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Micro-JLT GNSS™ User Manual
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if the GPS Timing Mode is set to ON or to RSTSURV, the dynamic state will always be set to 1
(Stationary)
3.3.22 GPS:REFerence:ADELay <float> <s | ns >
[-32767ns,32767ns]
The ADELay command allows bi-directional shifting of the 1PPS output in relation to the UTC
(USNO) 1PPS reference in one nanosecond steps. This allows antenna cable delay compensation, as
well as retarding or advancing the 1PPS signal arbitrarily. Typical antenna delays for a 30 foot
antenna cable with 1.5ns per foot propagation delay would be compensated with the following
command:
GPS:REF:ADEL 45ns
This command can be used to fine-tune different units to have co-incident 1PPS signal outputs.
Please note that during normal operation the 1PPS signal may wander around the UTC 1PPS signal
while the unit is tracking the GNSS signals. The present offset between the 1PPS output and the UTC
1PPS signal can be queried with the command SYNC:TINT? and this offset should be taken into
account when calibrating two unit’s 1PPS outputs to each other, since the lock algorithms will try to
steer the OCXO for a 0.0ns offset to the UTC 1PPS time-pulse.
Change in this command will be effective after the next power cycle or after the GPS:RESET ONCE
command is sent.
3.3.23 GPS:REFerence:PULse:SAWtooth?
This command returns the momentary sawtooth correction factor that the GNSS receiver indicated.
3.3.24 GPS:RESET ONCE
This command issues a reset to the internal GNSS receiver. This can be helpful when changing the
antenna for example, since the GNSS receiver measures the antenna system’s C/No right after reset,
and adjusts its internal antenna amplifier gains accordingly. It takes approximately 1 minute for
locking to commence after a GNSS receiver reset, as indicated by the red blinking LED.
3.3.25 GPS:TMODe <ON|OFF|RSTSURV>
This command selects the Timing Mode of the GNSS receiver.
If the Timing Mode is OFF, the receiver will act as a regular GNSS receiver in 3D mobile mode. This
mode has to be chosen if the unit is used with a moving antenna.
If the Timing Mode in ON, the timing features of the GNSS receiver are enabled. At power-up, the
Hold position stored in NVRAM will be sent to the GNSS receiver and will be used as the reference.
In order to use this mode, the receiver position must be known as exactly as possible. Errors in the
Hold position will translate into time errors depending on the satellite constellation.