Paper presented at International Conference on Intelligent Transportation Systems

The University of Luxembourg team have presented a technical paper at the 26th IEEE International Conference on Intelligent Transportation Systems (ITSC 2023) held on 24-28 September 2023 in Bilbao, Spain. The paper titled: GPS-aided Visual Wheel Odometry introduces a novel GPS-aided visual-wheel odometry (GPS-VWO) for ground robots. The state estimation algorithm tightly fuses visual, wheeled encoder and GPS measurements in the way of Multi-State Constraint Kalman Filter (MSCKF). To avoid accumulating calibration errors over time, the proposed algorithm calculates the extrinsic rotation parameter between the GPS global coordinate frame and the VWO reference frame online as part of the estimation process. The convergence of this extrinsic parameter is guaranteed by the observability analysis and verified by using real-world visual and wheel encoder measurements as well as simulated GPS measurements. Moreover, a novel theoretical finding is presented that the variance of unobservable state could converge to zero for specific Kalman filter system. The results demonstrate that better accuracy than GPS is achieved through the fusion of GPS and VWO.