Test and analysis on the errors of GPS observation in mining field

During the GPS observation in minefield especially in open-pit, the differences between stations are usually large, so that the influence of survey error is different from that in other flat area, and hence the various GPS methods are applied in the detailed surveys according to the different demands and typical site. Based on the analysis of our testing data, the key factor affecting the result precision exists in the coordinate transformation, that is, in the transformation of WGS84 ellipsoidal coordinates to the local planimetric coordinates and geodetic height. Therefore, South Toolbox 4.0 software is applied in the coordinates transformation to compute a set of ideal local coordinate transforming parameters in some region where may be ascertain problem happened, and the state coordinates system is not be used. Aiming at the various sources of GPS static positioning, both of absolute and relative positioning methods are applied in testing the factors influencing the precision of GPS positioning in minefields, considering PDOP value and coordinates transformation, and hence some practical conclusions about the static relative positioning accuracy of GPS dual frequency receivers in minefields are put forward here.