Guide Triangle Catalog Generation Based on Triangle Density and Utilization for Star Sensors

The guide star catalog is an important component of star identification algorithms for star sensors that indirectly determines their identification rate and other performance characteristics. Currently, star identification algorithms based on triangle features have high identification rates and strong anti-interference abilities. However, this type of method usually requires a large-size guide triangle catalog. Without proper construction, many triangles in the catalog are barely used in the pattern recognition process. In this paper, a guide triangle catalog generation method for star identification based on triangle density and utilization is proposed. First, a model of the star density and triangle density distribution in the celestial sphere is established. Then, considering factors such as the sizes and shapes of the triangles and the brightness levels of the stars, a triangle utilization model is established. Based on these models, a high-triangle-utilization, low-size guide triangle catalog is generated by eliminating low-utilization triangles to the greatest extent possible under the premise of ensuring a minimum triangle density. Some experiments were conducted to prove the performance of the proposed method. Compared with the existing methods under the same conditions, the size of the catalog constructed by the proposed method can be reduced by 70%–90%. Because the selected triangles are different, the proposed catalog exhibits a higher identification rate than other catalogs of the same size.