Articles for July 2016

Deleting my previous post on my UAV imager book

After carefully considering the commentary generated by my post, announcing my new UAV imaging system book, I have decided to delete the post and its link. Interested potential readers may Google my name and “drones” to find the website where it may be ordered. (They may also find my website. I have a _lot_ of experience explaining technical concepts, even in non-technical venues.)

I did, of course, read the TOS before posting; but didn’t realize that the issue was this dicey. Many thanks to those who found my post interesting and relevant.

Here’s part of my philosophy: I’ve been in the optics community for about 30 years. We don’t do that great of a job of outreach to the broader world where talented individuals are working on innovations that may benefit from the knowledge we have. In fact, many of our books and other publications are written strictly for our professional peers, and never find their way outside the university.

With UAV imaging, I sought to broaden that reach by designing my book to be as practical, and as applied, as possible. One should have an engineering/physics/or scientific background to understand every single detail; but smart individuals with even a high school physics understanding will benefit from it, I believe.

Before the book was published, I spoke to my publisher about my desire to attract a wide audience; I believe that review copies were sent to UST Magazine and Wired, as well as to our usual optical engineering/optical science publications.

My hope, I said, was that the work would come into the hands of individuals already working on drones, but without the background knowledge in fields of my expertise. I still hope so. Putting the two together will increase the disruptive potential of UAV imagers and further grow the industry and applications markets.

Best, to all.

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DALRC XR215 V2 FPV Racer Build


As a follow up of my latest blogs about FPV hardware, here is a build video. The build is made with the following components:

-DALRC XR215 V2 Full Carbon Fiber Quad Frame for FPV Racing FPV Build in OSD BEC BB Ring:

-Foxeer XAT600M DC5V-22V 600tvl Sony Super HAD CCD FPV Camera:

-Gearbest kindly provided motors for this project, Emax RS2205 2300KV Racing Edition :

-ESCs are taken from Gearbest’s Flycolor Fairy Series V2 20A BLHeli ESCs :

-F3 Flight controller Deluxe was kindly provided by Gearbest for this build :

-Propellers are DALprop J5040 :

-ESC firmware is BLHeli with oneshot125 downloaded and flashed with the BLHeliSuite software (latest version)

-F3 flight controller firmware is Betaflight (latest version) downloaded and installed via the Betaflight configurator (Chrome app)

Music by Kevin MacLeod – site =

Disclaimer : no chickens were hurt in the making.

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Ultra – stick style UAV platform

Thought I would share one of my recent projects. I am designing an ultra stick style UAV platform designed to carry a 3 axis mini 3D pro brushless gimbal for smooth fpv video while the aicraft carries out an autonomous mission. 

The construction uses lasercut balsa and lightply so it will be extremely cheap and easy to make, while the wing is hotwire cut out of eps and then skinned with a sheet of 1mm balsa for stiffness. 

I designed the wing using a constant airfoil section (NACA2414) with washout towards the tip so wing produces an elliptical lift distribution which will greatly improve stall characteristics. 

The wing is designed to fly at 16m/s (around 60km/h) if the airframe is kept at 2kg. so things need to be kept light. 

Let me know what you think!

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Work in progress : Indoor light track


I wanted to share with you our latest work in progress on lighting technologies for drone racing.

This is just the beginning but it look already amazing 🙂

I hope you’ll enjoy it !

I’ve you’re interested in such technologies feel free to contact me.

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Swarming with Solos and ROS

I’ve posted a bunch of teaser videos of the Solo swarming we do often at 3DR, but have not yet posted instructions on how to do it yourself — I was just waiting for the team to document the steps. Well good news: now they have!

The above video (sorry for the shaky camera — we were excited) shows a fun exercise in in using the Solo drones to autonomously play Pong with themselves. Each “paddle” is made up of two Solos. The “ball” is the fifth. All this is automatically controlled by ROS, running on the ground. Instructions on how to do this are in the documents below.



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FlightZoomer 2.1 is released! – Check out this top notch distributed avionics suite for drones!

