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Rayference Radiometric Calibration Reference Published

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Radiometric calibration plays a central role in ensuring that satellite sensors deliver accurate, reliable, and traceable Earth Observation data. Rayference has recently published a new article titled “Elaboration of Simulated Hyperspectral Calibration Reference over Pseudo-Invariant Calibration Reference“ in the journal MDPI Atmosphere, presenting a thorough methodology for calibration and validation across a wide range of sensors and missions. This work has been funded through the European Space Agency – ESA’s HyperPICS (QA4EO) and EUMETSAT’s RPV4PICS projects.

Ensuring radiometric accuracy of Earth observation satellites is a critical challenge, especially when SItraceable references are unavailable. In this paper, we introduce a refined methodology to generate Radiometric Calibration References (RCRs) based on hyperspectral simulated reflectances over bright desert PICS like Libya4 and Gobabeb. 

The methodology introduces several key advancements:

  • Improved surface reflectance modelling using the Rahman–Pinty–Verstraete (RPV) model combined with the CISAR algorithm, ensuring more realistic representation of surface–atmosphere interactions.
  • Enhanced atmospheric characterization through integration of multiple state-of-the-art datasets, reducing uncertainties linked to atmospheric variability.
  • Use of the Eradiate Monte Carlo-based radiative transfer model, allowing highly accurate simulations across the hyperspectral domain.

Together, these refinements reduce uncertainty in simulated top-of-atmosphere reflectance, achieving an accuracy within ±3% in high-transmittance spectral regions. Validation exercises against multispectral and hyperspectral missions — including EMIT, EnMAP, and PRISMA — confirm the robustness and reliability of the approach.

Beyond the publication itself, Rayference can offer RRCR products over key desert targets such as Libya (20 km resolution) and Gobabeb (2 km resolution) for any satellite acquisition in the visible and near-infrared spectral ranges, upon request (using this form or contacting us directly). These products provide users with traceable, high-fidelity calibration references to improve sensor accuracy and ensure the interoperability of EO datasets.