3dr_radio

Publish 3DR Radio status to diagnostics and topic.

Published Topics

~radio_status (mavros_msgs/RadioStatus)
  • Status received from modem, same as RADIO_STATUS message.

actuator_control

Sends acruator commands to FCU.

Subscribed Topics

~actuator_control (mavros_msgs/ActuatorControl)
  • actuator command

hil_controls

Publish HIL_CONTROLS New in 0.18

Published Topics

~hil_controls/hil_controls (mavros_msgs/HilControls)
  • HIL data

Parameters

~frame_id (string, default: "map")
  • frame for altitude messages

command

Send COMMAND_LONG to FCU.

Services

~cmd/command (mavros_msgs/CommandLong)
  • Send any COMMAND_LONG to FCU.
~cmd/command_int (mavros_msgs/CommandInt)
  • Send any COMMAND_INT to FCU.
~cmd/arming (mavros_msgs/CommandBool)
  • Change Arming status.
~cmd/set_home (mavros_msgs/CommandHome)
  • Change HOME location.
~cmd/takeoff (mavros_msgs/CommandTOL)
  • Send takeoff command.
~cmd/land (mavros_msgs/CommandTOL)
  • Send land command.
~cmd/trigger_control (mavros_msgs/CommandTriggerControl)
  • Send camera trigger control command.

Parameters

~cmd/use_comp_id_system_control (bool, default: false)
  • Use SYSTEM_CONTROL component id instead of mavros target component.

ftp

Support plugin for MAVLink-FTP (PX4).

Services

~ftp/open (mavros_msgs/FileOpen)
  • Open file (acquire session).
~ftp/close (mavros_msgs/FileClose)
  • Close file (release session).
~ftp/read (mavros_msgs/FileRead)
  • Read from opened file.
~ftp/write (mavros_msgs/FileWrite)
  • Write to opened file.
~ftp/list (mavros_msgs/FileList)
  • List directory.
~ftp/truncate (mavros_msgs/FileTruncate)
  • Truncate file.
~ftp/remove (mavros_msgs/FileRemove)
  • Unlink file.
~ftp/rename (mavros_msgs/FileRename)
  • Rename file/directory.
~ftp/mkdir (mavros_msgs/FileMakeDir)
  • Create directory.
~ftp/rmdir (mavros_msgs/FileRemoveDir)
  • Remove directory.
~ftp/checksum (mavros_msgs/FileChecksum)
  • Request to calculate CRC32 of file on FCU.
~ftp/reset (std_srvs/Empty)
  • Reset FCU server (dangerous).

global_position

Publish global position information fused by FCU and raw GPS data.

Published Topics

~global_position/global (sensor_msgs/NavSatFix)
  • GPS Fix. IMPORTANT: Altitude is specified as ellipsoid height and care must be taken to avoid a common pitfall. See this section for more.
~global_position/local (geometry_msgs/PoseWithCovarianceStamped)
  • UTM coords.
~global_position/gp_vel (geometry_msgs/TwistStamped)
  • Velocity fused by FCU.
~global_position/rel_alt (std_msgs/Float64)
  • Relative altitude.
~global_position/compass_hdg (std_msgs/Float64)
  • Compass heading in degrees.
~global_position/raw/fix (sensor_msgs/NavSatFix)
  • GPS position fix reported by the device.
~global_position/raw/gps_vel (geometry_msgs/TwistStamped)
  • Velocity output from the GPS device.

Parameters

~global_position/frame_id (string, default: fcu)
  • frame_id for messages.
~global_position/tf/send (bool, default: true)
  • Send or not local UTM coords via TF?
~global_position/tf/frame_id (string, default: local_origin)
  • frame_id for TF.
~global_position/tf/child_frame_id (string, default: fcu_utm)
  • Child frame_id for TF.

imu_pub

Publish IMU state

Published Topics

~imu/data (sensor_msgs/Imu)
  • Imu data, orientation computed by FCU
~imu/data_raw (sensor_msgs/Imu)
  • Raw IMU data without orientation
~imu/mag (sensor_msgs/MagneticField)
  • FCU compass data
~imu/temperature (sensor_msgs/Temperature)
  • Temperature reported by FCU (usually from barometer)
~imu/atm_pressure (sensor_msgs/FluidPressure)
  • Air pressure.

