Incorrect TF transforms

1. Symptoms

• A lookup fails (“frame does not exist”, “extrapolation into the future”).
• Sensor data appears shifted, rotated, mirrored or in the wrong place in RViz.
• A frame flickers between two positions.

2. Possible causes

• Name typo or a missing publisher.
• Two publishers (for example URDF and a static publisher) for one child frame.
• Parent and child swapped, so the transform is inverted.
• Wrong units (degrees as radians) or Euler-angle order.
• Clock or use_sim_time mismatch.
• The optical-frame permutation forgotten for a camera.

3. Measurements to collect

• The tree from view_frames.
• One transform from tf2_echo compared with a tape-measure value.
• Update rate and delay from tf2_monitor.
• The publishers on /tf_static and /tf.

4. Diagnostic commands

Commands are not executed by the site’s automated tests (they need a ROS 2 Jazzy installation or the robot).

ros2 run tf2_tools view_frames
ros2 run tf2_ros tf2_echo base_link lidar
ros2 run tf2_ros tf2_monitor
ros2 topic info /tf_static --verbose

5. Step-by-step investigation

1. Print the tree and check for one root and one parent per frame.
2. Compare one transform with a measurement: sign and magnitude of the translation.
3. Check the direction: swap parent and child if the sign is opposite.
4. Check for duplicate publishers and remove one.
5. Check time: use_sim_time, stamps and the clock source.
6. Check the camera optical frame permutation.

6. Corrective actions

• Define each fixed link once (URDF or static publisher).
• Correct names and direction; use quaternions or documented Euler order.
• Make time settings consistent.
• Add a tree check to your launch tests (see the tf2 guide).

7. Validation after the fix

• view_frames shows a single tree.
• tf2_echo values match measurements within tolerance for every sensor.
• Data from every sensor overlaps in RViz.

References

• ROS 2 Jazzy tf2 tutorial, debugging tf2 problems: docs.ros.org, read 2026-11-06.
• See the tf2 guide.