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SAOCOM-1

SAOCOM-1 spacecraft

SAOCOM-1 spacecraft, © CONAE

Mission and sensor parameters

SAOCOM (Satélite Argentino de Observación COn Microondas, Spanish for Argentine Microwaves Observation Satellite) is an Earth Observation satellite constellation of Comisión Nacional de Actividades Espaciales (CONAE) the Argentina's space agency.

SAOCOM-1 mission patch

The constellation comprises two satellite (SAOCOM 1A and 1B) both equipped with a L-band (12.75 GHz) full polarimetric SAR sensor1.

Mission parameters

SAOCOM-1A was launched on 7 October 2018, while SAOCOM-1B on 30 August 2020. The satellite carries a L-band SAR instrument, SAR-L, which provides imagery in all polarisations (HH,HV,VV,VH)2. In the Charter Governance CONAE acts as mission owner of SAOCOM-1.

Table 1 provides a summary of the SAOCOM-1 mission.

Parameter Specifications
EO Mission SAOCOM-1
Charter Owner Agency CONAE
Providing Agency CONAE, VENG
Date of launch 2018-10-07
EOL date 2025-08-30
Mission status Operational
Orbit Type Sun-synchronous
Nominal Altitude 620 km
Repeat Cycle 16 days (1 satellite) / 8 days (constellation)

Table 1 - SAOCOM-1 mission parameters.

Sensor specifications

Table 2 provides specifications of the SAR-L earth observation sensor on board the SAOCOM-1 platform. SAR-L is a multi-mode L-band Synthetic Aperture Radar (SAR) instrument.

Parameter Specifications
Center frequency 1275 MHz (L-band)
Maximum Bandwidth 50 MHz
Look direction Right (default). Also in left looking mode
Incidence angle range 18-50°
Polarization Single, dual or quad polarization HH, HV, VH, and VV. Compact Polarization also available
Imaging Modes StripMap (SM), TopSAR Narrow (TN), TopSAR Wide (TW),
Resolution 10m (SM), 30-50m (TN), 50-100m (TW)
Swath width 20-40Km (SM), 100-150m (TN), 220-350Km (TW)
Table 2: SAOCOM-1 SAR-L sensor parameters.

Acquisitions modes and polarizations

SAOCOM-1 SAR acquistion imaging modes are:

  • StripMap (SM)

  • TopSAR Narrow (TN)

  • TopSAR Wide (TW)

SAR-L imaging modes

Table 2: SAOCOM-1 SAR-L measurement modes (image credit: CONAE).

Different polarisation capabilities2 are provided:

  • SP: Two single polarization modes (HH, VV),

  • DP: Two dual polarization modes (HH/HV, VV/VH),

  • QP: One full polarization mode (HH/HV/VH/VV),

  • CP: One (technological1) compact polarization mode (CP).

The SM, TN, and TW modes support operations in single polarization SP (HH or VV), dual polarisation DP (HH+HV, VV+VH) or full pol QP.

Table 3 provides the characteristics of the Level 1 products of the SAOCOM-1 mission.

Beam Mode Beam Position Minimum Incidence Angle Range Nominal Spatial Resolution Minimum Swath Width (ground range)

[km]

 Nominal Azimuth Length

[km]

 Nominal Equivalent Number of Looks
L1A L1B, L1C, L1D L1A L1B, L1C, L1D
Near range

[deg]

 Far range

[deg]

 Rg X Az

[m x m]

 Rg x Az

[m x m]

Stripmap Single Pol and Dual Pol S1 20.7 25.0 10 x 5 10 x 10 49.7 74.1 1 2
S2 24.9 29.2 52.3
S3 29.1 33.8 61.4
S4 33.7 38.3 65.7
S5 38.2 41.3 49.1
S6 41.3 44.5 55.6
S7 44.6 47.1 48.0
S8 47.2 48.7 31.9
S9 48.8 50.2 31.1
Stripmap Quad Pol S1 17.6 19.6 10 x 6 10 x 10 21.9 74.1 1 2
S2 19.5 21.5 22.0
S3 21.4 23.3 21.0
S4 23.2 25.4 25.4
S5 25.3 27.3 23.4
S6 27.2 29.6 29.4
S7 29.6 31.2 20.9
S8 31.2 33.0 25.1
S9 33.0 34.6 22.1
S10 34.6 35.5 14.2
TOPSAR Narrow Single Pol and Dual Pol TNA 24.9 38.3 10 x 30 30 x 30 176.3 222.3 1 3
TNB 38.2 47.1 150.2
TOPSAR Narrow Quad Pol TNA 17.6 27.3 10 x 50 50 x 50 109.9 222.3 1 5
TNB 27.2 35.5 108.8
TOPSAR Wide Single Pol and Dual Pol TW 24.9 48.7 10 x 50 50 x 50 353.7 444.6 1 5
TOPSAR Wide Quad Pol TW 17.6 35.5 10 x 100 100 x 100 218.1 444.6 1 10
Table 3 - Characteristics of SAOCOM-1 SAR-L acquisitions modes.

