New concepts for on-board Precise Orbit Determination

Carrying out precise orbit determinations onboard a space craft can have advantages over traditional ground-based processing whether it means an ability to satisfy an immeadiate need on-board, or to aid in increased autonomy. Low Earth Orbit formations would particularly benefit from these determinations, although they would have different requirements in terms of accuracy and complexity compared to other cases, such as gravitational missions.

Current on-board orbit determination concepts are, in most cases, an integral part of the satellite avionics. But the full capability of on-board precise orbit determination requires new concepts.

A new activity with TDE and GMV, Spain, has developed a conceptual approach for an on-board precise orbit determination system, considering technologies from multiple GNSS constellations to different satellite orbits, and several scenarios from real time to non-real time.

The activity successfully identified the advance technologies and concepts that could be used in the future, for advance on-board precise orbit determination concepts. These included the use of optical inter-satellite links with other satellites, or with ground-based stations, providing very accurate observations. It also demonstrated the use of optical clocks, with remarkable stabilities on short to medium time scales and the use of advance accelerometers to substitute the estimation of non-conservative forces.

Two on-board precise orbit determination prototypes are now in the stages of initial development. One focuses on future mega-constellations in low Earth orbit, and the other in highly elliptical orbits, using GNSS and advance clocks.

These new concepts and technologies will lead to improvements in the positioning accuracy obtained on-board the satellite and will benefit both scientific missions requiring high positioning accuracy, and high-precision autonomous navigation.

4000119153 closed in 2021.