Comparisons of Autonomous Orbit Determination Methods for Spacecraft Using Starlight Refraction;

Four-pointed or six-pointed star sometimesKGcan be seen in a spinel, but it is rarely reported that there are multiple groups of asterism on the same spinel.

In this article, the spinel with both four groups of six-pointed star and three groups of four-pointed star have been studied by means of conventional gemmological techniques, Raman spectroscopy and electron probe.

An autonomous navigation scheme is designed by using the star sensor and horizontal instrument to observe the elevation angle of star.

Autonomous Orbit Determination by Stellar Refraction for Spacecraft;

In this technology,the space reference of constellation is obtained by using stellar refraction to provide absolute position information of all or .

Based on the analysis and reasoning of the star observation from carrier in low altitude and high altitude,a optimal star selection arithmetic of the celestial positioning is brought forward based on the spherical astronomy.