MARSH Dialect

This page documents all extensions to MAVLink that were required for the simulator.

The definitions are in the marsh.xml file on the dialect branch in our fork of main MAVLink repository. All other projects need to generate and appropriate libraries, following the mavlink.io – Generating MAVLink Libraries documentation.

When in need of a definition for a given functionality which is not covered here, first consult the Common Message Set, both our subset and full list. If a new definition is actually needed, follow the original guide on how to define MAVLink Messages & Enums.

Changing message definitions (id, field names, types, order) breaks over-the-wire compatibility by design. Thus it's strongly recommended to avoid doing that. Also, if a functionality can be achieved just by defining some new enums or commands, this means that the code will be able to use upstream MAVLink libraries without modifications.

Definition list

Generated on 2025-11-28T16:18:31 from commit 659be11

• Enums
  • MARSH_TYPE
  • MARSH_MODE_FLAGS
  • CONTROL_AXIS
  • MARSH_MANUAL_SETPOINT_MODE
  • MOTION_PLATFORM_MODE
  • MOTION_PLATFORM_HEALTH
  • EYE_TRACKING_EVENT_TYPE
  • HUMAN_BODY_POINT
• Mav Commands
• Messages
  • CONTROL_LOADING_AXIS
  • MOTION_PLATFORM_STATE
  • REXROTH_MOTION_PLATFORM
  • MOTION_CUE_EXTRA
  • EYE_TRACKING_DATA
  • EYE_TRACKING_EVENT
  • HUMAN_BODY_POSE

MAVLink Include Files: common.xml

This file has protocol dialect: 3.

MAVLink Type Enumerations

MARSH_TYPE

[Enum] Component types for different nodes of the simulator network (flight model, controls, visualisation etc.). Components will always receive messages from the Manager relevant for their type. Only the first component in a network with a given system ID and type will have its messages forwarded by the Manager, all other ones will only be treated as output (will be shadowed). This enum is an extension of MAV_TYPE documented at https://mavlink.io/en/messages/minimal.html#MAV_TYPE

Value	Field Name	Description
100	MARSH_TYPE_MANAGER	The simulation manager responsible for routing packets between different nodes. Typically MARSH Manager, see https://marsh-sim.github.io/manager.html
101	MARSH_TYPE_FLIGHT_MODEL	Component simulating flight dynamics of the aircraft.
102	MARSH_TYPE_CONTROLS	Component providing pilot control inputs.
103	MARSH_TYPE_VISUALISATION	Component showing the visual situation to the pilot.
104	MARSH_TYPE_INSTRUMENTS	Component implementing pilot instrument panel.
105	MARSH_TYPE_MOTION_PLATFORM	Component that moves the entire cockpit for motion cueing.
106	MARSH_TYPE_GSEAT	Component for in-seat motion cueing.
107	MARSH_TYPE_EYE_TRACKER	Component providing gaze data of pilot eyes.
108	MARSH_TYPE_CONTROL_LOADING	Component measuring and actuating forces on pilot control inputs.
109	MARSH_TYPE_VIBRATION_SOURCE	Component providing vibrations for system identification, road rumble, gusts, etc.
110	MARSH_TYPE_PILOT_TARGET	Component providing target for the pilot to follow like controls positions, aircraft state, ILS path etc.
111	MARSH_TYPE_EXPERIMENT_DIRECTOR	Principal component controlling the main scenario of a given test, (unlike lower level MARSH_TYPE_PILOT_TARGET or MARSH_TYPE_MANAGER for overall communication).

MARSH_MODE_FLAGS

[Enum] These values are MARSH-specific modes intended to be sent in custom_mode field of HEARTBEAT message. Prefer defining values in the most significant byte (between 2^24 and 2^31) to leave the lower three bytes to contain a message id

Value	Field Name	Description
0x1000000	MARSH_MODE_SINGLE_MESSAGE	Request Manager to only send one specific message, advised for very resource limited nodes or with control flow limitations like Simulink. That message id should be in the lower three bytes of the mode, which can be done by adding it to the flags.
0x2000000	MARSH_MODE_ALL_MESSAGES	Request Manager to send every message going out to any of the clients.

