工程控制网测站归心改正的有关问题探讨

就工程控制网而言，由于其边长较短（一般在2公里左右），有时为了工作快捷采用多个组同时作业或受地形条件的限制须采用偏心观测，据现行有关文献对测站偏心元素的测定精度要求势必给外业工作带来一定的困难。另外，当边长较短且偏心距较大时，推算控制网各边近似边长的误差相应增大，从而会导致在求取测站归心改正数时出现较大的残余误差，为解决这个问题，本文提出了循环求解归心改正数的方法，并针对实际情况就偏心元素的测定精度要求作了一定的探讨。

DISCUSSION ABOUT THE CORRECTION FOR CENTRING OF ENGINEERING CONTROL NETWORK

The sides of engineering control network are relatively short (about 2 km). Eccentricobservation has to be used if several teams work at the same time,or it is confined by the mappingconditions. Some difficulties may occur according to the surveying precis;on requirements for getting eccentric elements as mentioned in the present documents. Besides, when network sides arerelatively short and the eccentric ranges relatively long,the calculating error of each approximateside of the control network will accordingly be large,which leads to greater error remains in thecalculation of the correction for centring. In order to solve this problem,a method of circulatingcalculation for eccentric elemenrs is proposed in this paper and some discussions are also. offeredabout the surveying precision requirements for eccentric elements in view of practical work.