localization fails when rotating Z axis (so LiDAR points upside-down)

[greymfm]

For a drone application, I start the LiDAR in normal orientation ('Z axis up'), and when I rotate the LiDAR (MID-360) during a successful localization from 'Z axis up' to 'Z axis down', the localization does not flip the Z axis and fails. Is this supposed to work (and are there any options to tweak this)? Are there any assumptions about the motion model in the code that the LiDAR cannot flip upside-down from the normal orientation?

My map is complete (contains ceiling as well as floor LiDAR data), and my mapping software ('direct_lidar_inertial_odometry') has no issues when I rotate the LiDAR upside-down (correctly maps), and I can see that the IMU and LiDAR odometry output works correctly (I use 'fake_imu: true' as this is the only option that works for me when starting mcl_3dl).

Any ideas? :-)

Output of 'direct_lidar_inertial_odometry':

odometry.mp4

Output of 'mcl_3dl':

mcl3dl.mp4