Trumpf, Jochen2015-12-070024-3795http://hdl.handle.net/1885/23516We give characterizations and necessary and sufficient existence conditions for tracking and asymptotic observers for linear functions of the state of a linear finite-dimensional time-varying state space system. We specialize the results to affine parameter varying systems and bilinear control systems.Keywords: Bilinear systems; Linear functions; LTV systems; Asymptotic analysis; Linear control systems; Time varying systems Bilinear systems; LPV systems; LTV systems; Observers200710.1016/j.laa.2007.01.0152015-12-07