While on second thought, I think his question has been answered, when I first read the opening post, I read it as having trouble finding the warp gate.
To quickly center on a unit, right-click on it on the planetary summary on the right hand side of the screen. Repeat to cycle through multiple of the same unit.
I don't think this is documented anywhere and it's a feature I use all the time, so I'm mentioning it anyway.
D.