My Ardupilot Antenna Tracker


I thought, I share my antenna tracker build. It is not Navio powered (yet?), but I use it to track a Navio rover (amongst others).
The frame is made of plywood and a 125mm PVC airduct pipe (much lighter than a water channel pipe) and two matching endcaps.

The electronics:
HKpilot 2.5 with AntennaTracker firmware 0.4
Raspberry Pi B+ with MavStation image (Telemetry>Wifi bridge)
Hobbyking 433MHz telemetry radio
ImmersionRC DUO5800 v3 video receiver
FT951 video transmitter as FPV relay (soon)
Two Feetech FS5113R continouus servos
Navilock 652ETTL GPS (UBLOX6)
Two LC-filters for clean video

The HKpilot is connected to the RPi via USB and the telemetry radio to the UART2 of the HKPilot.
The tracker is able to move freely in pan direction, since no cabling is blocking its movement. You could fly circles around it all day. Tilt movement is about 250° before the antennas hit the frame, but only about 100° are needed.
The servos are able to do more than 60rpm, so I had to slow them down in the Antenna Tracker configuration.
I set both axes to +/-12us from stand still. This gives a nice smooth tracking, with only a little twitch now and then.
Operation is really simple. Power up your vehicle, wait for a GPS lock, power up the tracker and as soon as it has a GPS lock it starts tracking. Actually it even starts tracking before it has a GPS lock, using its last known position.
I use the tracker for FPV, but it could also be used to move a directional telemetry antenna (like discribed in the APM wiki) or a wifi antenna.

A few pictures:


The tracker looks great!
What is the range improvement with it?

With my previous tracker (ghettostation, antennas 180cm above ground), I was able to fly out to 750m, 50 to 100m high with clear video on 25mW. Since you are not allowed to fly beyond visual range in Germany, this is more than enough.
With my rover, I drove 350m away and still had clear video, but RC did not go any further (bad antenna placement). If you drive behind a bush or ridge, video is immediatly gone, of course.

Would be cool to use it for Wi-fi telemetry link :smile:

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I like the way you did this, the circular design is nice. It looks like those rollers provide good support and reduce slop on the pan.

How is the delay using the autopilot as the controller? I read it is one second or so?

I used the maestro servo controller method. The delay is minimal, but I haven’t measured it. For the navio I’ve got my 2.4ghz modem, filter, amp, antenna up there. It works like a champ :smile: