PerúSAT-1

PerúSAT-1 spacecraft

PerúSAT-1 spacecraft, © Airbus DS

Mission and sensor parameters

PeruSat-1 (also known as “PerúSAT-1”) is an operational Earth observation minisatellite mission, developed by Airbus Defence and Space for the government and Space Agency of Peru, with the support of the French government. The satellite was launched in September 2016 and has been providing high-resolution images for multiple applications, including crop monitoring, disaster risk management, road monitoring, and security. PeruSat-1 is equipped with a New AstroSat Optical Modular Instrument (NAOMI), built with silicon carbide (SiC), responsible for the image acquisition of the mission. NAOMI employs a compact Korsch telescope, including three aspheric mirrors and two folding mirrors.

Mission parameters

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

Parameter	Specifications
EO Mission	PerúSAT-1
Mission Short name	PER1
Providing Agency	CONIDA, Airbus, CNOIS
Date of launch	16/09/2016
Temporal coverage	Dec 2016 - present
Mission status	onGoing
Orbit Type	Sun-synchronous
Orbit Height	702.5 km
Orbit Period	99.79 min
Inclination	98.3°

Table 1 - PerúSAT-1 mission parameters.

Sensor specifications

Table 2 reports Instrument technical specifications

Parameter	Specifications
Instrument name	NAOMI (New AstroSat Optical Modular Instrument)
Imager Type	Pushbroom imager, Korsch telescope
Imaging Mode	PAN and MS (VIS, NIR)
Resolution	Very High Resolution - O-VHR (0 - 1m)
Ground Sampling Distance (m) at nadir	From 0.7 m to 2.5 m (PAN), from 2 m to 10 m (MS)
Viewing Angle	Standard +/-30°; maximum +/-47°
Nominal Swath Width at nadir	From 10 km to 60 km
Dynamic range at acquisition	12 bit per pixel

Table 2 - PerúSAT-1 instrument technical specifications.

Wavelength, Center wavelength, Bandwidth (or FWHM), and common band name (CBN) for each spectral band of the PerúSAT-1 sensor are described in table 3.

Spectral Band (ID)	Wavelength (nm)	Center Wavelength (µm)	Bandwidth or FWHM (µm)	CBN
Panchromatic (PAN)	450-750	0.600	0.3	pan
Blue (B)	450-520	0.485	0.07	blue
Green (G)	530-590	0.560	0.06	green
Red (R)	630-700	0.665	0.07	red
NIR (NIR)	752-885	0.818	0.133	nir

Table 3 - PerúSAT-1 spectral bands.

Geometric and radiometric processing

Geometric processing

A Primary product is in sensor geometry, synthesised on a perfect single and linear push-broom array.

The Ortho product is a georeferenced image in Earth geometry, corrected from acquisition and terrain off-nadir effects. The Ortho product also includes water and cloud masks.

Product processing levels and abbreviations are listed in table 4.

Product Processing level	Identifier	Value in DIMAP
Sensor or Primary	SEN	SENSOR
Orthorectified	ORT	ORTHO

Table 4 - PerúSAT-1 processing levels.

Radiometric processing

With the Basic radiometric processing the product represents raw data without any radiometric processing. Digital numbers quantify the energy recorded by the detector in 12 bits and thus in a 0-4095 range (stored as 16 bit in GeoTIFF). TOA reflectances can be derived from gain and offset provided in the product metadata.

Reflectance imagery is radiometrically corrected from sensor calibration and systematic atmospheric effects of the atmosphere (molecular or ‘Rayleigh’ diffusion).

In the Display radiometric option, a true color curve is computed by the Reflectance processing to obtain satellite imagery in 8-bit, optimised for a direct rendering on the screen.

Spectral modes

Acquisition spectral modes for PerúSAT-1 are P (panchromatic), and MS (multispectral). Table 5 provides the list of naming for the multiple PerúSAT-1 spectral modes.

Spectral processing	Spectral Mode
P	Panchromatic 1 band
MS	Multispectral 4 bands VNIR (Red, Green, Blue, NIR)
PMS	Pan-sharpened 4 bands VNIR (Red, Green, Blue, NIR)

Table 5 - PerúSAT-1 spectral modes.

PeruSAT-1 products are distributed as separate panchromatic and multispectral data sets, or as a pansharpened one.

Product description

Standard products options

PerúSAT-1 product includes panchromatic and/or multispectral data, delivered by the Image Production Facility under multiple standard product options that are listed in table 6.

