Abstract
A review of the state and parameter estimation theory in distributed systems is presented with an emphasis on providing a guide for the potential user of these techniques. The theoretical results for both linear and nonlinear systems are summarized, and a wide range of real-world examples are discussed. To make the review complete, various approximation techniques, choice of measurement locations and observability of distributed systems is also discussed. Based on recent experimental and numerical work, one must conclude that the practical application of these techniques to process control, environmental monitoring and energy recovery problems holds real promise.