GPS Module
HW-595 Board
- Based on uBlox NEO-6M-0-001
- 5V operation (3.3 V regulator onboard)
- UART: 9600 bps 8N1, TTL levels buffered by 220R resistors
- U.FL connector supplies 3.3 V to active antenna
- Crystal Osc, not TCXO
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
Software
U-Center
GPSD
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
Pulse Per Second (PPS)
dnf install pps-tools modprobe pps_ldisc ldattach 18 /dev/ttyS0
Check PPS signal:
ppstest /dev/pps0 ppscheck /dev/ttyS0