SpaceX星链卫星发布星历的研究

Research on Starlink Ephemeris Published by SpaceX

面对星链卫星(Starlink)严重干扰正常航天活动的现状,美国太空探索(SpaceX)公司发布的星链星历给星链卫星的相关研究带来契机,但缺乏明确说明也给进一步使用带来困难.分析星历文件后发现该星历基本是未来3d的预报轨道,平根数研究表明星历文件的前部分是至少考虑20阶非球形引力摄动的外推轨道,后部分是考虑J2项摄动的设计轨道,星历包含协方差信息,分析发现停泊和工作轨道卫星的星历在前1 d的精度优于2km,抬升阶段卫星星历的精度在半天不到的时间内迅速增长至数公里,通过发布星历的设计轨道可以更加精确地分析星链星座构型,尤其是各卫星的设计定点位置,有助于星链卫星的识别和跟踪.研究为星链星历的广泛应用提供有益参考,为星链卫星的机动检测和碰撞预警提供依据.

Faced with the significant disruption of normal space activities caused by Starlink satellites,the Starlink ephemeris published by SpaceX provides an opportunity for relevant research on Starlink satellites.However,due to the lack of clear instructions,it is challenging to utilize the data further.Analysis of the ephemeris file reveals that it primarily represents the predicted orbit for the next 3 days.Research on mean orbital elements indicates that the front part of the ephemeris is an extrapolated orbit with perturbations up to at least the 20th order of Earth’s gravitational field,while the latter part is a design orbit with J2 perturbation.The ephemeris includes covariance information,providing accuracy details.The covariance indicates that the accuracy of the ephemeris for satellites located in parking and working orbits is better than 2 km in the first day,while the accuracy of satellites in raising orbit increases rapidly to thousands of meters in less than half a day.Utilizing the designed orbit of the ephemeris enables a more accurate analysis of constellation configuration,especially the designated position of each satellite,thus facilitating the identification and tracking of Starlink satellites.The study provides valuable insights for the extensive application of Starlink ephemeris,serving as a beneficial reference for maneuver detection and collision warnings of Starlink satellites.