Safety & tech

GPS not found

No GPS lock — compass, location or firmware. Full diagnostics guide for DJI and FPV. Common on: DJI Mini/Mavic/Air, Autel, FPV with GPS module (BN-220, M10), INAV GPS rescue. GPS lock is required for RTH, position hold and geo compliance. In the EU, 10–12 satellites in open area is usually sufficient.

A2STS editorial12 min read

Contents

Overview

No GPS lock — compass, location or firmware. Full diagnostics guide for DJI and FPV.

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

GPS lock is required for RTH, position hold and geo compliance. In the EU, 10–12 satellites in open area is usually sufficient.

Symptoms

Typical "GPS not found" signs in flight, app or OSD:

  • GPS signal weak or searching >2 min
  • RTH grey / unavailable
  • Position hold drifts without wind
  • Satellite count <8 before arming
  • Home Point not set automatically
  • Log satellite count, HDOP and RTH status before arming.

Common causes

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

  • Urban canyon — buildings block satellites, multipath
  • Uncalibrated compass or magnetic interference (car, metal)
  • GPS module antenna or cable after crash
  • Firmware regression after update
  • Cold battery — slower GPS cold start

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. Move to open area, away from metal roofs and vehicles.
  • 2. Calibrate compass per app (360° rotations, phone/aircraft level).
  • 3. Wait for ≥10 satellites (ideally ≥12) and low HDOP before arming.
  • 4. Update aircraft, RC and app firmware to latest stable release.
  • 5. FPV: check GPS antenna mount, UART baud (57600/115200), mag alignment in Betaflight.
  • 6. If unresolved — flight log + GPS module replacement or service.

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.

  • DJI Fly → Safety → Compass/GPS status — screenshot errors for documentation.
  • Compare behaviour outdoors vs indoors — confirms environmental limitation.

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:

  • Home Point and RTH altitude — ritual before every flight
  • Do not arm without stable GPS lock
  • Warm battery before GPS start in winter
  • Do not store on car roof during transport

Frequently asked questions

Is it safe to fly with "GPS not found"?
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 “GPS not found” cases — 15–45 min on the ground. Complex ones (firmware, hardware) may need 1–2 h and service.
How long to wait for GPS lock?
In open area usually 30–90 s. In winter or after transport on car roof — up to 2 min. If >3 min without lock — calibrate compass.

Authority & sources

A2STS Editorial · Reviewed by: EASA UAS syllabus aligned