Car constantly chirps when off, parked, locked

What is your question?

A beeping noise approx every minute (sounds sort of like the chirp that sounds when you hit the lock fob) comes from the car. All lights off, doors closed, no indication on dashboard of any issue. A neighbor has complained, and I worry about the battery. It goes on apparently all day. No other issues apparent with the car. Could a recently replaced battery be related? Any other ideas? Been going for 2 weeks now that I've noticed, but I dont hang out with the parked car a lot so could be longer.

How long has your 2003 Toyota Camry had this problem?

At least 2 weeks