The heartbeat message shows that a system is present and responding. The type of the MAV and Autopilot hardware allow the receiving system to treat further messages from this system appropriate (e.g. by laying out the user interface based on the autopilot). Type of the MAV (quadrotor, helicopter, etc., up to 15 types, defined in MAV_TYPE ENUM) Type of the Autopilot: 0: Generic, 1: PIXHAWK, 2: SLUGS, 3: Ardupilot (up to 15 types), defined in MAV_AUTOPILOT_TYPE ENUM The boot message indicates that a system is starting. The onboard software version allows to keep track of onboard soft/firmware revisions. The onboard software version The system time is the time of the master clock, typically the computer clock of the main onboard computer. Timestamp of the master clock in microseconds since UNIX epoch. A ping message either requesting or responding to a ping. This allows to measure the system latencies, including serial port, radio modem and UDP connections. PING sequence 0: request ping from all receiving systems, if greater than 0: message is a ping response and number is the system id of the requesting system 0: request ping from all receiving components, if greater than 0: message is a ping response and number is the system id of the requesting system Unix timestamp in microseconds An action message allows to execute a certain onboard action. These include liftoff, land, storing parameters too EEPROM, shutddown, etc. The action ids are defined in ENUM MAV_ACTION in mavlink/include/mavlink_types.h The system executing the action The component executing the action The action id This message acknowledges an action. IMPORTANT: The acknowledgement can be also negative, e.g. the MAV rejects a reset message because it is in-flight. The action ids are defined in ENUM MAV_ACTION in mavlink/include/mavlink_types.h The action id 0: Action DENIED, 1: Action executed Set the system mode, as defined by enum MAV_MODE in mavlink/include/mavlink_types.h. There is no target component id as the mode is by definition for the overall aircraft, not only for one component. The system setting the mode The new mode Set the system navigation mode, as defined by enum MAV_NAV_MODE in mavlink/include/mavlink_types.h. The navigation mode applies to the whole aircraft and thus all components. The system setting the mode The new navigation mode The RAW IMU readings for the usual 9DOF sensor setup. This message should always contain the true raw values without any scaling to allow data capture and system debugging. Timestamp (microseconds since UNIX epoch) X acceleration (mg raw) Y acceleration (mg raw) Z acceleration (mg raw) Angular speed around X axis (adc units) Angular speed around Y axis (adc units) Angular speed around Z axis (adc units) X Magnetic field (milli tesla) Y Magnetic field (milli tesla) Z Magnetic field (milli tesla) The RAW pressure readings for the typical setup of one absolute pressure and one differential pressure sensor. The sensor values should be the raw, unscaled ADC values. Timestamp (microseconds since UNIX epoch) Absolute pressure (hectopascal) Differential pressure 1 (hectopascal) Differential pressure 2 (hectopascal) Raw Temperature measurement The attitude in the aeronautical frame (right-handed, Z-down, X-front, Y-right). Timestamp (microseconds) Roll angle (rad) Pitch angle (rad) Yaw angle (rad) Roll angular speed (rad/s) Pitch angular speed (rad/s) Yaw angular speed (rad/s) The filtered local position (e.g. fused computer vision and accelerometers). Timestamp (microseconds since unix epoch) X Position Y Position Z Position X Speed Y Speed Z Speed The global position, as returned by the Global Positioning System (GPS). This is NOT the global position estimate of the sytem, but rather a RAW sensor value. See message GLOBAL_POSITION for the global position estimate. Timestamp (microseconds since unix epoch) 0-1: no fix, 2: 2D fix, 3: 3D fix X Position Y Position Z Position in meters Uncertainty in meters of latitude Uncertainty in meters of longitude Overall speed Heading, in FIXME The global position, as returned by the Global Positioning System (GPS). This is NOT the global position estimate of the sytem, but rather a RAW sensor value. See message GLOBAL_POSITION for the global position estimate. This message can contain information for up to 20 satellites. Number of satellites visible Global satellite ID 0: Satellite not used, 1: used for localization Elevation (0: right on top of receiver, 90: on the horizon) of satellite Direction of satellite, 0: 0 deg, 255: 360 deg. Signal to noise ratio of satellite The general system state. If the system is following the MAVLink standard, the system state is mainly defined by three orthogonal