In order to meet the application requirements of autonomous vehicles,this paper proposes a simultaneous localization and mapping(SLAM)algorithm,which uses a VoxelGrid filter to down sample the point cloud data,with the combination of iterative closest points(ICP)algorithm and Gaussian model for particles updating,the matching between the local map and the global map to quantify particles' importance weight.The crude estimation by using ICP algorithm can find the high probability area of autonomous vehicles' poses,which would decrease particle numbers,increase algorithm speed and restrain particles' impoverishment.The calculation of particles' importance weight based on matching of attribute between grid maps is simple and practicable.Experiments carried out with the autonomous vehicle platform validate the effectiveness of our approaches.
Parking is an important and indispensable skill for drivers.With rapid urban development,the automatic parking assistant system is one of the key components in future automobiles.Path planning is always essential for solving parking problems.In this paper,apath planning method is proposed for parking using straight lines and circular curves of different radius without collisions with obstacles.The parking process is divided into two steps in which the vehicle reaches the goal state through the intermediate state from the initial state.The intermediate state will be selected from the intermediate state set with a certain criterion in order to avoid obstacles.Similarly,an appropriate goal state will be selected based on the size of the parking lot.In addition,an automatic parking system is built,which effectively achieves the parking lot perception,path planning and performs parking processes in the environment with obstacles.The result of simulations and experiments demonstrates the feasibility and practicality of the proposed method and the automatic parking system.
Context-aware is becoming standard on the most mobile navigation devices. The performance of MEMS IMU / GNSS gains significant benefits from context information in terms of improvement of filter 's adaptive capability. A context-aware algorithm using differential carrier phase was proposed to recognize a mobile MEMS IMU / GNSS equipped vehicle's stationary,slow moving or fast moving status. The corresponding context error in awarding was analyzed and consequently conducted two fading factors based on the analysis. The factors were applied in the system's adaptive filter with targeting applications in deep urban where severe multipath presents. The dense urban field test shows that the false alarm of proposed context-aware algorithm is less than 5% and the adaptive filtering can achieve around 15% improvement in terms of 1σ in two-dimension position accuracy.
