Fig. 1. Mathematical model of space-based ship detection

Fig. 2. Variation of sea surface temperature and solar zenith angle during one day：(a) changes in sea surface temperature；(b) solar zenith angle variation

Fig. 3. Temperature variation of the ship throughout the day

Fig. 4. The relationship between sun-ship atmospheric transmittance and solar zenith angle

Fig. 5. Ocean background irradiance

Fig. 6. Atmospheric transmittance and atmospheric path radiation：(a) ship-camera atmospheric transmittance；(b) atmospheric path radiation

Fig. 7. Detection spectrum optimization method

Fig. 8. Day and night ship detection images of the same detection site

Fig. 9. SNR under different sea-surface temperature differences：(a) detection of SNR under different temperature differences in summer；(b) SNR for detection of different temperature differences in winter

Fig. 10. SNR of 24 hours in a day