基于无人机正射影像的基坑位移观测精度研究  

The accuracy of foundation pit displacement observation based on UAV orthophoto maps

作　　者：张文选[1] 杨中委 黄晓明 ZHANG Wenxuan;YANG Zhongwei;HUANG Xiaoming(Sinohydro Bureau 7 Co.,Ltd.,Chengdu,Sichuan 610213,China)

机构地区：[1]中国水利水电第七工程局有限公司,四川成都610213

出　　处：《测绘标准化》2024年第2期46-52,共7页Standardization of Surveying and Mapping

摘　　要：基坑水平位移变化是基坑变形监测的重要参考指标,快速、精确的获取基坑位移变化量对基坑安全评价十分重要。常规监测方法利用全站仪、GNSS等手段获取监测点的坐标,通过各期数据对比,反映基坑的位移变化。但是这些常规方法工作强度大、自动化程度低,在某些不易到达的监测点,难以有效发挥作用。本文通过合理设置无人机飞行参数,采用摄影测量的方法生成高精度的基坑正射影像,获取监测点的平面坐标,实现了基坑水平位移变化的快速获取,并与全站仪测得的精确数据进行比较,验证了该方法的可行性。结果显示:当飞行高度为50 m时,所获取点位和距离的均方根误差分别为14.3 mm和14.9 mm;当飞行高度为20 m时,所获取点位和距离的均方根误差为7.2 mm和5.6 mm。因此,当无人机贴近飞行时,基于无人机正射影像获取的基坑监测点平面坐标精度较高,基本能够反映出基坑的位移变化,满足三等水平位移监测误差的要求。Horizontal displacement changes of foundation pits is an important indicator for its deformation monitoring,it is crucial for safety assessment of the foundation pit to quickly and accurately obtain the displacement changes.The conventional monitoring methods use total stations,GNSS,and other means to obtain the coordinates of monitored points,and reflect the displacement changes of the foundation pit through comparison of the data from different periods.However,these methods need great workloads and have low automation,so they have poor accessibility in difficult areas.This paper sets appropriate parameters for unmanned aerial vehicle(UAV)flights,produces high-precision orthophoto maps of the foundation pit using photogrammetric methods,obtains the horizontal coordinates of monitored points,realizes rapid perception of horizontal displacement changes in the foundation pit,and compares it with precise data measured by total station to verify the feasibility of this method.The experimental results show that when the flight altitude is 50 m,the root mean square errors(RMSE)of the point position and distance are 14.3 mm and 14.9 mm,respectively.When the flight altitude is 20 m,the RMSE of the point position and distance are 7.2 mm and 5.6 mm,respectively.When the UAV flies at a low altitude,the horizontal coordinate accuracy of the foundation pit monitored points obtained from UAV orthophoto images is relatively high,which can effectively reflect the displacement changes of the foundation pit and meet the requirements for the error of the third-level horizontal displacement monitoring.

关 键 词：正射影像 全站仪 基坑位移 均方根误差 

分 类 号：P228[天文地球—大地测量学与测量工程]