Todd Humphreys: Will GPS Change Our Standards for Privacy? GPS expert Todd Humphreys says the future of geolocation will change the way we think of privacy.

Will GPS Change Our Standards for Privacy?

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It's the TED Radio Hour from NPR. I'm Guy Raz. And today's show is all about predicting the future. So GPS, pretty amazing, right? It's totally changed road trips forever. But for our next guest, GPS is a lot more than that. It's about the future of privacy, which as you will hear, may not exist.

TODD HUMPHREYS: I'm Todd Humphreys. I'm an aerospace engineering professor at the University of Texas at Austin and the director of the Radionavigation Laboratory here at UT.

RAZ: I mean, you're a GPS guy.

HUMPHREYS: That's right.

RAZ: Do you ever use paper maps?

HUMPHREYS: I love paper maps.

RAZ: But do you use them?

HUMPHREYS: I still use them.

RAZ: Do you use them, really?

HUMPHREYS: Of course. I don't think that's going to go away anytime soon for me personally, but I see it going away for the community at large pretty fast.

RAZ: To understand what got us here, why paper maps have become virtually extinct, you have to back to May 2, 2000.

HUMPHREYS: And that was the day that ushered in this explosion of applications of GPS.

RAZ: And that just happened, like that.

HUMPHREYS: It was. It was magical.


UNIDENTIFIED REPORTER: Officials at the White House today announced that civilians will be able to find their way in the world a bit more easily after tonight.


HUMPHREYS: The change was silent, imperceptible, unless you knew exactly what to look for. U.S. president Bill Clinton ordered that a special switch be thrown in the orbiting satellites of the global positioning system. Instantaneously, every civilian GPS receiver around the globe went from errors the size of a football field to errors the size of a small room. It's hard to overstate the effect that this change in accuracy has had on us. Before this switch was thrown, we didn't have in-car navigation systems giving turn-by-turn directions because back then GPS couldn't tell you what block you were on, let alone what street. This level of accuracy has unleashed a firestorm of innovation. The holy grail, of course, is the GPS dot. Do you remember the movie "The Da Vinci Code?" Here's Professor Langdon examining a GPS dot, which his accomplice tells him is a tracking device accurate within two feet anywhere on the globe.

But we know that in the world of nonfiction the GPS dot is impossible, right? For one thing, GPS doesn't work indoors, and for another, they don't make devices quite this small, especially when those devices have to relay their measurements back over a network. Well, these objections were perfectly reasonable a few years ago, but things have changed. There's been a strong trend toward miniaturization, better sensitivity. Compare that with the device released just months ago that's now packaged into something the size of a key fob. Imagine what we could do with a world full of GPS dots. It's not just that you'll never lose your wallet or your keys anymore, or your child when you're at Disneyland; you'll buy GPS dots in bulk and you'll stick them on everything you own worth more than a few tens of dollars.

RAZ: So this is something that is just going to be normal, like, who knows, 10, 5, 10, 20 years from now. We just - we won't lose anything anymore.

HUMPHREYS: That's right. I see this as moving what we are accustomed to in the cyber world into the physical world. We'll be able to search our possessions just as we search e-mails and pull up something that's old and still useful and figure out where it was.

RAZ: So this is incredible. I mean, I can't see why I wouldn't - actually, you know what? I can see some reasons why I wouldn't want it now that I think about it. There are lots of reasons why you wouldn't want it.

HUMPHREYS: Well, that's what I call the flipside. As soon as you try to extract utility from knowing exactly where you are or where your things are, you're giving away a lot about who you are and where you travel. But this is just a symptom of our connected world. And when we want somebody to predict our actions so that it can be useful for us, you know, tell us when the traffic's going to be high or when we can expect rain in a certain area, we want those predictors to know our patterns. But what's more private than our exact location? That's about as private as it gets.

RAZ: Can you imagine a future in which governments - our government - could easily track us and make it a regular thing that it does?

HUMPHREYS: You know, what's most interesting in the aftermath of the Edward Snowden revelations is that the metadata that the government requested from Verizon did include position data, but the government didn't make any use of it. Even though they admitted, legally, they could have. And for me, that's not much of a barrier to them going ahead and making use of our position data. I see this as - if not a foregone conclusion - it's going to be an irresistible temptation for the government to find out where we are and what we were doing. We are selling our privacy for convenience. And everyone is doing this every day a little bit more, a little bit more. If at one moment you wake up and you're wanting to reclaim your privacy, you'll have to do that by relinquishing a lot of conveniences you've come to depend on.

RAZ: In your TED Talk, you mentioned something called a GPS spoofer.

HUMPHREYS: That's right.

RAZ: Which could do serious damage.


HUMPHREYS: The idea behind the GPS spoofer is simple. Instead of jamming the GPS signals, you imitate them. And if you do it right, the device you're attacking doesn't even know it's being spoofed. Up until very recently, nobody worried about GPS spoofers. People figured that it would be too complex or too expensive for some hacker to build one. But I and a friend of mine from graduate school, we didn't see it that way. And we wanted to be the first to build one, so we could get out in front of the problem and help protect against GPS spoofing. Now the Dr. Frankenstein moment, when the spoofer finally came alive and I glimpsed its awful potential, came late one night when I tested the spoofer against my iPhone. And this little blue dot started at my house and went running off toward the north leaving me behind. I wasn't moving. What I then saw in this little moving blue dot was the potential for chaos. I saw airplanes and ships veering off course with the captain learning only too late that something was wrong. I saw the GPS derived timing of the New York Stock Exchange being manipulated by hackers. You can scarcely imagine the kind of havoc you could cause if you knew what you were doing with a GPS spoofer.

RAZ: This is, like, a crazy, like, disaster movie.

HUMPHREYS: It was for me too that night. And the truth is that in the year that's passed since that TED Talk, there's been nothing to dissuade me from seeing that as a potentially awful future where we can't trust the devices that are telling us where we are. Within the next few years, many of you will be the proud owner of a GPS dot. The GPS dot will fundamentally reorder your life, but will you be able to resist the temptation to track your fellow man? Or will you be able to resist the temptation to turn on a GPS spoofer to protect your own privacy? What we see just beyond the horizon is full of promise and peril. It'll be fascinating to see how this all turns out. Thanks.


RAZ: Todd Humphreys is a professor at UT Austin. Check out his whole talk at

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