High-accuracy Long Arc Almanac Model Design for BDS

• Main Authors: CHANG Zhiqiao, HU Xiaogong, CHEN Liucheng, LI Xiaojie, ZU Anran, TANG Chengpan, HUANG Hua
• Format: Article
• Language: zho
• Published: Surveying and Mapping Press 2018-03-01
• Series: Acta Geodaetica et Cartographica Sinica
• Subjects: BDS; almanac fitting; signal acquisition; inter-satellite link; velocity
• Online Access: http://html.rhhz.net/CHXB/html/2018-3-298.htm

Almanac parameters can be used to assist signal acquisition for both conventional navigation and autonomous navigation. The extended validity of the almanac parameters not only enables the terrestrial receiver to make full use of almanac data when starting up,but also determines the frequency of the almanac uploaded and the satellite storage resources on-board for autonomous navigation with inter-satellite link observation. Based on analysis of the major perturbations of three types of BeiDou satellites and their effects on the long-term and long-period terms of the orbital elements,an almanac model with six orbital elements and five perturbation parameters is designed. The almanac fitting test is carried out based on the 90-day long arc orbit of BeiDou satellites in orbit throughout 2013. The results show that the new almanac model improves accuracy of almanac fitting. For Geostationary Earth Orbit (GEO) and Inclined Geosynchronous Orbit (IGSO) satellites,position fitting error is reduced from 200 km to more than 10 km even to several km and velocity error is reduced from 15 m/s to 0.6 m/s. The accuracy of the new model is about 20 to 30 times higher than that of the conventional model. For Medium Earth Orbit (MEO) satellite,position fitting error is about 5 km and velocity error is about 0.6 m/s regardless of which model,and the accuracy of the new method is improved about 15%. For 10 km position error upper limit of inter-satellite link,the maximum fitting arc length of the conventional model is about 14 days,and the maximum fitting arc length of the new almanac model can be extended to 45 days. The new almanac model extends the validity of almanac parameters,and optimizes almanac model for BeiDou Navigation Satellite System (BDS).