states/modes: The system mode, which is either LOCKED (motors shut down and locked), MANUAL (system under RC control), GUIDED (system with autonomous position control, position setpoint controlled manually) or AUTO (system guided by path/waypoint planner). The NAV_MODE defined the current flight state: LIFTOFF (often an open-loop maneuver), LANDING, WAYPOINTS or VECTOR. This represents the internal navigation state machine. The system status shows wether the system is currently active or not and if an emergency occured. During the CRITICAL and EMERGENCY states the MAV is still considered to be active, but should start emergency procedures autonomously. After a failure occured it should first move from active to critical to allow manual intervention and then move to emergency after a certain timeout. System mode, see MAV_MODE ENUM in mavlink/include/mavlink_types.h Navigation mode, see MAV_NAV_MODE ENUM System status flag, see MAV_STATUS ENUM Battery voltage, in millivolts (1 = 1 millivolt) Motor block status flag, 0: Motors can be switched on (and could be either off or on), 1: Mechanical motor block switch is on, motors cannot be switched on (and are definitely off) Dropped packets (packets that were corrupted on reception on the MAV) Message encoding a waypoint. This message is emitted to announce the presence of a waypoint. It cannot be used to set a waypoint, use WAYPOINT_SET for this purpose. The waypoint can be either in x, y, z meters (type: LOCAL) or x:lat, y:lon. The global and body frame are related as: positive Z-down, positive X(front looking north, positive Y(body:right) looking east. Therefore y encodes in global mode the latitude, whereas x encodes the longitude and z the GPS altitude (WGS84). System ID Component ID Sequence 0: global (GPS), 1: local, 2: global orbit, 3: local orbit Orbit to circle around the waypoint, in meters. Set to 0 to fly straight through the waypoint Direction of the orbit circling: 0: clockwise, 1: counter-clockwise For waypoints of type 0 and 1: Radius in which the waypoint is accepted as reached, in meters For waypoints of type 0 and 1: Time that the MAV should stay inside the orbit before advancing, in milliseconds false:0, true:1 local: x position, global: longitude y position: global: latitude z position: global: altitude yaw orientation in radians, 0 = NORTH autocontinue to next wp Request the information of the waypoint with the sequence number seq. The response of the system to this message should be a WAYPOINT message. System ID Component ID Sequence Set the waypoint with sequence number seq as current waypoint. This means that the MAV will continue to this waypoint on the shortest path (not following the waypoints in-between). System ID Component ID Sequence Message that announces the sequence number of the current active waypoint. The MAV will fly towards this waypoint. Sequence This message is emitted as response to WAYPOINT_REQUEST_LIST by the MAV. The GCS can then request the individual waypoints based on the knowledge of the total number of waypoints. System ID Component ID Number of Waypoints in the Sequence Delete all waypoints at once. System ID Component ID A certain waypoint has been reached. The system will either hold this position (or circle on the orbit) or (if the autocontinue on the WP was set) continue to the next waypoint. Sequence Ack message during waypoint handling. The type field states if this message is a positive ack (type=0) or if an error happened (type=non-zero). System ID Component ID 0: OK, 1: Error As local waypoints exist, the global waypoint reference allows to transform between the local coordinate frame and the global (GPS) coordinate frame. This can be necessary when e.g. in- and outdoor settings are connected and the MAV should move from in- to outdoor. System ID Component ID global x position global y position global z position global yaw orientation in radians, 0 = NORTH local x position that matches the global x position local y position that matches the global y position local z position that matches the global z position local yaw that matches the global yaw orientation Status text message. These messages are printed in yellow in the COMM console of QGroundControl. WARNING: They consume quite some bandwidth, so use only for important status and error messages. If implemented wisely, these messages are buffered on the MCU and sent only at a limited rate (e.g. 10 Hz). Severity of status, 0 = info message, 255 = critical fault Status text message, without null termination character Send a debug value. The index is used to discriminate between values. These values show up in the plot of QGroundControl as DEBUG N. index of debug variable DEBUG value