Precision Analysis on High-speed Railway CPⅢ Horizontal Control Network under Three Types of Adjustment Datum
In response to the situation where many coordinates of CPⅢ points exceed the limit during constrained adjust-ment by CPⅡ in the remeasurement of CPⅢ networks,a rational adjustment method was proposed for CPⅢ networks,with two types of CPⅢ plane networks,the standard network and densification network,being designed with a length of 4 020 m.Three types of adjustment datum,including gravity datum,one point with one long direction,and one point with one short direction,were established.The relative mean square errors between CPⅢ points with 600 m spacing were computed for the two types of CPⅢ plane networks under the three types of adjustment datum,and compared with the relative mean square error of CPⅡ,8 mm specified by the specification.The study results show that the range accu-racy has little impact on the relative precision of points,whereas the direction accuracy plays a major role in affecting the relative precision of points for the two types of CPⅢ network under the three types of adjustment datum.The relative mean square errors between CPⅢ points with 600 m spacing are significantly less than 8 mm for the two types of CPⅢnetwork under the gravity datum and the one point with one long direction(at a spacing of CP Ⅰ),indicating a higher precision of CPⅢ network than that of the CP 11 network.
high-speed railwayCPⅢ horizontal networkadjustment datumprecisionrelative mean square error
万方数据
维普
