A Process for Retrieval of Data from a Compiled Star Catalogue

Abstract

For certain space vehicles there is a need to accurately determine vehicle attitude. Some of these spacecraft, such as NASA’s planned LANDSAT-D and Gamma Ray Explorer, will use observations from star sensors to determine fine attitude. One input to the attitude determination software is a specialized stellar data base. The initial step in this software is to identify and match the star images with catalogue stars. The Naval Surface Weapons Center (NSWC) has compiled a special star catalogue for such applications. This paper describes the criteria for the NSWC catalogue and how it is utilized. Because of the large number of stars available, a subset can be divided into cells defined by mission criteria. The cells are stored as a random access mass storage file, thus allowing quick access to the information. This greatly reduces execution time for the software. One scheme for accessing stars from mass storage is described.