三卫星运动基础及GPS星历.pptVIP

卫星轨道及运动基础(Satellite Orbits and the Principle of the Satellite Movement 概述(General Description) 高度,速度与周期(height, velocity, period). 开普勒定律与牛顿法则(Kepler’s laws and Newton’s laws). 卫星轨道的相关术语(Terminology relating to satellite orbits). 卫星轨道坐标系统(Satellite orbit coordinate systems). 开普勒定律(Kepler’s Law) 开普勒第一定律(Kepler’s 1st Law) 牛顿定律（Newton’s Law） 轨道周期（Orbit Period） 根据开普勒第三定律，轨道周期T与卫星运行轨道的半长轴有关（Orbit period T is related to the semi-major axis of orbital ellipse a according to Keplers 3rd law: 因此，卫星越高，运行周期越长（Hence the higher the satellite, the longer the period）. 轨道周期与卫星高度对应关系（Orbital period Satellite altitude） GPS Satellite Groundtracks 一些评论（Some comments) 卫星越高，卫星的可视时间越长（The higher the satellite, the longer they are visible above the horizon）(the extreme case is that of the geostationary satellites). 卫星越高， 覆盖的区域愈大（The higher the satellite, the better the coverage ） 没有卫星能够在全球位置同时看到（No satellite can be seen simultaneously from all locations on the earth.） 根据测量及定位原理的要求，需要一个或多个观测站同时观测到几颗卫星（Depending on the measurement type and positioning principles being employed there may be a requirement for observations to be made to several satellites simultaneously from one or more ground stations. Principle of Satellite Positioning Satellite Orbits Satellite Orbits (2) 卫星轨道坐标计算（GPS Satellite Coordinate Computation） 轨道摄动（Orbit Perturbations） 摄动源（Sources for Disturbing Accelerations） 重力的（Gravitational） 地球的形状不规则影响（Non-sphericity of the Earth） 潮汐作用力（Tidal attraction ，direct and indirect) 非重力的（Non-Gravitational） 太阳辐射压力（Solar radiation pressure (direct and indirect)） 大气牵引（Air drag） 相对论影响（Relativistic effects） 太阳风，磁场力等（Solar winds, magnetic field forces） GPS Satellite Orbits(courtesy International GPS Service (IGS)) Global Positioning System Declared fully operational in 1995. Currently 28 satellites. Global coverage of at least 5 satellites 24 hours/day anywhere on the globe. All weather Relatively inexpensive 10m absolute accuracy or better. * GPS测量原理及应用 中国矿业大学 About satellite