基于星载高精度GPS观测数据的大气密度反演

Thermospheric density derived from onboard GPS observation data

星载高精度GPS观测数据可提供卫星速度和位置信息,而卫星的运行轨迹又与所处位置的大气密度紧密相关,因此可通过求解大气阻力微分方程,由高精度GPS观测数据反演出卫星运行轨迹上的热层大气密度.本文从星载高精度GPS观测数据出发,给出大气密度的反演方法,以及平均平动参数nM、反弹道系数B两个重要参数的解算过程,并以天宫一号为例,给出反演结果与天宫一号观测数据的比对.结果表明,反演结果与观测值符合很好,两者的均方差在2012年1月1日、2月24日分别为8.6%和8.4%,说明利用星载GPS观测数据反演大气密度是有效、可行的,可成为今后获取高精度大气密度的一种方法.

Onboard GPS observation data of a satellite includes accurate information of velocity and location,which are closely related to atmospheric density.Therefore,these GPS information can be used to derive thermospheric density through integration of differential equation.This paper presents a new method of deriving atmospheric density with a high temporal resolution from precise orbit data of low earth orbiting（LEO）space objects,and also presents the solution procedure of mean motion nM and the inverse ballistic coefficient B which are the two most important parameters for retrieving density.Tiangong-1is taken as an example to evaluate the effectiveness of the method.The result shows that the GPS-derived density is in good agreement with observed density with the average error 8.6% and 8.4% respectively on 1st January and24 th February in 2012 for Tiangong-1.This result indicates the method provides an effective and reliable way to obtain extensive and accurate thermospheric density.