@tom Thank you for your answer! Unfortunately the overlay does not appear, even when the drone is armed. We are using Starling 2 drones with SDK 1.6.2. Also in the voxl-open-vins-server.conf we can't find a setting for something related to the overlay. Do you have any ideas what we can try to see the ov_overlay again? Thank you in advance!

@wilkinsaf Do you happen to have any experience with this?

Hey @dvz, thanks for your query We’re currently in the process of updating the voxl-tag-detector to support additional AprilTag families beyond just the 36h11. If you’d like to try this yourself in the meantime, the following line in main.cpp creates the detector for the 36h11 family: here To add support for the tagCustom48h12 family, you can: Add the include: #include <tagCustom48h12.h> Replace the detector creation line with: tf = tagCustom48h12_create(); Please note that this change may affect the current functionality, you’ll likely need to make additional modifications in main.cpp to ensure it builds and runs correctly. As mentioned, we’re actively working on making this a much smoother process in the future. But if you’d like to get started now, the above steps should point you in the right direction.

@psafi Here are the steps I am taking for camera calibration: 1- run the following command: voxl-calibrate-camera tracking_down -f -s 6x9 -l 0.022 2- look at the overlay in portal (see the screenshot below) 3- calibration process is not progressing automatically even though it seems like the checkerboard is detected [image: 1760465700997-e47c8511-c92f-4ce7-83f6-49d59dd89e7d-screenshot-from-2025-10-14-11-14-52.png]

@Moderator thank you for the recommendation. I will try out this.

Detections is pertinent to voxl-tflite-server and onboard computer vision on yolo, NOT on april tags.

@Moderator Even I am facing the same issue. Did everything as per the instructions on the official website. But unable to calibrate the stereo front. I was able to calibrate stereo back though. I have attached the error along for your reference.

@Daniel-Rincon have you looked through the troubleshooting guide? https://docs.modalai.com/flying-with-vio/#troubleshooting-vio Usually looking at the ovins-overlay in voxl-portal offers good insight The common issues are vibration is too high, the extrinsics are incorrect or there are not enough features to track in the environment

@Cliff-Wong @Kessie Guys can you help me out here.

@tom can anyone help me with this

@Alex-Kushleyev Thank you for reverting, I will check this out and get back to you

@shawn_ricardo Hi! To my understanding EKF2_EV_CTRL 15-->13 only remove EV from pos_z estimation, so it should be ok to do that if the range sensor is active. However, I did revert all parameters to the default settings (matching the VOXL-SDK definitions). As my attempts to integrate the range-sensor data in altitude estimation did not seem to succeed, I decided to try and integrate the range-sensor in the VIO solution. I created a version of the voxl-qvio-server in which pos_z estimation from VIO is replaced by the equivalent value based on the rangefinder: s.T_imu_wrt_vio[2] = - down_range_m; This seem to work better, however it is a workaround and not a full solution. My current experiments are performed in low altitude (~40-90 cm), so I am not concerned with the limited range of the rangefinder sensor. I'm not sure what is the current implemented behaviour when EV estimation is not good, there should be some fall-back relying on the range sensor and imu. From my short experience with such cases of poor EV estimation mid-flight, the drone just crushes or jump to the ceiling with no control. Any suggestions or further explanations will be much appreciated. Thank you

@Eric-Katzfey Thank you for the reply, If I understand correctly, the example you provided shows MAVSDK running directly on the VOXL — so on the drone itself. However, we want to run our script on a separate PC to be able to control all drones at once. We're not sure which port to use to communicate with PX4 while also taking advantage of the relocalization handled by VOXL. Thank you again for your help!

@Alex-Kushleyev Thank you very much!

@SKA What pipes do you see listed in /run/mpa? If you run the command voxl-inspect-vio does it show that VIO is running okay?