Targetmotion State Estimation Ofquadrotor Vehicle Based On UWB

In recent years,quadrotor vehicle has been widely used in aerial photography,agriculture,mapping and express industry.Benefit from the wide range of commercial applications of quadrotor vehicle,the state estimation,flight control,obstacle avoidance,target tracking and other technologies has been rapid development.In the field of target tracking,has been achieved from GPS-based target tracking to vision-based target tracking technology,which has brought great convenience to people’s production and life.However,the GPS-based target tracking technology is constrainted by the lower GPS accuracy,can not used indoors or between large buildings.The monocular visual tracking technology,needs a lot of calculations,can not track blocked objects and it is difficult to get the relative position between target and quadrotor vehicle.Compared with those technologys,a target tracking technology,which is based on UWB(ultra-bandwidth)ranging technique,has the advantages of high precision(within tens of meters),can be used indoors,with less calculation,and the relative position of the target can be obtained directly.In this paper,the target motion state estimation of quadrotor vehicle based on UWB is studied.The main work is as follows:Firstly,the relative motion model of the target and the quadrotor vehicle,and the UWB range measurement model are established.For the situation of a pair of UWB range module,observability is analyzed.Secondly,since the measurement equation is nonlinear,the extended Kalman filter(EKF)is used to estimate the motion state of target.Considering the linearization error,the iterative extended Kalman filter(IEKF)is used to relinearized measurement equation at current estimation value.And the effectiveness of the state estimation method is verified by simulation.Considering the influence of the initial priori information,a initial relative position estimation algorithm,which is based on visual information and the height of quadrotor vehicle is proposed.Then,the influence of the layout of multiple UWB ranging modules on the positioning accuracy within constraint space is studied.The optimal layout based on confition number is designed and the target motion state estimation method based on QCEKF is given.Finally,the UWB hardware test platform is built.Target positioning accuracy under the optimal configurationthe and feasibility of the IEKF algorithm and QCEKF algorithm is verified.