# Issues with Fixed_Frame / ROS & MPA

Source: https://forum.modalai.com/topic/2547/issues-with-fixed_frame-ros-mpa
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2023-08-09 02:29:09 UTC by Dwangnoderbora
Replies: 1 · Views: 379

## Dwangnoderbora · 2023-08-09 02:29:09 UTC

Hi everyone!

We’re working on a precision landing project with a UAV using VOXL2 and Apriltag’s QR code tracking. Initially, we tried to use the reallocation config in ```/etc/modalai/voxl-vision-px4.conf```, and although we get ```debug_tag_local``` in ```voxl-vision-px4``` to work, we don't get any output to ```debug_fixed_frame``` , which we believe suggests that the re-localization didn't happen. Is this correct to assume?

Eventually we tried to solve the problem using ROS. We attempted to use ```apriltag_ros``` to do the same as above, however it is looking for ```camera_info```, and we don't know how to pass the camera intrinsic to ROS using MPA. Our /tag_detections and /tag_detections_image topics are empty. It seems like it is theoretically possible to pass the tag location and tag images to ROS using MPA, but we don’t know how to progress with this.

We are willing to continue working with ROS or revert to the provided software, but are unsure of how to progress, any assistance is highly valued!

Our ```voxl-vision-px4``` config:

```
{
	"config_file_version":	1,
	"qgc_ip":	"192.168.50.111",
	"en_secondary_qgc":	true,
	"secondary_qgc_ip":	"10.258.36.109",
	"qgc_udp_port_number":	14550,
	"udp_mtu":	512,
	"en_localhost_mavlink_udp":	true,
	"localhost_udp_port_number":	14551,
	"vio_pipe":	"qvio",
	"en_vio":	true,
	"en_send_vio_to_qgc":	false,
	"en_reset_vio_if_initialized_inverted":	true,
	"vio_warmup_s":	3,
	"send_odom_while_failed":	false,
	"horizon_cal_tolerance":	0.5,
	"offboard_mode":	"figure_eight",
    	"en_tag_fixed_frame": true,
    	"en_transform_mavlink_pos_setpoints_from_fixed_frame": true,
    	"en_fixed_frame_pipe": false,
	"follow_tag_id":	0,
	"figure_eight_move_home":	true,
	"robot_radius":	0.300000011920929,
	"collision_sampling_dt":	0.1,
	"max_lookahead_distance":	1,
	"en_tag_fixed_frame":	false,
	"fixed_frame_filter_len":	5,
	"en_transform_mavlink_pos_setpoints_from_fixed_frame":	false,
	"en_voa":	true,
	"en_send_voa_to_qgc":	false,
	"voa_upper_bound_m":	-0.15000000596046448,
	"voa_lower_bound_m":	0.15000000596046448,
	"voa_memory_s":	1,
	"voa_inputs":	[{
			"enabled":	true,
			"type":	"point_cloud",
			"input_pipe":	"dfs_point_cloud",
			"frame":	"stereo_l"
		}, {
			"enabled":	true,
			"type":	"point_cloud",
			"input_pipe":	"stereo_front_pc",
			"frame":	"stereo_front_l"
		}, {
			"enabled":	true,
			"type":	"point_cloud",
			"input_pipe":	"stereo_rear_pc",
			"frame":	"stereo_rear_l"
		}, {
			"enabled":	true,
			"type":	"tof",
			"input_pipe":	"tof",
			"frame":	"tof"
		}, {
			"enabled":	true,
			"type":	"rangefinder",
			"input_pipe":	"rangefinders",
			"frame":	"body"
		}],
	"land_on_tag_id": 0

}
```

Our tag_locations.conf:

```
{
	"locations":	[{
			"id":	0,
			"name":	"default_name",
			"loc_type":	"unknown",
			"size_m":	0.40000000596046448,
			"T_tag_wrt_fixed":	[0, 0, 0],
			"R_tag_to_fixed":	[[0, -1, 0], [1, 0, 0], [0, 0, 1]]
		}],
	"default_size_m":	0.40000000596046448
}
```

## Reply by afdrus · 2023-09-18 10:01:40 UTC

@Dwangnoderbora 
`loc_type` should be set as `"fixed"`