In this post I show videos of two real flights, the first above for FlightZoomer version 2.0 and another below with the freshly released version 2.1. Both videos show the same automatic flight including an ILS approach. In the videos the replay feature is used to sync the recorded video from the on-board Sony camera with the presentation of the groundstation.

While FlightZoomer 2.0 works nicely and was a huge step forward overall, the video also shows some areas, that leave room for improvement. In particular the LNAV, the VNAV and the ILS autopilot modes worked not as precisely as a Pixhawk based system in theory could.

All this was addressed with FlightZoomer version 2.1, so check out the following video to see how the behavior improved:

Version 2.1 is provided as a functional upgrade. It does not bring a single new button or any UI change, but under the hood a nice number of improvements have been implemented. Existing algorithms have been refined, new cascaded control layers have been added, the ILS can be captured much more robustly, flight plans are followed more precisely and a bunch of bugs have been ironed out.

The complete list of changes is here:

  1. The turn initiation time is considered now for the flight path calculations. The turn initiation time is the duration, during which the flight path over ground lags the ideal turn. This change increases significantly the precision, how the aircraft follows the planned flight track.
  2. For the LNAV and the ILS Localizer mode deviations along the straight legs are now actively corrected. Prior version 2.1 the aircraft always just pointed to the next waypoint and, as a result, deviations have not been corrected until the very end of each leg.
  3. A new algorithm has been implemented in LNAV mode to keep the turn radius constant even if the speed varies a bit. This was required because before the aircraft often deviated from the planned track during turns when the speed was dropping temporarily.
  4. Speed transitions have been abruptly prior version 2.1 but now are smooth as well. Every speed change happens over a period of 2 seconds.
  5. The vertical flight profile in VNAV mode has been improved. Due to inaccuracies in keeping the standard climb or descend rate, the actual altitude could deviate quite a bit from the correct altitude for a certain position. This is important especially during descends because we are moving towards the terrain and because the end of the descend and the end of the route should happen exactly at the same spot. The new VNAV algorithm in version 2.1 ensures this.
  6. Optimization and fine-tuning of the approach pattern calculation. The result is a more realistic and much more compact approach pattern, especially during the downwind and base.
  7. The ILS glideslope can now not only be captured from below and after having turned to the final approach course, but from below or even before the last turn.
  8. Totally 26 issues have been fixed.


In both videos basically the entire flight was flown with the autopilot. Along the route using the LNAV and the VNAV modes, using the TRACK OVER GROUND, ALTITUDE and FLCH modes for the downwind and base and finally using the ILS LOCALIZER and ILS GLIDESLOPE modes for the approach.


Some screenshots from the second video:

On the next image you can see how precisely the aircraft follows the planned track even during a turn. Consider that the turn radius first is a variable that depends on the cruise speed and the turn rate (angular velocity). In practice also the actual speed and the impact of the inertia on the actual track over ground have to be incorporated:

The second image shows the final approach to the runway 08 of my virtual airport. Consider how the runway elevation has been configured 5 m above the real road, in order to have some safety buffer:


Again I dont want to miss the opportunity to provide some high level information about FlightZoomer:

  • FlightZoomer is a top notch distributed avionics suite for drones
  • FlightZoomer is entirely a software solution. The hardware are COTS devices (Windows Phones smartphones).
  • Why distributed? Because there is an onboard device and a groundstation, both are connected via a Relay Server at home.
  • All the components are coupled with a cellular EDGE, 3G or 4G link.
  • The onboard smartphone is mated with an APM based flight controller via Bluetooth.
  • Currently supported is Arducopter 3.3 or higher.
  • Supporting Arduplane is on the to-do list.
  • For about 200$ you can get everything mentioned working (assumed, you need to buy two Windows Phones for the groundstation and the sensor device)


Much more details you can find on my homepage


The full documentation for version 1.5 is still valid for the basic functionality:

Version 1.5 full documentation


For the version 2.0 the additional features are described in this 50 page addendum:

Version 2.0 addendum


For version 2.1 there is currently no separate documentation (beside this post 😀 ) 

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AntennaTracker v1.0 on NAVIO2 with Bebop2

ArduPilot’s Antenna Tracker firmware has been making some quiet progress over the past few months.  They’re all documented in the Release Notes but at a high level the improvements include:

  • More accurate control due to bug fixes in how the vehicle’s position estimation was done
  • Smoother movement through additional filtering
  • Separate servo types possible for yaw and pitch axes
  • Tilt compensation meaning it tracks the vehicle accurately even when the tracker is leaned over
  • Improved Mission Planner setup screen (i.e. Extended tuning page)

The parts I used to build my tracker included:

I used a NAVIO2 instead of a Pixhawk mostly because it’s easier to make a Wifi connection this way.

