GPS在卫星追踪(SST)技术中的应用

Application of GPS in Satellite to Satellite Tracking (SST) Technology

GPS(Global Positioning System)通过终端接收并处理GPS卫星所发射的无线电磁波信号,从而确定用户接收端(观测站)到轨道卫星的天地距离,从而确定并定位观测站的方位。卫星对卫星的追踪(SST)技术实质是通过高分辨技术来测量两颗GPS卫星间的距离变化,SST技术主要是指高低卫星追踪和低低卫星追踪两类。前一种是高轨道卫星(如GPS卫星、对地静止轨道卫星等)追踪低轨道(LEO)卫星或者空间飞行器,后一种近似为同一低轨道上空的两颗卫星之间的追踪,两颗GPS卫星之间可以距离数百千米。这两种卫星对卫星的跟踪技术都将LEO卫星作为反映地球重力场变化的传感器,利用卫星之间单向或者双向的测距系统,来测定GPS卫星间的相对速度及速度变化率。本文在国内外SST研究基础上,针对目前的相关热点问题,对SST确定的重力场理论与方法进行了系统性学习与研究。

GPS （global positioning system） is used to determine distance between space to ground of user＇s receiving terminal （observation station） to orbit satellite by terminal receiving and processing radio electromagnetic wave signal transmitted by GPS satellite so as to determine and position observation station in azimuth.Technological essential of satellite to satellite tracking （SST） is to measure distance variation between two GPS satellites via high resolution technology,mainly referring to kinds of technology like high-low satellite tracking and low-low satellite tracking.The former refers to high orbit satellite （for example GPS satellite,to ground stationary orbit satellite,etc） tracking low orbit satellite （LEO） or aircraft in space; the latter is similar to tracking between two satellites over same low orbit.The distance between two GPS satellites can be up to hundreds of kilometer.These two-kinds of satellite to satellite tracking technology will use LEO satellite as sensor to reflect change of earth gravitational field to survey relative velocity and percentage velocity variation by using one-way or two-way ranging system between two satellites.On basis of study on domestic and oversea SST,aiming at actual correlated hotspot issue,the gravitational field theory and method determined with SST is studied systematically.