CONTROL_AXIS

[Enum] Specific axis of pilot control inputs, with order corresponding to x, y, z, r fields in MANUAL_CONTROL message.

Value	Field Name	Description
0	CONTROL_AXIS_ROLL	Roll axis, with positive values corresponding to stick right movement, causing the vehicle to roll right. For helicopters this is lateral cyclic.
1	CONTROL_AXIS_PITCH	Pitch axis, with positive values corresponding to stick forward movement, causing the vehicle to move nose down. For helicopters this is longitudinal cyclic.
2	CONTROL_AXIS_THRUST	Main thrust, with positive values corresponding to going faster and higher. For helicopters this is collective.
3	CONTROL_AXIS_YAW	Yaw axis, with positive values corresponding to pushing right pedal, causing the vehicle to face right direction. For helicopters this is tail collective.

MARSH_MANUAL_SETPOINT_MODE

[Enum] Usage of MANUAL_SETPOINT message, sent in mode_switch field.

Value	Field Name	Description
0	MARSH_MANUAL_SETPOINT_MODE_DEFAULT	Default meaning of the message. This should be sent by inceptors when using a flight control system in separate node to differentiate from FCS outputs.
1	MARSH_MANUAL_SETPOINT_MODE_TRIM	Values for inceptors trim positions, the exact meaning depends on the flight model.
2	MARSH_MANUAL_SETPOINT_MODE_TARGET	Values for target inceptors positions that the pilot should follow.

MOTION_PLATFORM_MODE

[Enum] Mode of a motion platform system.

Value	Field Name	Description
0	MOTION_PLATFORM_MODE_UNKNOWN	Mode information is unsupported on this device.
1	MOTION_PLATFORM_MODE_UNINITIALIZED	Mode is currently not available, but may be in different condition.
2	MOTION_PLATFORM_MODE_OFF	Platform actuators are turned off, but control system is responsive.
3	MOTION_PLATFORM_MODE_SETTLED	Platform is in the lowest position and/or locked, appropriate for personnel entry.
4	MOTION_PLATFORM_MODE_NEUTRAL	Platform is in a neutral reference position, not accepting movement commands.
5	MOTION_PLATFORM_MODE_FROZEN	Platform is stopped in any position, not accepting movement commands.
6	MOTION_PLATFORM_MODE_ENGAGED	Platform is in any position, accepting movement commands.

MOTION_PLATFORM_HEALTH

[Enum] General error state of a motion platform system.

Value	Field Name	Description
0	MOTION_PLATFORM_HEALTH_OK	System is operating correctly.
1	MOTION_PLATFORM_HEALTH_WARNING	There is at least one warning present, but operation can be continued.
2	MOTION_PLATFORM_HEALTH_ERROR	There is a failure or misconfiguration that requires operator's attention for correct operation.
3	MOTION_PLATFORM_HEALTH_CRITICAL	There is a major failure that requires immediate operator action to maintain safety.

EYE_TRACKING_EVENT_TYPE

[Enum] Type of event recognised from gaze data sent in EYE_TRACKING_EVENT.

Value	Field Name	Description
0	EYE_TRACKING_EVENT_TYPE_BLINK	Eye was partially closed.
1	EYE_TRACKING_EVENT_TYPE_FIXATION	Gaze remained at particular location. Magnitude is the dispersion of position.
2	EYE_TRACKING_EVENT_TYPE_SACCADE	Small rapid movement between fixations. Magnitude is the total angle of movement for this event.

HUMAN_BODY_POINT

[Enum] Location on human body tracked in HUMAN_BODY_POSE message. Initial 33 values correspond to points defined in MediaPipe Pose model.

