## 5 Conclusions  
In this paper, the radiometric calibration of the OHS-F satellite covering all CMOSs and integration stages was carried out using RadCalNet ground-measured reflectance and atmosphere parameters. With the aim of completing the on-orbit radiometric calibration of all sensors on board a satellite constellation at different integration stages with low cost and high efficiency, a normalized radiometric calibration model was proposed and evaluated. The consistency of the calibration results for different RadCalNet sites and different integration stages was also analyzed. The radiometric response performance and change was also evaluated based on the calibration results. The main conclusions of this paper are as follows:  
1. The calibration model developed in this paper is suitable for use with hyperspectral sensors designed with gradient filters, which will be very helpful to the calibration of low-cost commercial micro-nano satellite constellations such as the \"Zhuhai-1\" satellite constellation.
2. The comprehensive gains in 2020 and 2021 calculated by using the calibration data for four sites of RadCalNet displayed good consistency, which shows the rationality of the comprehensive gain defined in this paper. Except for a few bands, the relative error of the calibration results in a single observation period was less than 10%.
3. The consistency of the calibration results for satellite sensors in 2021 was significantly higher than that in 2020, mainly due to the poor radiometric stability of satellite sensors in the early stage of the launch.
4. The overall trend in the comprehensive gain in 2020 and 2021 fitted by the least squares method was similar, which can reflect the change in the sensors' radiation performance over time. Except for the individual gas absorption bands and low signal-to-noise ratio bands, the fitting error was below 10% during the calculation of the comprehensive gains.
5. The radiometric calibration results were applied to obtain the satellite reflectance data. Compared to the reflectance spectrum of cotton measured on the ground, the trend in the surface reflectance curve retrieved by the OHS-F satellite CMOS2 sensor was consistent.  
Conceptualization, J.Y., L.Z. and Z.Y.; methodology, Q.Z. and Y.Z.; software, Q.Z.; validation, J.W., W.L. and Q.Z.; formal analysis, X.J.; investigation, Z.Y. and L.Z.; resources, J.Z.; data curation, Q.Z.; writing--original draft preparation, Q.Z.; writing--review and editing, Y.Z. and J.W.; visualization, W.L. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the 2019 Zhuhai Introduction of Innovation and Entrepreneurship Team (ZH0405-1900-01 PWC), the Key project of Aerospace Information Research Institute, Chinese Academy of Sciences (ID. E0Z206010F), the Youth Innovation Promotion Association, Chinese Academy of Sciences (ID. 2022128), Zhuhai Social Development Field in Science and Technology Plan Project (2220004000003) and the Dragon 5 ESA-MOST Cooperation (ID. 59166).  
**Data Availability Statement:** Original data download path: [[https://www.radcalnet.org/#](https://www.radcalnet.org/#)]([https://www.radcalnet.org/#](https://www.radcalnet.org/#))!/; The data used to support the findings of this study are available from the corresponding author upon request.  
**Acknowledgments:** The authors would like to thank [PERSON] for excellent technical support.  
**Conflicts of Interest:** We declare that we have no financial and personal relationships with other people or organizations that could inappropriately influence our work, and there is no professional or other personal interest of any nature or kind regarding any product, service, and/or company that could be construed as influencing the position presented in, or the review of, the manuscript.