I've been developing on an Antenna Tracker based around my Ardupilot Mega V1 for the last few months and am just about to start on Mk 2.
The tracker is able to rotate continuosuly in azimuth. I wanted this feature so the tracker can be used for close range flying with low power transmitters.
The telemetry on the prototype is acquired from the Ardupilot using Mavlink in exactly the same way as done by Minimosd. Hopefully will also be compatible with PX4 too. The data is then sent down the FrSky telemetry link. I also have in development alternatives to send the data down the video or audio link, and one that attaches direct to a GPS, but am currently concentrating on the hardware side.
The brains on the ground is an STM32F4 Discovery board. Its cheaper than an Arduino and much more powerful. On the airborne side I use an Arduino Pro Mini.
Heres a video of V1 in action. (I am workin on V2 but this time am planning to make it look a bit smarter!)
There is more information about the tracker on my website at