Sentinel-1

Long name Sentinel-1
Short name STN1
Sensor type Synthetic-aperture radar (SAR)
Platform Sentinel-1
Frequency 5.405 GHz
Band (wavelength) C (5.6 cm)
Polarization HH, HV, VH, VV
Key file name (use to open data set) manifest.safe
Supported file extensions manifest.safe, *.xml, *.html, *.xsd
Data distributor  
Sections

Data product name and description
Distribution disk files
Returned data for supported format
References

Data product name and description

Sentinel-1 has four acquisition modes:
  • Stripmap [SM]
  • Interferometric Wide Swath [IW]
  • Extra-Wide Swath [EW]
  • Wave [WV]

Each mode is available at various processing levels. The supported acquisition modes of the Sentinel-1 sensor are described in the following tables.

Note: The information provided herein is based on the reference documentation cited under References.
Mode Swath width (km) Resolution (range x azimuth, m)* Polarization Description/notes
Stripmap [SM] 80 1.7 x 4.3 to 3.6 x 4.9 Single (HH or VV) A standard SAR Stripmap imaging mode in which the ground swath is illuminated by a continuous sequence of pulses, while the antenna beam is pointing at a fixed azimuth and elevation angle.
Interferometric Wide Swath [IW] 250 2.7 x 22.0 to 3.5 x 22.0

Single (HH or VV)
Dual (HH+HV or VV+VH)

Data is acquired in three swaths by using the Terrain Observation with Progressive Scanning SAR (TOPSAR) imaging technique.

In [IW] mode, bursts are synchronized between passes to ensure the alignment of interferometric pairs. [IW] is the primary operational mode of Sentinel-1 over land.

Extra Wide Swath [EW] 400 7.9 x 43.0 to 15.0 x 43.0

Single (HH or VV)
Dual (HH+HV or VV+VH)

Data is acquired in five swaths by using the TOPSAR imaging technique.

In [EW] mode, bursts are synchronized between passes to ensure the alignment of interferometric pairs. The [EW] mode provides very large swath coverage at the expense of spatial resolution.

* Resolution is always single-look complex (SLC) unless noted otherwise.

CATALYST Professional supports all Level 1 image modes ([SM], [IW], [EW]) for single-look complex (SLC) and ground-range detected (GRD) products.

Processing level Acquisition mode Description/notes

0
(RAW)

N/A Level 0 SAR products contain the raw SAR data from the unprocessed instrument source packets (ISP).

1
Single-look complex (SLC)

[SM]
[IW]
[EW]

Level 1 SLC products consist of focused SAR data georeferenced by using orbit and attitude data from the satellite, and provided in slant-range geometry.

SLC Stripmap [SM] and SLC TOPSAR [IW] and [EW] data is supported.

[IW] and [EW] data sets are automatically concatenated (debursted) into a continuous image. Overlapping portions of [IW] and [EW] bursts are stored as array segments.

1
Ground-range detected (GRD)

[SM]-FR
[SM]-HR
[SM]-MR

[IW]-HR
[IW]-MR

[EW]-HR
[EW]-MR

Level 1 GRD products consist of focused SAR data that has been detected, multilooked, and projected to ground range by using an Earth ellipsoid model. Ground-range coordinates are the slant-range coordinates projected onto the ellipsoid of the Earth at a constant ground spacing. Pixel values represent detected magnitude. Phase information is lost. The resulting product has approximately square sample spacing with reduced speckle, but with reduced resolution. GRD products are available in three resolutions, characterized by the acquisition mode and the level of multilooking applied:
  • FR - Full Resolution
  • HR - High Resolution
  • MR - Medium Resolution

Distribution disk files

Sentinel data products are distributed using a Sentinel-specific variation of the Standard Archive Format for Europe (SAFE) specification. The Sentinel-SAFE format wraps a folder containing image data in a binary format and product metadata in Extensible Markup Language (XML).

