The four spectral tunable light sources based on prism + DMD, grating + DMD, prism based + nematic liquid crystal and multicolor LED based are summarized. The first three spectral tunable light sources work similarly, mainly by projecting a fixed continuous spectrum of light output from the light source into the dispersive element, and then projecting onto the spectral modulation device through the converging lens to form a series of flat on the spectral modulation device. Straight spectral band, through the computer controlled spectral modulation device to change the output to the latter spectral distribution, and finally through the uniform mixing system to produce a prism + DMD-based spectral tunable light source with higher output energy, due to the prism used by the dispersive element, Therefore, its spectral resolution is non-linear, and the spectral resolution is higher at a shorter wavelength, and the uniform temperature source with adjustable color temperature and adjustable brightness. The spectral resolution is lower at longer wavelengths. The spectrally tunable source based on prism + DMD has a spectral resolution that does not change with wavelength due to the grating used by its dispersive element. However, due to the multi-level diffraction of the grating, its energy utilization is low, only 35% of the prism. about. The spectral modulation device based on the prism + nematic liquid crystal uses a nematic liquid crystal. The size of the nematic liquid crystal is large, and there is almost no diffraction phenomenon in the infrared band, so the spectral resolution in the infrared band is high. . The spectrally tunable light source based on multi-color LED has the lowest cost. It is combined by a plurality of monochromatic LEDs with different center wavelengths and different bandwidths, and the brightness and darkness of each LED is controlled by a special control algorithm to emit a whole band. The spectrally adjustable light output, and finally, after the light is mixed by the uniform light mixing system, a uniform light source with adjustable color temperature and adjustable brightness can be formed at the exit.
With the rapid development of vacuum ultraviolet detection technology, vacuum ultraviolet spectrum radiometers are increasingly used in space detection. Vacuum ultraviolet spectrum radiometers can acquire ionospheric disturbance information, solar activity information, celestial activity information, etc. Meteorological forecasting, defense and military security play an important role in supporting data. Typical examples of vacuum ultraviolet spectroradiometers are ionospheric photometers and wide-angle aurora imagers. Many of the satellites launched in the early stage are equipped with such vacuum ultraviolet spectroradiometers. Before the launch, the vacuum ultraviolet spectrometer needs to perform calibration test on the ground to establish a corresponding mathematical relationship between the output data and the input energy. However, the current domestic calibration device for the vacuum ultraviolet spectrometer has not been established, and vacuum ultraviolet light cannot be guaranteed. The accuracy of the calibration of the spectroradiometer, which in turn affects the accuracy of the inversion data, has a serious impact on national meteorological predictions, military safety, and so on. This paper provides a vacuum ultraviolet spectrum radiometer calibration scheme, including spectral radiance brightness responsivity calibration device, wavelength accuracy calibration device, vacuum ultraviolet BRDF measurement device, etc., which can achieve spectral radiance responsiveness and wavelength to vacuum ultraviolet spectroradiometer Calibration of parameters such as accuracy, and measurement of BRDF for vacuum ultraviolet diffuse reflectors. The spectral radiance responsiveness calibration device includes a vacuum chamber system, a vacuum ultraviolet light source, a vacuum ultraviolet integrating sphere, a vacuum ultraviolet diffuse reflector, a standard radiometer, and the like. The wavelength accuracy calibration device includes a vacuum chamber system, a vacuum ultraviolet light source, a vacuum ultraviolet monochromatic spectroscopic system, a standard filter, and a vacuum ultraviolet collimating optical system. The vacuum ultraviolet BRDF measuring device includes a vacuum chamber system, a vacuum ultraviolet light source, a vacuum ultraviolet monochromatic beam splitting system, a vacuum ultraviolet collimating optical system, a high-precision two-dimensional turntable, and a vacuum ultraviolet standard detector. Through technical breakthroughs, this paper breaks through the vacuum ultraviolet standard radiometer design technology, vacuum ultraviolet diffuse reflector BRDF measurement technology, large area high uniformity vacuum ultraviolet Lambertian radiation surface design technology, and synchronous radiation based traceability technology. The content of this paper mainly includes the overall scheme of calibration equipment, subsystem scheme, test data and uncertainty synthesis. Through the analysis and calculation of the test data, it can be known from the calculation results that the uncertainty of the spectral radiance responsivity measurement of the calibration device is better than 13% (K=2), and the uncertainty of the wavelength accuracy measurement is better than 0.1 nm (K= 2), BRDF measurement angle range is better than ± 60°. Compared with the measurement technology capabilities of other domestic research units, the calibration device covers the vacuum ultraviolet band, and the measurement uncertainty can meet the calibration requirements of the domestic vacuum ultraviolet space load development unit, effectively solving the calibration problem of vacuum ultraviolet space load. Through the development of the vacuum ultraviolet spectrum radiometer calibration device, the calibration problem of the domestic vacuum ultraviolet spectrum radiometer is solved, the vacuum ultraviolet measurement technology capability of China is improved, and the development of the vacuum ultraviolet spectrum radiometer is effectively guaranteed.
The spectrum not-matching of a calibration source with target source can affect star sensor measurement precision in the calibration of star sensor. Quantitatively analysis the different colour temperature light source due to the spectral mismatch to the focus light source at 0 magnitude. The results show that the star sensor calibration error caused by spectrum mismatch is up to 0.323 magnitude. Put forward a kind of spectrally tunable light source, which can simulate any spectral distribution of stars and applied to the star sensor calibration. The experimental results show that calibration accuracy can be enhanced within 0.62%.