# AprilTag Localization not affecting static coordinate system

Source: https://forum.modalai.com/topic/5197/apriltag-localization-not-affecting-static-coordinate-system
Category: VOXL 2 and VOXL 2 Mini (https://forum.modalai.com/category/26/voxl-2-and-voxl-2-mini)
Tags: voxl-2
Posted: 2026-05-06 15:09:15 UTC by casez
Replies: 0 · Views: 568

## casez · 2026-05-06 15:09:15 UTC

I am trying to get AprilTag localization working on the Starling 2 drone but I cannot get the fixed coordinate system to change based on the apriltag. I am able to detect it correctly, but relocalization does not work.

Here are relevant configuration files, I mainly followed the example [link](https://docs.modalai.com/voxl-vision-hub-apriltag-relocalization/).

voxl-tag-detector.conf
``` 
/**
 * This file contains configuration parameters for voxl-tag-detector.
 * You can specify up to 3 cameras to do detection on simultaneously.
 * For the stereo camera pair, only the left camera is used.
 */
{
	"detector_0":	{
		"enable":	true,
		"input_pipe":	"tracking_front",
		"en_fast_mode":	true,
		"n_threads":	1,
		"en_undistortion":	true,
		"undistort_scale":	0.600000023841858,
		"overlay_name":	"tracking_tag_overlay",
		"lens_cal_file":	"/data/modalai/opencv_tracking_front_intrinsics.yml",
		"skip_n_frames":	5
	}
}
```

tag_locations.conf
```
{
        "locations":    [{
                        "id":   0,
                        "name": "landing-pad",
                        "loc_type":     "fixed",
                        "size_m":       0.17145,
                        "T_tag_wrt_fixed":      [0, 0, 0],
                        "R_tag_to_fixed":       [[0, -1, 0], [1, 0, 0], [0, 0, 1]]
                }],
        "default_size_m": 0.17145 //  0.40000000596046448
}
```
in voxl-vision-hub.conf I have
```
"en_tag_fixed_frame": true,
"en_transform_mavlink_pos_setpoints_from_fixed_frame": true
```

When I run 
```
voxl-vision-hub -l
```
I am able to see the tags position update as it moves.

When I run
```
voxl-vision-hub -p
```
I can see the local_wrt_fixed change when the drone moves, but not when the tag moves. I would expect the local_wrt_fixed to also change with the tag moving since it is set to be [0,0,0]. 

I also often get a "WARNING, apriltag roll/pitch out of bounds", which appears to be a common issue.

Is there a configuration error I am missing or some way I can get the relocalization system to work?