Manz, H.; Hodon, M.:
POSSIBILITIES OF ASSISTED-GPS (A-GPS) EMPLOYMENT DURING GNSS SIGNAL LOST WHEN POSITIONING THE VEHICLE.
EURO – ZEL 2012 - 20th International Symposium, Juni 2012.
When the moving vehicle is positioned, with no respect to the technology employed
several accuracy-affecting problems could arise. In this article, focus to GNSS localization
with problem of signal lost when vehicle crossing an obstructed area will be given.
Comparison of presently used technologies such Dead Reckoning or GNSS/INS integration
with unusual possibilities of A-GPS utilization will be evaluated. The time of the lost
navigation signal reacquision analysis among various application scenarios will be stressed.
Application scenarios will be modelled with respect to situations that could come up during
vehicle/train positioning - tunnels and variously obstructed areas crossing as well as the
receiver systems problems revealing. By analysis and improvement of GNSS receiver TTFF
parameter (Time-To-First-Fix) an importance of A-GPS integration into the common
localization process will be shown. By examples of several A-GPS architectures the suitability
of this technology among European Area will be demonstrated.