Jackson Labs Mini-JLT GNSS, Руководство пользователя

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© 2017 Jackson Labs Technologies, Inc. 3
Mini-JLT GNSS™
User Manual
Quick-Start
Instructions
2.1 Powering Up the Unit
To operate the unit, simply follow these two steps:
1) Connect a 3.3V or 5V-compatible GNSS antenna to SMA connector J4. The antenna can
be passive or active. The Mini-JLT GNSS™ board will supply 3.3V to the antenna by
default, and this can be increased to up to 5.5V through the external antenna power supply
pin 5 of connector J1
2) C5V (+/-1V) DC Power to J1 pin 6 on the unit, and ground to pin 4 of J1
[The unit will consume up to 8W of power during oscillator warmup]
The unit will now lock to GNSS signals (Red LED D1 is blinking when satellites are being received)
and will indicate proper lock and no events pending when the Green LED D1 goes on. Once the
green LED D1 is on, the unit will output 10MHz with significantly better than 1ppb frequency
accuracy.
By default the unit will be set to Position Hold mode, and an antenna position
Auto Survey process is started after power-on that may take up to 3 hours to
finish. The antenna should never be moved when the unit is set to run in
Position Hold mode as this would result in loss of frequency and timing
accuracy and incorrect GNSS fixes. The unit must be configured to mobile
mode using the GPS:TMODE OFF command when used in an application
where the antenna position can move during normal operation. Using the
Auto Survey process and Position Hold mode allows the unit to
over-determine the timing solution, and also allows TRAIM operation which
will result in slightly higher timing stability and more robust GNSS
reception in challenged environmental conditions such as under foliage, in
urban canyons, etc.
Please note that the GNSS receiver establishes the internal antenna gain right after
power-on, so for proper operation the GNSS antenna should always be connected prior
to turning on the +5V power.