This paper describes spacecraft formation control and sensing research with application to a Separated Spacecraft Interferometer. A multi-layer control design that achieves very accurate alignment between spacecraft is described. Sensing for this control architecture is based on a global real-time relative position and orientation estimator that uses Carrier Di erential-phase GPS measurements. A local optical sensor is used as well. The experiments are performed on a fully functional indoor GPS environment using three prototype spacecraft on a granite table. Work continues on extending the control to a formation of three active vehicles and on extending the sensing system to a self-constellation.

The development of a GPS‐based relative position and attitude sensing system in a laboratory environment is presented, with application to spacecraft formation flying. Previous papers have discussed the demonstration of spacecraft rendezvous and capture in two dimensions, in a fully functional indoor GPS environment using simulated spacecraft on an air‐bearing table [1]. The work presented in this paper extends the previous GPS‐based sensing to a formation of three prototype spacecraft, and experimentally demonstrates very accurate real‐time solutions (≥ 2 cm and ≥ 0.5 deg errors) for the three relative vehicle positions and attitudes. In addition, candidate estimation architectures for the three vehicle formations are studied in simulation. Search‐based techniques for carrier‐phase integer ambiguity resolution are also demonstrated on simulation data.

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