3 th Bachelor Real Estate, Land Surveying Measuring Methods III Comparative study on the differences between the mobile mapping backpack systems ROBIN- 3D Laser Mapping, and Pegasus- Leica Geosystems. Sylvia De Vuyst Dhr. D. Devriendt 23 December 2016 Faculty of Science and Technology
Content 1. List of illustrations...3 2. Glossary...4 3. Introduction...5 4. Theory...5 5. Methodology...7 6. Discussion...8 7. Conclusion...9 8. References... 11 2
1. List of illustrations Figure 1 The backpack system ROBIN, 3D Laser Mapping, at InterGeo 2016. (Left): the hardware components. (Right): the operator carries the backpack. (De Vuyst, 2016)...6 Figure 2 The backpack system Pegasus, Leica, at InterGeo 2016. (De Vuyst, 2016)...7 3
2. Glossary FOG: Fibre Optic Gyros FOV: Field Of View GIS: Geographical Information System IMU: Inertial Measurement Unit INS: Inertial Navigation System MEMS: Microelectromechanical Systems RPAS: Remotely Piloted Aircraft System SLAM: Simultaneous Location And Mapping 4
3. Introduction While visiting the InterGEO fair 2016 in Hamburg, I became acquainted with two mobile mapping backpack systems. One of them going by the name of Pegasus, from Leica Geosystems and the other one going by the name of ROBIN, from 3D Laser Mapping. ROBIN, the mobile mapping system that is allowing you to see the world in 3D from your perspective (3D Laser mapping, 2016) was tested out. Pegasus, the award-winning wearable reality capture platform that collects data indoors, outdoors and underground (Leica Geosystems AG, 2016) was accurately observed. Both their weight, seize, flexibility and interface are relatively similar. However what is interesting to find out is what actually distinguishing them from each other. Therefore in this paper a comparison and an analysis of the differences between the two personal laser scanning systems ROBIN and Pegasus will be achieved. 4. Theory 3D Laser Mapping decided to launch its mobile mapping system ROBIN to the market at GeoBussiness 2016. This system has multiple mounting options. It can be used to scan and map areas via walking, driving or flying. Thus, depending on how you mount ROBIN, it can be used as a backpack system, a vehicle-based system and a drone or helicopter system. Mark Brown, business development director at 3D Laser Mapping told at InterGeo (2016) that the mobile mapping system integrates a 18MP camera in backpack-mode, 2 GNSS antennas and a microelectromechanical systems (MEMS) inertial measurement unit (IMU). Brown said this geographical information system (GIS) grade IMU can be upgraded to a fibre optic gyros (FOG) IMU. Namely a FOG IMU is more suitable for detailed topographic surveys, city modelling and constructions or mining environments. However the simultaneous location and mapping (SLAM) upgrade for the system that will allow the users to map in mines, forests and buildings will be launched later this year. Thereby more accurate indoor projects can be carried out. 5
Furthermore, ROBIN has a Riegl VUX-1 HA type laser scanner with a field of view (FOV) of 330, a range of 20 meter and an acquisition of 1 000 000 measurements per second. The position accuracy is 2 cm and the date rate amounts to 128 Hz (3D Laser Mapping, 2016). Figure 1 The backpack system ROBIN, 3D Laser Mapping, at InterGeo 2016. (Left): the hardware components. (Right): the operator carries the backpack. (De Vuyst, 2016) Another competitor firm, named Leica (2016), also announced its own personal mobile mapping solution- the Pegasus backpack. This system implements 5 camera s with a lens of 6,0 mm focal which results in a coverage of 360. Yet a horizontal FOV of 270 and a vertical FOV of 30 is obtained. By its Dual Velodyne VLP-16 type laser scanner the Pegasus backpack acquires range measurements up to 50 meter and has an acquisition of 600 000 points per 6
second (Lauterbach et al., 2015). This backpack is also characterised by its use of the largest sensor to pixel on the marked, 5,5 µm x 5,5 µm. The position accuracy of this system outdoors amounts 2 cm, the date rate 200 Hz. Nevertheless the position accuracy indoors amounts 3 cm as a SLAM and high precision IMU is integrated in the Pegasus backpack (Leica, 2016). Figure 2 The backpack system Pegasus, Leica, at InterGeo 2016. (De Vuyst, 2016) 5. Methodology By visiting InterGeo 2016, an initial collection of information was gathered. This conference and trade fair for geodesy, geoinformation and land management took place in Hamburg, Germany and was visited on 11th October 2016. 7
While attending this event, different companies that supply mobile mapping products gave lectures. Yet, the opportunity was also there to talk personally with different representatives. By interacting with these people, a vast amount of information was collected. At this fair, the personal mobile mapping backpacks from both Leica and 3D Laser Mapping were exposed. Hence they could be observed and analysed from a nearby perspective. Brown (InterGeo, 2016) allowed us to test out their ROBIN system during this day. On behalf of demonstrative YouTube videos a brother perspective on the actual working of the personal mobile mapping systems could be obtained. Further analysations were done by comparing different datasheets and brochures. In addition to what already mentioned, a reasonable quantity of articles have been read. Hereby a deeper understanding in the personal mobile mapping systems, the differences between FOG s and MEMS, and the diversity of laser scanners and camera sensors on the marked was learned. 