follow target

[hsoltani]

I'm running falkor_ardrone package on AR.Drone 2.0. As I see, this
code can control AR.Drone to follow moving targets which its path is
straight forward. So if the target move to left or right side or
rotate, the Drone can't follow it and move relative to its path. Is it
right? If yes, what should I do to append this ability to your code?
Do you have any reference or some pointers that can help me? I
couldn't find any reference that explain your algorithm.
Hope you can help me.