mavlinkdialect

Parse and store MAVLink dialect XML

Description

The mavlinkdialect object parses and stores message and enum definitions extracted from a MAVLink message definition file (.xml). The message definition files define the messages supported for this specific dialect. The structure of the message definitions is defined by the MAVLink message protocol.

Creation

Syntax

dialect = mavlinkdialect("common.xml")

dialect = mavlinkdialect(dialectXML)

dialect = mavlinkdialect(dialectXML,version)

dialect = mavlinkdialect(___,SigningChannel=channel)

Description

dialect = mavlinkdialect("common.xml") creates a MAVLink dialect using the common.xml file for standard MAVLink messages.

dialect = mavlinkdialect(dialectXML) specifies the XML file for parsing the message definitions. The input sets the DialectXML property.

dialect = mavlinkdialect(dialectXML,version) additionally specifies the MAVLink protocol version. The inputs set the DialectXML and Version properties, respectively.

dialect = mavlinkdialect(___,SigningChannel=channel) uses the MAVLink signing channel channel.

Input Arguments

channel — MAVLink signing channel

structure

MAVLink signing channel, specified as a structure containing these fields:

• Stream — Signing stream, specified as a mavlinksigning object.

• SystemID — System ID, specified by an integer in the range [0, 255].

• ComponentID — Component ID, specified by an integer in the range [0, 255].

• LinkID — Link ID, specified by an integer in the range [0, 255].

• Key — Key, specified by as a string.

• Timestamp — Time passed since 2015-01-01 UTC. Unit is 10 microseconds.

• CreationTime — Time of creation, specified as a datetime array.

You can create this structure by adding the signing channel using the addChannel object function of the mavlinksigning object.

Properties

DialectXML — MAVLink dialect name

string

MAVLink dialect name, specified as a string. This name is based on the XML file name.

Example: "ardupilotmega"

Data Types: char | string

Version — MAVLink protocol version

2 (default) | 1

MAVLink protocol version, specified as either 1 or 2.

Data Types: double

Object Functions

createcmd	Create MAVLink command message
createmsg	Create MAVLink message
deserializemsg	Deserialize MAVLink message from binary buffer
msginfo	Message definition for message ID
enuminfo	Enum definition for enum ID
enum2num	Enum value for given entry
num2enum	Enum entry for given value

Examples

Parse and Use MAVLink Dialect

This example shows how to parse a MAVLink XML file and create messages and commands from the definitions.

Parse and store the MAVLink dialect XML. Specify the XML path. The default "common.xml" dialect is provided. This XML file contains all the message and enum definitions.

dialect = mavlinkdialect("common.xml");

Create a MAVLink command from the MAV_CMD enum, which is an enum of MAVLink commands to send to the UAV. Specify the setting as "int" or "long", and the type as an integer or string.

cmdMsg = createcmd(dialect,"long",22)

cmdMsg = struct with fields:
      MsgID: 76
    Payload: [1x1 struct]

Verify the command name using num2enum. Command 22 is a take-off command for the UAV. You can convert back to an ID using enum2num. Your dialect can contain many different enums with different names and IDs.

cmdName = num2enum(dialect,"MAV_CMD",22)

cmdName = 
"MAV_CMD_NAV_TAKEOFF"

cmdID = enum2num(dialect,"MAV_CMD",cmdName)

cmdID = 
22

Use enuminfo to view the table of the MAV_CMD enum entries.

info = enuminfo(dialect,"MAV_CMD");
info.Entries{:}

ans=148×3 table
                    Name                     Value                                                                                                                                                                                                                  Description                                                                                                                                                                                                              
    _____________________________________    _____    _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

