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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Comment by Randy on July 28, 2016 at 5:16pm

@Simon, Thanks!  I'm afraid though that these later versions only run on the higher end hardware (Pixhawk or faster).  For me it's tough to prioritise back porting the changes to the older branches with so much else going on.


This PT785-S has 360 degrees in yaw and almost 90 up and down in pitch.  Maybe it's 70 down but it's a lot of range.

Comment by Ravi on July 28, 2016 at 6:39pm

I think it is a great idea to use RPi for tracker. using RPi for telemetry is a very cost effective solutions since the wifi dongles are available for under $10. eventually video will also zero down to RPi. so all three integrated into the same board. the raspi hardware is very cost effective and one gets lot of support for their configuration on net. great job randy. I am already flying a hexa using Navio2 with integrated telemetry using alpha wifi adapters.

Comment by Monroe King on July 29, 2016 at 4:40am

Randy can the tracker be mobile now? In other words can you mount the tracker on a vehicle and follow without loosing tracker lock?

Comment by Randy on July 29, 2016 at 5:31am


Yes, although I haven't tried that I think it will work fine.  In the latest set of changes we changed the tracker's position updates to come from the EKF (previously they were coming directly from the GPS).  This should make the tracker's position estimate better.  Also the tilt compensation (in particular the roll compensation) should make it function better if it happens to lean back and forth (like on a ship or a truck) as it's moved about.

Comment by Monroe King on July 29, 2016 at 6:26am

Wow that is really good news for some of the stuff I do. It also seems the prediction portion of the software has made a great deal of progress since I last tried the tracker! Do you think you had the slew rate optimized for the prediction I noticed a slight delay (which is acceptable) the aperture on my helical is 15 degrees if the tracker could maintain 10 degrees that would be astonishing!

Comment by Monroe King on July 29, 2016 at 6:31am

The only other thing I would be interested in seeing would be the capability to hand off from one tracking station to another. Lol I know I'm asking too much.

Great work Randy and Stefan and others working on the tracker. It's just wonderful to see this part of the project progress!

Comment by Simon Wunderlin on July 29, 2016 at 8:33am

@Randy: thank you for the update on hardware compatibility, I guess a PXFMINI+RpiZero would be a small and flexible solution. Do you have any infos on how to mod that wifi dongle ?

@lianpinkoh: thanks

Comment by OlliW on July 29, 2016 at 8:45am

Very cool stuff !!!

I totally missed that it's possible to have MP showing the heading lines (or whatever they are called correctly) for two units. How is that done? I mean, I would very much like to have that also for a gimbal attached to a copter, i.e. to see in addition to the copter's lines also an additional line for the gimbal's current heading. What would one have to do to achieve that? What messages should be send to the GCS? Would it be the MOUNT_STATUS? Or ATTITUDE? Else? Would the gimbal have to be a separate system, or component, or doesn't it matter (from the code it seems that the Tracker has SysID=2, i.e. a separate system)? Would that actually be the green Target Heading line? ??? I really totally missed that feature, and google didn't yielded much. I would be most thankful for any directions :).

(if that's too off-topic I'll be happy to move to e.g. the ardupilot forum, ATv1.0 hasn't shown up there yet)

(I noticed that with the "newer" MP and/or AC I don't get that selection box to choose between the STorM32 gimbal and Pixhawk anymore, which makes me wonder even more how that is done)

cheers, Olli

Comment by Randy on July 30, 2016 at 1:30am


Yes, I'd guess that an RPI Zero could do the same thing.  The Wifi dongle is one that allows the antenna to be removed.  When I ordered the antenna (from ReadyMadeRC) I was also careful to make sure I got the correct cables and connectors so that it could be connected to the wifi dongle.  There's RP-SMA and SMA and then male and female of each so I just had to be careful to get the right bits.  I hope to put the full and exact component list on the wiki in the next week or so.

Comment by Simon Wunderlin on July 30, 2016 at 1:33am

@Randi Thank you. Maybe it would be worth to update the tracker wiki front page to reflect the new hardware requirements for version 1.0.


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