RL-GNSS-001 · Navigation · KAMAL NAV GM1
Troubleshooting
GNSS, compass, wiring, parser, and external antenna symptoms with fixes.
Published May 4, 2026Updated May 9, 2026Reading time ~15 min
01Symptom table#
| Symptom | Likely cause | Fix |
|---|---|---|
| No serial output | Wrong UART pins, wrong baud, no 5 V supply | Swap RX/TX, confirm 5 V, and try the configured baud rate |
| No fix indoors | Poor sky view or weak antenna placement | Move outdoors or use an external active antenna |
| Fix drops near motors | Power noise or RF interference | Move antenna, separate wiring, improve 5 V filtering |
| Compass not detected | I2C wiring, address conflict, missing pullups | Check SDA/SCL, scan for address 0x30, move to another bus if needed |
| Heading wrong after install | Hard-iron or soft-iron distortion | Run calibration in the final airframe |
| NMEA parser overflows | Too many sentences at low baud | Raise baud rate or disable unused sentences |
| External antenna not improving fix | Wrong antenna band or poor placement | Use an active L1/L5 antenna with clear sky view |
02Isolation order#
Verify power first, then UART output, then GNSS sky view, then compass I2C detection. This order prevents antenna and firmware debugging from hiding basic wiring faults.