Safety & tech

IMU calibration error

Accelerometer/gyro calibration fails or flight is unstable. Common on: DJI Mini/Mavic/Air, Autel, FPV with GPS module (BN-220, M10), INAV GPS rescue.

A2STS editorial12 min read

Contents

Overview

Accelerometer/gyro calibration fails or flight is unstable.

Common on: DJI Mini/Mavic/Air, Autel, FPV with GPS module (BN-220, M10), INAV GPS rescue.

Symptoms

Typical "IMU calibration error" signs in flight, app or OSD:

  • App requests IMU calibration before every flight
  • Aircraft leans to one side in hover
  • After crash — IMU error or cannot arm
  • Log satellite count, HDOP and RTH status before arming.

Common causes

Before replacing parts, rule out software, mechanical and environmental causes:

  • Calibration on uneven surface or antenna touching table
  • Impact after crash — IMU mount misaligned
  • Moisture or sand inside FC
  • Firmware/app version mismatch

Tools needed

Prepare before diagnostics — saves time in the field:

  • Open area away from metal
  • DJI Fly / Pilot or Betaflight Configurator
  • Flight log export

Step-by-step fix

Work safely: battery off when working on ESC/motors; props removed; after repair — VLOS test flight.

  • 1. Place aircraft on level, stable surface — nothing touching antennas.
  • 2. DJI: Settings → Safety → IMU Calibration; FPV: Betaflight/INAV accel cal.
  • 3. After crash — check FC mounting (soft mount, anti-vibration).
  • 4. Update firmware; factory reset only as last resort.

Additional diagnostics

Log satellite count, HDOP and RTH status before arming.

Compare behaviour indoors vs outdoors — confirms GPS limitation.

FPV: Betaflight GPS tab — baud 57600/115200, mag alignment.

When to contact service

If any of the following apply — do not fly and contact authorised service:

  • GPS still shows no satellites after calibration and firmware update.
  • After crash — physical GPS antenna or cable damage.
  • Compass wrong even in open field — service required.

Prevention

Prevention reduces failure risk and supports EASA Open / VLOS compliance:

  • Calibrate after transport
  • Hard landing — always check IMU

Frequently asked questions

Is it safe to fly with "IMU calibration error"?
No if the fault affects navigation, power, ESC or link. Fix on the ground first, then conduct a VLOS test flight in open area.
How long does diagnosis take?
Most “IMU calibration error” cases — 15–45 min on the ground. Complex ones (firmware, hardware) may need 1–2 h and service.
How many times to repeat IMU calibration?
Once on a level surface. If error repeats — check FC mounting, do not repeat calibration without cause.

Authority & sources

A2STS Editorial · Reviewed by: EASA UAS syllabus aligned