坐标系统的介绍

1.1　　WGS—84坐标系统

WGS—84坐标系是目前GPS所采用的坐标系统，是由美国国防部制图局建立，于1987年取代了当时GPS所采用的坐标系统(WGS—72坐标系统)而成为GPS目前所使用的坐标系统。

WGS—84坐标系的坐标原点位于地球的质心，Z轴指向BIHl984.0定义的协议地球极方向，X轴指向BIHl984.0的起始子午面和赤道的交点，Y轴与X轴和Z轴构成右手系。WGS—84系所采用椭球参数为：a=6378138m；f=1／298.257223563。

-Coordinate system introduced 1.1 WGS-84 coordinate system WGS-84 coordinate system is used by GPS coordinate system is established by the U.S. Defense Mapping Agency in 1987, was replaced by the coordinate system used by GPS (WGS-72 coordinates system) and a GPS coordinate system currently in use. WGS-84 coordinate system origin is at the center of mass of the Earth, Z-axis earth pointing BIHl984.0 very definition of the direction of the agreement, X-axis starting point BIHl984.0 the intersection of the meridian and the equatorial plane, Y axis and X axis and Z axis constitute a right-handed system. Department of WGS-84 ellipsoid parameters are used: a = 6378138m　f = 1/298.257223563.