Value	Field Name	Description
0	HUMAN_BODY_POINT_NOSE	Nose.
1	HUMAN_BODY_POINT_LEFT_EYE_INNER	Left eye inner.
2	HUMAN_BODY_POINT_LEFT_EYE	Left eye.
3	HUMAN_BODY_POINT_LEFT_EYE_OUTER	Left eye outer.
4	HUMAN_BODY_POINT_RIGHT_EYE_INNER	Right eye inner.
5	HUMAN_BODY_POINT_RIGHT_EYE	Right eye.
6	HUMAN_BODY_POINT_RIGHT_EYE_OUTER	Right eye outer.
7	HUMAN_BODY_POINT_LEFT_EAR	Left ear.
8	HUMAN_BODY_POINT_RIGHT_EAR	Right ear.
9	HUMAN_BODY_POINT_MOUTH_LEFT	Mouth left.
10	HUMAN_BODY_POINT_MOUTH_RIGHT	Mouth right.
11	HUMAN_BODY_POINT_LEFT_SHOULDER	Left shoulder.
12	HUMAN_BODY_POINT_RIGHT_SHOULDER	Right shoulder.
13	HUMAN_BODY_POINT_LEFT_ELBOW	Left elbow.
14	HUMAN_BODY_POINT_RIGHT_ELBOW	Right elbow.
15	HUMAN_BODY_POINT_LEFT_WRIST	Left wrist.
16	HUMAN_BODY_POINT_RIGHT_WRIST	Right wrist.
17	HUMAN_BODY_POINT_LEFT_PINKY	Left pinky.
18	HUMAN_BODY_POINT_RIGHT_PINKY	Right pinky.
19	HUMAN_BODY_POINT_LEFT_INDEX	Left index.
20	HUMAN_BODY_POINT_RIGHT_INDEX	Right index.
21	HUMAN_BODY_POINT_LEFT_THUMB	Left thumb.
22	HUMAN_BODY_POINT_RIGHT_THUMB	Right thumb.
23	HUMAN_BODY_POINT_LEFT_HIP	Left hip.
24	HUMAN_BODY_POINT_RIGHT_HIP	Right hip.
25	HUMAN_BODY_POINT_LEFT_KNEE	Left knee.
26	HUMAN_BODY_POINT_RIGHT_KNEE	Right knee.
27	HUMAN_BODY_POINT_LEFT_ANKLE	Left ankle.
28	HUMAN_BODY_POINT_RIGHT_ANKLE	Right ankle.
29	HUMAN_BODY_POINT_LEFT_HEEL	Left heel.
30	HUMAN_BODY_POINT_RIGHT_HEEL	Right heel.
31	HUMAN_BODY_POINT_LEFT_FOOT_INDEX	Left foot index.
32	HUMAN_BODY_POINT_RIGHT_FOOT_INDEX	Right foot index.

MAVLink Commands (MAV_CMD)

MAVLink commands (MAV_CMD) and messages are different! These commands define the values of up to 7 parameters that are packaged INSIDE specific messages used in the Mission Protocol and Command Protocol. Use commands for actions in missions or if you need acknowledgment and/or retry logic from a request. Otherwise use messages.

MAVLink Messages

CONTROL_LOADING_AXIS ( #52501 )

WORK IN PROGRESS: Do not use in stable production environments (it may change).

[Message] (MAVLink 2) Send data about a control axis from a control loading system. This is the primary message for logging data from MARSH_TYPE_CONTROL_LOADING.

Field Name	Type	Units	Values	Description
time_boot_ms	uint32_t	ms		Timestamp (time since system boot).
axis	uint8_t		CONTROL_AXIS	Control axis on which the measurements were taken.
position	float	deg		Axis position
velocity	float	deg/s		Axis velocity
force	float			Force applied in the pilot in the direction of movement axis (not gripping force), measured at the position of pilot's third finger (ring). Unit N (Newton), currently not part of mavschema.xsd

MOTION_PLATFORM_STATE ( #52502 )

[Message] (MAVLink 2) State report for motion platform used for moving the cockpit with the pilot for motion cueing. This is the primary message for MARSH_TYPE_MOTION_PLATFORM.

