GGTO: Stability and Impact on Multi-constellation Positioning

Global Navigation Satellite Systems usually operate using independent time scales. For this reason, the determination of inter-system time offsets is required to enable multi-constellation navigation. The Galileo to GSP Time Offset (GGTO) defines the difference between the Galileo and GPS time scales. In this paper, three different approaches for the determination of the GGTO are considered and their performance are evaluated using measurements from four multi-constellation receivers. The GPS/GLONASS inter-system bias is also estimated and used as a comparison term for the GGTO analysis. From the analysis, it emerges that the GGTO is more stable than the GPS/GLONASS inter-system bias which is characterized by a small drift. Different receivers provides different estimates of the GGTO which are usually biased with respect to the broadcast parameter. The estimation of the GGTO significantly improves the position performance which is further enhanced when constraints are imposed on the GGTO time variations.

GIOIA Ciro;  BORIO Daniele; 

2016-01-19

Institute of Navigation

JRC94736

2331-5911,