QGC home position sender

This setup adds a QGroundControl Fly View action that tells an ArduPilot Lua script to send the flight controller's home position to the Cyclops computer.

Components

• ../home_position_sender.lua runs on the flight controller. It accepts either COMMAND_LONG 31000 or a marker request (COMMAND_LONG 512 with param1=242, param2=31000), reads the FC home position, then sends MAV_CMD_DO_SET_HOME to the Pi at sysid 218, compid 190.

• FlyViewCustomActions.json runs on the QGC computer. It adds the Send Home to Pi action in Fly View and sends command 31000 to the active vehicle.

Flight controller setup

1

Enable Lua scripting

Enable ArduPilot Lua scripting (SCR_ENABLE=1) and reboot the flight controller.

2

Home position sender script

home_position_sender.lua

7KB

Open

Copy home_position_sender.lua to the flight controller SD card:

/APM/scripts/home_position_sender.lua

3

MAVLink Lua modules

Copy the MAVLink Lua modules to:

/APM/scripts/modules/MAVLink/

At minimum, this script needs:

mavlink_msgs.lua
mavlink_utils.lua
mavlink_msg_COMMAND_LONG.lua
mavlink_msg_COMMAND_ACK.lua
mavlink_msg_HEARTBEAT.lua

4

Reboot

Reboot the flight controller or restart scripting.

Home and estimator-origin

The script has deterministic home selection logic:

1. Use vehicle:home() first.

2. Use ahrs:get_home() only if vehicle:home() did not return a home object.

What this means operationally:

• The script sends only the selected home position (lat/lon) to the Pi.

  • The device will use the terrain data from onboard maps to determine altitude.

• Estimator origin coordinates are never sent to the Pi by this script.

• Estimator origin must be initialized at least once before the home position is considered valid.

• Home position and estimator origin do not need exact coordinate equality, but they must be in the same operating area.

• If estimator origin is not initialized, or home resolves to an invalid value (nil or 0,0), the script does not send MAV_CMD_DO_SET_HOME and QGC can show a timeout.

Expected startup message:

Home Sender ready (REQUEST_MESSAGE marker 31000, ... MAV channels)

QGroundControl setup

FlyViewCustomActions.json

379B

Open

Copy FlyViewCustomActions.json to QGC's MAVLink actions directory.

~/Documents/QGroundControl/MavlinkActions/FlyViewCustomActions.json

Restart QGC after copying the file.

Testing the feature

1

Set estimator origin

Click on the map and select "Set Estimator Origin"

2

Set home

Click on the map and select "Set home here"

3

Send home to Pi

In Fly View, open the Actions menu and click "Send Home to Pi"

You should see the VPS startup status text messages in the MAV messages when the VPS restarts.

References

• ArduPilot Lua scripting: https://ardupilot.org/copter/docs/common-lua-scripts.html

• ArduPilot MAVLink command Lua example: https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/MAVLink_Commands.lua

• QGC custom MAVLink actions: https://docs.qgroundcontrol.com/Stable_V5.0/en/qgc-user-guide/custom_actions/custom_actions.html