Testing the “position tracking” python example from SDK 5.3, it fails: the translation is always 0.0, and this warning appears frequently:
[2026-05-27 18:22:34 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
if imu fusion is turned off, it works, if GEN 1 is used with imu on, it works.
Hi @Riccardo
Welcome to the StereoLabs community.
Please try to launch the ZED Sensor Viewer tool and let me know if it provides valid data feeds.
Please send a few screenshots or a screen recording.
Hello,
Unfortunaly i cannot upload media it seems, as I am a new user. IMU seems to work fine in the Sensor Viewer, in fact GEN_1 with IMU fusion works, the problem is IMU fusion with GEN_3 only,
thanks for your help!
Can you please share the full log with GEN_3
Sure, this is the log of the positional tracking example:
python /usr/local/zed/samples/positional\ tracking/positional\ tracking/python/positional_tracking.py
================================================================================
ZED Positional Tracking
[Sample] Positional tracking mode: Explore (default)
[2026-05-29 11:46:29 UTC][ZED][INFO] Logging level INFO
[2026-05-29 11:46:29 UTC][ZED][INFO] Using USB input… Switched to default resolution HD720
[2026-05-29 11:46:30 UTC][ZED][INFO] [Init] Camera successfully opened.
[2026-05-29 11:46:30 UTC][ZED][INFO] [Init] Camera FW version: 1523
[2026-05-29 11:46:30 UTC][ZED][INFO] [Init] Video mode: HD720@30
[2026-05-29 11:46:30 UTC][ZED][INFO] [Init] Serial Number: S/N 10027835
[2026-05-29 11:46:30 UTC][ZED][INFO] [Init] Depth mode selected: NEURAL. Ensure this mode matches your application’s performance and accuracy requirements. See
for help.
================================================================================
Positional Tracking Parameters
[Sample] set_floor_as_origin false
[Sample] set_gravity_as_origin true
[Sample] enable_area_memory true
[Sample] enable_pose_smoothing false
[Sample] enable_imu_fusion true
[Sample] set_as_static false
[Sample] depth_min_range -1.0
[Sample] enable_2d_ground_mode false
[Sample] mode GEN 3
================================================================================
Interaction
[Sample] ‘space’ to toggle camera view visibility
[Sample] ‘d’ to switch background color from dark to light
[Sample] ‘p’ to enable / disable current live point cloud display
[Sample] ‘l’ to enable / disable landmark display
[Sample] ‘f’ to follow the camera
[Sample] ‘z’ to reset the view
[Sample] ‘ctrl’ + drag to rotate
[Sample] ‘esc’ to exit
[2026-05-29 11:46:32 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:33 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:34 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:34 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:38 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:38 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:39 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:39 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:40 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:40 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:41 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:41 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:42 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:42 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:42 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:43 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:43 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:44 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:45 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:45 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:46 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:46 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:47 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:48 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:48 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:49 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:50 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:50 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
[2026-05-29 11:46:51 UTC][ZED][WARNING] Initial IMU prior rotation seems to be wrong, resetting positional tracking with a better prior.
I can see in the viewer the camera rotating with a stocking behavior (it stops whenever that warning appears), but the position is fixed in the origin and never changes.
This is a recording of the screen
You should give the module time to initialize the Inertial fusion.
Furthermore, the light in the environment looks very low, making it hard to detect good visual features to be tracked.
it has been tested in a lot of different conditions, and also pointing to texture rich scenes with a lot of light. What do you mean about give time to the module to initialize? I tried waiting a couple of seconds before moving the camera but this does not change the result
Please use ZED Explorer to record an SVO file under the same conditions and share it with me.
One minute of recording is enough.
Here is the SVO, It’s too big to be directly uplaoded here:
Hi @Riccardo
I analyzed the SVO file with samples and ZED Tools, and I cannot find anything weird about it.
I shared the SVO and the other details with the ZED SDK team to verify why this “hiccup” problem happens.
I also recommend you test your camera with the ZED SDK v5.3.1, which will be released in the next few days.
ok, I will test with the new release and let you know, thanks!!
Hello,
The new release did not solve the problem
Hi @Riccardo
Thank you for all the details.
The ZED SDK team is analyzing the problem and will fix it in one of the next releases.