Long distance FPV (First Person View) flying can be a handful. Keeping a video feed alive generally requires a high gain directional antenna. Going directional creates the chore of keeping the antenna pointed at the aircraft. [Brandon’s] smart antenna tracker is designed to do all that automatically. What witchcraft is this, you ask? The answer is actually quite simple: Telemetry! Many flight control systems have an optional telemetry transmitter. [Brandon] is using the 3DRobotics APM or PixHawk systems, which use 3DR’s 915 MHz radios.
The airborne radio sends telemetry data, including aircraft latitude and longitude down to a ground station. Equipped with a receiver for this data and a GPS of its own, the smart antenna tracker knows the exact position, heading and velocity of the aircraft. Using a pan and tilt mount, the smart antenna tracker can then point the antenna directly at the airborne system. Since the FPV antenna is co-located on the pan tilt mount, it will also point at the aircraft and maintain a good video link.
One of the gotchas with a system like this is dealing with an aircraft that is flying directly overhead. The plane or rotorcraft can fly by faster than the antenna system can move. There are a few commercial systems out there that handle this by switching to a lower gain omnidirectional whip antenna when the aircraft is close in. This would be a great addition to [Brandon’s] design.