Parameters

~imu/frame_id (string, default: fcu)
  • Frame ID for this plugin.
~imu/linear_acceleration_stdev (double, default: 0.0003)
  • Gyro's standard deviation
~imu/angular_velocity_stdev (double, default: !dec 0.02)
  • Accel's standard deviation
~imu/orientation_stdev (double, default: 1.0)
  • Standard deviation for IMU.orientation
~imu/magnetic_stdev (double, default: 0.0)
  • Standard deviation for magnetic field message (undefined if: 0.0)

local_position

Publish LOCAL_POSITION_NED in TF and PoseStamped topic.

Published Topics

~local_position/pose (geometry_msgs/PoseStamped)
  • Local position from FCU.
~local_position/velocity (geometry_msgs/TwistStamped)
  • Velocity data from FCU.

Parameters

~local_position/frame_id (string, default: fcu)
  • frame_id for message.
~local_position/tf/send (bool, default: true)
  • TF send switch.
~local_position/tf/frame_id (string, default: local_origin)
  • Origin frame_id for TF.
~local_position/tf/child_frame_id (string, default: fcu)
  • Child frame_id for TF.

manual_control

Publish MANUAL_CONTROL message (user input).

Subscribed Topics

~manual_control/send (mavros_msgs/ManualControl)
  • RC Rx, interpreted and normalized.

Published Topics

~manual_control/control (mavros_msgs/ManualControl)
  • RC Rx, interpreted and normalized.

param

Allows to access to FCU parameters and map it to ROS parameters in ~param/.

Services

~param/pull (mavros_msgs/ParamPull)
  • Request parameter from device (or internal cache).
~param/push (mavros_msgs/ParamPush)
  • Request send parameters from ROS to FCU.
~param/get (mavros_msgs/ParamGet)
  • Return FCU parameter value.
~param/set (mavros_msgs/ParamSet)
  • Set parameter on FCU immidiatly.

rc_io

Publish RC receiver inputs.

Subscribed Topics

~rc/override (mavros_msgs/OverrideRCIn)
  • Send RC override message to FCU. APM and PX4 only. APM requires setup FCU param SYSID_MYGCS to match mavros system id. Not recommended to use in automatic control because lack of safety mechanisms. Use one of setpoint plugins and OFFBOARD mode.

Published Topics

~rc/in (mavros_msgs/RCIn)
  • Publish RC inputs (in raw milliseconds)
~rc/out (mavros_msgs/RCOut)
  • Publish FCU servo outputs

safety_area

Sends safety allowed area to FCU. Initial area can be loaded from parameters.

Subscribed Topics

~safety_area/set (geometry_msgs/PolygonStamped)
  • Volumetric area described by two corners.

Parameters

~safety_area/p1/x (double)
  • Corner 1 X.
~safety_area/p1/y (double)
  • Corner 1 Y.
~safety_area/p1/z (double)
  • Corner 1 Z.
~safety_area/p2/x (double)
  • Corner 2 X.
~safety_area/p2/y (double)
  • Corner 2 Y.
~safety_area/p2/z (double)
  • Corner 2 Z.

setpoint_accel

Send acceleration setpoint.

Subscribed Topics

~setpoint_accel/accel (geometry_msgs/Vector3Stamped)
  • Acceleration or force setpoint vector.

Parameters

~setpoint_accel/send_force (bool)
  • Send force setpoint.

setpoint_attitude

Send attitude setpoint using SET_ATTITUDE_TARGET.

Subscribed Topics

~setpoint_attitude/cmd_vel (geometry_msgs/TwistStamped)
  • Send angular velocity.
~setpoint_attitude/attitude (geometry_msgs/PoseStamped)
  • Send attitude setpoint.
~setpoint_attitude/thrust (mavros_msgs/Thrust)
  • Send throttle value(0~1).

