Fig. 1. The blackbody count of Band 3 on 20180321

Fig. 2. The illustration of solar incidence during the satellite exiting penumbra

Fig. 3. Comparison of the blackbody counts between Band 3 and Band 10

Fig. 4. The systematic diagram of the full chain automatic simulation and analysis program for payloads

Fig. 5. The illustration of optical path for on-orbit IR calibration

Fig. 6. Results of the simulation for on-orbit IR calibration，Note： （a） distribution on the receiving plane，（b） distribution on the focal plane of the detector

Fig. 7. Results of the simulation for on-orbit IR calibration

Fig. 8. The distribution of the sunlight vector on 20180321

Fig. 9. The illustration of the stray light path for solar incidence：（a） the sunlight vector in satellite coordinate system，（b） the path of solar stray light inside the instrument

Fig. 10. The simulation results of the solar incidence

Fig. 11. Comparison between the simulation results and the on-orbit data，Note： （a） the equivalent blackbody temperature retrieved by the blackbody count of Band 3，（b） the simulation results of the solar incidence