CHIME's end to end simulator (CHEES): simulating, testing and generating hyperspectral products

The E2E Performance Simulators are key tools in the development of an Earth Observation mission. They enable the assessment of the fulfilment of the mission requirements from the early stages of the design, providing simulated products at Level-0, Level-1B/1C or Level-2, and testing the performance of the processing algorithms. This important role is essential for CHIME, the hyperspectral mission among the Copernicus Sentinel Expansion Missions. CHEES, the E2E simulator developed for CHIME, integrates several modules to create a simulation chain that models the behaviour of this space mission from the characteristics of the scene on ground to the retrieval of the L2 products. CHEES can generate synthetic scenes with high spatial and spectral resolution using ad-hoc spectral databases or ingest realistic input scenes from airborne campaigns and/or in-situ measurements. The detailed simulation of the CHIME platform and instrument, as well as the L0-L1 prototype processors, is inherited from a dedicated project, OPSI, within the frame of the industrial activities of the CHIME space segment contract, ensuring the fidelity of simulation with respect to the real mission design. The retrieval of the L2 products (different vegetation products, soil organic carbon and kaolinite content) is performed by the L2 prototype processors provided within this project. CHEES also includes a Performance Assessment Module (PAM), which enables the assessment of the different products against reference values, and the generation of performance indicators. Also, a preliminary performance assessment campaign has been carried out with CHEES simulations to check the fulfilment of the CHIME MRD requirements.