Sentinel-1 GRD

About Sentinel-1 GRD Data

Mission Information

The Sentinel-1 imagery is provided by two polar-orbiting satellites, operating day and night performing C-band synthetic aperture radar imaging, enabling them to acquire imagery regardless of the weather. Main applications are for monitoring sea ice, oil spills, marine winds, waves & currents, land-use change, land deformation among others, and to respond to emergencies such as floods and earthquakes.

Sentinel Hub currently supports Sentinel-1 Level-1 GRD (Ground Range Detected) products only. See other Sentinel-1 products offered by ESA.

Observation Scenarios

Observation scenario defines the acquisition mode and polarization with which the Sentinel-1 will acquire data over certain area. When searching for the data the observation scenario can be helpful when selecting a combination of values of different parameters. Below is an example of observation scenario but it may vary through time depending on requirements. The full archive of observation scenarios is available.

Image

(Source ESA)

More information:

Attribution and Use

The Sentinel products are released under the license available here.

Accessing Sentinel-1 GRD Data

To access data you need to send a POST request to our process API. The requested data will be returned as the response to your request. Each POST request can be tailored to get you exactly the data you require. To do this requires setting various parameters which depend on the datasource you are querying. This chapter will help you understand the parameters for S1GRD data. To see examples of such requests go here, and for an overview of all API parameters see the API Reference.

Endpoint Locations

ServiceNotes
services.sentinel-hub.com/api/Global since January 2017
eocloud.sentinel-hub.com/v1/Global since October 2014

Differences in Capabilities

  • Zoom out:

    • @ services.sentinel-hub.com/api/ : Zooming out will use multi-looked sources at an appropriate resolution to your viewing level. You can therefore expect high quality results at all zoom levels.
    • @ eocloud.sentinel-hub.com/v1/ : Zooming out will NOT use multi-looked sources. Zooming out is therefore more of a convenience preview as the images will be excessively noisy. If this is an issue consider using the AWS service instead.
  • Backscatter coefficient:

    • @ services.sentinel-hub.com/api/ : We support gamma0, sigma0 and beta0 backscatter coefficients.
    • @ eocloud.sentinel-hub.com/v1/ : We support gamma0 backscatter coefficient.

Data type identifier: S1GRD

Use S1GRD as the value of the input.data.type parameter in your API requests. This is mandatory and will ensure you get Sentinel-1 GRD data.

Filtering Options

This chapter will explain the input.data.dataFilter object of the S1GRD process API.

mosaickingOrder

The same as for S2L1C.

resolution (pixel spacing)

ValueDescription
HIGH10m/px for IW and 25m/px for EW
MEDIUM40m/px for IW and EW

A full table of resolutions is available (here)

acquisitionMode

Sentinel-1 operates in four different acquisition modes (more).

ValueDescriptionPolarization options
SMStripmap mode (more ).HH+HV, VV+VH, HH, VV
IWInterferometric Wide (IW) swath mode (more ).HH+HV, VV+VH, HH, VV
EWExtra Wide (EW) swath mode (more ).HH+HV, VV+VH, HH, VV
WVWave mode (more ).HH, VV

polarization

This table contains information about the polarization two letter code used by ESA and the product's contained polarizations.

ValueDescriptionNotes
SHHH
SVVV
DHHH+HVTypical for EW acquisitions
DVVV+VHTypical for IW acquisitions
HHPartial Dual, HH onlyHH+HV was acquired, only HH is available in this product
HVPartial Dual, HV onlyHH+HV was acquired, only HV is available in this product
VVPartial Dual, VV onlyVV+VH was acquired, only VV is available in this product
VHPartial Dual, VH onlyVV+VH was acquired, only VH is available in this product

orbitDirection

ValueDescription
ASCENDINGData acquired when the satellite was traveling approx. towards the Earth's North pole.
DESCENDINGData acquired when the satellite was traveling approx. towards the Earth's South pole.

timeliness

Value
NRT10m
NRT1h
NRT3h
Fast24h
Offline
Reprocessing
ArchNormal

Processing Options

This chapter will explain the input.data.processing object of the S1GRD process API.

ActionDescriptionValuesDefault
upsamplingThe same as for S2L1C.
downsamplingThe same as for S2L1C.
backCoeffBackscatter coefficientBETA0
SIGMA0_ELLIPSOID
GAMMA0_ELLIPSOID

orthorectify**Enables/disables orthorectificationTRUE - Orthorectified
FALSE - non-Orthorectified
TRUE on EOCloud, FALSE on AWS

*Gamma0 and sigma0 use an ellipsoid earth model. Radiometric terrain flattening is currently not supported.

** For orthorectification we use the Mapzen DEM. The non-orthorectified products use a simple earth model as provided in the products themselves. This may be sufficient for very flat target areas and is faster to process.

Available Bands and Data

Information in this chapter is useful when defining input object in evalscript. Any string listed in the column Name can be an element of the input.bands array in your evalscript.

NameDescriptionUnits
VVThis value can be used when polarization is SV, DV or VV.linear in the chosen backscatter coefficient
VHThis value can be used when polarization is VH or DV.linear in the chosen backscatter coefficient
HVThis value can be used when polarization is HV or DH.linear in the chosen backscatter coefficient
HHThis value can be used when polarization is SH, DH or HH.linear in the chosen backscatter coefficient
dataMaskThe mask of data/nodata pixels (more).0 - no data
1 - data

Mosaicking

SIMPLE and ORBIT mosaicking types are supported.

Dataset specific constraints

  • Noise: All products on both services have thermal noise reduction applied.
  • Decibel units: For decibel outputs, a conversion is necessary within your evalscript, see an example here. We offer pre-defined evalscripts, which return S1GRD values in decibel units, as products in the Configuration Utility for your convenience.
  • Orbit state vectors: We currently use the orbit state vectors provided in the products themselves as we find these sufficient for GRD use.

Catalog API Capabilities

To access Sentinel-1 GRD product metadata you need to send search request to our Catalog API. The requested metadata will be returned as JSON formatted response to your request. This chapter will help with understanding Sentinel 1 GRD specific parameters for search request.

Endpoint Locations

ServiceNotes
services.sentinel-hub.com/api/v1/catalog/collections/sentinel-1-grdGlobal since January 2017
shservices.mundiwebservices.com/api/v1/catalog/collections/sentinel-1-grd

Collection identifier: sentinel-1-grd

Query extension

Distinct extension

  • date
  • sar:istrument_mode
  • sat:orbit_state
  • polarization

Examples

S1 GRD examples