MAVLink Telemetry

Tether Ground Station MAVLink Functions

  • A computer running Alta Q Ground Control Software can be connected to the TGS via ethernet

  • Displays flight altitude on the screen.

  • Monitors the autopilot’s system_status (from the MAVLink HEARTBEAT message) to detect if the vehicle is airborne.

  • Reads the "system_status" field of the HEARTBEAT message from the autopilot to determine if the vehicle is in flight

  • When the vehicle is not in flight, the TGS limits charge current to 10 A to protect the batteries.

APU Connection to AUX Uart on AltaX

The AltaX Flight controller needs to be connected to the APU via Serial so these functions can work.

To do this, the APU should be connected to the AUX Uart, located in the AltaX IO Bay. This is done with the "EON Dronecode" Cable. No configuration is needed.

Accessing telemetry with a computer.

The TGS has an IP Address/Subnet of 192.168.2.20/24.

The TGS will stream a MAVLink connection to any device at 192.168.2.10/24 on port 14551.

  1. Plug computer into the TGS with an ethernet cable

  2. Configure the network connection of the Laptop with the manual IP address of 192.168.2.10 with a subnet mask of 255.255.255.0.

  3. In your ground control software, open a UDP connection with a local port of 14551.

Example QGroundcontrol Settings

(Optional) FRX Port Connection

We recommend the APU is connected to the FC using the AUX Uart as described above. However, it can also be connected using the FRX Cable. This cable is normally in use by either the Pilot Pro Air Unit, or the FRX radio, but if it is unused, it can be connected to the APU.

The "FRX Cable" is located at the front of the aircraft inside the frame. This is a 6 pin JST-GH Cable. This cable is too short to reach the APU, so the "Serial Patch Panel" is installed on the top plate of the aircraft, and then a patch cable connects this adapter to the APU.

Using this port requires configuration:

  • Set FF_WIFI_ENABLE to 0 (see this service bulletin

  • Set MAV_0_CONFIG to "TELEM1"

  • Set SER_TEL1_BAUD to 57600 8N1

  • Set MAV_0_FORWARD to Disabled

  • Set MAV_0_RATE to 20000

  • Set MAV_0_MODE to Normal

The settings above disable the Wifi, and reassign MAV_0 channel from the wifi module to the FRX port.

Troubleshooting the telemetry connection

  • If there is no telemetry connection, the automatic checks of the TGS will fail with a message "No Heartbeat From FC". If the TGS is in the Ready state, then the Telemetry connection is working.

  • If you have no connection despite correct settings, try switching TX and RX in the telemetry cable.

  • If you can't access telemetry with a computer connected via ethernet, try pinging 192.168.2.20 and 192.168.2.30 (TGS and APU), if you can't ping these devices, the issue is likely with the computer network configuration.

Last updated

Was this helpful?