A Submillimeter Level Relative Navigation Technology for Spacecraft Formation Flying in Highly Elliptical Orbit.

Spacecraft formation flying (SFF) in highly elliptical orbit (HEO) has attracted much attention since many applications in space explore, while precise guidance navigation and control (GNC) technology, especially precise ranging, conducted the basis of success for such SFF missions. In this paper, we introduced a novel K band microwave ranging (MWR) equipment that aimed for the on-orbit verification of submillimeter level precise ranging technology in future HEO SFF missions. The ranging technique is a synchronous dual one-way ranging (DOWR) microwave phase accumulation system, which achieved tens of microns of ranging accuracy in laboratory environment. Detailed design and development process of MWR equipment are provided, with ranging error sources analyzed, and relative orbit dynamic models for HEO formation scenes are given with real perturbations considered. Moreover, an adaptive Kalman filter algorithm is introduced for SFF relative navigation design, incorporating with process noise uncertainty. The performance of SFF relative navigation while using MWR are tested in a hardware in loop (HIL) simulation system within a high precision six degree of freedom (6-DOF) moving platform. The final range estimation errors from MWR using adaptive filter are less than 35 μm m and 8.5 μm/s for range rate, which demonstrated the promising accuracy for future HEO formation mission applications.