Field Name	Type	Units	Values	Description
time_boot_ms	uint32_t	ms		Timestamp (time since system boot).
health	uint8_t		MOTION_PLATFORM_HEALTH	Generic system health (error and warning) status.
mode	uint8_t		MOTION_PLATFORM_MODE	Generic system operating mode.
x	float	m		X axis (surge) position, positive forward.
y	float	m		Y axis (sway) position, positive right.
z	float	m		Z axis (heave) position, positive down.
roll	float	rad		Roll position, positive right.
pitch	float	rad		Pitch position, positive nose up.
yaw	float	rad		Yaw position, positive right.
vel_x	float	m/s		X axis (surge) velocity, positive forward.
vel_y	float	m/s		Y axis (sway) velocity, positive right.
vel_z	float	m/s		Z axis (heave) velocity, positive down.
vel_roll	float	rad/s		Roll velocity, positive right.
vel_pitch	float	rad/s		Pitch velocity, positive nose up.
vel_yaw	float	rad/s		Yaw velocity, positive right.
acc_x	float	m/s/s		X axis (surge) acceleration, positive forward.
acc_y	float	m/s/s		Y axis (sway) acceleration, positive right.
acc_z	float	m/s/s		Z axis (heave) acceleration, positive down.
acc_roll	float			Roll acceleration, positive right. Unit rad/s/s, currently not part of mavschema.xsd
acc_pitch	float			Pitch acceleration, positive nose up. Unit rad/s/s, currently not part of mavschema.xsd
acc_yaw	float			Yaw acceleration, positive right. Unit rad/s/s, currently not part of mavschema.xsd

REXROTH_MOTION_PLATFORM ( #52503 )

[Message] (MAVLink 2) State report specific for eMotion Motion System by Bosch Rexroth B.V. Values applicable to motion platforms in general are sent in MOTION_PLATFORM_STATE with the same timestamp. Actuators are numbered in a clockwise direction when looking from above, starting from the front right. Actuator position is 0 when actuator is in mid-stroke.

Field Name	Type	Units	Description
time_boot_ms	uint32_t	ms	Timestamp (time since system boot).
frame_count	uint32_t		Number of message as sent by the Motion System.
motion_status	uint32_t		Motion Status variable as sent by the system.
error_code	uint8_t		Error code extracted from motion status.
actuator1	float	m	Current actuator 1 position.
actuator2	float	m	Current actuator 2 position.
actuator3	float	m	Current actuator 3 position.
actuator4	float	m	Current actuator 4 position.
actuator5	float	m	Current actuator 5 position.
actuator6	float	m	Current actuator 6 position.
platform_setpoint_x	float	m	X axis (surge) platform setpoint, positive forward.
platform_setpoint_y	float	m	Y axis (sway) platform setpoint, positive right.
platform_setpoint_z	float	m	Z axis (heave) platform setpoint, positive down.
platform_setpoint_roll	float	rad	Roll platform setpoint, positive right.
platform_setpoint_pitch	float	rad	Pitch platform setpoint, positive nose up.
platform_setpoint_yaw	float	rad	Yaw platform setpoint, positive right.
effect_setpoint_x	float	m	X axis (surge) special effect setpoint, positive forward.
effect_setpoint_y	float	m	Y axis (sway) special effect setpoint, positive right.
effect_setpoint_z	float	m	Z axis (heave) special effect setpoint, positive down.
effect_setpoint_roll	float	rad	Roll special effect setpoint, positive right.
effect_setpoint_pitch	float	rad	Pitch special effect setpoint, positive nose up.
effect_setpoint_yaw	float	rad	Yaw special effect setpoint, positive right.

MOTION_CUE_EXTRA ( #52504 )

[Message] (MAVLink 2) These values are an extra cue that should be added to accelerations and rotations etc. resulting from aircraft state, with the resulting cue being the sum of the latest aircraft and extra values. An example use case would be a cockpit shaker.

Field Name	Type	Units	Description
time_boot_ms	uint32_t	ms	Timestamp (time since system boot).
vel_roll	float	rad/s	Roll velocity, positive right.
vel_pitch	float	rad/s	Pitch velocity, positive nose up.
vel_yaw	float	rad/s	Yaw velocity, positive right.
acc_x	float	m/s/s	X axis (surge) acceleration, positive forward.
acc_y	float	m/s/s	Y axis (sway) acceleration, positive right.
acc_z	float	m/s/s	Z axis (heave) acceleration, positive down.

