Measuring the Distance

HI, I'd like to measure the distance between an arduino and a moving object in a range from ~50m. The accuracy should be like 1cm or so... what possibilities do I have? Thanks in advance :) Julius

what possibilities do I have?

None other than a tape measure, unfortunately.

That's not the type of answer I was looking for :/ thtat about ultrasonic or laser or radar?

That's not the type of answer I was looking for

Of course not. Most people don't realize that this happens to be an extremely difficult problem.

In principle you might be able to use a laser range finder, but for this to work, you have to aim it at the moving object quite precisely, and the moving object has to be sufficiently reflective in the proper direction.