Systems Computing and C-S called the Sentinel Application Platform (SNAP) [5]. • The Sentinel-1 Toolbox (S1TBX) consists of a collection of processing tools, data product readers and writers and a display and analysis application to support the large archive of data from ESA SAR missions. The Sentinel-1 Toolbox is being developed for ESA by Array Systems Computing in partnership with DLR, Brockmann Consult and OceanDataLab.
- 11. Implemented algorithm overview • The interferometric processing chain has been divided in three tasks: 1. Input reading and subswath splitting 2. Core interferogram processing for each sub-swath (parallel processing) 3. Sub-swaths merging and output products formation Sub-swaths merging and output products formation Core interferogram (parallel processing) IW1 IW2 IW3 Input reading and subswath splitting
- 12. 1st Task 1. Input reading and subswath splitting (repeated for each sub-swath: IW1, IW2, IW3) IW1 IW2 IW3 Master Slave
- 13. 2nd Task 2. Core interferogram processing for each sub-swath, performed in parallel on 3 machines (one per sub-swath) IW1 IW2 IW3
- 14. 3rd Task (1/2) 3. Sub-swaths merging and output products formation a. Merge, topographic phase removal, Goldstein phase filtering, multilook, subset b. Terrain correction, coherence and phase writing Optional
- 15. 3rd Task (2/2) 3. Sub-swaths merging and output products formation c. Snaphu chain, phase to displacement and terrain correction on subset (optional if unwrap is required) Phase CoherenceDisplacement
- 16. HANDS ON SESSION HANDS ON “SNAP Sentinel-1 IW SLC Interferogram and Displacements” processing service on GEP
- 17. COIN OVERVIEW “COherence and INtensity processing (COIN)” processing service on GEP
- 18. Future improvements • SNAP Sentinel-1 IW SLC Interferogram and Displacements • Support resolution of „not uniform phase distribution‟ problem • Add UTM automatic projection mode used in terrain correction • Add DEM source used across interferometric chain steps • Further customization/improvements based on user needs • COherence and INtensity processing service (COIN) • Support to deployment on GEP production environment • Further customization/improvements based on user needs • Other services to be integrated based on Earth Observation community needs
- 19. References 1. Sentinel-1 mission ESA web page: https://sentinel.esa.int/web/sentinel/missions/sentinel-1 2. Interferometric Wide Swath ESA web page: https://sentinel.esa.int/web/sentinel/user-guides/sentinel-1-sar/acquisition- modes/interferometric-wide-swath 3. TOPSAR Processing ESA web page: https://sentinel.esa.int/web/sentinel/technical-guides/sentinel-1-sar/products- algorithms/level-1-algorithms/topsar-processing 4. InSAR Principles: Guidelines for SAR Interferometry Processing and Interpretation: http://www.esa.int/About_Us/ESA_Publications/InSAR_Principles_Guidelines_f or_SAR_Interferometry_Processing_and_Interpretation_br_ESA_TM-19 5. SNAP page: http://step.esa.int/main/toolboxes/snap/ 6. TopSAR interferometry with Sentinel-1 Toolbox tutorial: http://sentinel1.s3.amazonaws.com/docs/S1TBX%20TOPSAR%20Interferomet ry%20with%20Sentinel-1%20Tutorial.pdf
- 21. THANK YOU!
- 22. RSS contacts For general information: • RSS website: rssportal.esa.int For feedback or enquiries: • My contact: michele.caccia@cgi.com • RSS Team: rss_team@esa.int RSS Contacts