# A Comparative Study of Indoor Accuracies Between SLAM and Static Scanners
## 2 Materials and Methods
### Used Instruments  
A Trimble S9 HP robotic total station (Figure 3a) with a standard deviation of distance measurement of 0.8 mm + 1.0 ppm on a prism (2 mm + 2 ppm on an arbitrary surface) and the standard deviation of the horizontal direction and zenith angle measurement of 0.3 mgon was used for the absolute georeferencing of the coordinate network using the reflective targets as well as for the determination of the centers of the black and white paper targets. A Leica ScanStation P40 terrestrial scanner (Figure 3b) with a field of view of \(360^{\circ}\times 270^{\circ}\), distance measurement accuracy of 1.2 mm + 10 ppm, angular accuracy of 8\({}^{\prime\prime}\), liquid compensator with an accuracy of 1.5\({}^{\prime\prime}\), maximum measurement distance of 270 m (considering 18% reflectance), and scanning speed of 1 million points per s was used for terrestrial laser scanning. Black and white targets were used for georeferencing of the point clouds acquired from the individual positions. Figure 2: **(a)** Layout of the technical floor with black and white targets (black 6001–6018) serving for the georeferencing of the Leica ScanStation P40 reference cloud and spherical targets (red 5001–5006) serving as reference points for all evaluated scanners. **(b)** Paper black and white target on the wall for Leica P40. **(c)** Black and white targets for Leica ScanStation P40 on a magnetic element. **(d)** The spherical target with a magnetic element. **(e)** The mounting platform for spherical targets. The area used for the test is shown in blue hatching. Five scanners were evaluated: two static scanners Trimble X7 (Trimble Inc., Westminister, CO, USA) and Leica RTC 360 (Leica Geosystems AG, Heerbrugg, Switzerland) and three SLAM scanners (GeoSLAM ZEB Horizon RT (Faro, Lake Mary, FL, USA), Emesent Hovermap ST-X (Emesent Pty Ltd., Milton, Queensland, Australia), and FARO Orbis (Faro, Lake Mary, FL, USA)). The first of the tested scanners, Leica RTC 360 (Figure 3c), offers three scanning resolution options (3/6/12 mm at 10 m), determination of the scanner position through real-time tracking of movement using a VIS unit, and automatic filtering of moving objects. The scanner range is 130 m. An Apple tablet with a Leica Cyclone FIELD 360 app was used for the measurement. Trimble X7 (Figure 3d) is a static scanner characterized by its focus on measurement speed. ICP transformation is the primary method of registering clouds, with the option of manual targeting of the centers of targets serving as (ground) control points. The instrument features self-leveling within 10\({}^{\circ}\) and can take measurements even when upside down. An automatic calibration (approx. 20 s) was performed before triggering the measurement. Trimble X7 uses a wavelength of 1550 nm (invisible, Class 1 laser according to [27] for the measurement. It also features a field of view of 360\({}^{\circ}\) (horizontal) \(\times\) 282\({}^{\circ}\) (vertical), a range of 0.6 m to 80 m, a manufacturer-declared standard deviation of distance measurement accuracy of 2 mm and angular measurement accuracy of 21\({}^{\prime\prime}\). The measurement speed is up to 500,000 pts/s. It has three calibrated cameras, 10 Mpix each, acquiring up to 316 Mpix of  
Figure 3: Instruments used for georeferencing and testing: (**a**) total station Trimble S9 HP; (**b**) static laser scanner Leica ScanStation P40; (**c**) static scanner Trimble X7; (**d**) static scanner Leica RTC360; (**e**) SLAM scanner Emesent Hovermap ST-X; (**f**) SLAM scanner GeoSLAM ZEB Horizon RT; and (**g**) SLAM scanner Faro Orbis. image data per station. It is controlled via a Wi-Fi-connected Trimble T10 tablet (Trimble Inc., Westminster, CO, USA) with Trimble Perspective software ver. 2024.00. Its dimensions are 353 mm \(\times\) 178 mm \(\times\) 170 mm, and its weight is 5.8 kg (including battery). Data is stored on an SD card and was continuously transferred to the control tablet. The lidar range of the Emesent Hovermap ST-X (Figure 3e) is 0.5-300 m, with a declared distance accuracy of 10 mm.