Global Exponential Angular Velocity Observer for Rigid Body Systems
  We present a uniformly globally exponentially stable hybrid angular velocity observer for rigid body systems designed directly on $SO(3)\times\mathbb{R}^3$. The global exponential stability result makes this observer a good candidate for a controller-observer combination with a guaranteed separation property. Simulation results are provided to demonstrate the effectiveness of the proposed hybrid observer as a part of an attitude stabilization scheme. 
Soulaimane Berkane, Abdelkader Abdessameud and Abdelhamid Tayebi
math.OC