I haven’t yet tested the range of the telemetry connection to the Bebop2 but I suspect it’s between 1km ~ 2km.  In fact, the antenna used here is not ideal for use with the Bebop2, a simpler non-Helical antenna like this one would likely do better.

Some limitations of this setup:

  • we don’t yet support receiving live video from the Bebop2 but this is coming within the next couple of months so during this test I simply had telemetry data from both Tracker and Bebop2 visible in the Mission Planner
  • the networking connection between the PC to the RPI2 was quite simple but not very flexible.  For whatever reason the PC and RPI2 nearly always appear with the same IP addresses so the Tracker startup scripts were hardcoded to always uses these.  It would be better to setup dhcp on the RPI2 to set PC’s IP address
  • the bebop’s Wifi ssid is hard-coded in the script on the RPI2.  If someone wanted to repeat this setup they would need to change this to match their particular Bebop.

In case people want to replicate this setup, I’ve uploaded an image to here.

Thanks to the beta testers for their ideas and feedback and Stefan Lynka for his code contributions.

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Ardupilot on a Raspberry Pi Zero with Escape board

We’ve recently been pushing the low cost Raspberry Pi Zero to see what it can handle.

With a custom Raspbian linux build with real-time patches, Martin Evans ( @lostcaggy on Twitter ) has managed to get a slightly modified version of Ardupilot up and running on a Pi Zero controlled RC buggy using our (Dark Water Foundation) Escape board to control the motor and steering servo and transmitting video, GPS and IMU details back to QGroundControl.

The Buggy is being used to test the hardware and software before it’s loaded into a boat (old used Kayak) and sent out to survey the oceans (probably closer to shore though 🙂 ) –

Above is a short video showing its second run.

The Escape board is currently on Kickstarter – ending very soon.

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Enterprise Drone Solutions announces Théa: the world’s first UAS to meet the high standards for an ?FAA Airworthiness Certificate

Théa is the world’s first UAS to meet the high standards for an FAA Airworthiness Certificate, expanding its operational capabilities beyond those of any other commercial unmanned aircraft to allow legal flight over crowds, at night, and beyond. By providing unmatched aircraft-grade reliability (99.999 999 9%), Théa meets the stringent requirements necessary to go where consumer-grade systems can’t.

Théa has unmatched payload and flight-time capabilities, allowing you to do more

No Payload Full Payload (11kg)
Weight (Ready to fly) 27kg (60lb) 38kg (83lb)
Flight time 35 mins 21 mins
Max Speed 40kph (24mph)   30kph (20 mph)
Climb rate 7 m/s 5 m/s
Radio Range 1500m
Operating Temperature 120 to -20 deg F
Tech specs:

  • 1100mm Diagonal
  • 780mm x 780mm x 800mm unfolded
  • 29in props
  • 3 sets of high-power LiPo batteries
  • 4000w of charging power for continuous flight
  • Unmatched 99.9999999% reliability
Théa can handle the most demanding camera payloads, such as:
  • Canon C500
  • RED Epic X / Dragon
  • Sony FS7

Théa has unprecedented flexibility

  • Ability to fly at night, allowing you to capture striking footage
  • Can fly with weights above 55lb to carry the best camera equipment
  • Ability to fly beyond line of sight to capture footage that would be impossible to get otherwise
  • The ability to fly over uninvolved people like crowds and roads to allow you to go where you couldn’t before

Continuing Support

​Support packages are available to back Théa’s unparalleled reliability with unparalleled service. We provide next-day guaranteed service, including required maintenance intervals for flight worthiness, as well as 24/7 support, so you never have to worry.
Contact us at: [email protected]

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