Satellite orbit determination combining C-band ranging and differenced ranges by transfer

Abstract

The constraint in the transverse direction of satellite orbit with differenced ranges between master station and slave stations by transfer as an angular observation data is explained in theory. Differenced ranges in combination with C-band ranging by transfer were used in satellite orbit determination. The position error of overlapped orbit differences for combining is less than that for ranging only. The residual of predicted orbit forward 5.5 days for combining is 3.1762 m, while the residual for ranging only with the same duration is 3.5380 m. Both the orbital overlapping and orbit prediction experimentations can testify the constraint in the transverse direction of satellite orbit with differenced ranges, and the results show that the accuracy of orbit determination and orbit prediction is improved by combining differenced ranges and C-band ranging. The space segment of satellite navigation system of China consists of several geostationary Earth orbit (GEO) satellites. The orbit accuracy of GEO satellites has an influence on positing capability of navigation system directly. Therefore, the research on precise orbit determination of GEO satellites has a great significance. "Determination of satellite orbit by transfer" was developed by the National Time Service Center, Chinese Academy of Sciences. Owing to the high orbit determination accuracy, the system is suitable for GEO satellite tracking [1]. The accuracy of C-band ranging is better than one centimetre in the direction of line-of-sight. The GEO satellite is placed at an altitude of 36000 km above the equator. The angle of GEO satellite to the ranging stations is only a few degrees. The ranging data is unable to provide constrain in the transverse direction of the satellite orbit owing to the poor observation geometry.The observation mode of differenced ranges by transfer is the development for C-band ranging by transfer. The principle of the observation mode of differenced ranges is the same as very long baseline interferometry (VLBI). It can provide strongly constrain in the transverse direction of the satellite orbit, perpendicular to the line-of-sight. The improvement of orbit prediction accuracy combining differenced ranges and ranging by transfer has been implemented with short-arc data [2].In order to explaining the constraint in the transverse direction of satellite orbit by differenced ranges in theory, the relation between the measurement error of angular observation and satellite orbit is analyzed in detail. The experiments of orbital overlapping and orbit prediction are carried out to validate the improvement in accuracy of orbit determination and prediction with differenced ranges.

The zero gravity curve and surface and radii for geostationary and geosynchronous satellite orbits

“…The orbits of the above satellites can be determined analytically and/or directly monitored by observations (Soop 1994), such as satellite laser ranging and C-band ranging (e.g. Guo et al, 2010;Yang et al 2013), GNSS or Doppler shift observations by LEO satellites (Knogl et al 2011).…”