  We propose to explore switching methods in order to recover some properties
of Kalmanlike observers for output feedback stabilization of state-affine
systems that may present observability singularities. The self-tuning gain
matrix in Kalman-like observers tend to be singular in the case of
non-uniformly observable systems. We show in the case of state-affine systems
with observable target that it can be prevented by dynamically monitoring
observability of the system, and switching the control when it becomes
critical.
