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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      • MR60

        Hi Greg,

        Will link this to the Github issue tracker. Thx for the suggestion.

        I will compile a summary of my experiments. I can get the tracker to track but only in the positions limits of the servo (no reversal) (maybe it works better with continuous rotation servos ?) and had to discover by trial and errors what works and what does not, including a non documented way of how you physically have to position the external compass versus the moving plate, for the tracker to read a good heading (and I can tell you it is counter intuitive).

        So half joy, but already glad I can track in a limited 180 degrees.

        • Hello,

          Does any body have any idea of the maximum accuracy of the antenna tracker system?

          I do not want to build a system where the gain is too high for the tracker to deal with, it would be terrible if it "missed" the aircraft.

          • Developer

            I've never measured it but I think it's within a couple of degrees at least at longer ranges.

  • Hello! I am building a very high gain parabolic dish system - I wanted to ask how accurate the antenna tracker is in degrees?

    What would be a reasonable maximum gain for a parabolic dish on the antenna tracker? Would 30 db be too much? 


  • Is there a need to change something in code, if I want to use it with my APM 1.4, or can I directly compile and flash it  into AMP ?

  • MR60

    For info I posted a topic here :

    asking how SITL could replace a real vehicle in this schema to test a real antenna tracker "at home":

    3702234188?profile=originalI am using windows/Cygwin to run SITL+MAvproxy as described in the wiki, but did not find a succesful way to ouput SITL mavlink to the COM port on which the antenna tracker is connected to.

    Has anyone done it succesfully in this kind of setup where the antenna tracker is "in the middle" (between vehicle and GCS) ?

    • The open360tracker sketch runs on an APM2.5, too. The only APM2.5 I had, had the internal compass disabled, so I did not use it.
      I use a Crius Aio Pro which is also powered by an Atmega 2560.
    • The open360tracker is a hard- and software project. Two members of the forum designed the mechanics/case and wrote the arduino sketch. They use a Crius SE as the "brain". I run it on a Crius AIO Pro and there is a guy from spain, who ported/adopted it for 32bits on the Naze32 range of boards. It does not use a full IMU, only a compass and an optional GPS. I do not use their mechanics. I use my APM tracker mechanics and changed it to work with the open360tracker software (I also changed the arduino sketch a bit).
      • So you used this arduino sketch for open360tracker and ported it to APM?

        I'm just curious about it - what if we would use this sketch for APM, because it seems it works on Crius SE reliable.

    • I only used my APM tracker with CR servos, so I am not able to help you here.
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