Geometric Accuracy and Measurement Repeatability of Mobile Laser Scanning in Urban Areas of the Czech Republic

Abstract. Mobile Laser Scanning is an effective method for collecting high-resolution spatial data. The assessment of the geometric accuracy of the point clouds remains a key topic in land surveying. This paper focuses on the evaluation of the internal geometric accuracy and measurement repeatability of data acquired by the RIEGL VMX-2HA mobile laser scanning system. The objective of the research is to assess the system’s ability to generate spatially consistent outputs under identical input conditions. It is important to identify and quantify the influence of selected environmental variables such as the condition of the road surface, current meteorological conditions and time of day during data collection. The experimental part was conducted in the form of ten individual test runs along an identical route in an urban area in the city of Prague, the Czech Republic. Each test run was conducted under various scenarios – on dry and wet surfaces, at different hours of the day (morning, midday and evening hours), and under variable weather conditions. A combination of spatial statistics and point cloud comparison techniques was used to evaluate repeatability, focusing on the road surface. The results show that the RIEGL VMX-2HA mobile laser scanning system has a high level of internal accuracy under standard conditions. Specific environmental conditions may cause a slight increase in measurement uncertainty (e.g., a wet road surface). The observed deviations remain within the tolerance limits defined for standard engineering and land surveying applications.