CPⅢ平面网必要点位精度的研究

Research on the Positional Accuracy Required for CPⅢ Network

研究目的:在考虑CPⅢ网的观测网形以及网中观测值的必要观测精度的前提下,对CPⅢ标准网以及改进网的必要点位精度进行仿真计算。通过误差理论分析,探讨CPⅢ点在2种网形下的合理点位精度,并进一步推算CPⅢ标准网以及改进网2次测量CPⅢ点X、Y方向坐标较差的合理允许误差。研究结论:采用边角网精度估算的方法,推算CPⅢ控制网的必要点位精度。认为改进CPⅢ网的交互强度虽比标准的CPⅢ网好,但其点位精度却比标准的CPⅢ网差,在横向精度方面差异更大。对标准CPⅢ网而言,其合理的可重复性测量精度应≤±1.5mm,2次测量CPⅢ点X、Y方向坐标较差的允许值应≤±3.0mm;对改进的CPⅢ网而言,其合理的可重复性测量精度应≤±2.0mm,2次测量CPⅢ点X、Y方向坐标较差的允许值应≤±4.0mm。

Research purposes： In consideration of CPⅢ network and accuracy required for observed values, the simulated calculation on necessary positional accuracy of CPⅢ network and improved CPⅢ net form was performed. And through theoretical analysis of error, the discussions were made on the reasonable positioning precision of CPⅢ points in two circumstances and the reasonable permissible error of coordinate difference in the direction of x and y. Research conclusions：By calculating the positional accuracy required for CPⅢ control network based on the parameter adjustment of side- angle measurement network, the result shows the improved CPⅢ net form is better in integration intensity, but it is worse in positional accuracy, especially in lateral accuracy, compared with the CPⅢ network. For the CPⅢ network, the repeatable measurement accuracy should be less than ＋ 1.5 mm and the coordinate difference tolerance should be less than ＋ 3.0 mm in the direction coordinate of x and y. For the improved CPⅢ net form, the corresponding repeatable measurement accuracy and permissible difference should be less than ± 2.0 mm and ± 4.0 mm respectively.