By using constructing elements between GPS net work point and state control point determined by ordinary survey instruments and making use of converting formula of the WGS-84 coordinate system and occupation station original based grid system, the WGS-84 coordinates of the state control point were calculated.

This article introduced the conception of reference frame which were used for controlling and commanding the air defense missile, expatiated on the arithmetic and implementation for the transformation from nine nine pane coordinate to station center right-angle coordinate in horizon.

The other one is to obtain the true azimuth in topocentri coordinate system directly with the station local coordinate frame.

This article introduced a general method of drawing plane right-angle coordinates in Borland c++Builder 6 and explained how to use its code in detail.

After the correlative coordinate of earth is detailed,in virtue of the earth-rectangular coordinate,the position,velocity and attitude angle of the missile can be converted from space-earth coordinate to emission coordinate.