AP_DDS: null quaternion in /ap/tf_static not accepted by rviz2

[srmainwaring]

Bug report

Issue details

The null quaternion in /ap/tf_static appears to cause issues when passed to rviz2. The quaternion has all fields set to zero:

% ros2 topic echo /ap/tf_static
transforms:
- header:
    stamp:
      sec: 1713792800
      nanosec: 232813000
    frame_id: base_link
  child_frame_id: GPS_0
  transform:
    translation:
      x: 0.0
      y: -0.0
      z: -0.0
    rotation:
      x: 0.0
      y: 0.0
      z: 0.0
      w: 0.0

When the topic is remapped to /tf_static and passed to rviz2 an error is reported:

% ROS_DISCOVERY_SERVER="192.168.1.170:11812" rviz2 --ros-args --remap tf_static:=/ap/tf_static
[INFO] [1713794415.884889952] [rviz2]: Stereo is NOT SUPPORTED
[INFO] [1713794415.884937536] [rviz2]: OpenGl version: 2.1 (GLSL 1.2)
[INFO] [1713794415.921487525] [rviz2]: Stereo is NOT SUPPORTED
Error:   TF_NAN_INPUT: Ignoring transform for child_frame_id "GPS_0" from authority "Authority undetectable" because of a nan value in the transform (0.000000 -0.000000 -0.000000) (nan nan nan nan)
         at line 242 in /Users/rhys/Code/ros2/humble/ros2-humble/src/ros2/geometry2/tf2/src/buffer_core.cpp
Error:   TF_DENORMALIZED_QUATERNION: Ignoring transform for child_frame_id "GPS_0" from authority "Authority undetectable" because of an invalid quaternion in the transform (nan nan nan nan)
         at line 259 in /Users/rhys/Code/ros2/humble/ros2-humble/src/ros2/geometry2/tf2/src/buffer_core.cpp

We need to check the ROS 2 convention for a zero quaternion and whether normalisation is required (i.e. w:=1.0).

Publishing an empty TFMessage suggests that normalisation must be applied:

% ros2 topic pub /tf_static tf2_msgs/msg/TFMessage 'transforms: [{header: {frame_id: "map"}, child_frame_id: "base_link"}]' --once
publisher: beginning loop
publishing #1: tf2_msgs.msg.TFMessage(transforms=[geometry_msgs.msg.TransformStamped(header=std_msgs.msg.Header(stamp=builtin_interfaces.msg.Time(sec=0, nanosec=0), frame_id='map'), child_frame_id='base_link', transform=geometry_msgs.msg.Transform(translation=geometry_msgs.msg.Vector3(x=0.0, y=0.0, z=0.0), rotation=geometry_msgs.msg.Quaternion(x=0.0, y=0.0, z=0.0, w=1.0)))])

Version

• master: commit 5a21d0cb8a859b293eea087fb8c9be150c0ca910 (HEAD -> master, upstream/master)
• custom build: ./waf configure --board MatekH743-bdshot --enable-dds --enable-ppp

Platform [ ] All [ ] AntennaTracker [ ] Copter [ x] Plane [ ] Rover [ ] Submarine

Airframe type

Quadplane X

Hardware type

MatekH743-WING v3, RPi4

Logs

N/A