mavlinkio

R2026b

Create local MAVLink client

Description

The mavlinkio object represents a local MAVLink client. After you create a mavlinkio object, you can connect to UDP or serial port, and exchange messages with other MAVLink clients such as UAV and ground control stations using the object functions.

Creation

Syntax

mavlink = mavlinkio(msgDefinitions)

mavlink = mavlinkio(dialectXML)

mavlink = mavlinkio(dialectXML,version)

mavlink = mavlinkio(___,Name=Value)

Description

mavlink = mavlinkio(msgDefinitions) creates a local MAVLink client using a MAVLink message definition specified as a mavlinkdialect object.

mavlink = mavlinkio(dialectXML) creates a local MAVLink client using a MAVLink message definition specified as an XML file.

mavlink = mavlinkio(dialectXML,version) specifies the MAVLink protocol version of the XML file.

mavlink = mavlinkio(___,Name=Value) specifies options using one or more name-value arguments in addition to any combination of input arguments from previous syntaxes. For example, SystemID=2 sets the MAVLink system ID to 2.

Input Arguments

msgDefinitions — MAVLink message definition

mavlinkdialect object

MAVLink message definition, specified as a mavlinkdialect object.

dialectXML — MAVLink message definition filename

string scalar | character vector

MAVLink message definition XML filename, specified as a string scalar or character vector.

Example: mavlink = mavlinkio("common.xml")

Data Types: string | char

version — MAVLink protocol version

2 (default) | 1

MAVLink protocol version, specified as 2 or 1.

Data Types: double

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: mavlinkio("common.xml",SystemID=2) sets the MAVLink system ID to 2.

SystemID — MAVLink system ID

255 (default) | integer in the range [0, 255].

MAVLink system ID, specified as an integer in the range [0, 255].

Data Types: double

ComponentID — MAVLink component ID

1 (default) | integer in the range [0, 255].

MAVLink component ID, specified as an integer in the range [0, 255].

Data Types: double

ComponentType — MAVLink component type

"MAV_TYPE_GCS" (default) | string scalar | character vector

MAVLink component type, specified as a string scalar or character vector.

You must choose a MAVLink component type that is available in the MAV_TYPE enum.

Tip

To see the components available in the MAV_TYPE enum:

• If you create the mavlinkio object using MAVLink message definition specified as a mavlinkdialect object named MavlinkDialectObject, use the enuminfo function by running this command:

  enuminfo(MavlinkDialectObject,"MAV_TYPE").Entries{1,1}

• If you create the mavlinkio object using MAVLink message definition specified as an XML file named dialectXML.xml, first create a mavlinkdialect object by running this command:

  MavlinkDialectObject = mavlinkdialect("dialectXML.xml")

  Then, use the enuminfo function by running this command:

  enuminfo(MavlinkDialectObject,"MAV_TYPE").Entries{1,1}

Data Types: string | char

AutopilotType — MAVLink autopilot type

"MAV_AUTOPILOT_INVALID" (default) | string scalar | character vector

MAVLink autopilot type, specified as a string scalar or character vector.

You must choose a MAVLink autopilot type that is available in the MAV_AUTOPILOT enum.

Tip

To see the autopilots available in the MAV_AUTOPILOT enum:

• If you create the mavlinkio object using MAVLink message definition specified as a mavlinkdialect object named MavlinkDialectObject, use the enuminfo function by running this command:

  enuminfo(MavlinkDialectObject,"MAV_AUTOPILOT").Entries{1,1}

• If you create the mavlinkio object using MAVLink message definition specified as an XML file named dialectXML.xml, first create a mavlinkdialect by running this command:

  MavlinkDialectObject = mavlinkdialect("dialectXML.xml")

  Then, use the enuminfo function by running this command:

  enuminfo(MavlinkDialectObject,"MAV_AUTOPILOT").Entries{1,1}

Data Types: string | char

Properties

Dialect — MAVLink dialect

mavlinkdialect object

MAVLink message definition, specified as a mavlinkdialect object.

