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The non-scanning radiometer with short-wavelength (SW: 0.2–5.0 μm) and total-wavelength (TW: 0.2–50.0 μm) channels is the primary payload of the Integrated Earth–Moon Radiation Observation System (IEMROS), which is designed to provide comprehensive Earth radiation measurements and lunar calibrations at the L1 Lagrange point of the Earth–Moon system from a global perspective. This manuscript introduces a radiometer preflight calibration methodology, which involves background removal and is validated using accurate and traceable reference sources. Simulated Earth view tests are performed to evaluate repeatability, linearity, and gain coefficients over the operating range. Both channels demonstrate repeatability uncertainties better than 0.34%, indicating consistent and reliable measuring performance. Comparative polynomial regression analysis confirms significant linear response characteristics with two-channel nonlinearity less than 0.20%. Gain coefficients are efficiently determined using a two-point calibration approach. Uncertainty analysis reveals an absolute radiometric calibration accuracy of 0.97% for the SW channel and 0.92% for the TW channel, underscoring the non-scanning radiometer's capability to provide dependable global Earth radiation budget data crucial to environmental and climate studies. [ABSTRACT FROM AUTHOR]

The non-scanning radiometer with short-wavelength (SW: 0.2–5.0 μm) and total-wavelength (TW: 0.2–50.0 μm) channels is the primary payload of the Integrated Earth–Moon Radiation Observation System (IEMROS), which is designed to provide comprehensive Earth radiation measurements and lunar calibrations at the L1 Lagrange point of the Earth–Moon system from a global perspective. This manuscript introduces a radiometer preflight calibration methodology, which involves background removal and is validated using accurate and traceable reference sources. Simulated Earth view tests are performed to evaluate repeatability, linearity, and gain coefficients over the operating range. Both channels demonstrate repeatability uncertainties better than 0.34%, indicating consistent and reliable measuring performance. Comparative polynomial regression analysis confirms significant linear response characteristics with two-channel nonlinearity less than 0.20%. Gain coefficients are efficiently determined using a two-point calibration approach. Uncertainty analysis reveals an absolute radiometric calibration accuracy of 0.97% for the SW channel and 0.92% for the TW channel, underscoring the non-scanning radiometer’s capability to provide dependable global Earth radiation budget data crucial to environmental and climate studies.

The Earth's radiation budget (ERB), measured at the top of the atmosphere (TOP), quantifies the radiation imbalance between the Earth–atmosphere system and space. The ERB's measurement accuracy depends on the observation system's design and calibration technology. Fitting regional scanning data from polar satellite payloads is the most common way to obtain the global radiation budget. Additionally, the radiometers are calibrated by onboard stable radiation sources. We propose a new ERB radiometer operating at the Lagrange L1 point of the Earth–Moon system, which has the characteristic of observing the Earth and Moon on a hemispheric spatial scale. Hence, earth-integrated radiation can be measured directly. Furthermore, the Moon is used as a natural source for on-orbit calibration, and the attenuation of the instrument is monitored and corrected through periodic observations. This paper presents the concept of the radiometer and focuses on the design and analysis of the radiometer's observation systems based on optical design and stray radiation suppression. The results show that the system has good imaging quality. The external stray radiation suppression reached an order of 10−8, and the thermal stray radiation can be eliminated by temperature control and compensation. The radiometer will provide long-term integrated ERB data. [ABSTRACT FROM AUTHOR]

The Earth’s radiation budget (ERB), measured at the top of the atmosphere (TOP), quantifies the radiation imbalance between the Earth–atmosphere system and space. The ERB’s measurement accuracy depends on the observation system’s design and calibration technology. Fitting regional scanning data from polar satellite payloads is the most common way to obtain the global radiation budget. Additionally, the radiometers are calibrated by onboard stable radiation sources. We propose a new ERB radiometer operating at the Lagrange L1 point of the Earth–Moon system, which has the characteristic of observing the Earth and Moon on a hemispheric spatial scale. Hence, earth-integrated radiation can be measured directly. Furthermore, the Moon is used as a natural source for on-orbit calibration, and the attenuation of the instrument is monitored and corrected through periodic observations. This paper presents the concept of the radiometer and focuses on the design and analysis of the radiometer’s observation systems based on optical design and stray radiation suppression. The results show that the system has good imaging quality. The external stray radiation suppression reached an order of 10−8, and the thermal stray radiation can be eliminated by temperature control and compensation. The radiometer will provide long-term integrated ERB data.