MAVLink 주변 장치(OSD/GCS/보조 컴퓨터 등)

GCS(Ground Control Station), OSD(On-Screen Display), 보조 컴퓨터, ADS-B 수신기와 기타 MAVLink 주변 장치들은 서로 다른 직렬 포트를 통하여 전송되는 별도의 MAVLink 스트림을 통하여 PX4와 상호 작용합니다.

In order to configure that a particular serial port is used for MAVLink traffic with a particular peripheral, we use Serial Port Configuration, assigning one of the abstract "MAVLink instance" configuration parameters to the desired port. We then set other properties of the MAVLink channel using the parameters associated with our selected MAVLink instance, so that they match the requirements of our particular peripheral.

The most relevant parameters are described below (the full set are listed in the Parameter Reference > MAVLink).

MAVLink 인스턴스

In order to assign a particular peripheral to a serial port we use the concept of a MAVLink instance.

Each MAVLink instance represents a particular MAVLink configuration that you can apply to a particular port. At time of writing three MAVLink instances are defined, each represented by a parameter MAV_X_CONFIG, where X is 0, 1, 2.

Each instance has associated parameters that you can use to define the properties of the instance on that port, such as the set of streamed messages (see MAV_X_MODE below), data rate (MAV_X_RATE), whether incoming traffic is forwarded to other MAVLink instances (MAV_X_FORWARD), and so on.

INFO

MAVLink instances are an abstract concept for a particular MAVLink configuration. The number in the name means nothing; you can assign any instance to any port.

각 인스턴스의 매개변수는 아래와 같습니다.

• MAV_X_CONFIG - Set the serial port (UART) for this instance "X", where X is 0, 1, 2. It can be any unused port, e.g.: TELEM2, TELEM3, GPS2 etc. For more information see Serial Port Configuration.

• MAV_X_MODE - Specify the telemetry mode/target (the set of messages to stream for the current instance and their rate). 기본값은 아래와 같습니다.

  • Normal: Standard set of messages for a GCS.
  • Custom or Magic: Nothing (in the default PX4 implementation). 모드는 새 모드를 개발시 테스트용으로 사용할 수 있습니다.
  • Onboard: Standard set of messages for a companion computer.
  • OSD: Standard set of messages for an OSD system.
  • Config: Standard set of messages and rate configuration for a fast link (e.g. USB).
  • Minimal: Minimal set of messages for use with a GCS connected on a high latency link.
  • ExtVision or ExtVisionMin: Messages for offboard vision systems (ExtVision needed for VIO).
  • Iridium: Messages for an Iridium satellite communication system.

  INFO

  If you need to find the specific set of message for each mode search for MAVLINK_MODE_ in /src/modules/mavlink/mavlink_main.cpp.

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TIP

The mode defines the default messages and rates. A connected MAVLink system can still request the streams/rates that it wants using MAV_CMD_SET_MESSAGE_INTERVAL.

• MAV_X_RATE - Set the maximum data rate for this instance (bytes/second).

  • 이는 개별 메시지의 모든 스트림에 대한 결합 비율입니다 (총 비율이이 값을 초과하면 개별 메시지에 대한 비율이 감소됨).
  • 기본 설정은 일반적으로 허용되지만 원격 분석 링크가 포화 상태가 되고, 너무 많은 메시지가 삭제되는 경우에는 감소할 수 있습니다.
  • 값이 0이면 데이터 속도가 이론적인 값의 절반으로 설정됩니다.

• MAV_X_FORWARD - Enable forwarding of MAVLink packets received by the current instance onto other interfaces. 예를 들어 GCS가 보조 컴퓨터에 연결된 MAVLink 지원 카메라와 통신할 수 있도록 GCS와 보조 컴퓨터간에 메시지를 전송에 사용할 수 있습니다.

Next you need to set the baud rate for the serial port you assigned above (in MAV_X_CONFIG).

TIP

You will need to reboot PX4 to make the parameter available (i.e. in QGroundControl).

The parameter used will depend on the assigned serial port - for example: SER_GPS1_BAUD, SER_TEL2_BAUD, etc. 사용하는 값은 연결 유형과 연결된 MAVLink 주변 장치에 따라 달라집니다.

기본 MAVLink 포트

TELEM1

The TELEM 1 port is almost always configured by default for the GCS telemetry stream ("Normal").

To support this there is a default serial port mapping of MAVLink instance 0 as shown below:

• MAV_0_CONFIG = TELEM 1
• MAV_0_MODE = Normal
• MAV_0_RATE= 1200 Bytes/s
• MAV_0_FORWARD = True
• SER_TEL1_BAUD = 57600

TELEM2

The TELEM 2 port usually configured by default for a companion computer telemetry stream ("Onboard").

To support this there is a default serial port mapping of MAVLink instance 0 as shown below:

• MAV_1_CONFIG = TELEM 2
• MAV_1_MODE = Onboard
• MAV_1_RATE= 0 (Half maximum)
• MAV_1_FORWARD = Disabled
• SER_TEL2_BAUD = 921600

ETHERNET

Pixhawk 5x devices (and later) that have an Ethernet port, configure it by default to connect to a GCS:

On this hardware, there is a default serial port mapping of MAVLink instance 2 as shown below:

• MAV_2_CONFIG = Ethernet (1000)
• MAV_2_BROADCAST = 1
• MAV_2_MODE = 0 (normal/GCS)
• MAV_2_RADIO_CTL = 0
• MAV_2_RATE = 100000
• MAV_2_REMOTE_PRT= 14550 (GCS)
• MAV_2_UDP_PRT = 14550 (GCS)

For more information see: PX4 Ethernet Setup

See Also

• Serial Port Configuration
• PX4 Ethernet Setup > PX4 MAVLink Serial Port Configuration
• Serial Port Mapping