LocalClient — Local client information

Read-only: structure

This property is read-only.

Local MAVLink client information, represented as a structure. The structure contains these fields:

• SystemID — MAVLink system ID.

• ComponentID — MAVLink component ID.

• ComponentType — MAVLink component type.

• AutopilotType — MAVLink autopilot type.

Data Types: struct

Object Functions

connect	Connect MAVLink client to UDP or serial port
disconnect	Disconnect local MAVLink client from UDP or serial ports
sendmsg	Send MAVLink message to other connected MAVLink clients
listConnections	List all active MAVLink connections
listClients	List all connected MAVLink clients
listTopics	List all topics received by MAVLink client
sendudpmsg	Send MAVLink message to UDP port
sendserialmsg	Send MAVLink message to serial port
serializemsg	Serialize MAVLink message to binary buffer

Examples

Tune Maximum Yaw Rate Parameter of Pixhawk Board

Tune the maximum yaw rate parameter of a Pixhawk^® 4 board running PX4^® firmware by using the parameter microservice.

Create a mavlinkdialect object using the common.xml file.

dialect = mavlinkdialect("common.xml");

Create a local MAVLink client by using the mavlinkio object.

gcs = mavlinkio(dialect);

Store the remote MAVLink client information by using the mavlinkclient object. This Pixhawk board has a system ID of 1 and a component ID of 1.

uav = mavlinkclient(gcs,1,1);

Connect the local MAVLink client to the same serial port as the Pixhawk board by using the connect function. This Pixhawk board uses the COM5 port.

connect(gcs,"Serial",SerialPort="COM5");

Create a heartbeat microservice object.

heartbeat = mavlinkmicroservice(gcs,"heartbeat");

Start sending the HEARTBEAT messages to the Pixhawk board by using the start function. If the remote MAVLink system replies with HEARTBEAT messages, a connection is established.

start(heartbeat,uav,"Serial",SerialPort="COM5")

If the Pixhawk board replies with HEARTBEAT messages, a connection is established. Verify that the connection has been established by using the listClients function.

listClients(gcs)

ans = 2×4 table
    SystemID    ComponentID       ComponentType             AutopilotType     
    ________    ___________    ____________________    _______________________

      255            1            "MAV_TYPE_GCS"        "MAV_AUTOPILOT_INVALID"
       1             1         "MAV_TYPE_QUADROTOR"       "MAV_AUTOPILOT_PX4"

Create a parameter microservice object.

parameter = mavlinkmicroservice(gcs,"parameter");

Obtain the current value of all parameters by using the get function.

[status,param] = get(parameter,uav)

status = true
param = 10×5 table
    param_value   param_count    param_index       param_id           param_type     
    ___________   ___________    ___________    ______________    ____________________
        0             942            12         SYS_AUTOSTART             6            
        1             942            22         COM_ARM_WO_GPS            6            
      300             942            50         COM_RC_LOSS_T             9            
     15.5             942            88         BAT_LOW_THR               9            
     12.0             942           105         MPC_VEL_MAX_UP            9            
      5.0             942           106         MPC_VEL_MAX_DN            9            
      2.5             942           315         NAV_ACC_RAD               9            
      200             942           412         MC_YAWRATE_MAX            9            
      0.5             942           413         MC_PITCHRATE_P            9            
      0.1             942           418         MC_ROLLRATE_I             9            

Obtain the current value of the MC_YAWRATE_MAX parameter. The output shows that the current maximum yaw rate of the Pixhawk board is 200 degrees per second.

[status,param] = get(parameter,uav,"MC_YAWRATE_MAX")

status = true
param = 1×5 table
    param_value   param_count    param_index       param_id           param_type     
    ___________   ___________    ___________    ______________    ____________________
       200            942            412        MC_YAWRATE_MAX            9          

Specify a new maximum yaw rate parameter value of 150 degrees per second by using the set function. The function returns the updated parameter value to verify the success of the parameter set operation.

