Spectracom GSG-5 series, User Manual With Scpi Manual

Page: 63 / 378

In the event that dates for the user-specified data do not match the scenario’s start time, then
GSG will transform the start time in order to resolve the conflict.
If a satellite system (e.g., GPS, or Galileo) is selected (i.e., number of satellites selected is not 0)
and no navigation files are selected for that particular satellite system, then GSG will use
default data for that satellite system.
The RINEX format support includes version 2.x and 3.0.
The file extension for SP3 files must be *.sp3 (not case sensitive).
Downloading GPS RINEX files manually:
1.
Decide on the start date and time of the scenario, and the duration.
2.
Determine the number of files needed to cover the duration. (Each file contains up to
24 hours of information, i.e. midnight to midnight.
3.
Go to the website
ftp://cddis.gsfc.nasa.gov/pub/gps/data/daily/
and select the
required year, and then the day of year.
4.
In the directory for that day of year, choose the XXn folder, where XX is the 2-digit year.
5.
In the XXn folder, select and download the file brdcYYY0.XXn.Z , where XX is the 2-digit
year and YYY is the 3-digit DOY value.
6.
Inside the zipped folder you download is the file to use in the unit.
7.
Repeat this procedure for each day you plan on simulating in your scenario.
YUMA
Optionally, GPS and QZSS almanac data may also be provided in the form of YUMA files,
which are identified by their
.alm file extension. GPS and QZSS almanac files are identified
by a first-letter file naming convention:
g*.alm
: If the first letter of the file name is a ‘g’, GSG assumes the file contains
Galileo
satellite almanac data.
b*.alm : If the first letter of the file name is a ‘b’, GSG assumes the file contains Beidou
satellite almanac data.
q*.alm : If the first letter is ‘q’, then GSG assumes the file contains QZSS satellite
almanac data.
qg*.alm : If the first 2 letters are ‘qg’, then GSG assumes the file contains both GPS, and
QZSS satellite almanac data.
*.alm : If the first letter is anything other than ‘g, b, or q’, GSG assumes the file contains
only GPS almanac data.
YUMA almanac data can be used with custom RINEX files, or default ephemeris data. If no cus
tom RINEX files are provided, the default data will be used.
This allows testing using GPS and QZSS satellites with the same, or different GPS almanac
data. The GSG supports multiple GPS and QZSS almanac files. The YUMA almanac is con
sidered valid for ±3.5 days from the TOA value (Time-of-almanac) listed in the YUMA almanac.
3.5 "Select" Menu
CHAPTER
3
•
User Manual GSG-5/6 Series Rev. 26
47