[jacquesm]

Oh, that's really nice. So if you have a fix (and even if you don't) you can use dead reckoning and tie any points where the GPS is accessible and then re-create the path the phone took. That's a bit of a leak. Wonder how long after or before a GPS fix this would be effective, those phone accelerometers probably aren't all that accurate but you might be able to calibrate the one in a specific phone if you have data available for both of them for some stretch of trajectory.

[fest]

Even using calibrated and temperature controlled consumer level accel/gyro sensors for dead reckoning results in estimated velocity error reaching few meters/s in a second or two.

Current consumer level sensor quality is enough for: a) attitude estimation; b) smooth interpolation between GPS updates if they arrive often enough;

[hueving]

IIRC the accelerometers are way to imprecise to correctly detect starts and stops. Errors compound so quickly that any kind of useful accuracy for dead reckoning is a long ways out.

[jacquesm]

For once a bad sensor is good news.

[throwahey]

More proof that Javascript and HTML5 are cancer for privacy on the internet