genies, bottles & GPS

Over the past few months I’ve been idly picking my way through¬†You Are Here, a review copy of which was generously sent to me while I was still at Sunlight and in the wrong industry to review it. It’s enjoyable!

Inertial navigation — tracking position by keeping a careful tally of acceleration¬†(originally, by using gyrocopes) — is particularly badass.

giphy

This is even more amazing now that we have solid-state accelerometers in our phones and wiimotes and laptops.

The RoomScan app uses these techniques to let you build accurate models of interiors by sliding your iPhone along the wall. Using it during the home-buying process was an I’m-living-in-the-future moment. (Making light saber noises is also good.)

The two things that jumped out at me from the book were about the GPS system and the silliness of politics. First, on the popular myth that Ronald Reagan’s bold vision is the reason the military-built GPS system was opened to civilian use:

reagan_gps

And second, on the idea that Bill Clinton’s brave decision to unlock the GPS system’s full precision to civilian uses is what delivered our current era of accurately-positioned benefits:

coast_guard_gps

It turns out various other agencies were successfully building systems to defeat selective availability, too, notably including the FAA. But good for you, Coast Guard. This might have been the highest-altitude DRM system of all time, but it didn’t work any better than the rest.

Our positioning is going to get even better, incidentally. iPhone chips can already use not only GPS signals but those of GLONASS, Russia’s competing (and never-crippled) system. The EU is launching Galileo, which promises to improve accuracy even further. In fact, its (paywalled) commercial version will allegedly deliver precisions of just a few centimeters.