    "MAV_CMD_NAV_WAYPOINT"                    16      "Navigate to waypoint."                                                                                                                                                                                                                                                                                                                                                                                                                
    "MAV_CMD_NAV_LOITER_UNLIM"                17      "Loiter around this waypoint an unlimited amount of time"                                                                                                                                                                                                                                                                                                                                                                              
    "MAV_CMD_NAV_LOITER_TURNS"                18      "Loiter around this waypoint for X turns"                                                                                                                                                                                                                                                                                                                                                                                              
    "MAV_CMD_NAV_LOITER_TIME"                 19      "Loiter at the specified latitude, longitude and altitude for a certain amount of time. Multicopter vehicles stop at the point (within a vehicle-specific acceptance radius). Forward-only moving vehicles (e.g. fixed-wing) circle the point with the specified radius/direction. If the Heading Required parameter (2) is non-zero forward moving aircraft will only leave the loiter circle once heading towards the next waypoint."
    "MAV_CMD_NAV_RETURN_TO_LAUNCH"            20      "Return to launch location"                                                                                                                                                                                                                                                                                                                                                                                                            
    "MAV_CMD_NAV_LAND"                        21      "Land at location."                                                                                                                                                                                                                                                                                                                                                                                                                    
    "MAV_CMD_NAV_TAKEOFF"                     22      "Takeoff from ground / hand. Vehicles that support multiple takeoff modes (e.g. VTOL quadplane) should take off using the currently configured mode."                                                                                                                                                                                                                                                                                  
    "MAV_CMD_NAV_LAND_LOCAL"                  23      "Land at local position (local frame only)"                                                                                                                                                                                                                                                                                                                                                                                            
    "MAV_CMD_NAV_TAKEOFF_LOCAL"               24      "Takeoff from local position (local frame only)"                                                                                                                                                                                                                                                                                                                                                                                       
    "MAV_CMD_NAV_FOLLOW"                      25      "Vehicle following, i.e. this waypoint represents the position of a moving vehicle"                                                                                                                                                                                                                                                                                                                                                    
    "MAV_CMD_NAV_CONTINUE_AND_CHANGE_ALT"     30      "Continue on the current course and climb/descend to specified altitude. When the altitude is reached continue to the next command (i.e., don't proceed to the next command until the desired altitude is reached."                                                                                                                                                                                                                    
    "MAV_CMD_NAV_LOITER_TO_ALT"               31      "Begin loiter at the specified Latitude and Longitude. If Lat=Lon=0, then loiter at the current position. Don't consider the navigation command complete (don't leave loiter) until the altitude has been reached. Additionally, if the Heading Required parameter is non-zero the aircraft will not leave the loiter until heading toward the next waypoint."                                                                         
    "MAV_CMD_DO_FOLLOW"                       32      "Begin following a target"                                                                                                                                                                                                                                                                                                                                                                                                             
    "MAV_CMD_DO_FOLLOW_REPOSITION"            33      "Reposition the MAV after a follow target command has been sent"                                                                                                                                                                                                                                                                                                                                                                       
    "MAV_CMD_DO_ORBIT"                        34      "Start orbiting on the circumference of a circle defined by the parameters. Setting any value NaN results in using defaults."                                                                                                                                                                                                                                                                                                          
    "MAV_CMD_NAV_ROI"                         80      "Sets the region of interest (ROI) for a sensor set or the vehicle itself. This can then be used by the vehicle's control system to control the vehicle attitude and the attitude of various sensors such as cameras."                                                                                                                                                                                                                 
      ⋮

Query the dialect for a specific message ID. Create a blank MAVLink message using the message ID.

info = msginfo(dialect,"HEARTBEAT")

info=1×4 table
    MessageID    MessageName                                                                                                                                                                                             Description                                                                                                                                                                                               Fields   
    _________    ___________    _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________    ___________

        0        "HEARTBEAT"    "The heartbeat message shows that a system or component is present and responding. The type and autopilot fields (along with the message component id), allow the receiving system to treat further messages from this system appropriately (e.g. by laying out the user interface based on the autopilot). This microservice is documented at https://mavlink.io/en/services/heartbeat.html"    {6x6 table}

msg = createmsg(dialect,info.MessageID);

Version History

Introduced in R2019a