全球导航卫星系统的测高研究

以美国全球定位系统为代表的全球导航卫星系统具有广泛的应用领域，特点是能够在全球范围和近地空间，全天候地提供飞行器的位置、速度和时间信息。

Height Measuring With GNSS

The Global Navigation Satellite System - GNSS (such as GPS ) can be widely used for positioning, navigation and guidance of ships, land vehicles, aircrafts and spacecrafts. It will give the user's position, velocity and exact time information through proper processing of signals from GPS satellites. During the process, a transformation of positioning data from a mathematical earth to a physical earth is involved, which will give rise to a height measuring error of 2 to 6 meter with the present method available,due to the irregularity of the earth gravitational field. In this paper, height measurement is studied and three methods for more accurate height measuring are developed: by differential GPS, or by one or three added surveyed points. With computing of a practical example, the new approach is proved to be effective.