Even older cell phones know where you are

In the movies, the Good Guys can the location of someone’s cell phone just by punching their number into a computer. Up pops a map with a blinking dot.

You’re expecting me to say that “In the real world it doesn’t work like that.”

Actually, it does.

I was chatting with John Johnson, director of corporate communications for Verizon Wireless, about the Migo phone. It’s designed for kids, with only four buttons (you can only call four numbers, plus 911). The new version adds a “chaperon” feature: If the kid strays from a certain area, the parents are alerted.

You might think this is done strictly with the GPS chips that are in most modern phones. But Verizon Wireless doesn’t just use that — after all, GPS requires a clear view of the sky, and people aren’t always out in the open.

Instead, VZW supplements GPS with AFLT: Advanced Forward Link Trilateration. By computing the signal strength between a phone and a couple of cell towers (that’s right, a couple — it doesn’t need three), the system can get a general location of a phone. Granted, it won’t work for geocaching, but if your kid goes missing, locating him within a couple of hundred feet is darned good enough.

So I asked Johnson if this kind of technology could be used as a “poor man’s Lojack” — that is, a locater for stolen cars.

(I had thought it required GPS. In fact, in January, when a car was stolen with a baby in the back seat, Sprint refused to help police locate it despite (the news reports said) the phone’s having a GPS receiver.)

Yes, said Johnson, it could be used to locate a person or a car, although he didn’t know offhand if it had ever been done. Next question: Would the technology work with any phone, or would it need to be specially equipped with AFLT technology? Any phone, Johnson said.

So, while TV and the movies generally play fast and loose with the capabilities of technology, in this case they’ve actually got it right.