[status,param] = set(parameter,uav,"MC_YAWRATE_MAX",150)

status = true
param = 1×5 table
    param_value   param_count    param_index       param_id           param_type     
    ___________   ___________    ___________    ______________    ____________________
        150           942            412        MC_YAWRATE_MAX            9          

Send Waypoint Command to Pixhawk Board

Send a waypoint command to a Pixhawk 4 board running PX4 firmware by using the command microservice.

Create a mavlinkdialect object using the common.xml file.

dialect = mavlinkdialect("common.xml");

Create a local MAVLink client by using the mavlinkio object.

gcs = mavlinkio(dialect);

Store the remote MAVLink client information by using the mavlinkclient object. This Pixhawk board has a system ID of 1 and a component ID of 1.

uav = mavlinkclient(gcs,1,1);

Connect the local MAVLink client to the same serial port as the Pixhawk board by using the connect function. This Pixhawk board uses the COM5 port.

connect(gcs,"Serial",SerialPort="COM5");

Create a heartbeat microservice object.

heartbeat = mavlinkmicroservice(gcs,"heartbeat");

Start sending the HEARTBEAT messages to the Pixhawk board by using the start function.

start(heartbeat,uav,"Serial",SerialPort="COM5")

If the Pixhawk board replies with HEARTBEAT messages, a connection is established.

Verify that the connection has been established by using the listClients function.

listClients(gcs)

ans = 2×4 table
    SystemID    ComponentID       ComponentType             AutopilotType     
    ________    ___________    ____________________    _______________________

      255            1            "MAV_TYPE_GCS"        "MAV_AUTOPILOT_INVALID"
       1             1         "MAV_TYPE_QUADROTOR"       "MAV_AUTOPILOT_PX4"

Create the waypoint command message structure by using the createcmd function.

cmdMsg = createcmd(dialect,"INT","MAV_CMD_NAV_WAYPOINT")

cmdMsg = 

  struct with fields:

      MsgID: 75
    Payload: [1×1 struct]

Specify these parameters of the waypoint command message:

• Acceptance radius — 2 meters

• Latitude — 42.2831 degrees

• Longitude — –71.3468 degrees

• Altitude — 50 meters

For more information on the waypoint command parameters, see the MAV_CMD_NAV_WAYPOINT section of the MAVLink documentation.

cmdMsg.Payload.param2(:) = 2.0;
cmdMsg.Payload.param5(:) = 42.2831;
cmdMsg.Payload.param6(:) = -71.3468;
cmdMsg.Payload.param7(:) = 50.0;

Create a command microservice object.

command = mavlinkmicroservice(gcs,"command");

Send the command message to the Pixhawk board by using the send function. The function returns the status and the acknowledgement message sent by the Pixhawk board.

[status,ack] = send(command,uav,cmdMsg)

status = true
ack = 
  struct with fields:

             command: 16
              result: 0
            progress: 255
       result_param2: 0
       target_system: 1
    target_component: 1

     

Upload Mission to Pixhawk Board

Upload a mission to a Pixhawk 4 board running PX4 firmware by using the mission microservice.

Create a mavlinkdialect object using the common.xml file.

dialect = mavlinkdialect("common.xml");

Create a local MAVLink client by using the mavlinkio object.

gcs = mavlinkio(dialect);

Store the remote MAVLink client information by using the mavlinkclient object. This Pixhawk board has a system ID of 1 and a component ID of 1.

uav = mavlinkclient(gcs,1,1);

Connect the local MAVLink client to the same serial port as the Pixhawk board by using the connect function. This Pixhawk board uses the COM5 port.

connect(gcs,"Serial",SerialPort="COM5");

Create a heartbeat microservice object.

heartbeat = mavlinkmicroservice(gcs,"heartbeat");

Start sending the HEARTBEAT messages to the Pixhawk board by using the start function.

start(heartbeat,uav,"Serial",SerialPort="COM5")

If the Pixhawk board replies with HEARTBEAT messages, a connection is established.

