varmint said:
This approach is why I would never buy a Flytrex. It's a waste of weight and money to fly something on the Phantom, when you can simply read it from the ground courtesy of DJI, for free.
This also means Flytrex will need to change their model to a software solution or they're going to die on the vine because of the SDK. There is no point in flying expensive, heavy telemetry hardware once some apps start popping up. These apps can just as easily (if not more), upload live telemetry to any server in the world, and could even steam live flight video.
Until your Phantom goes out of WiFi range, then you can forget all the telemetry. No data anymore for pointing the antenna...
At least Flytrex 3G provides you with a separate channel(GSM network) to your Phantom which does not depend on distance from you. And therefore actually, data provided from the Flytrex system could be much easier used for the tracking system!
Admittedly I never looked into this antenna tracking problem before, but I would try something like the following.
Range extender that sits on your remote has OpenWRT software running and therefore it is easy to get WiFi signal strength from it. I would put that extender unit separately from the remote, on the tripod with servos for pointing the antenna. The Arduino board(or Raspberry Pi) that controls the servos would have a wifi module and would also connect to the range extender(your phone/tablet is already connected to it, there is nothing preventing multiple connections). I would make a program to get WiFi signal strength from OpenWRT on the extender and I would make the servos constantly move left,right,up,down by small amount, monitoring if with each move the signal gets better or worse. If it is better I would stay a that new position, if it is worse I would move to the old position. This would be a continuous loop.
As for your control signal from the RC(the 5.8GHz one) I would simply look at what direction the WiFi antenna is pointing and manually point/orient the RC antenna in the same direction.
The SDK idea is fine, but only good untill you have steady WiFi connection. As soon as that connection breaks, anything can happen and you can easily lose your Phantom. Also the SDK is actually(at this point) at a bit high level(in a bad way). That means there is no fiddling with low level stuff for configuration. For example you can't change the WiFi network setup(how it connects, IP addresses and similar stuff), that means when you connect to your Phantom you lose any internet connectivity. No possibility for streaming any info on the net. That is why Flytrex still has a coolness factor to it, because it can do that.