1. 1 Error Categories 1. Errors related to GPs Satellites 2. Errors related to GPS signal propagation

Perigee and Apogee: The point of closest approach of the satellite with respect to the earth's center of mass is called perigee and the most distant position is the apogee. Nodes: The intersection between the equatorial and the nit sphere is termed the nodes, where the ascending node defines the northward

Today's Lecture Examine specifics of GPS signals Multiple modulations on same carrier signal Structure of signals GPS receiver operation and satellite acquisition

3. Reference Systems Book: p 25-38 Dr Guoqing Zhou 1.1 Overview 1.2 A Group of Basic Ce GPS Basic Positioning Principle

GPS Basic Positioning Principle Two reference systems: Time and Coordinate Syst

Fundamental knowledg Quick Overview Kelperian 3 Laws First Law: ellipse, Sun is a focus Second law: the same area in same time Earth

一、GPS高程问题 二、复习

利用GPS进行绝对定位时,定位精度受卫星轨道误 差、钟差及信号传播误差等因素影响,尽管其中的- 些系统误差,可以通过模型加以消除,但残差仍不 忽视。实践表明,目前静态绝对定位精度为米级 态绝对定位精度仅为10-40m。 GPS相对定位也叫差分GPS定位,是目前GPS定位中 精度最高的一种,广泛用于大地测量、精密工程测 量、地球动力学研究和精密导航

假设在同一观测时段,只有两台接收机在一条基线上进行了 同步观测工作。从这一条件出发,根据间接平差原理,讨论载 波相位观测量不同线性组合的平差模型。这些模型易于推广到 多台接收机观测情况

一、单基线平差模型 二、模型简单、易于编程实现 三、基线之间相关性被忽略 四、不易发现粗差