Editing Observability (section)

==Definition==
Consider a physical system modeled in [[state-space representation]]. A system is said to be '''observable''' if, for every possible evolution of [[State space representation#Linear systems|state and control vectors]], the current state can be estimated using only the information from outputs (physically, this generally corresponds to information obtained by [[sensor]]s). In other words, one can determine the behavior of the entire system from the system's outputs. On the other hand, if the system is not observable, there are state trajectories that are not distinguishable by only measuring the outputs.