Geometry-free error analysis and cycle slips detectionof GPS observations on the basis of dynamic information and its applications on LEO precise orbit determination

The quality of low Earth orbit (LEO) satellite-borne global positioning system (GPS) observation data has an important influence on the precise orbit determination of LEO satellite and the study of the ionosphere. In this contribution, we develop a geometry-free orbit-dynamic-constraint approach to analyze the satellite-borne GPS observations errors, including code errors, carrier phase errors, receiver clock errors, ionospheric delay, to detect and repair cycle slips for satellite-borne dual-frequency carrier phase observations. Different from the traditional methods suitable to satellite-borne GPS observations, we take full advantage of the correlations between the dual-frequency observations, between the satellite orbit variations and the orbit dynamic background models, without a prior precise orbit. The proposed approach can not only remove the geometry variations between GPS satellites and LEO satellite, but also have partial characteristics of other signals separated from GPS observations, such as the receiver clock offset. Then, the performance of the proposed approach is verified by GPS measurement data of GOCE/GRACE satellite with different sampling interval. The results indicate that the proposed approach preforms well on observations error analysis, can effectively detect and fix cycle slips with high success rates, even in real-time applications.