Spectracom GSG-5 series, User Manual With Scpi Manual

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GPS and QZSS almanac data may optionally be provided in the form of
YUMA files
(for
details, see below).
In addition, SBAS message files are also supported (see "SBAS Satellites" on page 77 and
"User-Uploaded Ephemeris" on the next page below for more details).
Under the menu item Select > Select Scenario > Configure > Ephemeris , there are two or three
options to choose from (as described below), in order to select a source for your scenario nav
igation data:
Default
Download
User-uploaded files .
Figure 3-6:
Ephemeris selection
3.5.5.1 Default Ephemeris
The default RINEX data for GPS and GLONASS is based on the
CDDIS GNSS archive
, using
the brdc files. The non-redundant brdc file merges the individual site navigation files into one,
and thus can be used instead of the many individual navigation files.
This data is complemented by GLONASS almanac data downloaded from
ftp://www.glonass-iac.ru/MCC/ALMANAC/
, covering the same period (file names are
prefixed by receiver types, e.g. MCCT_ , MCCJ_, GG-24, or TOPCOM_).
The default navigation data begins Jan 8, 2012 and runs for 33 consecutive days.
For Galileo, BeiDou, and IRNSS, the GSG unit comes shipped with its own ephemeris data set.
When the ephemeris setting is set to Default , the GSG unit builds all scenarios, any start date,
using the default data. If there is an exact match for the scenario Start time and preloaded nav
igation files, that navigation data will be used. If an exact date match is not found, then the
GSG unit will use the first preloaded navigation data with the same day of the week as the scen
ario’s start time. Further simulation days will use consecutive in date navigation data.
In general, the start time of the scenario always supersedes the time stamps in the navigation
data files. If file date and scenario start time do not match, then the loaded data is transformed
accordingly to match the scenario’s start time. If the scenario defines a GPS almanac files only,
the YUMA files will define the almanac and the ephemeris will be derived from the default
RINEX data.
3.5 "Select" Menu
CHAPTER
3
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