Hyper-500 Data Specification

The Hyper-500 product offers high-resolution hyperspectral imagery, capturing 32 bands at under 5m resolution.

Technical Specifications Overview

• 2 satellites
• Ground Sampling Distance (GSD): 4.75m @ Nadir
• Swath Width: 19 km
• Bit Depth: 8, or 12 bits
• Sun-Synchronous Orbit (SSO) at 14:00 hours Local Time Descending Node (LTDN).
• Swath Resolution: 4096 pixels wide

Spectral Bands

The hyperspectral payload captures 32 channels in the visible and near infrared spectral range. The imager captures in linescan mode using a wedge filter. The 32 spectral bands central wavelengths can be chosen by the band start row, with the filter width being influenced by the number of dTDI stages in use. For simplicity, below the central wavelengths are listed at 1 dTDI stage with the nominal band start rows selected.

• PAN: 625nm (FWHM: 250nm)
• Band 0: 440nm - Blue (FWHM: 16.40nm in Hammer and 17.40nm in Acc1)
• Band 1: 455nm - Blue (FWHM: 16.93nm in Hammer and 17.93nm in Acc1)
• Band 2: 469nm - Blue (FWHM: 17.42nm in Hammer and 18.42nm in Acc1)
• Band 3: 485nm - Blue (FWHM: 17.98nm in Hammer and 18.98nm in Acc1)
• Band 4: 499nm - Blue (FWHM: 18.47nm in Hammer and 19.47nm in Acc1)
• Band 5: 515nm - Blue/Green (FWHM: 19.03nm in Hammer and 20.03nm in Acc1)
• Band 6: 529nm - Green (FWHM: 19.52nm in Hammer and 20.52nm in Acc1)
• Band 7: 545nm - Green (FWHM: 20.08nm in Hammer and 21.08nm in Acc1)
• Band 8: 560nm - Green (FWHM: 20.60nm in Hammer and 21.60nm in Acc1)
• Band 9: 574nm - Green (FWHM: 21.09nm in Hammer and 22.09nm in Acc1)
• Band 10: 589nm - Green/Yellow (FWHM: 21.62nm in Hammer and 22.62nm in Acc1)
• Band 11: 605nm - Yellow (FWHM: 22.18nm in Hammer and 23.18nm in Acc1)
• Band 12: 620nm - Yellow/Red (FWHM: 22.70nm in Hammer and 23.70nm in Acc1)
• Band 13: 634nm - Red (FWHM: 23.19nm in Hammer and 24.19nm in Acc1)
• Band 14: 649nm - Red (FWHM: 23.72nm in Hammer and 24.72nm in Acc1)
• Band 15: 664nm - Red (FWHM: 24.24nm in Hammer and 25.24nm in Acc1)
• Band 16: 679nm - Red (FWHM: 24.77nm in Hammer and 25.77nm in Acc1)
• Band 17: 694nm - Red (FWHM: 25.29nm in Hammer and 26.29nm in Acc1)
• Band 18: 709nm - RedEdge (FWHM: 25.82nm in Hammer and 26.82nm in Acc1)
• Band 19: 724nm - RedEdge (FWHM: 26.34nm in Hammer and 27.34nm in Acc1)
• Band 20: 739nm - RedEdge (FWHM: 26.87nm in Hammer and 27.87nm in Acc1)
• Band 21: 755nm - RedEdge (FWHM: 27.43nm in Hammer and 28.43nm in Acc1)
• Band 22: 770nm - RedEdge (FWHM: 27.95nm in Hammer and 28.95nm in Acc1)
• Band 23: 785nm - RedEdge (FWHM: 28.48nm in Hammer and 29.48nm in Acc1)
• Band 24: 799nm - Near Infra-Red (FWHM: 28.97nm in Hammer and 29.97nm in Acc1)
• Band 25: 814nm - Near Infra-Red (FWHM: 29.49nm in Hammer and 30.49nm in Acc1)
• Band 26: 830nm - Near Infra-Red (FWHM: 30.05nm in Hammer and 31.05nm in Acc1)
• Band 27: 844nm - Near Infra-Red (FWHM: 30.54nm in Hammer and 31.54nm in Acc1)
• Band 28: 860nm - Near Infra-Red (FWHM: 31.10nm in Hammer and 32.10nm in Acc1)
• Band 29: 874nm - Near Infra-Red (FWHM: 31.59nm in Hammer and 32.59nm in Acc1)
• Band 30: 884nm - Near Infra-Red (FWHM: 31.94nm in Hammer and 32.94nm in Acc1)

File Naming Convention

The file names for Hyper-500 data products follow a standard convention as defined in the table below. This convention captures high level metadata in the name to allow for quick and easy visual identification.

