Optimal attitude and position determination by integration of INS, star tracker, and horizon sensor

Navigation, for many years, has been one of the issues that preoccupied the human mind. The compass was the first instrument built for navigation by the Chinese. The compass determined geographical north instead of a magnetic one [1]. Gradually over time, humans found that it was possible to make orientations by celestial bodies. However, positioning was still impossible. In 1757, the first sextant able to measure angles of celestial bodies and the Earth´s horizon was invented by John Bird [1], [2], [3]. Also, the first star catalog containing 992 stars was obtained by Hip-parchus in 1437. The star catalog and the sextant were used for simple navigation [4]. More elaborate star catalogs were developed by advanced sky observation devices, such as SKY2000 with 299,460 stars, introduced in 2006 [5].