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TECHNOLOGY AND CODE article

Front. Remote Sens.
Sec. Multi- and Hyper-Spectral Imaging
Volume 5 - 2024 | doi: 10.3389/frsen.2024.1347507
This article is part of the Research Topic Optical Radiometry and Satellite Validation View all 21 articles

HYPSTAR: a Hyperspectral Pointable System for Terrestrial and Aquatic Radiometry

Provisionally accepted
  • 1 Tartu Observatory, University of Tartu, Tõravere, Estonia
  • 2 Laboratoire Océanographique de Villefranche, Sorbonne Université, Villefranche-sur-mer, France
  • 3 Royal Belgian Institute of Natural Sciences, Brussels, Belgium

The final, formatted version of the article will be published soon.

    Optical Earth observation satellites provide vast amounts of data on a daily basis. The top-ofatmosphere radiance measured by these satellites is usually converted to bottom-of-atmosphere radiance or reflectance which is then used for deriving numerous higher level products used for monitoring environmental conditions, climate change, stock of natural resources, etc. The increase of available remote sensing data impacts decision-making on both regional and global scales, and demands appropriate quality control and validation procedures. A HYperspectral Pointable System for Terrestrial and Aquatic Radiometry (HYPSTAR) has been designed to provide automated, in-situ multiangular reflectance measurements of land and water targets. HYPSTAR-SR covers 380 -1020 nm spectral range at 3 nm spectral resolution and is used at water sites. For land sites the HYPSTAR-XR variant is used with the spectral range extended to 1680 nm at 10 nm spectral resolution. The spectroradiometer has multiplexed radiance and irradiance entrances, an internal mechanical shutter, and an integrated imaging camera for capturing snapshots of the targets. The spectroradiometer is mounted on a two-axis pointing system with 360• range of free movement in both axes. The system also incorporates a stable light emitting diode as a light source, used for monitoring the stability of the radiometric calibration during long-term unattended field deployment. Autonomous operation is managed by a host system which handles data acquisition, storage, and transmission to a central WATERHYPERNET or LANDHYPERNET server according to a pre-programmed schedule. The system is remotely accessible over the internet for configuration changes and software updates. The HYPSTAR systems have been deployed at 10 water and 11 land sites for different periods ranging from a few days to a few years. The data are automatically processed at the central servers by the HYPERNETS processor and the derived radiance, irradiance, and reflectance products with associated measurement uncertainties are distributed at the WATERHYPERNET and LANDHYPERNET data portals.

    Keywords: Satellite validation, hyperspectral surface reflectance, automated field spectroradiometry system, WATERHYPERNET, LANDHYPERNET, HYPSTAR

    Received: 30 Nov 2023; Accepted: 12 Jun 2024.

    Copyright: © 2024 Kuusk, Corizzi, Doxaran, Duong, Flight, Kivastik, Laizans, Leymarie, Muru, Penkerc’h and Ruddick. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Joel Kuusk, Tartu Observatory, University of Tartu, Tõravere, Estonia

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