If there is a legal custody agreement, then there should be a place on there where it says you are both responsible for reporting a change in address within 30 days of the change. If you want to have the right to know where your child is at all times, then you will have to get another court order (possibly a "rule 11 agreement") with that amendment.
But, if he has to tell you, then you will have to tell him where the baby is at all times. Seems a bit absurd - That would mean you would have to report the addresses of the stores and friend's homes you visit with your child.
If you had to do it, maybe just request that each party notify within 3 hours of knowledge, where the baby is staying if the baby is staying somewhere over-night, or past midnight.
at 9:50 PM on Dec. 4, 2010