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

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GSG can simulate SBAS satellites. Each scenario defines the number of SBAS satellites that
should be simulated. There can be 0, 1, 2, or 3 SBAS satellites per scenario.
To review/edit the number of SBAS satellites for the scenario chosen, navigate to: Select >
[ Select Scenario ] > Configure Scenario : View 3/3 "Number of Satellites" on page 71
The GSG unit will select SBAS space vehicles based on their elevation relative to the user pos
ition. When the scenario is running, the SBAS satellite positions and speed will be updated
with the information found in the SBAS messages. These messages comprise different
Message
Types , one of which—MT9—is used to update the satellite’s position and speed.
The SBAS satellites transmit their signals utilizing Coarse/Acquisition Pseudo-Random Noise
(see also "Encryption" on page 76).
PRN numbers , which have been internationally coordin
ated, have been allocated to each of the SBAS constallations. Although PRN120 … PRN158
are all reserved for SBAS systems, only a few of them are actually used by satellites.
When determining the elevation angle of SBAS satellites, the GSG unit looks for the SBAS satel
lites listed below. This is in contrast to the signal generator mode (see "Signal Generator" on
page 87) where the user can specify any SBAS PRNs to be simulated.
The currently supported SBAS satellites are:
EGNOS : 120, 124, and 126
WAAS : 133, 135, and 138
MSAS : 129, 137
GAGAN : 127, 128
The simulator uses two approaches for SBAS messages:
Default SBAS messages (MT63)
EGNOS/WAAS message files
The default SBAS messages are always available. These messages should be recognized by
SBAS-compatible receivers. However, they carry no information and will therefore not enable
the receiver to correct GPS signals.
SBAS message files for both EGNOS, and WAAS are supported. EGNOS files (.ems) are
ASCII and hourly, while WAAS files are typically in binary format and cover a whole day.
Both systems share the same format of the messages. For details, see
www.navipedia.net
.
When the scenario has the Ephemeris set to Download , the GSG unit will download the SBAS
messages from official sites and match these messages to the time of the scenario. The SBAS
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3
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User Manual GSG-5/6 Series Rev. 26
3.5 "Select" Menu