High-constraint based extended Kalman filter (EKF) positioning method

The invention discloses a high-constraint based extended Kalman filter (EKF) positioning method which is applicable to a GNSS navigation positioning system. The method is characterized in that a state estimation value of the current epoch can be obtained through an EKF algorithm according to the state estimation value of the previous epoch; then the high-constraint conditions are created to limit the positioning height of the current epoch so as to obtain the optimal state estimation value meeting the high-constraint condition of the current epoch and the corresponding mean square error; finally, the measuring residue between pseudorange and Doppler shift can be obtained through the measure square error and can be used for further correcting the state estimation value so as to obtain the final state estimation value of the current epoch. Therefore, the location information of a target to be positioned at the current epoch can be accurately obtained, and the GNSS navigation and positioning accuracy can be impr