Jackson Labs LTE-Lite, User Manual

Page: 29 / 34

© 2020 Jackson Labs Technologies, Inc. 25
LTE-Lite User Manual
20MHz/19.2MHz/10MHz frequency output to the US Naval master clock for very high frequency
accuracy (typically better than 1ppb of frequency accuracy when locked to GPS). Over the long term,
the LTE-Lite Evaluation Board GPSDO will out-perform free-running Cesium Atomic Frequency
Standards.
2.5 USB serial connection
•
The unit outputs strings to the USB Serial port at 38400 baud, 8N1.
•
The unit cannot receive serial data and ignores serial data sent to it.
•
The unit supplies a 1PPS signal to the DCD# pin of the USB port which can be used to synchronize
programs such as NTP or GPSD.
•
Connect the PC via the USB cable and connector, attaching the LTE-Lite Evaluation Board to your
PC’s Hyperterminal, TeraTerm, or a NMEA compatible program such as the uBlox u-center
application. Please initialize your PC application software to the proper COM port (automatically
assigned by Windows) and configure the application software for 38400 Baud, 8 bits, no parity, 1
stop bit, and no flow control where applicable.
2.5.1 Proprietary $PSTI NMEA GPS Status Sentence
When in timing mode, the GPS receiver NMEA serial status output sentences contain a timing status
message in NMEA proprietary format. This $PSTI message is encoded as follows:
$PSTI,00,1,1985,-12.4,30,5*28
$[Proprietary Message String ID], [00], [Timing Mode], [Survey Length in 1PPS fixes], [1PPS
Quantization Error in ns][Position Standard Deviation Threshold][Calculated Position Standard
Deviation After Self-Survey]*[NMEA compatible checksum]
The Timing Mode parameter field is encoded as follows:
0 = PVT Mode
1 = Survey Mode
2 = Static (Position Hold) Mode
2.5.2 JLT Proprietary STATUS Output Sentence
Selecting the STATUS setting on toggle-switch SW1 will enable the JLT proprietary NMEA-style
oscillator status and health output string to be sent to the USB port. The string has the following
exemplary format:
$PJLTS,0.33,-31.15,189,2,1.6970169,56.5672,1.6E-8,0,7,0x228*44
$PJLTS,-1.35,-31.15,190,2,1.6970190,56.5672,1.6E-8,0,7,0x228*60
The fields of this status string are encoded as follows:
$PJLTS,-1.35,-31.15,190,2,1.6970190,56.5672,1.6E-8,0,7,0x228*60