Warning: Data sets for this sensor are organized in a specific folder structure on disk. GDB uses this structure and the file names to identify the data product type. Do not alter the folder structure or any file names prior to data ingestion to ensure the image data and auxiliary information are imported correctly.
File name Format Required Contents/details
manifest.safe Extensible Markup Language Yes Key file name. Use this file to open the data set.
*.tiff GeoTIFF Yes Image data (measurement folder).
*.xml Extensible Markup Language Yes Product metadata (annotation folder).
calibration-*.xml Extensible Markup Language Yes Calibration lookup tables (calibration folder).
noise-*.xml Extensible Markup Language Yes Noise file (calibration folder). The noise file can be used to determine calibrated noise profiles that match the calibrated GRD data.

Returned data for supported format

Sentinel-1 data can be opened directly in its raw vendor format or imported into a PCIDSK (*.pix) file using the key file (manifest.safe). For optimal processing, use the PCIDSK format.

In the following table, the data structure after it is imported into a PCIDSK file is described.

Data product Data returned Details

Level 1
Single-look complex (SLC), single pol
[SM]

1 x  [C16S] Raster channel (uncalibrated)
—or—
1 x [C32R] raster channel (calibrated)

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model
1 x [ARR] Incidence angle array

Data can be calibrated in sigma, gamma, or beta nought.

Level 1
Single-look complex (SLC), dual pol
[SM]

2 x  [C16S] Raster channels (uncalibrated)
—or—
2 x [C32R] Raster channels (calibrated)

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model
1 x [ARR] Incidence angle array

Data can be calibrated in sigma, gamma, or beta nought.

Level 1
Single-look complex (SLC), single pol
[IW] or [EW]

1 x  [C16S] Raster channel (uncalibrated)
—or—
1 x [C32R] Raster channel (calibrated)

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model
1 x [ARR] Incidence angle array
N x [ARR] Overlap segments

Where N = 2 x Required Number of Bursts x Required Number of Swaths covering the area of interest (AOI)

Data can be calibrated in sigma, gamma, or beta nought.

The overlap segments hold the overlapping portions of the image bursts and are required for interferometric processing.

Level 1
Single-look complex (SLC), dual pol
[IW] or [EW]

2 x [C16S] Raster channels (uncalibrated)
—or—
2 x [C32R] Raster channels (calibrated)

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model
1 x [ARR] Incidence angle array
N x [ARR] Overlap segments

Where N = 2 x Required Number of Bursts x Required Number of Swaths x 2 Polarizations covering the area of interest (AOI).

Data can be calibrated in sigma, gamma, or beta nought.

The overlap segments hold the overlapping portions of the image bursts and are required for interferometric processing.

Level 1
Ground-range detected (GRD), single pol
[SM] (FR, HR, MR)
[IW] (HR, MR)
[EW] (HR, MR)

1 x [16U] Raster channel (uncalibrated)
—or—
1 x [32R] Raster channel (calibrated)

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model
1 x [ARR] Incidence angle array

Data can be calibrated in sigma, gamma, or beta nought.

Level 1
Ground-range detected (GRD), dual pol
[SM] (FR, HR, MR)
[IW] (HR, MR)
[EW] (HR, MR)

2 x [16U] Raster channels (uncalibrated)
—or—
2 x [32R] Raster channels (calibrated)

1 x [TEX] Main product annotation
1 x [ORB] Orbit segment
1 x [BIN] Rational function model
1 x [ARR] Incidence angle array

Data can be calibrated in sigma, gamma, or beta nought.

References

Sentinel-1 Product Specification. Date: Feb. 18, 2013. MDA Document Number: SEN-RS-52-7441, Sentinel-1 IPF CDRL Numbers: PFL1-4, PFL2-3. 178 pages.

Sentinel-1 Technical Guide. Webpage. Version 8.7, last updated: October 20, 2014.

Sentinel-1 User Handbook. European Space Agency (ESA), Reference GMES-S1OP-EOPG-TN-13-000. Date of Issue: September 1, 2013, Issue 1, Rev 0. 80 pages.

You can find the preceding publications on the website of the European Space Agency.

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