Novatel GNSS Receiver and Antenna SMART-AG - Manual (Page 38)

38 SMART-AG User Manual Rev 5
Chapter 3 Operation
3.3.5 EGNOS
EGNOS (European Geostationary Navigation Overlay Service) has been developed to work with
existing satellite navigation systems to improve the accuracy of navigation signals. The EGNOS
signal is transmitted by two geostationary satellites and covers all of Europe. EGNOS transmits a
signal containing information on the reliability and accuracy of the positioning signals sent out by
GPS.
The EGNOS Open Service has been available since October 1, 2009 and the EGNOS Safety-of-Life
Service since March 2, 2011. If you wish to use the EGNOS signal you must issue the following
command:
sbascontrol enable egnos 0 none
ESTB (EGNOS System Test Bed) is a reduced version of EGNOS using dedicated monitoring stations
and processing devices. EGNOS and ESTB are two independent systems making use of its own
ground segment infrastructure and different GEOs. EGNOS and ESTB broadcast two different
signals.
The ESTB is broadcasted on PRN (pseudorandom number) 126 and EGNOS is broadcasted on PRNs
120 and 124.
Due to the experimental nature of the ESTB, the signals are broadcast without any guarantee of
service.
Use of the ESTB signal is not recommended by NovAtel. Use this command to prevent tracking
PRN 126: WAAS17 0 1 0 126 255 0 0 0 0 0 0 0.
More information on the ESTB can be found at http://www.esa.int/estb . More information on EGNOS
can be found at http://www.esa.int/egnos .
3.4 GL1DE
SMART-AG contains NovAtel’s GL1DE which is a positioning algorithms for single frequency GPS
and GPS/GLONASS applications. GL1DE produces a smooth position output tuned for applications
where optimal time relative (pass to pass) accuracy is more important than absolute accuracy. Because
of this, it is well suited for agricultural applications.
Multipath signals tend to induce time-varying biases and increase the measurement noise on the L1
pseudorange measurements. Carrier phase measurements are much less susceptible to the effects of
multipath. The GL1DE algorithm fuses the information from the L1 code and the L1 phase
measurements into a Position-Time-Velocity (PVT) solution.
GL1DE includes settings for a dynamic mode, a static mode, and an “auto” mode, where the filtering
parameters are automatically adjusted as vehicle velocity varies between stationary and dynamic
states.
Refer to the NovAtel white papers at www.novatel.com/support/knowledge-and-learning/published-
papers-and-documents/white-papers/ for more information on GL1DE. Refer also to application note
“APN-038 Pseudorange/Delta-Phase (PDP) and GL1DE Filters” at www.novatel.com/support/
knowledge-and-learning/published-papers-and-documents/application-notes/ .