EKF2 with high precision Motion Capture data


I’ve got some problems with the EKF2 using high precision motion capture data as vision input.
I configured everything according to the [PX4 Dev Guide] concerning [Discuss 9154], [Issue 7408], [Issue 8520], [Issue 10146], [Issue 10172], and [Issue 10310].
So if anyone has any further input, be it another issue on GitHub or one’s solution to this, I’d really appreciate it.

What I tried:

  • Lowering the rate of pose information from the mocap system.
  • Trusting the mocap system more than normal (lowering the noise params and raising the gate size).
  • Not trusting the IMU/Gyro data (raising the noise params).

What I didn’t (yet) try:

  • Aligning the IMU center to the center of the mocap data via EKF2_IMU_POS_X, EKF2_IMU_POS_Y, and EKF2_IMU_POS_Z.

My results:
Note: plots are at the end

  • While the position (/mavros/local_position/pose) generally follows the mocap pose, a lot of times, it overshoots.
  • Often it also starts oscillating while the pose is changed only a little, mostly to my inability to really fix an axis by hand.
  • In general, the results are not stable as it seems that the EKF still does not trust the pose information from the mocap.

My setup:

  • OptiTrack System with VRPN-client for ROS, noise is < 1 mm
  • PX4 v1.8.2dev running_ on Aerocore 2 (build based on [v1.8.2 tag])
  • Data streaming to EKF2 via remap of /mavros/local_position/pose at constant 50 Hz. (Data is coming from the VRPN at 200 Hz and throttled to 50 Hz via a [topic_tools/throttle]-node; confirmed the 50 Hz via rostopic hz.)
  • Moving my quadrotor by hand, trying to only move it along one axis and fixing the other two (completely fixing its orientation).

My params:

  • EKF2_ACC_B_NOISE: 0.01
  • EKF2_ACC_NOISE: 1.00
  • EKF2_AID_MASK: 24
  • EKF2_EVA_NOISE: 0.01
  • EKF2_EVP_NOISE: 0.01
  • EKF2_EV_DELAY: 10.0
  • EKF2_EV_GATE: 10
  • EKF2_GYR_B_NOISE: 0.01
  • EKF2_GYR_NOISE: 0.1
  • EKF2_HGT_MODE: Vision



Hello, I am also paying attention to this issue recently. Do you have any new developments? What is the approximate horizontal and vertical error in your actual flight?