Parameter	Specifications
Geometric processing options	Sensor, Ortho
Radiometric processing options	Basic, Reflectance, Display
Imagery Format	JPEG 2000, GeoTIFF, JPEG 2000 Optimised, NITF
Product Encoding	12, 16, or 8 bits
Spectral band combination 1	P: Panchromatic (1 band)
Spectral band combination 3	MS: Multispectral (4 bands RGB+NIR)
Spectral band combination 3	PMS: Pansharpening (4 bands RGB+NIR)

Table 6 - PerúSAT-1 standard product options.

Imagery and metadata formats

PerúSAT-1 is distributed using DIMAP V2. The entire dataset can be opened by selecting the DIM*.xml file. Imagery formats are: JPEG 2000, GeoTIFF, JPEG 2000 Optimised, NITF.

Ingested format

Information extracted from product annotation included in the STAC item of a PerúSAT-1 ORT P panchromatic and MS multispectral Dataset are listed below.

Properties

STAC item content about properties for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

  "properties": {
    "datetime": "2017-03-07T15:06:57Z",
    "created": "2024-10-28T10:06:39.2614108Z",
    "updated": "2024-10-30T22:38:52.0135803Z",
    "platform": "perusat-1",
    "constellation": "perusat",
    "mission": "perusat-1",
    "instruments": [
      "naomi-1"
    ],
    "sensor_type": "optical",
    "gsd": 1,
    "spectral_mode": [  
     "P",
     "MS"
    ],
    "title": "PERUSAT-1 NAOMI-1 ORTHO 2017-03-07 15:06:57",
    "providers": [
      {
        "name": "CONIDA, CNOIS, Airbus",
        "description": "PerúSAT-1 is a very-high-resolution Earth observation satellite system built for the government and Space Agency of Peru. Launched in 2016, this satellite is the first of its kind operated by Peru.",
        "roles": [
          "producer",
          "processor",
          "licensor"
        ],
        "url": "https://www.airbus.com/en/space/earth-observation/earth-observation-portfolio/perusat"
      },
      {
        "name": "CONIDA",
        "roles": [
          "licensor"
        ]
      }
    ],
    "license": "proprietary",
    "disaster:call_ids": [
      777
    ],
    "disaster:resolution_class": "VHR",
    "cpe:cos2_id": "777-CONIDA-PERUSAT_1-urn_ogc_def_EOP_ORT_PER1_20170307150657_000"
  }

Satellite

STAC item content about Satellite for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

  "properties": {
    "sat:platform_international_designator": "2016-058A"
}

View

STAC item content about View for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

  "properties": {
    "view:azimuth": 105.5,
    "view:sun_azimuth": 81,
    "view:sun_elevation": 56.9,
    "view:incidence_angle": 38.7
}

Processing

STAC item content about Processing for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

  "properties": {
    "processing:level": "ORTHO",
    "processing:software": {
      "M12Processor": "1.2.2"
    }
  }

Projection

STAC item content about Projection for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

  "properties": {
    "proj:epsg": 32718,
    "proj:shape": [
      41992,
      44768
    ]
  }

Geometry

STAC item content about Geometry for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

  "geometry": {
    "type": "Polygon",
    "coordinates": [
      [
        [
          -76.80828263,
          -12.34188494
        ],
        [
          -76.8621118,
          -12.58622352
        ],
        [
          -76.65052524,
          -12.6261459
        ],
        [
          -76.59040614,
          -12.38380893
        ],
        [
          -76.80828263,
          -12.34188494
        ]
      ]
    ]
  },
  "bbox": [
    -76.8621118,
    -12.6261459,
    -76.59040614,
    -12.34188494
  ]

Assets

STAC item content about assets (annotation, quicklooks and spectral bands files harvested from the source product) and EO bands for a PerúSAT-1 ORT P MS panchromatic and multispectral Dataset is the following:

