RockBlock to MAVLink gateway

Simple Python script for sending and receiving MAVLink messages using the RockBlock SBD modems, allowing worldwide telemetry with an ArduPilot platform.

This gateway runs on the GCS, and will send/recieve MAVLink messages between the GCS and RockBlock servers.

Due to bandwidth constraints (50 bytes per message) MAVLink 1 is used, as it uses slightly less bytes per message compared to MAVLink2.

Required hardware, software and services:

• Rockblock Modem (such as https://www.sparkfun.com/products/14498 and cable https://www.sparkfun.com/products/14720)
• ArduPilot 4.4+ with a flight controller capable of running Lua scripts
• Active RockBlock account (https://rockblock.rock7.com/Operations)
• Adafuit.io account (https://io.adafruit.com/)

Due to limitations of the Rockblock web service, all received packets need to go via a public-facing web service. See https://docs.rockblock.rock7.com/docs/integration-with-application for details. For the purposes of this configuration, adafruit.io is used.

Setup:

1. Connect the Rockblock modem to a spare UART on the flight controller. Only the +5V, RX, TX and GND lines need to be connected
2. Ensure the modem is activated in the RockBlock account
3. Create a new feed on adafuit.io. Ensure the Feed History is OFF and a webhook is active. Connect this to your Rockblock account (https://learn.adafruit.com/using-the-rockblock-iridium-modem/forwarding-messages).
4. Copy the Ardupilot Rockblock Lua script to the flight controller, configuring as required.
5. On the GCS install the required Python libraries via pip3 install adafruit-io pymavlink
6. On the GCS run rockblock2mav.py to send/receive telemetry on 127.0.0.1:16000. Ensure the GCS is connected to this ip/port.

Note for QGC users:

• Use the "udpin" output option, as the default "udpout" isn't compatible. For example rockblock2mav.py -out:udpout:127.0.0.1:16000

Note that Mission Planner is not supported at this time.

Limitations:

• The flight controller will only send HIGH_LATENCY2 MAVlink messages. This will give basic position and status information. This message is sent once per 20 seconds
• The Rockblock modem does require a full view of the sky to work reliably. It will not work indoors.
• The only command (COMMAND_LONG, COMMAND_INT) messages sent from the GCS to the Rockblock modem are the following:
  • MAV_CMD_NAV_RETURN_TO_LAUNCH
  • MAV_CMD_NAV_LAND
  • MAV_CMD_NAV_TAKEOFF
  • MAV_CMD_NAV_VTOL_TAKEOFF
  • MAV_CMD_NAV_VTOL_LAND
  • MAV_CMD_DO_SET_MODE
  • MAV_CMD_MISSION_START
  • MAV_CMD_COMPONENT_ARM_DISARM
  • MAV_CMD_CONTROL_HIGH_LATENCY

The MISSION_ITEM_INT message is also supported.