Drone (ArduPilot) - Bedrock Dynamics

Simulation Container

docker pull bedrockdynamics/substrate-sim:ardupilot-gazebo

The container bundles ArduPilot SITL, Gazebo Harmonic, and the MAVLink gRPC bridge.

Port	Protocol	Purpose
9090	gRPC	ros2-bridge (telemetry streaming + MAVLink command relay)

Differences from PX4

ArduPilot and PX4 are both MAVLink-based autopilots, but they differ in several ways that affect the bridge implementation:

Aspect	PX4	ArduPilot
Velocity control mode	OFFBOARD	GUIDED
Mode switching	`COMMAND_LONG` with `MAV_CMD_DO_SET_MODE`	`SET_MODE` message with ArduPilot mode numbers
MAVLink dialect	Standard MAVLink 2	`ardupilotmega` dialect with extra messages
Setpoint message	`SET_POSITION_TARGET_LOCAL_NED`	`SET_POSITION_TARGET_LOCAL_NED` (same)
Arming	`COMMAND_LONG` with `MAV_CMD_COMPONENT_ARM_DISARM`	Same, but may require arming checks to be disabled in SITL

The flight sequence is similar but uses GUIDED mode instead of OFFBOARD:

ARM

Send the arm command. ArduPilot enables the motors.

TAKEOFF

Command takeoff. ArduPilot handles the climb in its current mode.

GUIDED

Switch to GUIDED mode. ArduPilot accepts external velocity setpoints.

Velocity Control

WASM controllers write body velocity commands at 100Hz. The bridge relays these as MAVLink setpoint messages.

LAND

Switch to LAND mode. ArduPilot handles descent and motor disarm.

WASM Channels

ArduPilot drones use the same ChannelManifest::quadcopter() manifest as PX4 drones — 4 body velocity command channels and 4 position state channels at 100Hz.

Command Channels (4)

Index	Name	Unit	Limits
0	`body/velocity.x`	m/s	-5.0 to 5.0
1	`body/velocity.y`	m/s	-5.0 to 5.0
2	`body/velocity.z`	m/s	-3.0 to 3.0
3	`body/yaw_rate`	rad/s	-pi/2 to pi/2

State Channels (4)

Index	Name	Unit	Type
0	`body/position.x`	m	Position
1	`body/position.y`	m	Position
2	`body/position.z`	m	Position
3	`body/yaw`	rad	Position

The NED frame negation applies here too — the bridge negates vz so that positive values in the WASM controller mean “go up.”

ArduPilot support is less tested than PX4. The SITL simulation and bridge integration have had less validation. If you encounter issues, please report them at github.com/BedrockDynamics/roz-oss.

Source Code

Channel manifest: crates/roz-core/src/channels.rs (ChannelManifest::quadcopter())
MAVLink bridge: crates/roz-worker/

​Simulation Container

​Differences from PX4

​WASM Channels

​Command Channels (4)

​State Channels (4)

​Source Code

Simulation Container

Differences from PX4

WASM Channels

Command Channels (4)

State Channels (4)

Source Code