  In this paper we are interested in the problem of adaptive state observation
of linear time-varying (LTV) systems where the system and the input matrices
depend on unknown time-varying parameters. It is assumed that these parameters
satisfy some known LTV dynamics, but with unknown initial conditions. Moreover,
the state equation is perturbed by an additive signal generated from an
exosystem with uncertain constant parameters. Our main contribution is to
propose a globally convergent state observer that requires only a weak
excitation assumption on the system.
