Retrospective-cost-based adaptive model refinement for the ionosphere and thermosphere.

The article presents a study which addressed the problem of how to use data to improve the fidelity of a given model. Retrospective cost optimization was utilized which uses data to recursively update an unknown subsystem interconnected to a known system. Using global ionosphere-thermosphere model (GITM) as the truth model, it was demonstrated that measurements can be used to identify unknown physics.