How to set the handheld GPS related parameters and coordinate conversion parameters throughout the country
Three parameter test DX, DY, DZ, DA, DF after the conversion parameters of the five, must be prompted to enter the handheld GPS, while the input area of the central meridian longitude. E on behalf of the east longitude, projection ratio of 1, the deviation of things to the north and south of the deviation of 0, and set the unit for M. Enter these parameters, should be taken to the field test, check whether these five parameters are correct. The method is selected, vision, GPS receiving signal strength of the feature points in the field (such as linear object intersections, independent features, etc.) is the best stone control points were measured and compared with theory and find out the coordinates of these points. If the results of the comparison exceed the nominal accuracy of the instrument, the conversion parameters or the problems that should be found should be recalculated.
Collect the application area of high grade control data in GPS receiver applied earth area (such as a county) find three (or more) uniform grade (accuracy better) or GPS "B" network, the best point is around without interference of electromagnetic wave, vision, the satellite signal is strong. To the local surveying and mapping management department (such as: the local bureau of Surveying and mapping, surveying and Mapping Institute) Gauss plane coordinate copy these points of the Beijing 54 Coordinate System (x, y), the elevation of H and WGS-84 coordinates of the geodetic coordinates (B, L), the high H.
Two. To coordinate the coordinate data of the control points obtained provide technical support unit of Beijing Unistrong companies around the branch responsible person to calculate the coordinate transformation parameters conversion parameters, or to obtain their own conversion conversion software. After the conversion parameters are calculated by the prompt input handheld GPS. Only after such a setup, after all the soil in the region when the coordinates of the GPS read out the coordinates of the point for the Beijing 54 coordinates.
