Assessment of Laser Scanner in Topographic Surveying

Abstract

The main idea in this contribution assess the accuracy of TLS relative to other traditional surveying instruments. This is done throughout five different case studies. In the first fourth case studies the 3D coordinates, obtained using total station (TS), are assumed the reference coordinates, while in the fifth case study, level heights considered as the reference heights. First, a control point network, that consists of nine points, is measured using TS, TLS, and real time kinematic global navigation satellite system (RTK-GPS). The precision of each instrument is investigated considering the standard deviation (SD) of measurements. In addition, the accuracy of TLS and RTK-GPS is investigated considering the measurements RMS. Secondly, a grid levelling for a 30,000m2 ground terrain was performed using TS and TLS. After words, the RMS of TLS measurements is computed and a grid of 5mx5m is generated from both surfaces; formed using TS and TLS measurements. Thirdly, the effect of incidence angle on TLS measurements is assessed by measuring fifty-six points fixed on a building façade using different incident angles. Those points were measured using both TS and TLS, then the absolute height differences between TS and TLS measurements were calculated to figure out the