Autonomous Airborne Docking for Refueling or Recharging

This video shows some recent flight test results from my PhD research on autonomous UAV docking, that was conducted with the Australian Centre for Field Robotics (ACFR) at The University of Sydney. To the best of our knowledge, these experiments are the first time two UAVs have docked in mid-air.

Some of my other videos provide more specifics on the hardware/software, but I'm using my own autopilot, a Beaglebone Black as the formation flight computer and an Odroid U3 to do the onboard vision processing. All the guidance, navigation and control algorithms on all the hardware is developed in Simulink and automatically converted to C/C++.

The IR vision aspect is probably of interest to some of the guys doing auto-landing with IR beacons. We use a C920 with narrow bandpass filter and 940nm LED markers without modulation. It works in all lighting conditions except when looking directly at the sun where the high number of false positives are difficult to distinguish from the actual markers, but there are a number of ways to handle this infrequent situation.

There are some nice airborne shots so watch in HD!

Views: 3748

Comment by Andrew Rabbitt on April 18, 2015 at 10:23pm

Very impressive indeed!  Congratulations!

Comment by Emery c. Chandler on April 18, 2015 at 10:38pm

It has been done two global hawks had refueled off eacho ther here in america- done by nasa I believe

Comment by Tiziano Fiorenzani on April 19, 2015 at 12:41am

Very impressive result. Great job!

Comment by Rob_Lefebvre on April 19, 2015 at 4:48am

Amazing work.  This would be awsome for the new outback challenge.

Comment by lukechencqu on April 19, 2015 at 6:28am

What a pity that we can not access to the video in China mailand...

Anyhow, it was a great news!

Comment by lukechencqu on April 19, 2015 at 6:56am

Hi, Dan Wilson, could you please tell me the paper name of your PHD research about this? thank you!

Comment by Armin Strobel on April 19, 2015 at 8:26am

Amazing work. Love how well it works. To refuel at hight altitude in relative calm air a global hawk is one thing, but doing it in low altitude with a small UAV is a completely different challenge. Especially since you use a simple modified web-cam.

I am using as some other people too a very similar technology to land a VTOL UAV on a ship. It is great to see that it works with a simple web-cam, that gives me some confidence with my project.

Would be great to combine your technology with a big mother-ship to deploy, refuel/recharge and recover UAVs (maybe even VTOL UAVs). So you could have a swarm of UAVs with long endurance and long distance capabilities

Comment by Justice Bentz on April 19, 2015 at 9:47am

Would like to see this for landing airplanes on a moving boat autonomously.

Comment by Emery c. Chandler on April 19, 2015 at 10:39am
Comment by Dan Wilson on April 19, 2015 at 3:21pm

Thanks for the kind words everyone, Ali and I really appreciate it. To address some of the comments:


Modulation is a good idea and definitely necessary if using one marker. We had to use multiple markers to get range information but you could just use a laser for that for landing so multiple markers may not be necessary. I'd only be increasing the complexity when absolutely necessary. I'd be happy to discuss this further is you like - dan.wilson00 at

@ Jason Franciosa and Hans Miller

Using this for net recovery is certainly a potential application. The current Pixhawk with companion computer could do this, infact that architecture is very similar to what I used, where my autopilot is a BeagleboneBlack cape and the sensors/microcontroller are the same as Pixhawk. All the algorithms will be published in my thesis (probably July) as well as in a few upcoming conference/journal papers. Making the code available is more difficult since it is auto-generated so hundreds of files but I'd be happy to help out anyone who wants to do something similar.

@ Emery c. Chandler

I'm certainly aware of the NASA/DARPA Global Hawk formation flight tests at close separation, however there was no docking. This is backed up in a recent survey paper (Advances in Air to Air Refuelling - Thomas et al., July 2014) and is also mentioned on the KQ-X Wikipedia page. In saying that, this is only what is publicly known, I wouldn't be surprised if companies like Northrop Grumman have done this without making it public.

@ Rob_Lefebvre

Haha yes, using this for the Outback Challenge also crossed my mind, they would have to award you style points for that.

@ Lukechencqu

That's a shame, but I think there are some ways to get around those restrictions? I'm finalising my thesis now so it won't be available until July/August most likely. There are a few papers here and more being published shortly.

@ Armin Strobel

Nice concept study! Air launch/capture is definitely something I want to try to use this system for. I believe DARPA were interested in that concept too. I'd be happy to make some suggestions for your project based on our experiences. Turbulence from wind interacting with the terrain at low altitude and even thermals on hot days really injects a lot of instability into the system. However, at high altitude with larger aircraft, the effects from wake turbulence are much greater.


You need to be a member of DIY Drones to add comments!

Join DIY Drones

© 2019   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service