4:30 a.m. EST December 25, 2014  PETERSON AIR FORCE BASE, Colo. — The constant ringing of phones sounding like so many jingles of bells can mean only one thing: Santa is on his way.

Thousands of phone calls are pouring into NORAD Tracks Santa headquarters at this Colorado Air Force base as volunteers chart his progress around the globe.

Last year, trackers fielded more than 170,000 calls from around the world in this annual tradition.

"Where are you? Oh, Oklahoma? Well, Santa is coming your way between 9 and midnight tonight — as long as you're all asleep," volunteer Wendy Erlanger tells a young caller.

"This is a hoot," says Erlanger after hanging up. "This is a story we will always be able to tell."

About 1,300 volunteers like Erlanger and her kids are fielding calls and e–mails on Christmas Eve. The tracker is a longstanding tradition at the North American Aerospace Defense Command, which is a joint U.S.-Canadian military operation.

No taxpayer money supports the tracker, and private companies provide volunteers and funding to maintain the tradition. Christmas Eve day, Santa had been spotted over Indonesia, Islamabad and Kabul.

As technology has improved, so has the tracker, which one was nothing more complicated than a map hung on the wall. Today, the tracker available online shows Santa's exact GPS coordinates and his current present-delivery count.