Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Collapse
Brand Logo

ModalAI Forum

  1. ModalAI Support Forum
  2. Autonomy: VIO, Mapping and Navigation
  3. Apriltag as a reference cordinate

Apriltag as a reference cordinate

Scheduled Pinned Locked Moved Unsolved Autonomy: VIO, Mapping and Navigation
apriltag
5 Posts 2 Posters 3.5k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • Amin BassiriA Offline
    Amin BassiriA Offline
    Amin Bassiri
    Contributor
    wrote on last edited by
    #1

    Hello,

    I would like to use apriltag as a reference (0, 0, 0). I mean, for example, when the drone detects the tag, show it in the "T_imu_wrt_vio (m)" (0, 0, 0) coordinate.
    How can I do that?

    Drone Model: RB5
    Hardware Version: M0052
    VOXL-Suite Version: 1.1.2
    PX4 Version: 1.14.0dev

    Thanks,
    Amin

    Amin BassiriA 1 Reply Last reply
    0
    • Amin BassiriA Amin Bassiri

      Hello,

      I would like to use apriltag as a reference (0, 0, 0). I mean, for example, when the drone detects the tag, show it in the "T_imu_wrt_vio (m)" (0, 0, 0) coordinate.
      How can I do that?

      Drone Model: RB5
      Hardware Version: M0052
      VOXL-Suite Version: 1.1.2
      PX4 Version: 1.14.0dev

      Thanks,
      Amin

      Amin BassiriA Offline
      Amin BassiriA Offline
      Amin Bassiri
      Contributor
      wrote on last edited by
      #2

      @Amin-Bassiri could you please someone answering my question.

      Alex KushleyevA 1 Reply Last reply
      0
      • Amin BassiriA Amin Bassiri

        @Amin-Bassiri could you please someone answering my question.

        Alex KushleyevA Offline
        Alex KushleyevA Offline
        Alex Kushleyev
        ModalAI Team
        wrote on last edited by
        #3

        @Amin-Bassiri , can you please clarify the question?

        The april tag detector detects the tag in the camera frame and using extrinsics file, the tag's coordinate can be converted into the vehicle's reference frame.

        With that in mind, what would you like to do? What is unclear to me is the following statement : "show it in the "T_imu_wrt_vio (m)" (0, 0, 0) coordinate"

        Alex

        Amin BassiriA 1 Reply Last reply
        0
        • Alex KushleyevA Alex Kushleyev

          @Amin-Bassiri , can you please clarify the question?

          The april tag detector detects the tag in the camera frame and using extrinsics file, the tag's coordinate can be converted into the vehicle's reference frame.

          With that in mind, what would you like to do? What is unclear to me is the following statement : "show it in the "T_imu_wrt_vio (m)" (0, 0, 0) coordinate"

          Alex

          Amin BassiriA Offline
          Amin BassiriA Offline
          Amin Bassiri
          Contributor
          wrote on last edited by
          #4

          @Alex-Kushleyev

          I have an RB5 drone that I plan to fly indoors, but I require very accurate localization. For this purpose, I need a fixed reference coordinate system. For example, I want to designate point A (associated with Apriltag0) as (X=0, Y=0, Z=0). This means that even if the drone flies away and later returns to point A, once it detects the AprilTag, its coordinates should reset exactly to (0, 0, 0) without any error.
          Since I plan to fly the drone multiple times along a route from point A to point B and back to point A, I need the system to reliably reset the drone’s position to (0, 0, 0) whenever it sees Apriltag0—even if there are slight changes in the tag's position.
          How can I achieve this using the AprilTag as a reference coordinate?
          I want to reset T_imu_wrt_vio to 0,0,0, when the drone detect the Apriltag.Screenshot from 2025-02-11 10-34-36.png

          1 Reply Last reply
          0
          • Amin BassiriA Offline
            Amin BassiriA Offline
            Amin Bassiri
            Contributor
            wrote on last edited by
            #5

            Problem solved,
            Thanks anyway

            1 Reply Last reply
            0

            Reading along? Create a free ModalAI Forum account to join in.

            With an account you can reply, ask your own question, get an email when a ModalAI engineer answers, and mark the reply that solved it. Your place in each thread is saved between visits.

            Questions about VOXL, Flight Core, ESCs and ModalAI drones are answered here by the engineers who build them.

            Register Login
            Reply
            • Reply as topic
            Log in to reply
            • Oldest to Newest
            • Newest to Oldest
            • Most Votes


            ModalAI
            Categories Recent Tags ModalAI.com Docs
            © 2026 ModalAI® · Accelerating autonomy for smaller, smarter, safer drones · Powered by NodeBB
            • Login

            • Don't have an account? Register

            • Login or register to search.
            • First post
              Last post
            0
            • Categories
            • Recent
            • Tags
            • Popular
            • Users
            • Groups