自动全站仪动态基准测边网变形观测的研究

由于大型建筑的空间结构复杂,在利用自动全站仪对其进行实时变形监测时,常常不得不将全站仪站点布设在变形区内,这必然导致测量精度急剧下降。针对这一问题,根据变形区通视角度较小的特点,提出了一种新的观测方法。该方法的基本思想是:在变形区布设多台全站仪使其与稳定基准点构成测边网,在每台全站仪顶部手柄处安装反射棱镜,使相邻两台全站仪之间能够相互通视。在每次观测前,首先进行动态基准测边网观测,通过测边网平差解算各个动态基准点坐标;若动态基准点的移动相对于前期坐标小于设定阈值(根据变形体的变形范围设定),分别以各个动态基准点处全站仪为测站进行其他观测点的变形观测。若大于阈值,则利用动态基准补偿算法求解观测点坐标。观测实验证明,该方法能够满足一般应用要求,直接更新测站坐标方式的中误差在3 mm以内,而动态基准补偿方法的中误差在5 mm以内。

Study on the Triangulateration Network of Dynamic Benchmarks of Auto Total Station in Structural Health Monitoring

Nowadays,the auto total station has been used in dam/bridge/ tunnel real-time monitoring,due to its character of high precision and fast response.While more than one total station have to be arranged in de-formation areas,when large structures are complicated and the inner interlaced parts of large structures cause blocking of light beam.Unstable settlement of total stations may introduce measuring error.To address this problem,the dynamic observation stations(called as dynamic benchmarks) based on triangulateration network is presented.In this triangulateration network,more than two total stations are settled on unstable bases used as dynamic benchmarks,two total stations are arranged on stable benchmarks.Reflective prisms are installed on each total station,so that neighboring two total stations can see each other.Approximate coordinates of dy-namic benchmarks are calculated based on this triangulateration network observation.Accurate coordinates of them are obtained by adjustment.If coordinate difference of dynamic benchmarks between two observation peri-ods is less than a threshold(given by deformation range of structure),dynamic benchmarks are used as datum applied to measuring other measuring points.While,if difference between two observation periods is larger than the threshold,a compensation method is introduced to correct coordinate of measuring points.Further-more,observation simulation experiment is presented based on this principle.The experiment is carried out with one Leica TC 405 total station.The experimental results show that triangulateration network of dynamicbenchmarks method is correct and feasible.Coordinates error of measuring points using updating coordinate da-ta of dynamic benchmarks is less than 3 mm,Coordinates error by compensation method is about 5 mm.