Abstract:Aiming at the application requirements of high attitude measurement accuracy of interferometric star tracker, the influence of grating diffraction efficiency on the measurement accuracy of starlight interferometry is analyzed. Based on the angular spectrum propagation theory, the imaging angle measurement model of the interferometric star tracker is constructed, and the energy distribution of the interference star point is simulated by numerical calculation. At the same time, the influence of the diffraction efficiency change caused by the change of the incident angle and the wavelength on the angle measurement accuracy of the starlight is analyzed respectively. The results show that the change of grating diffraction efficiency caused by the change of incident angle has little effect on the accuracy of starlight interferometry in the field of view of star sensor. The change of diffraction efficiency caused by wavelength change has a great influence on the accuracy of starlight interferometry. With the increase of spectral width, the accuracy of starlight interferometry decreases as a whole. When the starlight changes from monochromatic light to polychromatic light with spectral width of 300 nm, the accuracy of starlight interferometry decreases from about 0.01″to about 0.3″. The analysis results of this paper can provide theoretical basis and technical support for the engineering application of interferometric star tracker.