ESP32 as MAVLink Bridge for QGroundControl - High Packet Loss & Disconnections

ArduCopter
1

I’m trying to use an ESP32 as a Wi-Fi bridge for PX4 to send MAVLink telemetry data to QGroundControl. The ESP32 is configured as a TCP server, connected to the flight controller via UART (currently using GPIO 4 for RX and GPIO 5 for TX), and acting as a transparent bridge. Here’s the setup:

  1. ESP32 connects successfully to the Wi-Fi access point.
  2. QGroundControl detects the ESP32 and establishes a connection, but the connection frequently drops with “remote host closed connection” errors.
  3. MAVLink packets (detected as 0xFE or 0xFD) are being forwarded between the UART and TCP, but I’m experiencing over 60% packet loss in QGroundControl.

Debugging Steps I’ve Taken:

  1. Pin Reconfiguration:
  • Tried alternative pins (e.g., GPIO 16/17) for UART RX/TX.
  1. Wi-Fi Stability:
  • Conducted continuous ping tests with 0% packet loss but observed higher-than-expected latency (~100ms).
  1. MAVLink Stream Rates:
  • Reduced rates to minimize data load (e.g., 5 Hz for position, 10 Hz for attitude).
  1. TCP Connection Debugging:
  • Verified that the ESP32 accepts connections and forwards data, but disconnections persist.
  1. Direct Flight Controller Test:
  • Verified MAVLink data output using a USB-to-serial adapter, confirming telemetry is sent.

Observations:

  • MAVLink heartbeats are detected, but data transmission isn’t stable.
  • QGroundControl often displays “Waiting for connection” even though the ESP32 is responding.

Question:

What could be causing the high packet loss and frequent TCP disconnections? Should I optimize the ESP32’s buffer sizes, change UART pins, or investigate a potential Wi-Fi bottleneck? Any advice or alternative configurations for reliable MAVLink bridging would be greatly appreciated!