Autonomous Vehicle Navigation with Carrier Phase DGPS and Laser-Scanner Augmentation

摘要

This paper describes the design implementation and evaluation of a horizontal navigation system aided by a carrier phase di_erential Global Positioning System (GPS) receiver and a Laser-Scanner (LS) for an Autonomous Ground Vehicle (AGV). The high accuracy vehicle navigation system is highly demanded for advanced AGVs. Although high positioning accuracy is achievable by a high performance RTK-GPS receiver, the performance should be considerably degraded in a high-blockage environment due to tall buildings and other obstacles. The navigation system proposed here is to provide decimetre-level positioning accuracy in such a severe environment for precise GPS positioning. The horizontal navigation system is composed of a low cost Fiber Optic Gyro (FOG) and a precise odometer. The navigation errors are estimated using a tightly coupled Extended Kalman Filter (EKF). The measurements of the EKF are double di_erenced code and carrier phase from a dual frequency GPS receiver and relative positions derived from laser scanner measurements. The performance was analysed by numerical simulations and was verified by field test results. This paper shows that decimetre-level positioning accuracy is achievable under poor satellite visibility. The robustness of the system is evaluated in some partial-satellite-blockage cases having less than four satellites. This result was confirmed by postprocessing analysis based on the real field data.