CBERS-4

CBERS-4 spacecraft

CBERS-4 spacecraft, © INPE, AEB, CAST

Mission description

The CBERS-4 satellite is part of the China-Brazil Earth-Resources Satellite (CBERS) mission and is equipped with different cameras: Câmera Pancromática e Multiespectral (PAN), Câmera Multiespectral Regular (MUX), Imageador Multiespectral e Termal (IRS), and Câmera de Campo Largo (WFI). This second generation of the CBERS satellites include two similar medium resolution satellites: CBERS-4 and CBERS-4A.

CBERS-4 mission patch

The CBERS-4 PAN sensor is able to acquire images with different GSD, 5 meter for panchromatic (PAN5M) and 10 meter for multispectral green, red, and NIR bands (PAN10M). The MUX multispectral camera, on board of CBERS-4 satellite, provides wide-swath (120 km) images at 20 meter GSD under Blue, Red, Green and NIR channels. The WFI camera provides extra wide-swath (866 km) images at 64 meter spatial resolution under Blue, Red, Green and NIR channels¹,².

Table 1 provides a summary of the CBERS-4 mission.

Parameter	Specifications
EO Mission	China-Brazil Earth Resources Satellite 4
Mission Short name	CBERS-4
Charter Owner Agency	INPE
Providing Agency	INPE, AEB, CAST
Date of launch	07/12/2014
Temporal coverage	03/2015 - present
Mission status	onGoing
Mission Life Expected	>10 years
Orbit Type	Sun-synchronous
Equator crossing Time	10:30 AM asc
Orbit Height	778 km
Orbit Period	100.3 minutes
Inclination	98.5 deg
Repeat Cycle	26 days

Table 1 - CBERS-4 mission parameters.

Instruments

Table 2 describes the EO sensors on board of CBERS-4 satellite, spectral modes and combinations.

Acronym	Specifications
PanMUX	Panchromatic and Multispectral imager
MUXCam	Multispectral Camera
AWFI	Advanced Wide Field Imager
IRS	InfraRed medium-resolution Scanner

Table 2 - CBERS-4 earth observation sensors.

Table 3 describes the spectral combinations of the CBERS-4 products often received in the Charter.

Instrument	Spectral mode	Spectral combinations
PanMUX	PAN5M	Panchromatic single band: `BAND1` (PAN)
PanMUX	PAN10M	Multispectral 3 bands: `BAND2` (Green), `BAND3` (Red), and `BAND4` (NIR)
MUXCam	MUX	Multispectral 4 bands: `BAND5` (Blue), `BAND6` (Green), `BAND7` (Red), and `BAND8` (NIR)
AWFI	AWFI	Multispectral 4 bands: `BAND13` (Blue), `BAND14` (Green), `BAND15` (Red), and `BAND16` (NIR)

Table 3 - Spectral combinations for most recurrent CBERS-4 products in the charter.

Spectral modes and bands

PanMUX

Table 4 reports technical specifications of the CBERS-4 PANMux instrument.

Parameter	Specifications
Instrument	PanMUX
Imager Type	Panchromatic and Multispectral imager
Spectral mode	PAN5M, PAN10M
Scanning technique	Pushbroom
Resolution	Medium Resolution - O-MR (4 - 25m)
GSD	5 m (PAN5M), 10 m (PAN10M)
Swath width	60 km
Coverage	Global
Revisit time	52 days
Data type	L2 or L4
Dynamic range at acquisition	12 bit per pixel

Table 4 - CBERS-4 PANMux instrument technical specifications.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the CBERS-4 PanMUX sensor in PAN5M mode are described in table 5.

Spectral Band (ID)	Spectral interval (nm)	Center Wavelength(µm)	Bandwidth or FWHM (µm)	CBN
BAND1 (PAN)	510-890	0.700	0.38	pan

Table 5 - Spectral bands for a CBERS-4 PANMux product in PAN5M mode.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the CBERS-4 PanMUX sensor in PAN10M mode are described in table 6.

Spectral Band (ID)	Spectral interval (nm)	Center Wavelength(µm)	Bandwidth or FWHM (µm)	CBN
BAND2 (Green)	520-590	0.555	0.07	green
BAND3 (Red)	630-690	0.660	0.06	red
BAND4 (NIR)	770-890	0.830	0.12	nir

Table 6 - Spectral bands for a CBERS-4 PANMux product in PAN10M mode.

