直接观测太阳的星上定标方案中,设计了直径分别为20 mm和0.5 mm的光阑用于切换观测地球和太阳,两个光阑面积比的高精度测量是保证定标精度的关键。 论述了光阑面积的测量原理,基于光阑面积测量的特点,利用激光点阵扫描法和通量比较法分别测得两个光阑与参考光阑的面积比,最终得 出Φ20 mm和Φ0.5 mm光阑的面积比值为1604.381,评估合成不确定度为0.046%。为光阑大面积比的高精度测量提供了可行方案,支持直接观测太阳的星上定标方法。

In the project of on-orbit calibration, two apertures were designed with nominal diameters of 20 mm and 0.5 mm for switching observations of the earth and the scen, the high precision measurement of the two apertures area ratio is the key to ensure the calibration accuracy. The measurement method of the area of aperture was discussed briefly. Based on the measurements characteristics of the area of aperture, the ratio of the area of the two apertures to the area of the referenced aperture was measured by utilizing laser raster scanning and flux comparison. The area ratio of aperture Φ20 mm to Φ0.5 mm was 1604.381 with a total relative combined standard uncertainty 0.046%. The conclusion provides a feasible solution for the high-precision measurement of the aperture area ratio, and supports the on-orbit calibration of direct solar viewing.