大气竖直折光系数确定的实验研究

An Experimental Study on Defining the Coefficient of Atmospheric Vertical Refraction

大气竖直折光是影响精密三角高程测量精度的关键问题,也是目前国内外测绘界普遍关心和重点研究的课题。本文简单介绍了竖直折光系数与温度梯度的关系,以及大气湍流转换模型的应用。以此为基础,在校园内进行了竖直折光系数变化的实验研究,初步得出不同季节、不同时间的变化规律,所得结果与理论分析基本一致。作者认为,通常用一个定值(0.14)来计算k值是不合适的。文章对两个水电站实测资料就k值的变化进行了计算与分析,提出中间法观测较同时对向观测所得的高差精度为好。同时建议在监测网数据处理与建立地区性折光模型方面继续进行研究,以使三角高程测量的精度,最终代替精密水准测量。

Atmospheric vertical refraction is a key factor affecting the accurancy of exact triangular elevation surveying.It is also a key subject which attracts great attention and interest.The relationship between vertical light refraction and temperature gradient and the application of atmospheric turbu- lence are intruduced in this paper.An experimental study on both subjects has been completed on the campus.From the experiment,the regularity of change of them with seasons and time is obtained, and the result obtained is basically in agreement with the result of theoretical analysis.The authors consider that the common practice of using a definite number(0.14)to calculate k is not satisfactory. In this paper,two sets of surveying results at two hydro-power stations are used to calculate and anal- yse the change of k.The mothed of middle double surveying is put forward.The difference in altitude between double surveying in opposite dinections is small.It is suggested that research should be contin- ued on monitoring network data processing and local light refraction models,so that the accurancy of triangular levellig can be improved,and finally,triangular levelling can be used to replace geodetic levelling.