Decentralized Estimation and Control in High Precision Spacecraft Formations: Comparison Studies

High-precision formation flying missions can implement very large science instruments, but require a very high level of coordination and control. Two coordination and control architectures are described and evaluated on two small prototypical formation flying missions. The first architecture is based on a decentralized, parallel estimation approach with every spacecraft in the formation maintaining an estimate of the entire formation state. Each spacecraft updates its estimator on the basis of local measurements and communicated information from other spacecraft. The second architecture uses a central spacecraft to maintain the formation estimate and calculate the required control actions for all other spacecraft. Communication is required to convey the measurements and actuation commands between the central spacecraft and the rest of the formation. These case studies illustrate that in the presence of small communication delays and communication channel noise, the decentralized architecture outperforms the centralized one, even in the case where it has fewer communication links.