Jackson Labs Mini-JLT GNSS, Руководство пользователя

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Mini-JLT GNSS™
User Manual
3.6.10 SYNChronization:LOCKed?
This query returns the lock state (0=OFF, 1=ON) of the PLL controlling the TCXO.
3.6.11 SYNChronization:OUTput:1PPS:RESET [ON|OFF]
This command allows the generation of the 1PPS pulse upon power-on without an external GPS
antenna being connected to the unit. By default the unit does not generate a 1PPS pulse until the
GNSS receiver has locked onto the Satellites. With the command SYNC:OUT:1PPS:RESET ON the
unit can now be configured to generate an asynchronous 1PPS output after power-on even if a GNSS
antenna is not connected to the unit. Once the GNSS receiver locks, the 1PPS pulse will align itself
to UTC by stepping in 10 equally spaced steps toward UTC alignment. The default setting is OFF
which means the 1PPS pulse is disabled until proper GNSS lock is achieved.
3.6.12 SYNChronization:health?
The SYNChronization:health? query returns a hexadecimal number indicating the system’s
health-status. Error flags are encoded in a binary fashion so that each flag occupies one single bit of
the binary equivalent of the hexadecimal health-status flag.
The following system parameters are monitored and indicated through the health-status indicator.
Individual parameters are ‘ored’ together which results in a single hexadecimal value encoding the
following system status information:
As an example, if the unit is in GNSS receiver holdover, and the OCXO voltage is too high, and the
UTC phase offset is > 250ns then the following errors would be indicated:
1) UTC phase > 250ns: 0x4
2) OCXO voltage too high: 0x40
3) GNSS receiver in holdover: 0x10
‘Oring’ these values together results in:
If the OCXO coarse-DAC is maxed-out at 255 HEALTH STATUS |= 0x1;
If the OCXO coarse-DAC is mined-out at 0 HEALTH STATUS |= 0x2;
If the phase offset to UTC is >250ns HEALTH STATUS |= 0x4;
If the run-time is < 300 seconds HEALTH STATUS |= 0x8;
If the GNSS receiver is in holdover > 60s HEALTH STATUS |= 0x10;
If the Frequency Estimate is out of bounds HEALTH STATUS |= 0x20;
If the OCXO voltage is too high HEALTH STATUS |= 0x40;
If the OCXO voltage is too low HEALTH STATUS |= 0x80;
If the short-term-drift (ADEV @ 100s) > 100ns HEALTH STATUS |= 0x100;
For the first 7 minutes after a phase-reset, or a coarsedac change: HEALTH STATUS |= 0x200;
If the GNSS receiver indicates a strong jamming signal of >=50
(range is 0 to 255) HEALTH STATUS |= 0x800;