Parameters

~setpoint_attitude/reverse_throttle (bool, default: false)
  • Allow to send -1.0 throttle or not.
~setpoint_attitude/use_quaternion (bool, default: false)
  • Enable ~setpoint_attitude/target_attitude PoseStamped topic subscriber and disable ~setpoint_attitude/cmd_vel Twist topic.
~setpoint_attitude/tf/listen (bool, default: false)
  • TF listen switch. Disable topics if enabled.
~setpoint_attutude/tf/frame_id (string, default: local_origin)
  • Origin frame_id for TF.
~setpoint_attitude/tf/child_frame_id (string, default: attitude)
  • Child frame_id for TF.
~setpoint_attitude/tf/rate_limit (double, default: 10.0)
  • Rate limit for TF listener [Hz].

setpoint_position

Sends position setpoint using SET_POSITION_TARGET_GLOBAL_INT or SET_POSITION_TARGET_LOCAL_NED.

Subscribed Topics

~setpoint_position/global (geographic_msgs/GeoPoseStamped)
  • Global frame setpoint position. Sends an LLA to the flight controller. Only YAW axis extracted from orientation field. IMPORTANT: Altitude is interpreted as AMSL and care must be taken to avoid a common pitfall. See this section for more.
~setpoint_position/local (geometry_msgs/PoseStamped)
  • Local frame setpoint position. Only YAW axis extracted from orientation field.
~setpoint_position/global_to_local (geographic_msgs/GeoPoseStamped)
  • The old implementation of ~setpoint_position/global. Converts LLA to local ENU. This was done as a workaround before the flight controller could accept LLA setpoints directly. Consider using ~setpoint_position/global instead. See the details here. Only YAW axis extracted from orientation field.

Parameters

~setpoint_position/tf/listen (bool, default: false)
  • TF listen switch. Disable topic if enabled.
~setpoint_position/tf/frame_id (string, default: local_origin)
  • Origin frame_id for TF.
~setpoint_position/tf/child_frame_id (string, default: setpoint)
  • Child frame_id for TF.
~setpoint_position/tf/rate_limit (double, default: 50.0)
  • Rate limit for TF listener [Hz].

setpoint_raw

Send RAW setpoint messages to FCU and provide loopback topics (PX4).

Subscribed Topics

~setpoint_raw/local (mavros_msgs/PositionTarget)
  • Local position, velocity and acceleration setpoint.
~setpoint_raw/global (mavros_msgs/GlobalPositionTarget)
  • Global position, velocity and acceleration setpoint.
~setpoint_raw/attitude (mavros_msgs/AttitudeTarget)
  • Attitude, angular rate and thrust setpoint.

Published Topics

~setpoint_raw/target_local (mavros_msgs/PositionTarget)
  • Local target loopback.
~setpoint_raw/target_global (mavros_msgs/GlobalPositionTarget)
  • Global target loopback.
~setpoint_raw/target_attitude (mavros_msgs/AttitudeTarget)
  • Attitude target loopback.

setpoint_velocity

Send velocity setpoint to FCU.

Subscribed Topics

~setpoint_velocity/cmd_vel_unstamped (geometry_msgs/Twist)
  • Velocity setpoint.

sys_status

System status plugin. Handles FCU detection. REQUIRED never blacklist it!.

Published Topics

~state (mavros_msgs/State)
  • FCU state
~battery (mavros_msgs/BatteryStatus)
  • FCU battery status report. DEPRECATED
~battery (sensor_msgs/BatteryState)
  • FCU battery status report. New in Kinetic
~extended_state (mavros_msgs/ExtendedState)
  • Landing detector and VTOL state.

Services

~set_stream_rate (mavros_msgs/StreamRate)
  • Send stream rate request to FCU.
~set_mode (mavros_msgs/SetMode)
  • Set FCU operation mode. See custom mode identifiers at modes page.

Parameters

~conn/timeout (double, default: 30.0)
  • Connection time out in seconds.
~conn/heartbeat_rate (double, default: 0.0)
  • Send HEARTBEAT message rate [Hz] (or disabled if 0.0)
~sys/min_voltage (double, default: 6.0)
  • Minimal battery voltage for diagnostics.
~sys/disable_diag (bool, default: false)
  • Disable all diag except HEARTBEAT message.

sys_time

System time plugin. Does time syncronization on PX4.

