Tightly-coupled ultra-wideband-aided monocular visual SLAM with degenerate anchor configurations
- PDF / 2,959,605 Bytes
- 16 Pages / 595.276 x 790.866 pts Page_size
- 68 Downloads / 181 Views
Tightly-coupled ultra-wideband-aided monocular visual SLAM with degenerate anchor configurations Thien Hoang Nguyen1
· Thien-Minh Nguyen2
· Lihua Xie1
Received: 29 March 2020 / Accepted: 20 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract This paper proposes an enhanced tightly-coupled sensor fusion scheme using a monocular camera and ultra-wideband (UWB) ranging sensors for the task of simultaneous localization and mapping. By leveraging UWB data, the method can achieve metric-scale, drift-reduced odometry and a map consisting of visual landmarks and UWB anchors without knowing the anchor positions. Firstly, the UWB configuration accommodates any degenerate cases with an insufficient number of anchors for 3D triangulation (N ≤ 3 and no height data). Secondly, a practical model for UWB measurement is used, ensuring more accurate estimates for all the states. Thirdly, selected prior range measurements including the anchor-world origin and anchor–anchor ranges are utilized to alleviate the requirement of good initial guesses for anchor position. Lastly, a monitoring scheme is introduced to appropriately fix the scale factor to maintain a smooth trajectory as well as the UWB anchor position to fuse camera and UWB measurement in the bundle adjustment. Extensive experiments are carried out to showcase the effectiveness of the proposed system. Keywords Simultaneous localization and mapping · Ultra-wideband · Sensor fusion
1 Introduction
stereo or multi-camera setup (Mohta et al. 2018). However they suffer from the scale ambiguity and scale drift issues Visual simultaneous localization and mapping (VSLAM) (Taketomi et al. 2017). While recovering metric scale would methods have been extensively researched in recent years. be beneficial for control and navigation tasks, scale drift Many mobile robotic applications have emerged thanks changes the map structure which adversely affects other parts to their ability to provide accurate short-term ego-motion of the SLAM system such as loop-closure and keyframe without any external infrastructure (Huang 2019). Howselection. ever, they typically require ample amount of features and On the other hand, RF ranging devices provide direct inevitably accumulate drift in long-term operations. Monocpoint-to-point range measurements that are not affected by ular VSLAM systems enjoy the advantages of small size/weight the visual features or lighting condition of the environand impose lower mechanical complexity on the system over ment (de Ponte Müller 2017). Among the popular wireless technologies such as Bluetooth, Wi-Fi, Zigbee etc., UltraB Thien-Minh Nguyen wideband (UWB) sensor is gaining popularity in robotic [email protected]; [email protected] researches. One strong advantage of UWB is its robustness Thien Hoang Nguyen in the presence of multi-path effect in cluttered environments [email protected] (Nguyen et al. 2018). Localization methods based on UWB Lihua Xie typically requires that sufficient number of UWB anchors b
Data Loading...
