Broadcast Ephemeris Model of the BeiDou Navigation Satellite System

Abstract

The BeiDou Navigation Satellite System (BDS) space constellation is composed of geostationary earth orbit (GEO), medium earth orbit (MEO), and inclined geosynchronous satellite orbit (IGSO) satellites, all of which adopt the Global Positioning System (GPS) broadcast ephemeris model of the United States of America (U.S.A). However, in the case of small eccentricity and small orbit inclination angle, the coefficient matrix is non-positive when fitting the broadcast ephemeris parameters due to the fuzzy definition of a few Keplerian orbit elements, thereby resulting in low precision or even failure. This study proposed a novel broadcast ephemeris model based on the second class of non-singular orbit elements. The proposed model can address the unsuitability of the classical broadcast ephemeris model in the condition of small eccentricity and small orbit inclination angle, and unify the broadcast ephemeris parameters user algorithm models of GEO, MEO, and IGSO. The proposed model is a 14-parameters broadcast ephemeris model constructed with the second class of non-singular orbit elements and the corresponding broadcast ephemeris parameters perturbation over time. Lastly, the proposed model was verified by precision orbit data generated by the Satellite Tool Kit (STK). Results show that the 14-parameters broadcast ephemeris model is suitable for the GEO, MEO, and IGSO satellites and has high fitting precision to fully meet the requirements of the BDS. Moreover, compared with the existing 16-parameters broadcast ephemeris model, two ephemeris parameters are decreased without reducing precision, thereby possibly saving communication resources. The proposed method provides a good prospect to optimize the design of the BDS broadcast ephemeris model.

Extended Kalman filter based statistical orbit determination for geostationary and geosynchronous satellite orbits in BeiDou constellation

“…• . The values of orbital parameters were selected to address all possible orientations of geostationary and geosynchronous orbits in BDS constellation (Huang and Tsai 2008;Xiaoganag and Mingquan, 2017). The satellite position estimated in ECI reference frame using these orbital parameters at time t 0 was considered as the initial guess for orbit determination algorithm using EKF.…”

Study on Optimal Broadcast Ephemeris Parameters for GEO/IGSO Navigation Satellites

“…Furthermore, this ephemeris can precisely describe predominant characteristics of east–west drifts of the subsatellite point of GEO satellites by simply adding two parameters. Xiaogang and Mingquan [ 17 ] presented a 14-element broadcast ephemeris model for GEO, IGSO, and MEO satellites meeting the requirements of BeiDou. As this model can avoid singularities in small inclination/eccentricity by introducing nonsingular orbital elements, its algorithm for computing satellite positions is more complicated than that for the GPS-type ephemeris model.…”