High-dynamic baseline determination for the Swarm constellation

High-dynamic baseline determination for the Swarm constellation

Mao, X. (TU Delft Astrodynamics & Space Missions)
Visser, P.N.A.M. (TU Delft Astrodynamics & Space Missions)
van den IJssel, J.A.A. (TU Delft Astrodynamics & Space Missions)

2019

Baseline determination for the European Space Agency Swarm magnetic field mission is investigated. Swarm consists of three identical satellites -A, -B and -C. The Swarm-A and -C form a pendulum formation whose baseline length varies between about 30 and 180 km. Swarm-B flies in a higher orbit, causing its orbital plane to slowly rotate with respect to those of Swarm-A and -C. This special geometry results in short periods when the Swarm-B satellite is adjacent to the other Swarm satellites. Ten 24-hr periods around such close encounters have been selected, with baseline lengths varying between 50 and 3500 km. All Swarm satellites carry high-quality, dual-frequency and identical Global Positioning System receivers not only allowing precise orbit determination of the single Swarm satellites, but also allowing a rigorous assessment of the capability of precise baseline determination between the three satellites. These baselines include the high-dynamic baselines between Swarm-B and the other two Swarm satellites. For all orbit determinations, use was made of an Iterative Extended Kalman Filter approach, which could run in single-, dual-, and triple-satellite mode. Results showed that resolving the issue of half-cycle carrier phase ambiguities (present in original release of GPS RINEX data) and reducing the code observation noise by the German Space Operations Center converter improved the consistency of reduced-dynamic and kinematic baseline solutions for both the Swarm-A/C pendulum pair and other combinations of Swarm satellites. All modes led to comparable consistencies between the computed orbit solutions and satellite laser ranging observations at a level of 2 cm. In addition, the consistencies with single-satellite ambiguity fixed orbit solutions by the German Space Operations Center are at comparable levels for all the modes, with reduced-dynamic baseline consistency at a level of 1-3 mm for the pendulum Swarm-A/C formation and 3-5 mm for the high-dynamic Swarm-B/A and -B/C satellite pairs in different directions.

Ambiguity fixing
Half-cycle ambiguity
Precise baseline determination
Precise orbit determination
Swarm

http://resolver.tudelft.nl/uuid:e3f7b9e6-d429-4684-953e-8ac9de32d20c

https://doi.org/10.1016/j.ast.2019.03.031

2021-03-27

1270-9638

Aerospace Science and Technology, 88, 329-339

Accepted author manuscript

Institutional Repository

journal article

© 2019 X. Mao, P.N.A.M. Visser, J.A.A. van den IJssel