  This paper deals with the problem of full state estimation for vehicles
navigating in a three dimensional space. We assume that the vehicle is equipped
with an Inertial Measurement Unit (IMU) providing body-frame measurements of
the angular velocity, the specific force, and the Earth's magnetic field.
Moreover, we consider available sensors that provide partial or full
information about the position of the vehicle. Examples of such sensors are
those which provide full position measurements (e.g., GPS), range measurements
(e.g., Ultra-Wide Band (UWB) sensors), inertial-frame bearing measurements
(e.g., motion capture cameras), or altitude measurements (altimeter). We
propose a generic semi-globally exponentially stable nonlinear observer that
estimates the position, linear velocity, linear acceleration, and attitude of
the vehicle, as well as the gyro bias. We also provide a detailed observability
analysis for different types of measurements. Simulation and experimental
results are provided to demonstrate the effectiveness of the proposed
estimation scheme.
