Use Custom IMU for EKF2

1

I want to PX4’s EKF2 use AI-corrected IMU data instead of the raw sensor stream.

My intended flow is: /mavros/imu/data → AI model (denoising/filtering) → UDP port 14560 → vehicle_imu_ai (uORB) → EKF2

Issue
From a structural point of view, publishing data through the vehicle_imu_ai topic is correct — the message format and timing fields match vehicle_imu.
However, once EKF2’s IMU source is switched to vehicle_imu_ai, two major problems occur.

  1. EKF2 logs poll timeout 0, 22

After setting EKF2_IMU_SRC=1, EKF2 stops receiving IMU updates at the expected rate.

  • The AI IMU feed currently runs at about 35 Hz, which is much slower and less regular than the default IMU rate (~200 Hz).
  • PX4’s scheduler waits for IMU updates that don’t arrive on time, so it logs poll timeouts.
  • As a result, EKF2 stops updating because the AI data is too slow or inconsistent.
  1. /mavros/imu/data drops to ~1 Hz after switching to AI

Immediately after switching EKF2 to use vehicle_imu_ai, the /mavros/imu/data topic slows to ~1 Hz ~ only heartbeat messages remain.

This likely happens because EKF2 unsubscribes from the raw vehicle_imu topic once it switches to the AI feed.
In SITL, if no one is subscribed, the simulator stops publishing IMU data.

Consequences:

  • MAVROS loses high-rate IMU data and pose updates stop.
  • The AI inference script stops receiving IMU input and therefore stops sending corrected data.
  • EKF2 then times out waiting for new vehicle_imu_ai samples, and the entire estimation pipeline halts.
2

Have you tested this with ROS2? It will pass the mavros, so you don’t have to go through mavros. might it save some time delays