Posts made by kgn-mdlai

Re: Apriltag relocalization not relocalizing?

Hello, I have the following issue similar to one above about apriltag relocalization with fixed frame:

Platform / Version:
Starling 2 (C27)
voxl-suite v1.5.0
Front-facing camera used for VIO
Down-facing camera used for AprilTag detection

Issue
AprilTag relocalization works correctly when the tag detector runs on the front-facing camera, but consistently fails when running on the down-facing camera, even though:

• The down-facing camera intrinsics are correct
• The camera→body extrinsics in /etc/modalai/extrinsics.conf are correct
• R_tag_to_fixed is correctly set for a flat ground tag R_tag_to_fixed= [[0, -1, 0], [1, 0, 0], [0, 0, 1]]
• The tag is physically flat and the vehicle is level
• With the down-facing camera, voxl-vision-hub repeatedly reports: "WARNING, apriltag roll/pitch out of bounds" does not relocalize.

Confirmation
Using the same tag, same fixed-frame configuration, and same environment:

• Detection from front camera → relocalization succeeds.
• Detection from down-facing camera → relocalization rejected.
• Swapping only the camera input is sufficient to reproduce the failure.

Conclusion
This strongly suggests that the AprilTag relocalization path in voxl-vision-hub is composing R_tag_to_cam → R_cam_to_imu/body using the wrong camera extrinsics (appears to default to the front/tracking camera), rather than the extrinsics corresponding to the camera that actually produced the detection. As a result, the inferred R_tag_to_local ∘ R_fixed_to_tag contains spurious roll/pitch and is rejected by the ±10° gate.

Could you please solve the issue in new SDK? (You might add additional parameters in /etc/modalai/voxl-vision-hub.conf to select fixed frame pipe)

Best,
Kağan

Dear all,

I would like to ask you a couple of questions about reliably simulating the Starling-2 drone in a robotic simulator (preferably Gazebo).

• Do you have/provide an SDF of Starling-2 for Gazebo?
• Do you have some documentation for simulation in general that is similar to this (https://developer.parrot.com/docs/sphinx/index.html)?
• Do you have some system identification results for the motor and propeller couple (speed vs thrust)?
• I know the autopilot part (PX4) can be run as software in the loop (https://docs.px4.io/main/en/simulation/), but I wonder if the VOXL SDK can be run in an Ubuntu desktop computer (as a ROS node or non-ROS)?

Thank you in advance.
Best regards,
Kağan

@Moderator Thank you for your reply but I am able reach only the files of latest version of Starling from the datasheet and I need the CAD files of the one below if you have it:

Thank you in advance. Best,
Kağan

Hello,

I am working with the initial version of the Starling drone (V1) in our lab at EPFL. Do you have the CAD files for this version? I need the frame files, in particular.

Best,
Kağan