EYE_TRACKING_DATA ( #52505 )

[Message] (MAVLink 2) Data for tracking of pilot eye gaze. This is the primary message for MARSH_TYPE_EYE_TRACKER. This is the average information about both eyes, if you need separate measurements send information with different sensor_id.

Field Name	Type	Units	Description
time_usec	uint64_t	us	Timestamp (UNIX Epoch time or time since system boot).
sensor_id	uint8_t		Sensor ID, used for identifying the device and/or person tracked. Set to zero if unknown/unused.
gaze_origin_x	float	m	X axis of gaze origin point, NaN if unknown. The reference system depends on specific application.
gaze_origin_y	float	m	Y axis of gaze origin point, NaN if unknown. The reference system depends on specific application.
gaze_origin_z	float	m	Z axis of gaze origin point, NaN if unknown. The reference system depends on specific application.
gaze_direction_x	float		X axis of gaze direction vector, expected to be normalized to unit magnitude, NaN if unknown. The reference system should match origin point.
gaze_direction_y	float		Y axis of gaze direction vector, expected to be normalized to unit magnitude, NaN if unknown. The reference system should match origin point.
gaze_direction_z	float		Z axis of gaze direction vector, expected to be normalized to unit magnitude, NaN if unknown. The reference system should match origin point.
video_gaze_x	float		Gaze focal point on video feed x value (normalized 0..1, 0 is left, 1 is right), NaN if unknown
video_gaze_y	float		Gaze focal point on video feed y value (normalized 0..1, 0 is top, 1 is bottom), NaN if unknown
surface_id	uint8_t		Identifier of surface for 2D gaze point, or an identified region when surface point is invalid. Set to zero if unknown/unused.
surface_gaze_x	float		Gaze focal point on surface x value (normalized 0..1, 0 is left, 1 is right), NaN if unknown
surface_gaze_y	float		Gaze focal point on surface y value (normalized 0..1, 0 is top, 1 is bottom), NaN if unknown
pupil_diameter	float	mm	Estimated pupil diameter, NaN if unknown.

EYE_TRACKING_EVENT ( #52506 )

WORK IN PROGRESS: Do not use in stable production environments (it may change).

[Message] (MAVLink 2) Periodic events identified in eye tracking.

Field Name	Type	Units	Values	Description
time_usec	uint64_t	us		Start timestamp (UNIX Epoch time or time since system boot). Should match time_usec field of EYE_TRACKING_DATA.
sensor_id	uint8_t			Sensor ID, used for identifying the device and/or person tracked. Set to zero if unknown/unused. Should match sensor_id field of EYE_TRACKING_DATA.
type	uint8_t		EYE_TRACKING_EVENT_TYPE	Type of event.
duration	uint64_t	us		Duration of event. Set to zero if not applicable.
confidence	float			Estimator confidence between 0 and 1.
magnitude	float	deg		Magnitude of the event dependent on type. Examples: dispersion of fixation, or range of movement for saccade etc.

HUMAN_BODY_POSE ( #52507 )

WORK IN PROGRESS: Do not use in stable production environments (it may change).

[Message] (MAVLink 2) Data for tracking of pilot body pose location.

Field Name	Type	Units	Values	Description
time_usec	uint64_t	us		Timestamp (UNIX Epoch time or time since system boot).
sensor_id	uint8_t			Sensor ID, used for identifying the device and/or person tracked. Set to zero if unknown/unused.
body_point	uint8_t		HUMAN_BODY_POINT	Specific point on the body described in this message.
position_x	float	m		X axis of body point location, NaN if unknown. The reference system depends on specific application.
position_y	float	m		Y axis of body point location, NaN if unknown. The reference system depends on specific application.
position_z	float	m		Z axis of body point location, NaN if unknown. The reference system depends on specific application.
video_x	float			Body point on video feed x value (normalized 0..1, 0 is left, 1 is right), NaN if unknown
video_y	float			Body point on video feed y value (normalized 0..1, 0 is top, 1 is bottom), NaN if unknown