Astronomic Positioning and Orientation Method for Inhomogeneous Stellar Distributions

Abstract

Astronomic positioning and orientation can be used to obtain the astronomic longitude and latitude of a station and the astronomic azimuth of a ground target by observing stars. The results of the positioning and orientation depend not only on the instrument, environment, and observed star, but also on the solution method. Due to atmospheric refraction and instrumentation, there is a systematic error in the zenith distance of observed starlight during astronomic measurements using theodolites. The existing methods either do not consider the systematic error of the zenith distance, or do not fully utilize all directional information of the star. Therefore, existing methods cannot simultaneously achieve high-accuracy astronomic positioning and orientation, particularly in the case of poor stellar distribution. To address this problem, an astronomic positioning and orientation method that considers the zenith distance system error is proposed. The experimental results showed that the proposed method had a higher positioning accuracy than the traditional astronomic positioning method. In addition, the new method showed significant advantages in instances of inhomogeneous distribution such as cloudy or daytime observation.