1. A method of maintaining prognostic health management accuracy of a system following on-site replacement of a component in the system, the method comprising the steps of: generating a system characterization model of at least portions of the system, the system characterization model adapted to receive a plurality of signals that are each representative of an operational parameter within the system and responsive to each of the signals to (i) generate simulation response data and (ii) determine system health based, at least in part, on the simulation response data; embedding the system characterization model into a controller within the system; replacing a component within the system with a replacement component; determining if the replacement component exhibits one or more operational performance characteristics that differ from the component it replaced; and updating the embedded system characterization model in-situ if it is determined that the replacement component exhibits one or more operational performance characteristics that differ from the component it replaced.