turret for a quad robot

I have a problem to position the turret of my robot. I use a continuous 360 servo. I would like to position the servo for an angle between 0 and 180 degree. The goal is to have a kind of radar to detect the obstacle. So the turret should go on the left and on the right continuously.

At the beginning with a 360 servo, I get the good positions for my servo but after some time it is become difficult to know exactly the position of the servo.

So I plan to buy and use a servo with a limit angle to 180. But I would like to know if I will get the same problem? How I will know the position after many movement of the turret? Do you think I will lose some precision?

AFAIK, with the ones limited to 180 you tell them where they should be and they go there. So if you tell it to go to 45 degrees then it will work out how far to move in what direction by its self.

Makes it slightly easier dont you think? ;)

Ok if I want the servo goes to -90 to 90. It is should be easy. But what happend if I want my servo goes from -45 to 45 and 45 to -45 many time (during one hour) ? After few minuits the servo starts to go more one left ou on the right... Do you think there is a way to recalibrate the servo ?

AFAIK, with the ones limited to 180 you tell them where they should be and they go there. So if you tell it to go to 45 degrees then it will work out how far to move in what direction by its self.

Makes it slightly easier dont you think? ;)

Ok I get your point. Servo 360 doesn't work the same a servo with limited angle. Thank you very much.