Precision Comparison and Analysis of Reflector-less Total Station Observations

Abstract

In order to achieve the results that meet the specifications of given project, such as setting out and monitoring the structural deformation, the knowledge of reliability and accuracy of surveying equipment is inevitable. Reflector-less total station are widely used nowadays for several applications in geodetic engineering due to its highly accurate and fast measurements. A shortcoming is that it gives less accurate measurements in some cases of observations. The point position determination using reflector-less total station is subjected to some uncertainty due to angle of observation, incidence angle of signal to the surface, distance from the instrument to the point, instrument precision and material of reflecting surfaces. This paper investigates the accuracy of reflector-less total station observations during the process of monitoring and setting out of engineering structures. This paper is performed also to find out the effect of inclined angle of reflecting surface, its color and type on the accuracy of reflector- less total station measurements. It has been converted to a group of charts that assure the accuracy required in determining the point coordinates. A formula is developed to represent the effect of these parameters on the uncertainty of the observations. The results of the practical measurements, adjustment and analysis of the observations are also presented. From the results, It can be concluded that the white reflector surface have stronger reflectivity than any other surface. The unpainted metal target was the worst reflecting surface and the brick target was the best surface.