MAVLink Mode vs. Raw Mode for BVLOS Command & Control Explained

Sky Drone has always been about connectivity. To be able to remotely control drones from anywhere in the world, was always a main goal for us and is a key feature for truly autonomously operating unmanned air/ground/surface vehicles. Reliable BVLOS operation of such vehicles is required for almost any use case in that field.

Sky Drone FPV 3, Sky Drone Link 3 and older legacy products that run the latest firmware, have the "MAVLink Mode" option available.

MAVLink Mode Explained

First off, a bit of background about MAVLink: "MAVLink or Micro Air Vehicle Link is a protocol for communicating with small unmanned vehicle. It is designed as a header-only message marshaling library. MAVLink was first released early 2009." (source: Wikipedia) More about MAVLink is also available at: https://mavlink.io/en/

In an essence, MAVLink is a great protocol for talking to flight controllers / autopilots. It is extremely versatile and a standard that is now within the realm of the Dronecode foundation*.

In order to optimize data transmission for in-flight BVLOS operation, the latest Sky Drone firmware offers a "MAVLink Mode". By turning on that MAVLink mode, the system processes MAVLink data actively. Internally a "MAVLink router" processes the data stream and discards all non-MAVLink messages. At the same time, data package size is being optimized for real-time communication. 

The positive effect of this is to lower latency and increase liability in terms of the bi-directional command & control as well as telemetry downstream.

This is how the MAVLink mode can be turned on during setup:

MAVLink in its original design dates back to 2009 when BVLOS remote operations in real-time were not part of the standard / expected use case. As such, MAVLink is a powerful protocol standard that has a virtually unlimited range of capabilities. While that kind of versatility is in many cases very useful, in real-time BVLOS operations it is more important for operators to be able to communicate with the aircraft or ground/surface vehicle in the fastest and most lean way possible. With that in mind, the MAVLink mode in the latest Sky Drone firmware ensures a lean and fast way of communication, while preserving the MAVLink protocol standard.

NON-MAVLink Mode (Raw Mode) Explained

If the MAVLink Mode is turned off, the system operates in the so-called "Raw Mode". That is a protocol agnostic mode, which allows any protocol for telemetry / command & control, or any other data as a matter of fact, to be transported from the Sky Drone client software running on the desktop to the Sky Drone device (e.g. FPV 3, Link 3) on the drone.

That data may come as a different text-based protocol (like MAVLink) or a binary protocol or it may even be an encrypted data stream. 

Note: If a non-MAVLink protocol is being used, but the MAVLink mode is turn "on", the system will discard all non-MAVLink data and such the entire data that is being sent. To ensure data sent using a non-MAVLink protocol, it is essential to turn the MAVLink mode to "off". 

Conclusion and Best Practice

If the flight controller / autopilot you are using operates on MAVLink (e.g. Cube, Pixhawk 4 Mini), we do always recommend to use our products with the MAVLink mode turned "on". Because most of our users actually use MAVLink, that is also the default setting. If your flight controller / autopilot does not use MAVLink you have to turn it "off" otherwise your data connection will not work.

* Sky Drone supports the Dronecode Foundation as a silver member along side many innovative drone companies like 3DR, Yuneec, FLARM, DroneDeploy, Wingtra and many more.