GPS Module: Difference between revisions

Revision as of 21:30, 27 February 2023

Based on uBlox NEO-6M-0-001
5V operation (3.3 V regulator onboard)
UART: 4800 - 230400 bps (9600 bps 8N1 default), TTL levels buffered by 220R resistors
U.FL connector supplies 3.3 V to active antenna
Crystal Osc, not TCXO
LED:
- Constant: Searching
- Blink 1s: Position fix
Battery-backed RAM contains config data and clock and speeds first-time-to-fix
Data in NMEA 0183 format
More background here

Board pinouts:

Pin	Function	Description
1	PPS	1 pulse/s, synchronised at rising edge, length 100 ms
2	RXD	UART input
3	TXD	UART output
4	GND	Ground
5	VCC	3.3 - 5 V

PPS can be reconfigured as a frequency reference:

Send PPS to UART via CTS
0.25 Hz - 10 MHz
Configure in u-Center here
Output has high frequency accuracy, but suffers from jitter except at a few specific frequencies

Enable and start gpsd. Should auto-detect which UART is GPS connected to (baud rate, etc, with no configuration):

systemctl enable gpsd
systemctl start gpsd

Use gpsmon to monitor GPS data, or xgps

dnf install pps-tools
modprobe pps_ldisc
ldattach 18 /dev/ttyS0

Check PPS signal:

ppstest /dev/pps0
ppscheck /dev/ttyS0

@@ Line 5: / Line 5: @@
 * Based on [https://www.u-blox.com/en/product/neo-6-series uBlox NEO-6M-0-001]
 * 5V operation (3.3 V regulator onboard)
-* UART: 9600 bps 8N1, TTL levels buffered by 220R resistors
+* UART: 4800 - 230400 bps (9600 bps 8N1 default), TTL levels buffered by 220R resistors
 * [https://en.wikipedia.org/wiki/Hirose_U.FL U.FL] connector supplies 3.3 V to active antenna
 * Crystal Osc, not TCXO
+* LED:
+** Constant: Searching
+** Blink 1s: Position fix
+* Battery-backed RAM contains config data and clock and speeds first-time-to-fix
 * Data in [http://www.gpsinformation.org/dale/nmea.htm NMEA] 0183 format
 * More background [https://www.electroschematics.com/neo-6m-gps-module/ here]