[Cryptography] Intel Management Engine pwnd

[Henry Baker]

At 05:39 PM 11/29/2017, Ryan Carboni wrote:
>(bafflingly, the iphone compass app requires a barometer to determine altitude when GPS is three-dimensional)

Barometers I know something about.

The reason for barometers is for precision altitude calculations.  It turns out that GPS is not particularly precise when it comes to altitudes, unless you average over a large number of readings and satellites.

So you use the GPS to *calibrate* the barometer, and then use the barometer for precision altitude measurements.

Airplanes use barometers (suitably calibrated) for altimeters, as do many sports watches.  A Garmin bike computer, for example, can easily handle rises and falls of just a few feet (i.e., the distance between your feet and your head), which is a precision not possible using just an unaided GPS.

I don't see barometers being obsoleted by GPS anytime in the next 50 years -- they're simply too cheap and too reliable not to use them.