Processing levels

SAOCOM-1 EO data are distributed at L1 processing level in the following 4 product types:

  • L1A - SLC single look complex. Complex data in slant range, radiometrically calibrated with no geometric corrections.

  • L1B - DI detected image. Data projected to ground range, radiometrically calibrated and georeferenced.

  • L1C - GEC geocoded on ellipsoid. Radiometrically calibrated data, geocoded and georeferenced exploiting ellipsoid.

  • L1D - GTC geocoded on DEM. Radiometrically calibrated data, geocoded and georeferenced exploiting topography.

Default product

In general, CONAE contributes to the Charter with the provision of radiometrically calibrated, geocoded and georeferenced radar data from SAOCOM-1 A/B satellites. Thus, imported Dataset in the ESA Charter Mapper from COS-2 are often GTC (L1D) products. The ESA Charter Mapper also supports GEC (L1C) and SLC (L1A) products.

Native format

SAOCOM-1 data is provided to the Charter as XML Annotated SAR image within a compressed ZIP archive containing:

  • an XEMT metadata file (manifest)
  • XML and BIN files for Data (includes multiple single-band images for each polarization)
  • XML and BIN files for Quality
  • XML and BIN files for Config
  • a KML file of Scene Quicklook Map Overlay
  • a PNG file of Merged Beams Quicklook

L1 product naming convention and data files

The product name in CUSS format is composed by alphanumeric characters separated by underscores (one or two) or by the “T” character, according to the following structure:

S1<X>_OPER_SAR_EOSSP__CORE_<LLL>_<Orbit>_<DDDDDDDD>T>TTTTTT>

where each placeholder is described in the below Table 4.

Placeholder Format Description
<X> 1 alphabetic A for SAOCOM-1A, B for SAOCOM-1B
OPER 4 alphabetic Operative
EOSSP 5 alphabetic Earth Observation – SAOCOM SAR Processor
<LLL> 3 alphabetic Level 1 Data product: L1A for SLC processing level. L1B for DI processing level. L1C for GEC processing level. L1D for GTC processing level.
<Orbit> 3 or 4 alphabetic Orbit estimation OLVF for On Line Very Fast OLF for Off Line Fast
<DDDDDDDD> 8 numeric Product L1 date in format yyyymmdd (date of processing)
<TTTTTT> 6 numeric Processing time in format hhmmss
Table 4 - SAOCOM-1 Product name convention.

This structure is used for both components of the product, i.e., for the .XEMT and the .ZIP files. Examples are:

  • S1A_OPER_SAR_EOSSP__CORE_L1A_OLF_20211117T174240.xemt

  • S1A_OPER_SAR_EOSSP__CORE_L1A_OLF_20211117T174240.zip

In a SAOCOM-1 L1 product, the file name is composed by a common root, containing lowercase alphanumeric characters, separated by a hyphen character, in accordance to the following specification:

slc-acqId<cccccccccc>-<x>-<mmm>-<hhhhhhhhhh>-<ssss>-<pp>

where each placeholder is described in the below Table 5.

Placeholder Format Description
<cccccccccc> 10 numeric Acquisition ID identifier
<x> 1 alphabetic a for SAOCOM-1A, b for SAOCOM-1B
<mmm> or <mmmm> 3/4 alphanumeric Acquisition mode: smx for stripmap x, with x the beam number 1 to 10. tna for topsar narrow A; tnb for topsar narrow B; tw- for topsar wide.
<hhhhhhhhhh> 10 alphanumeric Reserved field for future use.
<ssss> or <sssss> 4/5 alphanumeric Swath name: s1dp, s2dp, s3dp, s4dp, s5dp, s6dp, s7dp, s8dp, s9dp, s1qp, s2qp, s3qp, s4qp, s5qp, s6qp, s7qp, s8qp, s9qp, s10qp, merg for topsar SLC merged products.
<pp> 2 alphabetic Polarization: hh, vv, hv, vh for the different linear polarization combination; ch, cv for compact polarization;
Table 5 - Measurements file name convention for SAOCOM-1 L1A files.

The extension “.xml” is added to the corresponding file name to identify the annotation product accompanying the data.

Example:

  • slc-acqId0000588416-a-sm5-2111181029-s5dp-hh

  • slc-acqId0000588416-a-sm5-2111181029-s5dp-hh.xml

Ingested format

During the ingestion key information is extracted from product annotation and included in the STAC item of a SAOCOM-1 SLC, GEC or GTC dataset.

Product Calibration

For SAOCOM-1 products calibration refer to the Radar Products Calibration (SAR-Calib) service and the calibration sheet available here.

  1. CONAE, SAOCOM-1 mission page, available at: www.argentina.gob.ar ↩

  2. CONAE, SAOCOM-1 Level 1 Products Format Product Specification catalogos.conae.gov.ar ↩↩