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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                • jDrones has started 2 years ago an antenna tracker that never arrive...

                  Ardustation mega was forgive to.

                  Lot of people have tweak the MFD antenna tracker. 

                  I understood that guys from Quantracker with VBI and PlayUAV-OSD project are working on a good tracker with VBI instead of telemetry (like Eagle Tree use). 

                  PlayUAV OSD (I'm using it) is really so good that we could hope Quantracker will be to...Thanks Randy to have help Tom from playuav-osd to resolve issue with Arm status.

                  Must wait ....

                  (nb playuav-osd vid sample test under HIL : and

      • There is a good file for me.  But I do not have Pixhawk but miniAPM.

  • I flashed my tracker with 0.73 today.

    On/off servo mode works fine as it did before, but I can´t get CR mode to work.

    I am testing with a SITL copter flying around the tracker on a auto mission or joystick control.

    At first it works with a few degrees offset in yaw. I try different PID and PWM settings to get rid of the offset and suddenly the tracker follows the simulated copter with a huge offset (up to 180°). I change the settings back to the previous ones, but the offset remains. I switch to on/off mode and the tracker is back on target immediatly.

    I am using +/- 20us PWM for yaw and pitch speed, because my servos are really fast (50rpm max). My PID settings for on/off are:

    P: 9

    I: 4

    D: 0.05

    IMAX: 4000

    Rate: 0

    This is for yaw and pitch, because my pitch axis is balanced around the pivot point and both servos are the same.

    • I had similar results when my YAW servo was reversed. Try reversing it

  • I succeeded in getting the tracker to work via usb using a pololu controller.  I can set the ranges and offsets for both pan and tilt.  The tracker tracks my drone just fine in pan, however tilt moves to -45 and stays there for the duration of the tracking, even when I fly to altitude.

    Is there something I need to do to set my altitude so that the tilt tracking works, or something else I am missing?

    • Jon,

      If I understand correctly you are confusing AntennaTracker with tracking function built into Mission Planner. AntennaTracker is a firmware that runs on hardware (APM or Pixhawk) and is independent - it doesn't need any instance of Mission Planner to operate. Classic tracking build into Mission Planner needs an "actuator" connected via USB (for example Pololu controller).

  • Developer

    Hi all,

    i want to test my AntennaTracker with SITL and i am wondering if anybody did this successfully ?

    I have connected a second pair of 3DR radios to my computer and loaded the mavproxy tracker module.

    Started SITL (ArduCopter) and with a `tracker start` it opens the correct device, i can configure the tracker in the console.

    But it insists to track my virtual Copter. Dialing PID's down and up it at most behaved erratically shaking back/forth on yaw axis.

    I am Using a HK micro apm on the tracker and standard servos with last AntennaTracker version or even compiled from master a few weeks ago i think.

    Am i on the right track  or should i better try outdoors with a real vehicle ?



    • I used SITL a lot when I played around with firmware. I didn't use MAVProxys tracker module since it didn't work for me. Instead I just add an additional output to SITLs MAVProxy - in SITL manual search for "output add" command. That way I can feed virtual data into an actual tracker to see it in action just as Ted P described.

      Ted - if the procedure you described doesn't work for you try uploading a simple mission with takeoff command and switch it into AUTO mode. You can do it either via MAVProxy or Mission Planner provided you add an output for it (output add x.x.x.x:14550). When you have Mission Planner connected to SITL you can use it to takeoff and fly around.

      • Developer

        thanks for the hint Jakub,i tried that once but then found the tracker module.


    • It's not clear if you are using a virtual tracker or not, but for my setup I am successfully using a SITL Arduplane with a REAL tracker. Depending on your tracker configuration there might be other parameters to tweak on the TRACKER. I also think that many people make the mistake of using the tracker too close to the vehicle. If your tracker has a GPS, then it will have "noise" on it making the vehicle appear to move relative to the tracker. In the worst case condition, if your vehicle GPS is on top of your tracker GPS, you've created a "singularity" where any small noise on the GPS location can make the tracker go crazy.

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