    "PAN": {
      "type": "image/tiff",
      "roles": [
        "data",
        "dn"
      ],
      "title": "ORTHO P",
      "href": "https://.../ORT_PER1_20170307150657_000/PAN.TIF",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_P_000041/IMG_PER1_20170307150657_ORT_P_000041.TIF",
      "file:size": 3785166577,
      "eo:bands": [
        {
          "name": "PAN",
          "description": "Raw radiometric counts (DN) to TOA Radiance (L). Formulae L=DN/GAIN+BIAS",
          "common_name": "pan",
          "center_wavelength": 0.6,
          "full_width_half_max": 0.15,
          "solar_illumination": 1706.514896
        }
      ]
    },
    "PAN-wf": {
      "type": "image/tiff",
      "roles": [
        "data",
        "world-file"
      ],
      "href": "https://.../datasets/ORT_PER1_20170307150657_000/PAN-wf.TIF",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_P_000041/IMG_PER1_20170307150657_ORT_P_000041.TIF",
      "file:size": 3785166577
    },
    "metadata-P": {
      "type": "application/xml",
      "roles": [
        "metadata"
      ],
      "title": "Metadata file",
      "href": "https://.../ORT_PER1_20170307150657_000/metadata-P.XML",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_P_000041/DIM_PER1_20170307150657_ORT_P_000041.XML",
      "file:size": 147381
    },
    "overview-P": {
      "type": "image/jpeg",
      "roles": [
        "overview"
      ],
      "href": "https://supervisor.charter.uat.esaportal.eu/assets/calls/1033/acquisitions/datasets/ORT_PER1_20170307150657_000/overview-P.JPG",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_P_000041/PREVIEW_PER1_20170307150657_ORT_P_000041.JPG",
      "file:size": 25698
    },
    "thumbnail-P": {
      "type": "image/jpeg",
      "roles": [
        "thumbnail"
      ],
      "href": "https://.../ORT_PER1_20170307150657_000/thumbnail-P.JPG",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_P_000041/ICON_PER1_20170307150657_ORT_P_000041.JPG",
      "file:size": 1321
    },
    "MS": {
      "type": "image/tiff",
      "roles": [
        "data",
        "dn"
      ],
      "title": "ORTHO MS",
      "href": "https://.../ORT_PER1_20170307150657_000/MS.TIF",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_MS_000041/IMG_PER1_20170307150657_ORT_MS_000041.TIF",
      "file:size": 969003141,
      "eo:bands": [
        {
          "name": "B2",
          "description": "Raw radiometric counts (DN) to TOA Radiance (L). Formulae L=DN/GAIN+BIAS",
          "common_name": "red",
          "center_wavelength": 0.665,
          "full_width_half_max": 0.035,
          "solar_illumination": 1540.494123
        },
        {
          "name": "B1",
          "description": "Raw radiometric counts (DN) to TOA Radiance (L). Formulae L=DN/GAIN+BIAS",
          "common_name": "green",
          "center_wavelength": 0.56,
          "full_width_half_max": 0.03,
          "solar_illumination": 1826.087443
        },
        {
          "name": "B0",
          "description": "Raw radiometric counts (DN) to TOA Radiance (L). Formulae L=DN/GAIN+BIAS",
          "common_name": "blue",
          "center_wavelength": 0.485,
          "full_width_half_max": 0.035,
          "solar_illumination": 1982.671954
        },
        {
          "name": "B3",
          "description": "Raw radiometric counts (DN) to TOA Radiance (L). Formulae L=DN/GAIN+BIAS",
          "common_name": "nir",
          "center_wavelength": 0.8185,
          "full_width_half_max": 0.066,
          "solar_illumination": 1094.747446
        }
      ]
    },
    "MS-wf": {
      "type": "image/tiff",
      "roles": [
        "data",
        "world-file"
      ],
      "href": "https://.../ORT_PER1_20170307150657_000/MS-wf.TIF",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_MS_000041/IMG_PER1_20170307150657_ORT_MS_000041.TIF",
      "file:size": 969003141
    },
    "metadata-MS": {
      "type": "application/xml",
      "roles": [
        "metadata"
      ],
      "title": "Metadata file",
      "href": "https://.../ORT_PER1_20170307150657_000/metadata-MS.XML",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_MS_000041/DIM_PER1_20170307150657_ORT_MS_000041.XML",
      "file:size": 152203
    },
    "overview-MS": {
      "type": "image/jpeg",
      "roles": [
        "overview"
      ],
      "href": "https://.../ORT_PER1_20170307150657_000/overview-MS.JPG",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_MS_000041/PREVIEW_PER1_20170307150657_ORT_MS_000041.JPG",
      "file:size": 31603
    },
    "thumbnail-MS": {
      "type": "image/jpeg",
      "roles": [
        "thumbnail"
      ],
      "href": "https://.../ORT_PER1_20170307150657_000/thumbnail-MS.JPG",
      "filename": "VOL_PER1_ORT_001_000041/IMG_PER1_ORT_MS_000041/ICON_PER1_20170307150657_ORT_MS_000041.JPG",
      "file:size": 1781
    }
  },

Product Calibration

For PerúSAT-1 products calibration refer to the Optical Products Calibration (OPT-Calib) service and the calibration sheet available here.

[2]: CARACTERISTICAS DEL SATÉLITE PERUANO PERUSAT-1. CONIDA Agencia Espacial del Peru V1.0, 1 page.

[3]: EO Portal, PeruSat-1 Earth Observation Minisatellite, available at: www.eoportal.org

Airbus Defence and Space, PerúSAT mission, available at: www.airbus.com ↩