CBERS-4A

CBERS-4A spacecraft

CBERS-4A spacecraft, © INPE, AEB, CAST

Mission description

The CBERS-4A 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-4A mission patch

CBERS-4A cameras are able to acquire optical imagery at higher GSD than the ones on board CBERS-4. Concerning CBERS-4A cameras, the PAN sensor is able to acquire images with different GSD, 2 meter for panchromatic (PAN5M) and 8 meter for multispectral green, red, and NIR bands (PAN10M). The MUX multispectral camera, on board of CBERS-4 satellite, provides wide-swath (95 km) images at 16.5 meter GSD under Blue, Red, Green and NIR channels. The WFI camera provides extra wide-swath (684 km) images at 55 meter spatial resolution under Blue, Red, Green and NIR channels¹,².

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

Parameter	Specifications
EO Mission	China-Brazil Earth Resources Satellite 4A
Mission Short name	CBERS-4A
Charter Owner Agency	INPE
Providing Agency	INPE, AEB, CAST
Date of launch	20/12/2019
Temporal coverage	2020 - present
Mission status	onGoing
Mission Life Expected	>10 years
Orbit Type	Sun-synchronous
Equator crossing Time	10:30 AM asc
Orbit Height	629 km
Orbit Period	97.3 minutes
Inclination	97.9 deg
Repeat Cycle	31 days

Table 1 - CBERS-4A mission parameters.

Instruments

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

Acronym	Specifications
WPM	Wide Scan Panchromatic and Multispectral Camera
MUX	Multispectral Camera
WFI	Wide Field Camera

Table 2 - CBERS-4A earth observation sensors.

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

Instrument	Spectral combinations
WPM	Panchromatic 1 band `BAND0` (PAN)
WPM	Multispectral 4 bands: `BAND1` (Blue), `BAND2` (Green), `BAND3` (Red), and `BAND4` (NIR)
MUX	Multispectral 4 bands: `BAND5` (Blue), `BAND6` (Green), `BAND7` (Red), and `BAND8` (NIR)
WFI	Multispectral 4 bands: `BAND13` (Blue), `BAND14` (Green), `BAND15` (Red), `BAND16` (NIR)

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

Spectral modes and bands

WPM

Table 4 reports technical specifications for the CBERS-4A WPM instrument.

Parameter	Specifications
Instrument	WPM
Imager Type	Wide Scan Panchromatic and Multispectral Camera
Spectral mode	WPM
Scanning technique	Pushbroom
Resolution	High Resolution - O-MR (1 - 4m)
GSD (nadir)	2 m (panchromatic) 8 m (multispectral)
Swath width	92 km
Coverage	Global
Revisit	31 days
Data type	L2 or L4

Table 4 - CBERS-4A WPM instrument technical specifications.

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

Spectral Band (ID)	Spectral interval (nm)	Center Wavelength(µm)	Bandwidth or FWHM (µm)	CBN
BAND0 (PAN)	450-900	0.675	0.45	pan
BAND1 (Blue)	450-520	0.485	0.07	blue
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 5 - Spectral bands for a CBERS-4A WPM product.

MUX

Table 6 reports technical specifications for the CBERS-4A MUX instrument.

Parameter	Specifications
Instrument	MUX
Imager Type	Multispectral Camera
Spectral mode	MUX
Scanning technique	Pushbroom
Resolution	Medium Resolution - O-MR (4 - 25m)
GSD (nadir)	16.5 m
Swath width	95 km
Coverage	Global
Revisit	31 days
Data type	L2 or L4

Table 6 - CBERS-4A MUX instrument technical specifications.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the CBERS-4A MUX sensor are described in table 7.

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 7 - Spectral bands for a CBERS-4A MUX product.

WFI

Table 8 reports technical specifications for the CBERS-4A WFI instrument.

Parameter	Specifications
Instrument	WFI
Imager Type	Advanced Wide Field Imager Camera
Spectral mode	WFI
Scanning technique	Pushbroom
Resolution	Low Resolution - O-LR (25 - 60m)
GSD	55 m (nadir)
Swath	684 km
Coverage	Global
Revisit	5 days
Data type	L2 or L4

Table 8 - CBERS-4A WFI instrument technical specifications.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the CBERS-4A WFI sensor are described in Table 9.

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 9 - Spectral bands for a CBERS-4A WFI product.

For more information see the CBERS-4A website and the EO Portal.

Geometric and radiometric processing

Processing levels of CBERS-4A are:

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

Imagery and metadata formats

CBERS-4A 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-4A WPM 4-Bands multispectral compose pansharpening dataset are listed below.

