Guidance, Navigation and Control Systems of manned and

An advanced attitude observer for rigid bodies evolving in 3D-space using GPS-velocity and INS measurements has been proposed recently in the literature without specifying its domain of convergence and stability. With respect to conventional solutions, which do not involve linear velocity measurements, this observer is better adapted for vehicles subjected to important linear accelerations. The present paper proposes further modifications yielding two other attitude observers with rigorous semi-global convergence and stability results. Simulation results illustrate the compared performance of the three solutions and classical methods