My crazy iPhone GPS

This post goes into the category of “curiosity-inducing but not critically important.”

I’ve been noticing a strange behavior with my phone’s GPS. It’s an iPhone 4 on AT&T wireless. Sometimes when I land after a flight, the phone thinks I’m at a totally different airport.

The first time this happened to me, I landed in Memphis and the phone said I was in Detroit. At the airport. Then it thought I was in Minneapolis. At the airport. About 15 minutes later, the phone finally figured out where I was physically located.

This strange bug has become consistent – I land in Philadelphia, the phone’s in Atlanta. Austin shows Los Angeles. Minneapolis, Detroit. Tonight in Detroit, I was accurately located while in the terminal but pinpointed moments later in Newark once I had boarded the plane.

The only time this happened outside of an airport was during Austin City Limits at Zilker Park (Austin, TX), when I was supposedly in Arthur Ashe Stadium in Flushing, NY.

I understand that the iPhone uses A-GPS which accounts for some of the discrepancy. But what’s in the nature of  airport-based networks where the inaccurate location gets fixes on other airports (instead of coffee shops or football stadiums)? And the strange DTW-to-EWR shift from terminal to tarmac?

Has this happened to you? And / or can you explain why? I’ve asked AT&T for help via Twitter but they were not able to help. Do you know a network engineer who might know the answer?

Tweet