DIGISTAR - A low cost micro star tracker

Abstract

We describe an analytical, computational, and experimental study designed to gain the insights needed for a third generation star tracker and realtime attitude determination system. Novel features include some refinements of methods for preliminary and final attitude estimation, and star catalog design and real-time access. We summarize analysis, computation,. design, and ground validation of hardware and software.

A new star pattern identification technique using an improved triangle algorithm

“…In order to improve the retrieval speed, it is necessary to partition the star catalogue properly. The star catalogue partitioning approaches mainly include the declination belt method, 13 circular cone method, 10 sphere rectangle method 14 and inscribed cubes method. 15 Relatively speaking, the inscribed cubes method can make the partition of star catalogue have better uniformity, but it actually partitions the surface of inscribed cubes uniformly with no overlap.…”

“…9 Currently, the triangle star pattern identification algorithm has been widely used in practical engineering, such as Denmark's spaceborne star sensor of Oereted small satellite and America's DIGISTAR mini star tracker. 10 It has many variants, such as sixfeature algorithm proposed by Scholl et al 11 and pyramid algorithm proposed by Mortari et al 12 The traditional triangle algorithm is simple in structure and easy in use. The basic principle is that all the guide triangles constituted by guide stars are stored for retrieval matching, taking the angular distances between three stars as the characteristic parameters.…”

Relative Attitude Determination of Formation Spacecraft Based on Flight Mechanics

“…In this section, the measurement models of VisNav is shown. Photogrammetry is the technique of measuring objects (two or three dimensions) [2] from photographicimages or LOS measurements. The relationship between the position/attitude and the observations used in photogrammetry involves a set of collinearity equations, which are reviewed in this section.…”

Full-sky autonomous star identification based on radial and cyclic features of star pattern

“…Using two stars and their pairings in reference, we can easily calculate the attitude matrix of star sensor [14]. Furthermore, a virtual sky image, called as the reference sky image, can be generated from the attitude matrix [1].…”