Observers for linear distributed-parameter systems: A survey

This paper reviews different observer design methods for linear dynamic distributed-parameter systems. In such systems, the states, inputs, and outputs depend on some spatial variable. This dependence, along with additional aspects such as the boundary conditions, increase the complexity of the state estimation problem and of the design methods. The paper in particular surveys observers for first-order and second-order linear distributed-parameter systems based on their infinite-dimensional and finite-dimensional descriptions.