由中央子午线惹起的投影变形题目标处理方法(国外英文资料).docVIP

由中央子午线引起的投影变形问题的解决方法(国外英文资料) So the engineering plane coordinate system adopts 1954 Beijing coordinate system, the central meridian longitude 121 ° 30 achievements should be adopted. ??????????? Changing with the authentication: after using two sets of tianbao R3 static machine and a set of tianbao R8 GPS receiver to known control points, a total of 4 sets of 3190 and 3194 using static observation method is used to detect the length, the synchronous observation time is more than 45 minutes, observation condition is good. Length of side calculated by observation and length are 0.016 meters, the relative accuracy is 1/132000, in accordance with the measurement of water transport engineering, for port engineering measurement scale is not less than the latter, its length deformation should not be more than 1/40000, so D GPS points 3190 and 3194 can be used as the project of plane control points. ??????????? 4 conclusion? ??????????? Long line engineering control network layont quantity bedding face is wide, except the data on analysis of reasonable, count, the determination of the coordinate system is the primary step of work, and determine the coordinate system of the key problem is the side length projection correction control, reasonable utilization of the zoning of this article discusses the projection method, the partition counter method, side length constraint will be well control long distances projection length deformation of engineering control network measurement values, offering reliable guarantee for engineering construction. The principle of determination of frame is: ??????????? 4.1 the project according to the diameter across the east long lines, the preferred by gauss first 3 ° orthomorphic projection plane rectangular coordinate system. ? ??????????? When the line is away from the central meridian (such as about 45km in the plain area), a gaussian conformal projection is applied to the rectangular coordinate system. ? ??????????? The network of contact