INAV + ExpressLRS (ELRS) — Complete Setup Guide

ExpressLRS (ELRS) is the most popular open-source radio control link, offering incredible range and low latency. Combined with INAV's GPS navigation, it creates the ultimate long-range drone system. Here's how to set it up.

Hardware Requirements

• ELRS receiver (900MHz for long range, 2.4GHz for general use)
• INAV-compatible flight controller with free UART
• ELRS-compatible transmitter module (RadioMaster, BetaFPV, HappyModel)

Wiring

Connect your ELRS receiver to a free UART on your flight controller:

• TX pad on receiver → RX pad on FC UART
• RX pad on receiver → TX pad on FC UART
• 5V and GND from FC to receiver

INAV Configuration

Step 1: Port Configuration

In INAV Configurator → Ports tab:

• Find the UART connected to your ELRS receiver
• Set Serial RX on that UART
• Save and reboot

Step 2: Receiver Settings

In Configuration tab:

Receiver Mode: Serial
Serial Receiver Provider: CRSF

ELRS uses the CRSF (Crossfire) protocol — select CRSF, not ELRS.

Step 3: Telemetry

ELRS supports full telemetry back to your radio. In CLI:

set crsf_use_rx_snr = ON
set telemetry_inverted = OFF

Step 4: Failsafe

set failsafe_procedure = RTH
set rx_min_usec = 885
set rx_max_usec = 2115

ELRS Settings for INAV

• Packet rate: 150Hz for racing, 50Hz for long range
• Telemetry ratio: 1:4 or 1:8 for stable telemetry
• Switch mode: Wide or Hybrid for more aux channels

Troubleshooting

• No connection: Check UART assignment, make sure TX/RX are not swapped
• No telemetry: Enable CRSF telemetry on the same UART, set correct baud rate
• Failsafe not working: Set failsafe_procedure to RTH, verify GPS lock