Example: HAMMER_L0_raw_000000000X_20211001101205_20211001101210_E72EFC12.extension

L1C Data Product Definition

Collection ID: [mission]-l1C-cogs

Level 1C data products have TOA reflectance units and have been orthorectified with a moderate resolution DEM, resulting in a cartographic product with accurate geolocation.

Applied Processes

A L1C data product is taken as input, and the following processes are performed:

1. Conversion from TOA radiance to TOA reflectance
2. RPC refinement using a global reference image (GRI) and a digital elevation model (DEM)
3. Orthorectification

Assets

All Hyper-500 L1C Items in the Collection have the following assets with the corresponding asset field key, file format and descriptions.

Specifications

• Geoaccuracy < TDB m CE90
• DEM resolution 30 m (SRTM 1 arcsecond)

STAC Extensions

• Processing (partially implemented)
• Electro-Optical (band object implemented)
• Item assets (assets object implemented)
• Satellite (Field platform_international_designator implemented)
• Raster (band object implemented)

L1B Data Product Definition

Collection ID: [mission]-l1B-cogs

Level 1B data products have been radiometrically corrected and converted to physical units of TOA radiance (W m⁻² sr⁻¹ um⁻¹). Products are also geometrically corrected, removing spatial distortions due to scale variations, satellite rotation, and warping caused by the curvature of the Earth's surface and viewing angle. Corresponding pixels in each of the 32 bands are co-aligned, permitting accurate band-to-band calculation and multispectral composite imagery. Ancillary and additional platform metadata is included in additional assets.

Applied Processes

A L1A data product is taken as input, and the following processes are performed:

1. Radiometric correction
   • Apply the radiometric coefficients, part of the L1A product assets, to convert L1A DNs into radiance, accounting for dark and flat fields.
2. Geometric correction
   • Perform the band alignment of all bands with respect to the reference one (red band)
   • Apply the RPCs, part of the L1A product assets, to georeference the rasters

Assets

All Hyper-500 L1B Items in the Collection have the following assets with the corresponding asset field key, file format and descriptions.

Specifications

• Geoaccuracy < TDB m CE90
• Band alignment < 0.2 pixels
• Radiometric accuracy < TBD %

STAC Extensions

• Processing (partially implemented)
• Electro-Optical (band object implemented)
• Item assets (assets object implemented)
• Satellite (Field platform_international_designator implemented)
• Raster (band object implemented)

L1A Data

Collection ID: [mission]-l1A-cogs

This collection consists of Hyper-500 Level-1A data products. Products in this collection have been reconstructed into a common image format. Each of the bands have a relative correction, removing inconsistent illumination generated by sensor characteristics identified in lab-based calibration. Metadata is included that can be used to radiometrically correct the images. Ancillary data from the platform is included in the metadata asset.

STAC Properties

Information about the assets, geometry, and bands can be accessed in STAC via the following standard extensions:

• Electro-Optical Extension
• Item Assets
• View Geometry
• Raster Extension (only bits_per_sample)

In addition, the following custom properties have been added:

• opencosmos:compression: none, lossless, or lossy

Assets

All Hyper-500 L1A Items in the Collection have the following assets with the corresponding asset field key, file format and descriptions.

L0 Data

Collection ID: [mission]-l0

This collection consists of Hyper-500 Level-0 data products, which are unprocessed outputs from the satellite payload. Level-0 products are the basis from which all other higher level products are produced. This collection contains assets that might not be processable to a higher level product, this normally happens when an acquisition was carried out to test, calibrate, or commission some part of the satellite.

STAC Properties

Information about the assets, geometry, and bands can be accessed in STAC via the following standard extensions:

• Electro-Optical Extension
• Item Assets
• View Geometry
• Raster Extension (only bits_per_sample)

In addition, the following custom properties have been added:

• opencosmos:compression: none, lossless, or lossy
• opencosmos:capture_mode: which mode was used to capture the image, can be snapshot or linescan
• opencosmos:processable: boolean that indicates if the file can be processed to L1A level. Some configurations, like snapshots, cannot be processed to level 1A

Assets

All Hyper-500 L0 Items in the Collection have the following assets with the corresponding asset field key, file format and descriptions.

Metadata

This file is included for ease of access to the metadata without needing to decode the binary file. Most of the information contained in this file is also contained in the binary file.

Ancillary

See the common Open Cosmos Ancillary Format.