MUXCam

Table 7 reports technical specifications of the CBERS-4 MUXCam instrument.

Parameter	Specifications
Instrument	MUXCam
Imager Type	Multispectral camera
Spectral mode	MUX
Scanning technique	Pushbroom
Resolution	Medium Resolution - O-MR (4 - 25m)
GSD	20 m
Swath width	120 km
Coverage	Global
Cycle	26 days
Data type	L2 or L4
Dynamic range at acquisition	12 bit per pixel

Table 7 - CBERS-4 MUXCam instrument technical specifications.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the CBERS-4 MUXCam sensor are described in table 8.

Spectral Band (ID)	Spectral interval (nm)	Center Wavelength(µm)	Bandwidth or FWHM (µm)	CBN
BAND5 (Blue)	450-520	0.485	0.07	blue
BAND6 (Green)	520-590	0.555	0.07	green
BAND7 (Red)	630-690	0.660	0.06	red
BAND8 (NIR)	770-890	0.830	0.12	nir

Table 8 - Spectral bands for a CBERS-4 MUXCam product.

AWFI

Table 9 reports technical specifications for the CBERS-4 AWFI instrument.

Parameter	Specifications
Instrument	AWFI
Imager Type	Advanced Wide Field Imager Camera
Spectral mode	AWFI
Scanning technique	Pushbroom
Resolution	Very Low Resolution - O-VLR (> 60m)
GSD	64 m (nadir)
Swath	866 km
Coverage	Global
Revisit time	5 days
Data type	L2 or L4
Dynamic range at acquisition	12 bit per pixel

Table 9 - CBERS-4 AWFI instrument technical specifications.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the CBERS-4 AWFI sensor are described in table 10.

Spectral Band (ID)	Spectral interval (nm)	Center Wavelength(µm)	Bandwidth or FWHM (µm)	CBN
BAND13 (Blue)	450-520	0.485	0.07	blue
BAND14 (Green)	520-590	0.555	0.07	green
BAND15 (Red)	630-690	0.660	0.06	red
BAND16 (NIR)	770-890	0.830	0.12	nir

Table 10 - Spectral bands for a CBERS-4 AWFI product.

For more information see the CBERS-4 website.

Geometric and radiometric processing

Processing levels of CBERS-4 are:

L2 system corrected image, expect some translation error,
L4 orthorectified with ground control points.

Imagery and metadata formats

CBERS-4 imagery format is GeoTIFF. Annotation is delivered by COS-2 in CSV format.

Ingested format

Information extracted from product annotation included in the STAC item of a CBERS-4 AWFI L4 4-band multispectral BAND16151413 dataset are listed below.

Properties

STAC item content about properties for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "properties": {
    "datetime": "2022-07-31T10:12:38Z",
    "created": "2022-07-31T10:12:38Z",
    "platform": "cbers-4",
    "constellation": "cbers-4",
    "mission": "cbers-4",
    "instruments": [
      "AWFI"
    ],
    "spectral_mode": [
      "AWFI"
    ],    
    "sensor_type": "optical",
    "gsd": 64,
    "title": "CBERS-4 AWFI L4 2022-07-31 10:12:38",
    "cbers:path": 111,
    "cbers:row": 63,
    "providers": [
      {
        "name": "INPE",
        "description": "China–Brazil Earth Resources Satellite 4 (CBERS-4), also known as Ziyuan I-04 or Ziyuan 1E, is a remote sensing satellite intended for operation as part of the China–Brazil Earth Resources Satellite program between the Chinese Center for Resources Satellite Data and Application and Brazilian National Institute for Space Research.",
        "roles": [
          "producer",
          "processor",
          "licensor"
        ],
        "url": "http://www.cbers.inpe.br/sobre/cbers3-4.php"
      }
    ],
    "license": "proprietary",
    "disaster:call_ids": [
      956
    ],
    "disaster:resolution_class": "MR",
    "cpe:cos2_id": "956-INPE-CBERS-4-Call956_AWFI_20220731_111_063_L4_BAND16151413",    
  }

