Vision-Based Relative Attitude Formation Tracking
  Relative attitude formation control systems are developed for multiple spacecraft, based on the line-of-sight measurements between spacecraft in formation. The proposed control systems are unique in the sense that they do not require constructing the full attitudes of spacecraft and comparing them to obtain the relative attitudes indirectly. Instead, the control inputs are directly expressed in terms of line-of-sight measurements to control relative attitude formation precisely and efficiently. It is shown that the relative attitudes almost globally asymptotically track their desired relative attitudes. The desirable properties are illustrated by a numerical example. 
Tse-Huai Wu and Taeyoung Lee
math.OC