The Influence of Target Properties on the Accuracy of Reflectorless Distance Measurements

Abstract

Recent years have brought dynamic developments in surveying equipment and techniques. These include reflectorless electromagnetic distance measurement (RL EDM), which is used in a range of devices, especially total stations. Studies concerning the influence of the reflecting surface on the accuracy of RL EDM tend to focus on the colour of the measurement surface, while the influence of the density and thickness of materials is usually neglected. Therefore, this study undertook to examine 53 samples representing various materials of dissimilar features: colour, type of surface and density. The results show that dark and mat surfaces cause higher RL EDM errors than bright, gloss materials. Nonetheless, 76% of the results were in compliance with equipment specifications. Moreover, it was found that the density of the samples had significant impact on the overall accuracy. RL EDM to EPS (expanded polystyrene sheets, low-density material, commonly called Styrofoam) involved a significantly higher error rate. It demonstrates that total station measurements and laser scanning should be performed cautiously, especially with regard to materials of low density (e.g., EPS) and on short distances, where the value of relative error is high.

Monitorización de glaciares y glaciares rocosos pirenaicos: más de una década aplicando técnicas geomáticas en La Paúl y Maladeta

“…En ciertos casos, es posible determinar la incertidumbre teórica de los levantamientos teniendo en cuenta estas variables y las características técnicas del equipo. Si bien las precisiones de medida a sólido suele encontrarse dentro de los definidos en las especificaciones técnicas (Gmitrowicz-Iwan et al, 2021), no es tan evidente poder cuantificar de forma sencilla la influencia que puede tener el ángulo de incidencia de las medidas a sólidos (Lambrou, 2018). Este último aspecto, podría ser especialmente relevante en medidas sobre superficies heladas o nevadas debido a la elevada reflectividad que presentan en algunas longitudes de onda.…”