Properties

STAC item content about properties for a CBERS-4A WPM 4-Bands multispectral compose pansharpening Dataset is the following:

  "properties": {
    "datetime": "2023-03-19T15:48:46Z",
    "created": "2023-03-19T15:49:00Z",
    "platform": "cbers-4a",
    "constellation": "cbers-4a",
    "mission": "cbers-4a",
    "instruments": [
      "WPM"
    ],
    "spectral_mode": [
      "WPM"
    ],    
    "sensor_type": "optical",
    "gsd": 2,
    "title": "CBERS-4A WPM L4 2023-03-19 15:48:46",
    "cbers:path": 245,
    "cbers:row": 107,
    "providers": [
      {
        "name": "INPE",
        "description": "Due to the successful launch of the China–Brazil Earth Resources Satellite 4 (CBERS-4) satellite, Brazil and China decided to sign a new complementary protocol for the manufacture of a new satellite of the CBERS Program: CBERS-4A.",
        "roles": [
          "producer",
          "processor",
          "licensor"
        ],
        "url": "http://www.cbers.inpe.br/sobre/cbers04a.php"
      }
    ],
    "license": "proprietary",
    "disaster:call_ids": [
      956
    ],
    "disaster:resolution_class": "MR",
    "cpe:cos2_id": "956-INPE-CBERS-4A-CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0",    
  }

Satellite

STAC item content about Satellite for a CBERS-4A WPM 4-Bands multispectral compose pansharpening Dataset is the following:

  "properties": {
    "sat:platform_international_designator": "2019-093E"
}

Processing

STAC item content about Processing for a CBERS-4A WPM 4-Bands multispectral compose pansharpening Dataset is the following:

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

Projection

STAC item content about Projection for a CBERS-4A WPM 4-Bands multispectral compose pansharpening Dataset is the following:

  "properties": {
    "proj:epsg": 32618
  }

View

STAC item content about View for a CBERS-4A WPM 4-Bands multispectral compose pansharpening Dataset is the following:

  "properties": {
    "view:off_nadir": 0,
    "view:sun_azimuth": 107.07,
    "view:sun_elevation": 71.2643
  }

Geometry

STAC item content about Geometry for a CBERS-4 WPM 4-Bands multispectral compose pansharpening Dataset is the following:

  "geometry": {
    "type": "Polygon",
    "coordinates": [
      [
        [
          -74.064,
          4.549
        ],
        [
          -73.604,
          4.549
        ],
        [
          -73.605,
          4.276
        ],
        [
          -74.064,
          4.277
        ],
        [
          -74.064,
          4.549
        ]
      ]
    ]
  },
  "bbox": [
    -73.604,
    4.549,
    -74.064,
    4.276
  ]

Assets

STAC item content about assets (annotation, quicklooks and spectral bands files harvested from the source product) and EO bands for a CBERS-4 WPM 4-Bands multispectral compose pansharpening Dataset is the following:

  "assets": {
    "L2_compose_pansharpening_AOI_0": {
      "type": "image/tiff",
      "roles": [
        "data",
        "dn"
      ],
      "title": "WPM L2 compose pansharpening AOI 0",
      "href": "https://.../CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0.tif",
      "filename": "CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0.tif",
      "file:size": 0,
      "eo:bands": [
        {
          "name": "BAND1",
          "common_name": "blue",
          "center_wavelength": 0.485,
          "full_width_half_max": 0.07,
          "solar_illumination": 1984.65
        },
        {
          "name": "BAND2",
          "common_name": "green",
          "center_wavelength": 0.555,
          "full_width_half_max": 0.07,
          "solar_illumination": 1823.40
        },
        {
          "name": "BAND3",
          "common_name": "red",
          "center_wavelength": 0.66,
          "full_width_half_max": 0.06,
          "solar_illumination": 1536.38
        },        
        {
          "name": "BAND4",
          "common_name": "nir",
          "center_wavelength": 0.83,
          "full_width_half_max": 0.12,
          "solar_illumination": 981.91
        }
      ],
      "raster:bands": [
        {
          "data_type": "uint16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.184471,
          "offset": 0.0
        },
        {
          "data_type": "uint16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.29107,
          "offset": 0.0
        },
        {
          "data_type": "uint16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.297832,
          "offset": 0.0
        },
        {
          "data_type": "int16",
          "bits_per_sample": 12,
          "statistics": {
            "minimum": 0,
            "maximum": 32767.0
          },
          "scale": 0.232504,
          "offset": 0.0
        }
      ],
      "product_type": "WPM"
    },
    "metadata": {
      "type": "text/plain",
      "roles": [
        "metadata"
      ],
      "title": "Metadata file",
      "href": "https://.../urn_ogc_def_eop_inpe_cbers_4a_wpm_20230319_245_107_l2_compose_pansharpening_aoi_0-metadata.csv",
      "filename": "urn_ogc_def_eop_inpe_cbers_4a_wpm_20230319_245_107_l2_compose_pansharpening_aoi_0-metadata.csv"
    },
    "thumbnail": {
      "type": "image/jpeg",
      "roles": [
        "thumbnail"
      ],
      "href": "https://.../urn_ogc_def_EOP_INPE_CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0-icon.jpg",
      "filename": "urn_ogc_def_EOP_INPE_CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0-icon.jpg"
    },
    "overview": {
      "type": "image/png",
      "roles": [
        "overview"
      ],
      "href": "https://.../urn_ogc_def_EOP_INPE_CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0-preview.png",
      "filename": "urn_ogc_def_EOP_INPE_CBERS_4A_WPM_20230319_245_107_L2_compose_pansharpening_AOI_0-preview.png"
    }
  }

Product Calibration

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

INPE, CBERS-4A website, available at www.cbers.inpe.br. ↩
EO portal, CBERS-4A satellite mission, available at www.eoportal.org. ↩