Application of the adaptive two-stage EKF algorithm in geomagnetic aided inertial navigation

The Inertial Navigation System (INS) can provide a variety of high precision navigation parameters full independently, but there exists error accumulation. The geomagnetic navigation has the benefits of passive detection, autonomy, well concealed, high availability and low cost. So in this paper the geomagnetic aided inertial navigation method is introduced to enhance precision of the land vehicle navigation system. A nonlinear system model is developed, and the noise covariance is unknown random bias. In this condition, the traditional EKF method may be divergent, so an adaptive two-stage EKF algorithm is proposed that can resolve this problem. Simulation results show that, compared with the EKF algorithm, the adaptive two-stage EKF algorithm has the advantage of reducing the computational complexity and the result can be convergent.