Spectracom GSG-5 series, Руководство пользователя с руководством по SCPI

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MSAS:
default MT63
GAGAN:
default MT63
GSG uses an anonymous login. However, note that both FTP sites are likely to track and record
all FTP access, including access by the GSG-55.
The SBAS download starts when the constellation simulation of the scenario has started; not dur
ing initialization of the scenario.
If a scenario needs SBAS messages that cannot be downloaded from these FTP sites, the scen
ario continues, but the GSG unit transmits null- messages (SBAS message type:
MT63
). An
SBAS-compatible receiver should still be able to see the SBAS signals, but it will not find any
useful information (range corrections, time offsets, etc.) in the SBAS messages.
It follows that SBAS scenarios run best with a live Internet connection. Furthermore, since the
aforementioned FTP sites store only a limited amount of SBAS records, the start time of SBAS
scenarios has to be chosen carefully. Usually, SBAS records that are less than a year
(EGNOS)/6 months (WAAS) old can be found on the aforementioned FTP sites. Select a start
time that is not older than one year for EGNOS scenarios, and not older than 6 months for
WAAS scenarios. Moreover, the start time shall not be too close to the current time. For
EGNOS, there can be a one day delay before the SBAS messages are published on the FTP
site. For WAAS the delay can possibly be longer (up to 3 or 4 days).
The Internet connection is not always needed. All downloaded ephemeris data and SBAS data
will be locally stored on the unit once they are downloaded. So, the next time the same scen
ario runs, the ephemeris data and SBAS messages are read from the local storage and no Inter
net connection is needed. The unit performs automatic clean- up of downloaded files. Such
clean-up will occur when free disc space is less than 20% of the total disc space.
Note:
Currently SBAS corrections are not ‘applied backwards’ to the outputted
GPS signals, even though the corrections will be transmitted in the SBAS signal.
4.9.14 Record and Playback
Note: This is an optional feature for which the Record and Playback option (OPT-
RP) is required.
The Record and Playback software converts recorded NMEA messages into scenario, tra
jectory, and event files. You can then upload these files to your GSG unit where they can be
played back in order to recreate the original scenario.
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CHAPTER
4
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User Manual GSG-5/6 Series Rev. 26
4.9 Studioview Tasks