figuring out the Antenna Tracker

3691139590?profile=originalNot many people know but we have an piece of open source software for controlling an Antenna Tracker.  It's been built by Tridge (Arduplane lead developer) for use in the outback challenge.

Sadly we have no documentation and, as far as I know, nobody except Tridge has used it.  Still given Tridge's track record on building great software I suspect it works well and if it doesn't, I'm sure we can fix it.  So to not let this piece of code go to waste, I'd like some help from people who are interested to give it a try and help me figure out how it works.

Here's the little that I know:

  • It runs on any of our supported board (APM1, APM2, PX4, Pixhawk, Flymaple and perhaps VRBrain)
  • For APM1/APM2 users building the code is as easy as opening our hacked ArduinoIDE and selecting File > SketchBook > Tools > AntennaTracker and then building in the normal way.  For PX4/Pixhawk, our autobuilder doesn't automatically build a binary but I can provide one if people are interested.
  • It can control a Pan and Tilt gimbal like this or this found on
  • It may or may not require a GPS
  • It must somehow receive vehicle position updates from the ground station which has the telemetry radio that is connected to the vehicle. Maybe through a USB cable.  Tridge probably uses the python ground station, MAVProxy, to passthrough the vehicle position data to the AT but perhaps we can get MichaelO to build out a similar feature in Mission Planner.
  • I imagine this antenna tracker could also be used to keep a camera focused on the vehicle which might be good for easing the burden on creating videos of our vehicles.

So if you want to give it a try please do and stick any findings, questions or issues below. Alternatively Issues can go into the issues list.

I'll start sticking things into the wiki as they become clear.

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    • I agree.

      What we need is a list of changes that we would like to see to make a new baseline. It’s about time we decided what V1.0 should look like.

      It should log all voltages (servo, VCC, Battery) and battery current just like the airplane software does. I think it would be very to copy some of these features over from the airplane or multirotor firmware.




  • Hi guys, I recently designed and 3D printed parts for an Ardutracker, assembled everything and it works fine, but for one thing: the pitch axis does not work!

    I have field tested the tracker, the YAW axis works like a charm, but the Pitch axis works in reverse, and no matter what I do I cannot make it work in the right direction, consequently it does not move up when the plane gains altitude. Clicking the "Reverse" box does absolutely nothing! I have the 0.73 firmware installed, because at the time of flashing it said the 0.75 was not available on the server for download.

    Any advise on what to do would be very much appreciated!

    Thank you.

    • Nikola,

      Yes, many of us are having issues with pitch control on the official AT firmware. For now, try using this custom firmware by Jakob Oller that I have attached. Use the PX4 version for Pixhawk controller or the .hex version for APM2 controller.


      • Thanks Greg, will give this firmware a try next chance I get.

        Right now I moved the plane I was using for testing this back to the MFD tracker, will have to setup a platform just for that... and possibly a copter... will make it much easier to test. :)

        Thanks again for the fast reply.

        • The easiest way to test AT is to use SITL. It is as simple as running a simulation and adding an output for antenna tracker

      • Developer
        What is the difference in this code? Has this been offered ass a pull request for the main code?

        Where is the git repo for those changes?
        • My code is in my GitHub:

          I didn't have time to play around with it for some time and my repo is quite messy but as far as I remember that this code is in branch "0.7.1 full". Every time someone asks about this code I promise to push some updates "soon" but it is taking me forever :( But I will eventually do it! :) I am working on pushing my current version into master (via pull request) and master (probably called 0.7.7) will soon work as expected.

          APM Plane, APM Copter, APM Rover source. Contribute to rcairman/ardupilot development by creating an account on GitHub.
  • By the way, I can confirm the altitude error on the MinimOSD, mentioned before. I also have a problem using the latest version arduplane 3.5. It give me only 60% telemetry. Switching back to 3.4 solved the problem.

    A bit about my setup:
    Airplane: Hugin with 20A/H lithium ion batteries

    We are flying agricultural mapping missions to measure the growth rate of the sugar canes in Thailand.
  • I also noticed it is extremely important to have the tracker balanced. I neglected this issue before and gave me a lot of problems. That's why you see the counter weights on the antenna boom.

    The tracker performs very well, apart from burning servos when I lose data connection. Pitch and yaw are spot on and track the plane perfectly.

    My wishlist for the "perfect" tracker:

    - Auto tune function

    - possibility to add end switches

    - enter a search pattern upon loss of connection, based on last known position

    - rlog and tlog files written seperately in mission planner

    - mission planner showing vehicle by default (not the antenna tracker)

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