Current Proceedings on Technology

Yazarlar: Serkan Doganalp, Aydin Ustun, Robert Weber

Konular:-

Anahtar Kelimeler:Dynamic orbit model,Orbit perturbations,LEO

Özet: For the determination of high precision earth gravity field models derived from satellite missions in Low Earth Orbits (LEO) accurate orbit information of the satellites plays a crucial role. Therefore the requirement on orbit accuracy for the CHAMP, GRACE and GOCE satellites was at the few cm-level over one revolution. Generally dynamic, kinematic and reduced-dynamic orbit models are used. The dynamic model is based on the integration of the equations of motions within a given force field while the kinematic approach determines the trajectory from point positioning on basis of the on-board GNSS-data. Finally the most frequently used approach is the reduced dynamic orbit determination which is based on the integration of assumed force field but introduces a number stochastic and deterministic parameters accounting for velocity and acceleration changes of the satellite at regular intervals (e.g. once per revolution). In this paper, software for orbit determination utilizing a dynamic model developed in MATLAB is presented. The individual effects of orbit perturbations caused by the inhomogeneous Earth gravity field and atmospheric drag etc. were tested. Also, various computations were performed for different gravity field coefficients and models. Thus, satellite position and velocity were predicted taking into account above-mentioned effects. The estimated satellite orbit was validated by comparison to the reference orbit from GFZ. The achieved orbit accuracy is in the range of one meter over two satellite revolutions.

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