Location Algorithm of GPS/INS Closely Coupled System Based on Federation Kalman Filter Algorithm

In the traditional GPS/INS closely coupled system,whole system exists bias because of the bias of pseudo range and doppler shift.To remove the bias,the location algorithm based on federation Kalman filter algorithm is designed.This algorithm has two Kalman filters.The first Kalman filter filters the pseudo range and doppler shift get from the GPS module.Then,the results get from the first Kalman filter is filtered by the second Kalman filter with the data get from the INS module.The correcting value of the location results get from the second Kalman filter can be used to correct the position and velocity to get the optimum estimate.The simulation results show that the federation Kalman filter algorithm can decrease the bias compared with the traditional Kalman filter algorithm.The federation Kalman filter algorithm has theoretical and practical value.