93-111
Odem - An Improved Approach Towards Rapid Satellite Maneuver Calibration
Eberhard Gill* and Helio Koiti Kuga**
Abstract
Resulting from a cooperation program between the German Space Operations Center (GSOC) of the German Aerospace Research Establishment and the Brazilian Instituto Nacional de Pesquisas Espaciais (INPE) a new general orbit determination system has recently been developed. Although the software supports orbit determination for all types of Earth satellite orbits it is especially suited to orbit determination in the course of the positioning phase of geostationary satellites. The features of the ODEM (Orbit Determination including Extended Maneuvers) software comprise the precise modeling of extended thrust phases and utilization of 3-way Doppler data which is essential for an improved orbit determination accuracy based on short tracking data arcs.
The mathematical algorithms implemented to model the extended spacecraft thrust phases for different types of satellites are presented together with a brief overall software description. Extended thrust phase monitoring and estimation is particularly interesting for two main fields of application, which are analyzed using data from a recently performed positioning: Rapid diagnosis of the apogee boost maneuvers and calibration of station acquisition maneuvers. Results are presented for the achieved level of the final residuals as well as for the comparison of the estimated thrust values obtained from ODEM and conventional methods. The benefit, resulting from the processing of 3-way Doppler data, is discussed.
*German Space Operations Center (GSOC), German Aerospace Research Establishment (DLR), DW 8031 Oberpfaffenhofen, Federal Republic of Germany.
**Instituto Nacional de Pesquisas Espaciais (INPE/DMC), CP 515, CEP 12.201-970 San Jose Campos - SP, Brazil .