Verify that the connection has been established by using the listClients function.

listClients(gcs)

ans = 2×4 table
    SystemID    ComponentID       ComponentType             AutopilotType     
    ________    ___________    ____________________    _______________________

      255            1            "MAV_TYPE_GCS"        "MAV_AUTOPILOT_INVALID"
       1             1         "MAV_TYPE_QUADROTOR"       "MAV_AUTOPILOT_PX4"

Create a mission microservice object.

mission = mavlinkmicroservice(gcs,"mission");

Upload the mission SampleMission.plan to the Pixhawk board by using the upload function. The function returns the upload status and acknowledgement message.

[status,ack] = upload(mission,uav,"SampleMission.plan")

status = true
ack = 
  struct with fields:

       target_system : 255
    target_component : 1
                type : 0
        mission_type : 0
     

Download and Delete Flight Logs from Pixhawk Board

Download and delete flight logs from a Pixhawk 4 board running PX4 firmware by using the FTP microservice.

Download the latest version of common.xml file from the MAVLINK Common Message Set (common.xml) section of the MAVLink documentation, then create a mavlinkdialect object using the file.

dialect = mavlinkdialect("common.xml");

Create a local MAVLink client by using the mavlinkio object.

gcs = mavlinkio(dialect);

Store the remote MAVLink client information by using the mavlinkclient object. This Pixhawk board has a system ID of 1 and a component ID of 1.

uav = mavlinkclient(gcs,1,1);

Connect the local MAVLink client to the same serial port as the Pixhawk board by using the connect function. This Pixhawk board uses the COM5 port.

connect(gcs,"Serial",SerialPort="COM5");

Create a heartbeat microservice object.

heartbeat = mavlinkmicroservice(gcs,"heartbeat");

Start sending the HEARTBEAT messages to the Pixhawk board by using the start function.

start(heartbeat,uav,"Serial",SerialPort="COM5")

If the Pixhawk board replies with HEARTBEAT messages, a connection is established.

Verify that the connection has been established by using the listClients function.

listClients(gcs)

ans = 2×4 table
    SystemID    ComponentID       ComponentType             AutopilotType     
    ________    ___________    ____________________    _______________________

      255            1            "MAV_TYPE_GCS"        "MAV_AUTOPILOT_INVALID"
       1             1         "MAV_TYPE_QUADROTOR"       "MAV_AUTOPILOT_PX4"

Create an FTP microservice object.

ftp = mavlinkmicroservice(gcs,"ftp");

List the available flight logs stored in the /fs/microsd/log directory of the Pixhawk board by using the list function.

[status,directory] = list(ftp,uav,"/fs/microsd/log")

status = true
directory = 4×3 table
      Type           Name            Size                 
    ________    _______________    _________  

      File       2026-03-01.ulg     7340032 
      File       2026-03-02.ulg     7540432 
      File       2026-03-03.ulg     6320031 
      File       2026-03-04.ulg     8221332 

Download the 2026-03-02.ulg flight log into the Documents/logs directory by using the read function.

[status,~] = read(ftp,uav,"/fs/microsd/log/2026-03-02.ulg", ... 
LocalPath="Document/logs/2026-03-02.ulg")

status = true

After you have downloaded the 2026-03-02.ulg flight log, delete the flight log from the Pixhawk board to save memory space by using the remove function.

status = remove(ftp,uav,"/fs/microsd/log/2026-03-02.ulg")

status = true

Verify that the file has been deleted by using the list function again.

[status,directory] = list(ftp,uav,"/fs/microsd/log")

status = true
directory = 3×3 table
      Type           Name            Size                 
    ________    _______________    _________  

      File       2026-03-01.ulg     7340032 
      File       2026-03-03.ulg     6320031 
      File       2026-03-04.ulg     8221332 

Version History

Introduced in R2019a

R2026a: Warning for invalid XML file input

The mavlinkio object now displays a warning if you create the object using an XML file that does not contain a MAVLink message definition. Previously, the object did not display a warning if you created the object using an invalid XML file.