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The lunar is a stable radiation source, which can be used as an ideal source for in-orbit calibration of remote sensors and evaluation of detector degradation performance. A passive lunar calibration method is proposed for Chinese ocean color satellite, which reuses field of view of cryogenic-deep-space calibration, periodically achieves monthly lunar calibration tasks. This work enriches ocean color satellite in-orbit calibration methods and improves data accuracy of products. The start and stop angle vector of cryogenic-deep-space, satellite-lunar pointing vector and imaging observation model are established in simulation software. The satellite and payload parameters are used as input conditions to carry out the simulation of the lunar calibration timing. The lunar calibration timing of payload COCTS (Chinese Ocean Color and Temperature Scanner) is simulated 00:00:00~24:00:00UTC on June 28, 2020. The result shows that lunar calibration was carried out for twice. The starting UTC (Universal Time Coordinated) time was 15:16:44 and 16:56:37, respectively. The duration was two seconds. Through analyzing the 0-level products of in-orbit satellite received by the application system, the cryogenic-deep-space data showed abnormal changes at 15:16:45 and 16:56:38 on June 28, 2020, and the DN (Digital Number) values dropped from 300 to 62 and 73, respectively. The in-orbit calibration timing is basically the same as the simulation results, and the numerical anomalies of cryogenic-deep-space data are consistent with the principle design, indicating that the simulation model can be used to predict the in-orbit lunar calibration timing of ocean color satellite. The analysis method can be used for cryogenic-deep-space imaging mission mode and payload design of the follow-up ocean color satellites.
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