精密测距三角高程精度分析及高程混合网定权

推导了对向精密测距三角高程计算公式,并分析了对向精密测距三角高程主要误差的影响规律,从而说明竖直角测量和大气垂直折光差是精密测距对向三角高程的主要误差源;在精密测距三角高程精度估算中,提出了往返折光系数差的计算模型及其精度估算方法;分析说明了,采用实测数据计算测距三角高程的垂直折光系数差,可以有效地估算垂直折光系数差的精度.在精密高程混合网的平差中,提出基于各段测距三角高程估算精度的定权方案.最后通过对高程控制网实测数据的计算结果的比较分析,验证了精密测距三角高程精度的分析方法和定权方案的合理性,说明在精密高程混合网中不宜采用长距离的三角高程测量.

Accuracy Analysis of Subtend Trigonometric Leveling and Determination of Weight Matrix for Adjustment of Elevation Mixed Network

The rigorous estimation formula of subtend trigonometric leveling is proposed and the law of main errors of subtend trigonometric leveling is analyzed in the paper.It is found that vertical angular measurement and difference of refraction coefficient cause the fundamental errors in the precise subtend trigonometric leveling.In estimating the accuracy of subtend trigonometric leveling,a model that computes the difference of refraction coefficient and its accuracy is proposed in the paper.The analysis indicates that the differences of refraction coefficient computed with observations may effectively estimate the accuracy of difference of refraction coefficient.A method of determination of weight matrix for adjustment of elevation mixed network is proposed according to the precision estimation formula.Through the test of bridge construction,it is found that the precision estimation formulas of subtend trigonometric leveling and the determination of weight matrix for adjustments of elevation mixed network are feasible and valuable.The results indicate that subtend trigonometric leveling with long distance is unsuitable for a precise height mix network.