A Nonlinear GPS/IMU based observer for rigid body attitude and position estimation

This work proposes a position and attitude nonlinear observer based on inertial measurements and GPS pseudorange readings. The observation problem is formulated on SE(3), and the solution yields exponential convergence of the attitude and position estimates. The GPS pseudorange measurements and inertial sensor readings are exploited directly in the observer, and the integration of vector readings in the observer is discussed. The proposed observer dynamics compensate for the bias in the angular velocity sensor and the clock offset in GPS pseudorange measurements. The stability of the position and velocity estimates in the presence of bounded accelerometer noise is also analyzed. The properties of the GPS/IMU based observer are illustrated in simulation for a rigid body describing a challenging trajectory.