LTE-Lite User Manual
24 © 2020 Jackson Labs Technologies, Inc.
2.4 Connecting a GPS Antenna
Connect the GPS antenna to the MMCX connector J4 shown in Figure 2.3. Alternatively the GPS
antenna may be connected to the small U.Fl coax connector on the LTE-Lite SMT Module itself. Do
not use both antenna connectors at the same time as they are wired in parallel. Please make sure to
connect the GPS antenna prior to connecting the USB or power cable to the unit.
Caution: use a Lightning Arrestor on your Antenna setup.
The unit will provide +3.3V DC to the external antenna with up to 60mA of current. The LTE-Lite
Evaluation Board GPS receiver includes a 65 channel high-sensitivity GPS receiver with very fast
lock time that supports QZSS/WAAS/EGNOS/MSAS Satellite Based Augmentation Systems
(SBAS). By default a self-survey position-hold mode (auto survey) establishes the antenna position
over the first 2000 fixes after which the unit only requires a single satellite in-view to operate
properly, or it can be used in mobile platforms by disabling the Auto Survey mode by inserting a
jumper between pins 1 and 2 of the three pin header J3 (with the unit powered-off).
The LTE-Lite Evaluation Board GPSDO is capable of generating a number of standard navigation
messages that are compatible with most GPS based navigation software and are sent to the USB port.
Alternatively a toggle switch can be used to select a NMEA-style proprietary oscillator status and
health string. The GPS NMEA output can be generated in 1Hz (default) or 5Hz (insert 5Hz jumper
into JP1) update rates.
The GPS receiver generates a 1PPS time signal that is phase synchronized to UTC. This 1PPS signal
is used to frequency-lock the TCXO output of the unit to UTC, thus disciplining the unit’s
29 SURVEY_
Active
Auto Survey
Active Indicator
3.3V CMOS (Auto Survey
Active), 0V (Auto Survey
finished)
Indicates the status of the Auto
Survey process. Can be used to
drive an LED with up to 10mA.
Stays high for the duration of the
Auto Survey process
30 LOCK-OK LOCK-OK/No-E
vent indicator
3.3V CMOS (LOCK OK), 0V
(Event Pending)
LOCK-OK indicator. Goes low
if any event is pending. Stays
high if the unit is locked to GPS,
and no events are pending. Can
be used to drive an LED with up
to 10mA. If indicated, events can
be checked in the JLT
Proprietary Status output
message on the serial output pin
14
31 ALARM Alarm output 3.3V CMOS Alarm output.
Goes high if hardware or
software fault is detected
3.3V CMOS ALARM output.
Can be used to drive an LED
with up to 10mA. A hard- or
software fault has occured if this
signal goes high
32 GND5 Ground Ground Ground. Connect all module
grounds together
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