6. Discussion As mentioned above, the accuracy of both systems is 2cm outdoors. Indoors the accuracy for Pegasus is 3 cm. Whereas 3D Laser Mapping s SLAM upgrade will only be presented later this year, their indoor accuracy will probably be announced simultaneously. In terms of FOV, both systems have approximately the same value. Pegasus with a horizontal FOV of 270, a vertical FOV of 30 and ± 15 per scanner versus ROBIN with a FOV of 330. With Pegasus 5 camera sensors 3D stereoscopic view errors decreases and throughout increases. As well as shadowed or missing 3D points can be acquired via photogrammetric processes. This makes the Pegasus backpack superior to the ROBIN system that s only using 1 camera sensor. As the Leica backpack is applicable for photogrammetric usage, the 3D Laser Mapping system is applicable for vehicles and drones or helicopters usage. This makes the system more flexible and suitable for different ranges of environments (3D Laser Mapping, 2016). However, Leica s system can only be used in a backpack mode, yet it already has an integrated SLAM. Which makes environments such as mines, tunnels, forests and buildings easily 8
mappable on the spur of the moment. In spite of that, the SLAM upgrade for ROBIN will be released later this year. Moreover, Leica s backpack has an integrated scanner that s achieving a range of 50m, while the 3D Laser Mapping system only reaches a range of 20m. Nevertheless the last one is measuring 1 000 000 points a second while Pegasus is comparatively measuring 600 000 points a second. Advantageous on the ROBIN system in backpack mode is that the total weight is barely 10 kg opposite the 13 kg of the Pegasus backpack. The standard IMU that comes with the 3D Laser Mapping system is a MEMS, while Leica already integrated a FOG IMU. Nonetheless, the battle between MEMS and FOGS is a close one. FOGs still have an advantage on performance, yet are 10 times more costly than MEMS (Goodall, 2013). Although IMU- free mobile mapping systems are also upcoming. They will be inexpensive as they don t need GNSS information nor an expensive IMU. Nevertheless, further research on this still remains (Nüchter et al., 2015). Furthermore, the two systems provide different software- packages. Pegasus is recommended for users of AutoCAD and/or ArcGIS. Across from ROBIN who s supplying application software like Terrasolid or Orbit GT. Argue for what is the best software cooperation. 7. Conclusion This paper evaluates the differences between the mobile mapping backpack Pegasus on the one hand and the mobile mapping system ROBIN on the other hand. ROBIN was originally designed for outdoor applications. However, with the SLAM- upgrade this system will also be usable indoors. Through the unification with a FOG IMU in the Pegasus backpack, Leica is a step ahead on 3D Laser Mapping who supplies a FOG IMU as an upgrade. Furthermore, Leica s integration with 5 camera sensors decreases 3D stereoscopic view errors, increases throughput and shadowed or missing 3D points can be acquired via photogrammetric processes. This with a pixel size of 5,5 µm opposite a 3,1 µm pixel size of ROBIN. 9
In addition to that Leica s solution has also an advantage in the range dimension. Measurements up to 50m can be achieved, although the 3D Laser Mapping s system can only measure distances up to 20m. Both systems perform relatively equal in terms of weight, accuracy and FOV. Leica s personal mapping system obtains more details, scans a wider range and integrates a SLAM and high performance IMU. Consequently, Pegasus perform generally better for high professional usage. However, ROBIN is more versatile the system can be used as a backpack, on a vehicle or on a remotely piloted aircraft system (RPAS). 10
8. References 3D Laser Mapping. (2016). ROBIN Technical Specifications [Datasheet]. 3D Laser Mapping. (2016). ROBIN, The World s First Universal Mapping System [Brochure]. Glennie, C., Brooks, B., Ericksen, T., Hauser, D., Hudnut, K., Foster, J., & Avery, J. (2013). Compact multipurpose mobile laser scanning system Initial tests and results. Remote Sensing, 5(2), 521-538. Goodall, C.; Carmichael, S.; Scannell, B. (2013). The Battle Between MEMS and FOGs for Precision Guidance. Analog Devices, MS 2432, pp. 1-6. Accessed at 6 December 2016 via http://www.analog.com/en/index.html Lauterbach, H. A., Borrmann, D., Heß, R., Eck, D., Schilling, K., & Nüchter, A. (2015). Evaluation of a backpack-mounted 3D mobile scanning system. Remote Sensing, 7(10), 13753-13781. Leica Geosystems AG. (2016). Leica Pegasus:Backpack [Brochure]. Leica Geosystems AG. (2016). Leica Pegasus:Backpack specifications [Datasheet]. Leica Pegasus:Backpack Wearable Mobile Mapping Solution (2016). Accessed at 1 December 2016 via http://leica-geosystems.com/products/mobile-sensor-platforms/captureplatforms/leica-pegasus-backpack Nüchter, A., Borrmann, D., Koch, P., Kühn, M., & May, S. (2015). A man-portable, IMU-free mobile mapping system. ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-3 W, 5, 17-23. Riegl. (2015). The New VUX -1 series, High- Performance lidar Sensors for KINEMATIC Laser Scanning [Datasheet]. ROBIN (2016). Accessed at 1 December 2016 via http://www.3dlasermapping.com/robin/ Velodyne lidar, Inc. (2016). Puck, Real-Time 3D lidar Sensor [Datasheet]. 11