How to find under slab drain pipe?

I want to install a kitchen sink in my basement. Rough-in plumbing was installed when house was built so I know there is a drain line under the slab, but is there a way to find it? Or do I have to take educated guesses with a jackhammer.

Greg

There are companies which put inspection cameras into your drain pipes. The camera module has a locator transmitter on it, and they have a scanner which will locate the beacon. You could map the pipe run this way.

It might come to that but I would prefer something that I might do myself. Just to get me to within a foot to a foot and a half. Then I can see how much concrete I will need to bust out and if it's worth the work or to just scuttle the idea.