A nonlinear observer for integration of GNSS and IMU measurements with gyro bias estimation

We present an observer for estimating position, velocity, attitude, and gyro bias, by using inertial measurements of accelerations and angular velocities, magnetometer measurements, and satellite-based measurements of position and (optionally) velocity. The design proceeds in two stages: in Stage I, an attitude and gyro bias estimator is designed based on an unmeasured signal. In Stage II, that design is recovered using measured signals only, by combining it with a position and velocity estimator. We prove global exponential stability of the estimation error and test the design using realistic flight simulation.