Research Based On EKF Visual Integrated Navigation Method

With the rapid development of navigation technology,pure navigation system can not meet the demand of the accuracy and stability of the carrier navigation,integrated navigation has become the main developing trend currently.GPS/SINS integrated system is one of popular navigation method,it can provide speed,attitude and position information of the carrier well,but when the GPS signal of carrier is not of full(for example:streets,tunnels,canyons and so on),it will decrease the navigation accuracy and stability of GPS/SINS integrated system.In order to solve the impact of lacking of GPS signal,this paper introduces optical flow vision navigation system,integrates GPS/SINS/optical flow systems.First of all,this paper designs carrier's track generator according to the principle of the strapdown inertial navigation system and the mathematical model of the inertial navigation element.It carries out matlab experiment strapdown algorithm by using carrier's speed,attitude and position information provided by track generator,results show that the lack of pure strapdown inertial navigation system.To solve the problem of error divergence problem of the stapdown inertial navigation system,GPS/SINS integrated system method is introduced.The quadrotor's system is nonlinear,uses EKF instead of KF to do data fusion filter.Simulation results show that GPS/SINS integrated system is better than pure strapdown inertial navigation system.Then,this paper introduces optical flow navigation system and Horn-Schunck method to calculate the speed information of the carrier.In order to improve the fault tolerance capability of the navigation system,a federated filter structure is used.Designs two sub filters consist of GPS/SINS and SINS/optical flow,composes GPS/SINS/optical flow integrated navigation system and uses EKF for data filtering.Through the comparison of the quadrotor actual flight test,the results show that the GPS/SINS/optical flow integrated navigation effect is better than the GPS/SINS integrated system.