Fig. 1. Flow chart of NESR calibration

Fig. 2. Diagram of an infrared remote sensor NESR calibration system

Fig. 3. Uncertainty of spectral radiance of standard blackbody

Fig. 4. Schematic diagram of calibration optical path

Fig. 5. (a) Fourier transform spectrometer output changing with the rotation angle of reflector when observing standard blackbody @T=303 K, λ=10 μm; (b) Uncertainty u₂(λ) due to angle repeatability of rotating mirror

Fig. 6. (a) Fourier transform spectrometer observation of output signal of infrared integrating sphere changing with the rotation angle of reflector, T=153 K, λ=10 μm; (b) The uncertainty u₃(λ) affected by angle repeatability of rotating mirror

Fig. 7. (a) Temperature curve of calibration period; (b) Uncertainty u₄(λ) effected by the background radiation

Fig. 8. (a) Response curve of standard low temperature blackbody (300 K) measured by Fourier transform spectrometer; (b) Repeatability measurement results u₅(λ)

Fig. 9. (a) Output signal of primary integrating sphere tested by Fourier spectrometer; (b) Repeatability of primary integrating sphere u₆(λ)

Fig. 10. (a) Average of Fourier spectrometer output signal; (b) Instability u₈(λ)

Fig. 11. Relative radiance of primary integrating sphere during 30 min

Fig. 12. Surface uniformity measurement result of primary integrating sphere

Fig. 13. Relative spectral radiance of primary integrating sphere changed with measurement angle

Fig. 14. (a) Measurement result of L₁(λ) and L₂(λ) ; (b) SNR of Fourier spectrometer

Fig. 15. (a) Calibration result of NESR; (b) Uncertainty of NESR