Published Topics

~time_reference (sensor_msgs/TimeReference)
  • Time reference computed from SYSTEM_TIME.

Parameters

~conn/system_time_rate (double, default: 0.0)
  • Send SYSTEM_TIME to device rate [Hz] (disabled if 0.0).
~conn/timesync_rate (double, default: 0.0)
  • TIMESYNC rate. PX4 only.
~time/time_ref_source (string, default: "fcu")
  • Ref source for time_reference message.
~time/timesync_avg_alpha (double, default: 0.6)
  • Alpha for exponential moving average.

vfr_hud

Publish VFR_HUD and WIND messages.

Published Topics

~vfr_hud (mavros_msgs/VFR_HUD)
  • Data for HUD.
~wind_estimation (geometry_msgs/TwistStamped)
  • Wind estimation from FCU (APM).

waypoint

Allows to access to FCU mission (waypoints).

Published Topics

~mission/reached (mavros_msgs/WaypointReached)
  • Publishes on reaching a waypoint from MISSION_ITEM_REACHED message.
~mission/waypoints (mavros_msgs/WaypointList)
  • Current waypoint table. Updates on changes.

Services

~mission/pull (mavros_msgs/WaypointPull)
  • Request update waypoint list.
~mission/push (mavros_msgs/WaypointPush)
  • Send new waypoint table.
~mission/clear (mavros_msgs/WaypointClear)
  • Clear mission on FCU.
~mission/set_current (mavros_msgs/WaypointSetCurrent)
  • Set current seq. number in list.

Parameters

~mission/pull_after_gcs (bool, default: false)
  • Defines pull or not waypoints if detected GCS activity.

Notes

Plugins: `vision_position` and `vision_speed` moved to mavros_extras. New in 0.13 GPS and global_position plugins are merged. TF params moved to tf/ subnamespace. New in 0.16 Waypoint GOTO service removed. Please use setpoint plugins. New in 0.18 Experimental MAVLink 2.0 support (without packet signing).

When controlling the FCU using global setpoints, you specify the altitude as meters above mean sea level (AMSL). But when sensing the global position, the altitude reported by ~global_position/global is specified as meters above the WGS-84 ellipsoid. This can lead to differences in altitude that are dozens of meters apart.

MAVROS uses GeographicLib to convert AMSL to ellipsoid height. When you install MAVROS using a package manager, this library gets installed as a dependency in Ubuntu.

To convert between AMSL and ellipsoid height, you add or subtract the geoid separation to the altitude. To go from AMSL to ellipsoid height, you add the value. And to go from ellipsoid height to AMSL you subtract the value. Consider these examples. 

   1 #!/usr/bin/env python3
   2 # Example code that helps you convert between AMSL and ellipsoid height
   3 # To run this code you need:
   4 #
   5 # 1) the egm96-5.pgm file from geographiclib.
   6 # To get it on Ubuntu run:
   7 # sudo apt install geographiclib-tools
   8 # sudo geographiclib-get-geoids egm96-5
   9 #
  10 # 2) PyGeodesy
  11 # To get it using pip:
  12 # pip install PyGeodesy
  13 
  14 from pygeodesy.geoids import GeoidPGM
  15 
  16 _egm96 = GeoidPGM('/usr/share/GeographicLib/geoids/egm96-5.pgm', kind=-3)
  17 
  18 def geoid_height(lat, lon):
  19     """Calculates AMSL to ellipsoid conversion offset.
  20     Uses EGM96 data with 5' grid and cubic interpolation.
  21     The value returned can help you convert from meters 
  22     above mean sea level (AMSL) to meters above
  23     the WGS84 ellipsoid.
  24 
  25     If you want to go from AMSL to ellipsoid height, add the value.
  26 
  27     To go from ellipsoid height to AMSL, subtract this value.
  28     """
  29     return _egm96.height(lat, lon)

In general, the ellipsoid height is better for calculations and AMSL is better for user interfaces. If you're calculating the distance between LLA positions, you most likely want to specify both altitudes in terms of height above the ellipsoid. Both representations have their uses.

For background information regarding ellipsoid height and AMSL, see this video:

Wiki: mavros/Plugins (last edited 2021-09-15 18:12:32 by Michael Murphy)

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