Satellite

STAC item content about Satellite for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "properties": {
    "sat:platform_international_designator": "2014-079A"
}

Processing

STAC item content about Processing for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "properties": {
    "processing:level": "L4"
  }

Projection

STAC item content about Projection for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "properties": {
    "proj:epsg": 32632
  }

View

STAC item content about View for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "properties": {
    "view:off_nadir": 0,
    "view:sun_azimuth": 125.0133,
    "view:sun_elevation": 65.9144
  }

Geometry

STAC item content about Geometry for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "geometry": { 
    "type": "Polygon",
    "coordinates": [
      [
        [
          3.086,
          37.153
        ],
        [
          8.925,
          37.301
        ],
        [
          8.928,
          34.277
        ],
        [
          3.304,
          34.145
        ],
        [
          3.086,
          37.153
        ]
      ]
    ]
  },
  "bbox": [
    3.086,
    34.145,
    8.928,
    37.301
  ]

Assets

STAC item content about assets (annotation, quicklooks and spectral bands files harvested from the source product) and EO bands for a CBERS-4 AWFI L4 4-band multispectral BAND16151413 Dataset is the following:

  "assets": {
    "L4_BAND16151413": {
      "type": "image/tiff",
      "roles": [
        "data",
        "dn"
      ],
      "title": "AWFI L4 BAND16151413",
      "href": "https://.../Call956_AWFI_20220731_111_063_L4_BAND16151413.tiff",
      "filename": "Call956_AWFI_20220731_111_063_L4_BAND16151413.tiff",
      "file:size": 0,
      "eo:bands": [
        {
          "name": "BAND16",
          "common_name": "nir",
          "center_wavelength": 0.83,
          "full_width_half_max": 0.12,
          "solar_illumination": 981.91
        },
        {
          "name": "BAND15",
          "common_name": "red",
          "center_wavelength": 0.66,
          "full_width_half_max": 0.06,
          "solar_illumination": 1536.38
        },
        {
          "name": "BAND14",
          "common_name": "green",
          "center_wavelength": 0.555,
          "full_width_half_max": 0.07,
          "solar_illumination": 1823.40
        },      
        {
          "name": "BAND13",
          "common_name": "blue",
          "center_wavelength": 0.485,
          "full_width_half_max": 0.07,
          "solar_illumination": 1984.65
        }
      ],
      "raster:bands": [
        {
          "data_type": "int16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.189,
          "offset": 0.0
        },
        {
          "data_type": "uint16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.218,
          "offset": 0.0
        },
        {
          "data_type": "uint16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.267,
          "offset": 0.0
        },
        {
          "data_type": "uint16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.235,
          "offset": 0.0
        }
      ],
      "product_type": "AWFI"
    },
    "metadata": {
      "type": "text/plain",
      "roles": [
        "metadata"
      ],
      "title": "Metadata file",
      "href": "https://.../urn_ogc_def_eop_inpe_call956_awfi_20220731_111_063_l4_band16151413-metadata.csv",
      "filename": "urn_ogc_def_eop_inpe_call956_awfi_20220731_111_063_l4_band16151413-metadata.csv"
    },
    "thumbnail": {
      "type": "image/jpeg",
      "roles": [
        "thumbnail"
      ],
      "href": "https://.../urn_ogc_def_eop_inpe_call956_awfi_20220731_111_063_l4_band16151413-icon.jpg",
      "filename": "urn_ogc_def_eop_inpe_call956_awfi_20220731_111_063_l4_band16151413-icon.jpg"
    },
    "overview": {
      "type": "image/png",
      "roles": [
        "overview"
      ],
      "href": "https://.../urn_ogc_def_eop_inpe_call956_awfi_20220731_111_063_l4_band16151413-preview.png",
      "filename": "urn_ogc_def_eop_inpe_call956_awfi_20220731_111_063_l4_band16151413-preview.png"
    }
  }

Product Calibration

For CBERS-4 products calibration refer to the Optical Products Calibration (OPT-Calib) service and the calibration sheet available here.

INPE, CBERS-4 website, available at www.cbers.inpe.br. ↩
AEB, CBERS-4 declared operational, available at www.gov.br. ↩