In agreement with theory, wide-band Galileo codes, which use advanced BOC modulations, show exceptional multipath rejection, especially with respect to the long-range multipath, which is practically eliminated by L1A, E6A and E5AltBOC modulations, the latter being the most remarkable because it brings exceptional multipath performance to open-service users. In accordance with expectations, it is confirmed that the tracking noise and multipath characteristics of L2C and C/A codes are quite similar, while all the Galileo codes significantly outperform both existing GPS signals. It is shown that in the future multi-signal multi-frequency GNSS some new methods of noise assessment shall become possible, such as the use of 3-frequency multipath combinations as indicators of phase multipath. The paper begins with an overview of the methods to estimate tracking noise based on the analysis of real-life as well as simulated data. This paper is the first public presentation of the results of the observation data analysis of Galileo ranging signals, especially of their multipath performance, and of their comparison with both available GPS civil signals. The ground reception of these signals, which give an indication as to the performance of the ranging codes of the future Galileo and GPS was performed with GETR, a dedicated GSTB V.2 receiver, and with PolaRx2C respectively. The GSTB v.2 signal is available since January 2006. The L2C signal transmitted by GPS PRN 17 since December 2005 is the first of the new generation of signals actually available for tracking. Until recently, the tracking of the new signals and assessment of receiver performance was only possible with GNSS simulators. Septentrio has recently released new receiver models, which are able to track experimental Galileo signals transmitted by GSTB v.2 satellites and GPS L2C.
0 kommentar(er)
