ROS 2 Integration

Full ROS 2 Humble package. The lyrebird_controller node publishes all telemetry fields as individual topics and subscribes to command topics. It checks for new telemetry at 20 Hz but publishes only when the drone has actually sent a new snapshot, so the topic rate follows the aircraft’s telemetry interval (default ~2 Hz) rather than repeating each sample.

Package structure

GroundStation/ROS/
├── lyrebird_controller/   # Main control + telemetry node
│   ├── controller.py        # DjiNode: 45+ topics, publishes on new telemetry
│   └── dji_interface.py
├── lyrebird_videofeed/    # RTSP video feed -> sensor_msgs/Image
└── lyrebird_bringup/
    ├── auto_discovery_native.launch.py  # one namespaced lyrebird_controller per discovered drone, re-scans periodically
    ├── swarm_connection.launch.py
    └── config/parameters.yaml

Published topics (per drone namespace, e.g. /mini1/)

Topic	Type	Description
speed	Float64	Velocity magnitude (m/s)
speed_vector	Vector3	Velocity vector x, y, z (m/s)
heading	Float64	Compass heading (degrees)
attitude	String	{pitch, roll, yaw} JSON
location	NavSatFix	GPS latitude, longitude, altitude
gimbal_attitude	String	{pitch, roll, yaw} JSON
gimbal_joint_attitude	String	Joint angles JSON
gimbal_yaw / gimbal_pitch	Float64	Individual gimbal angles
zoom_fl / hybrid_fl / optical_fl	Float64	Focal lengths (-1 if N/A)
zoom_ratio	Float64	Camera zoom ratio
battery_level	Float64	Battery %
satellite_count	Int32	GPS satellite count
waypoint_reached	Bool	Final WP flag
intermediary_waypoint_reached	Bool	Intermediate WP flag
altitude_reached / yaw_reached	Bool	Reach flags
home_location	NavSatFix	Home GPS coordinates
home_set	Bool	Home point set flag
distance_to_home	Float64	Distance to home (m)
remaining_flight_time	Float64	Remaining flight time (s)
time_needed_to_go_home	Float64	Time to RTH (s)
time_needed_to_land	Float64	Time to land (s)
time_to_landing_spot	Float64	Go-home + land (s)
max_radius_can_fly_and_go_home	Float64	Max safe radius (m)
battery_needed_to_go_home	Float64	Battery % for RTH
battery_needed_to_land	Float64	Battery % to land
camera/is_recording	Bool	Recording status
flight_mode	String	Current DJI flight mode string
manual_override_active	Bool	Pilot override active
waypoint_seq / yaw_seq / altitude_seq	Int32	Sequence id of the command currently executing
command_ack/waypoint_seq / yaw_seq / altitude_seq	Int32	Sequence id assigned when the command was accepted
ready_to_takeoff	Bool	Preflight conditions satisfied
takeoff_block_reason	String	Why takeoff is blocked
camera/capture_result	String	Capture descriptor JSON (async)
camera/media_list	String	SD card listing JSON (async)
camera/download_result	String	Download result JSON (async)
camera/thermal_max_temp	Float64	Thermal max temperature (°C)
lrf/measurement	String	Laser rangefinder reading JSON
lrf/target	NavSatFix	Geo-referenced laser target

Subscribed topics (commands)

Camera, media, and LRF commands block for as long as the aircraft takes to answer (up to 120 s for a download), so they run on a single-worker thread pool and answer asynchronously on their own camera/* and lrf/* result topics rather than stalling the telemetry loop.

Topic	Type	Body
command/takeoff	Empty	—
command/land	Empty	—
command/rth	Empty	—
command/abort_mission	Empty	—
command/abort_all	Empty	—
command/enable_virtual_stick	Empty	—
command/abort_dji_native_mission	Empty	—
command/deactivate_manual_override	Empty	—
command/camera/start_recording	Empty	—
command/camera/stop_recording	Empty	—
command/goto_waypoint_nose_forward	Float64MultiArray	[lat, lon, alt, yaw, speed?] — yaw = final arrival heading
command/goto_waypoint_hold_heading	Float64MultiArray	[lat, lon, alt, yaw, speed?] — yaw held for the whole flight
command/goto_trajectory_dji_native	String	"(speed, [(lat,lon,alt),...])"
command/goto_yaw	Float64	Yaw angle (degrees)
command/goto_altitude	Float64	Altitude (m)
command/gimbal_pitch	Float64	Pitch (degrees)
command/gimbal_yaw	Float64	Yaw joint angle
command/zoom_ratio	Float64	Zoom ratio
command/set_rth_altitude	Float64	RTH altitude (m)
command/stick	Float64MultiArray	[leftX, leftY, rightX, rightY] ∈ [-1,1]
command/gimbal_rel_pitch	Float64	Pitch relative to current angle (degrees)
command/gimbal_rel_yaw	Float64	Yaw relative to current angle (degrees)
command/camera/capture	Empty	Capture on the thermal lens
command/camera/capture_temperature	Empty	Read thermal max temperature
command/camera/list_media	Empty	List SD card contents
command/camera/download_media	String	Download one media file by name
command/lrf/measure	Empty	Fire the laser rangefinder
command/drop	Empty	Release the payload

Usage

Docker (single-drone, auto-discovery):

cd GroundStation
docker build -t lyrebird-ros .
docker run --rm --network=host lyrebird-ros

The image is based on ros:humble with CycloneDDS, cv-bridge, vision-opencv, image-transport, plus all Python dependencies.

Manual multi-drone launch:

cd GroundStation/ROS
colcon build --symlink-install && source install/setup.bash
ros2 launch lyrebird_bringup auto_discovery_native.launch.py

# Example commands (namespace is the drone's own name, e.g. "mini1")
ros2 topic pub /mini1/command/takeoff std_msgs/msg/Empty "{}"
ros2 topic pub /mini1/command/goto_waypoint_nose_forward std_msgs/msg/Float64MultiArray \
  "data: [49.306254, 4.593728, 20.0, 90.0, 5.0]"