R&S SMW-K44, User Manual

Page: 190 / 455

Loading Historical Data Satellite Navigation
190 User Manual 1178.6379.02 ─ 01
17 Loading Historical Data
The default satellite's constellation and the navigation message are extracted from offi-
cial navigation source files and emulates the GNSS navigation system at 9 February
2016 at 06:00:00 am.
Internal algorithms use the predefined navigation source information and predicts the
satellite's constellation and the navigation messages at any given moment of time. For
most test cases this prediction is sufficient.
When to change the default satellite's constellation and navigation data sour-
ces?
If your test scenario requires realistic GNSS signal or a historical situation has to be
reproduced, you can load constellation and navigation data for any of the GNSS sys-
tems separately.
Loading user-defined constellation is useful, if the HDOP and PDOP values exceed
your specific limits. To observe current values, select "GNSS > Simulation Monitor >
Sky View".
Constellation data and navigation message files formats
Supported are constellation and navigation message files in the following formats:
●
GPS: YUMA, SEM, TXT or RINEX files
See:
–
"YUMA, SEM, TXT, XML and AGL files download links" on page 190
– "RINEX download links" on page 191
●
GLONASS and QZSS: AGL, YUMA and XML
See
"YUMA, SEM, TXT, XML and AGL files download links" on page 190
●
Galileo and Beidou: these systems are not yet fully in orbit.
Hence, there are no files available.
●
SBAS:
*.ems
or
*.nstb
See "SBAS correction files download links" on page 191
YUMA, SEM, TXT, XML and AGL files download links
You can download GNSS YUMA, SEM and XML or RINEX files via the Internet. Trans-
fer them to the R&S
SMW and load them if required.
Use for example the following sources:
●
US Coast Guard Navigation Center GPS Homepage
http://www.navcen.uscg.gov/?pageName=gpsAlmanacs
Provides YUMA (
xxx.alm
) and SEM (
xxx.al3
files, where xxx denotes the day
of a year
●
http://www.celestrak.com/GPS/almanac/
Provides
almanac.sem/yuma.weekXXXX.YYYYYY.txt
files, where
xxxx
denotes the GPS week and
yyyyyy
the time of almanac (TOA)
●
ftp://ftp.glonass-iac.ru/MCC/ALMANAC/