Sentinel-1 GRD CARD4L Processing

Short Description

Sentinel Hub provides the full archive of global Sentinel-1 GRD data, which can be processed based on CARD4L NRB (Normalised Radar Backscatter) requirements to reduce the complexity of SAR data. The satellite data is processed to a minimum set of requirements and organized into a form, that allows immediate analysis with minimum user effort. Through the Euro Data Cube Insights On Demand service, you can trigger on-demand processing of CARD4L compliant Sentinel-1 GRD data through EDC Browser and have the products delivered to a specified S3 bucket.
To access sample processed data, we provide freely accessible Sentinel-1 GRD archived CARD4L data covering Africa Continent here, in collaboration with Geoscience Australia and ESA.

Steps to process Sentinel-1 CARD4L data

1. Create EDC account here and purchase enough credits
2. Navigate to EDC Browser
3. Select the required input parameters
4. Follow the check-out wizard to complete your order.

Algorithm Input Parameters

Based on the selected input parameters, an analysis is run to determine the number of datatakes, distinct dates and total area of the data to be processed. The processing is currently limited to 20 datatakes. For larger orders, customers should get in contact with Sentinel Hub support.

Table 1: Required parameters

Parameter	Possible values	Description
Area of Interest	Polygon or Rectangle	Area of Interest
Time range	From 2014-10-01 to date	Start and end date of the data to be processed
Bucket Name	The name of the AWS S3 bucket where the processed products will be delivered	Bucket must be in eu-central-1 region and configured to allow full access to Sentinel Hub. Check aws bucket settings

Product specifications

Table 2: Sentinel-1 CARD4L product specifications

Specification	Description
Data source	Sentinel-1 GRD (read more)
Sensor	C-SAR
Frequency	C-band (5.405 GHz)
Acquisition mode	Interferometric Wide (IW) swath mode (read more ).
Polarisation	VV + VH
Backscatter	Gamma-0 (γ°)
Backscatter scaling	Linear power
Coordinate reference system	EPSG: 4326
Pixel spacing - X (degree)	0.0002 (≈22.2 m at the Equator)
Pixel spacing - Y (degree)	0.0002 (≈22.2 m at the Equator)
Number of bands	5
Radiometric Terrain Correction	Yes, based on Flattening Gamma: Radiometric Terrain Correction for SAR Imagery
Digital Elevation Model	Copernicus DEM (10m in EEA, 30m elsewhere)

Output Information

Table 3: Output Bands

Read more details on the bands here

Name	Description	Typical Range	Sentinel Hub units
VV	Linear backscatter intensity in VV polarization	0 - 0.5 (Can reach very high values such as 1000)	LINEAR_POWER
VH	Linear backscatter intensity in VH polarization	0 - 0.5 (Can reach very high values (such as 1000)	LINEAR_POWER
MASK	Data mask	0, 1, 2	DN
AREA	Normalized scattering area	0 - 2 (Can reach high values on fore-slopes.)	DN
ANGLE	Local incidence angle	0 - 180 degree	DN

Table 4: Output Metadata

Name	Description
userdata.json	Intermediate metadata used to produce final CARD4L metadata
metadata.json	Local incidence angle
metadata.xml	STAC compliant CARD4L compliant general metadata

Table 5: Data mask definition

Value	Description
0	Nodata
1	Valid data
2	Invalid (in/near radar shadow)

Pricing

Price	Unit
10 EUR	1.000.000 km²

Resources

• David Small's article Flattening Gamma: Radiometric Terrain Correction for SAR Imagery
• CEOS Analysis Ready Data for Land (CARD4L) Product Family specifications
• CARD4L Product Family Specification, Normalised Radar Backscatter
• EDC Checking-out "data on demand" documentation
• Access processed archived data for areas within Africa here

Examples

RGB visualisation of Blue Nile river looping across northwest Ethiopia . Contains modified Copernicus data [2022], processed by Sentinel Hub.

---