"No GPS Fix"

Symptom

The MAVLink GPS app is running, the "Radar" shows a fix, but Mission Planner (or the HUD) shows No GPS.

Troubleshooting Steps

1. Check the Driver (GPS_TYPE)

ArduPilot will not listen to MAVLink GPS data unless you tell it to.

• Parameter: GPS_TYPE (or GPS1_TYPE).
• Required Value: 14 (MAVLink).
• Note: You must reboot the flight controller after changing this.

2. Check the Baud Rate

The USB connection (SERIAL0) requires a specific baud rate to match the app.

• Parameter: SERIAL0_BAUD.
• Required Value: 115 (115200).
• Parameter: SERIAL0_PROTOCOL.
• Required Value: 2 (MAVLink 2).

3. Check Android Permissions

Android requires explicit user permission to access the USB device.

• Action: When you plug in the USB cable, a popup asks "Allow MAVLink GPS to access...?"
• Requirement: You MUST click OK. If you clicked Cancel, unplug and replug the cable.

4. Check the "Traffic"

Does the app see the drone?

• App UI: Look at the top bar. Does it say "Connected: ArduPilot"?
• Heartbeat: If the app says "Waiting for Heartbeat...", the TX line (Phone -> Drone) might be working, but the RX line (Drone -> Phone) is broken. Check your cable.