Continuous globally exponential rigid-body angular velocity estimation   from attitude measurements
  A continuous solution is proposed to the problem of uniform global exponential estimation of the angular velocity for rigid bodies by means of direct attitude measurements. The proposed observer is designed on $\mathbb{R}^3\times\mathbb{R}^3\times\mathbb{R}^3$, and not on the inherent geometry $\mathtt{SO}(3)\times\mathbb{R}^3$, which allows for a simple structure of the observer, being a copy of the system plus some correction terms, and a straightforward classical Lyapunov stability proof. The performances of the observer are illustrated by means of a simple simulation scenario. 
Ioannis Sarras
math.OC