The Method Research Of Indoor And Outdoor Pedestrians Seamless Navigation Based On GNSS And IMU

The accuracy of pedestrian positioning is helpful to ensure the pedestrian safety in indoor and outdoor environment.It is the key research to improve the accuracy of pedestrian positioning.In order to solve the problem of discontinuous positioning and low accuracy in indoor and outdoor pedestrian navigation at present,the authors propose a pedestrian seamless navigation and positioning method based on BDS/GPS/IMU.Outdoor,In order to improve the availability of dynamic positioning when the single system observation geometry is bad,dual mode positioning of BDS/GPS is adopted to solve the problem that the number of visible satellites are less and the space geometric distribution is poor.Aiming at the heading divergence problem of the current pedestrian navigation system,and in order to avoid bringing external error for magnetometer,proposed a heading correction algorithm of magnetic angular velocity update(MARU)based on zero velocity update,the magnetic field is constant during the stance phase in the foot-mounted,when the inertial device is rotated,three-dimensional vector of the magnetometer will change,we can use the change in the magnetic filed to provide a measurement of the turn rates of the gyroscope,and use the extended Kalman filter(EKF)to correct the error of angular velocity of the inertial sensor,to limit the drift in the yaw.According to the above method the paper is divided into three parts,the first part introduces the /GPS relative positioning principle and method,the second part introduces the realization method of strapdown inertial navigation and integrated navigation algorithm,the third part introduces the design and implementation of indoor and outdoor seamless pedestrian navigation scheme.Through the indoor and outdoor pedestrian seamless navigation experiment,we can see that,in the combined positioning experiment results of BDS and GPS,from the visual satellite,when using the combined system,the number of visible satellites will rise to around 16 compared with single system.The increase of the number of visible satellites greatly improved the observation geometry.For PDOP,the maximum PDOP of the dual system is 2.7,which is significantly lower than that of the single system PDOP,and the observation geometry performance has been greatly improved.In the time of effective positioning,for BDS/GPS,the positioning accuracy of elevation direction is better than 4 cm,and the positioning precision of South and East direction is better than 2 cm.Indoor,the experimental results show that the MARU&ZUPT algorithm can correct the heading direction efficiently,and the final positioning error is about 0.5% of the total distance,which achieves a good positioning accuracy.