[sawaruna]

>Also important to remember is that GPS is not the same as location services. Even if GPS and cellular data are unavailable, a mobile device calculates location using Wi-Fi and/or BT. Apps and websites can also use other sensor data (that does not require user permission) and web browser information to obtain or infer location information.

Wondering what kind of sensory data they meant here, I had a look at the citation[0]. If anyone else is curious:

>We describe PinMe, a novel user-location mechanism that exploits non-sensory/sensory data stored on the smartphone, e.g., the environment’s air pressure and device’s timezone, along with publicly-available auxiliary information, e.g., elevation maps, to estimate the user’s location when all location services, e.g., GPS, are turned off. Unlike previously- proposed attacks, PinMe neither requires any prior knowledge about the user nor a training dataset on specific routes. We demonstrate that PinMe can accurately estimate the user’s location during four activities (walking, traveling on a train, driving, and traveling on a plane).

[0] https://arxiv.org/abs/1802.01468

[imglorp]

Microphones too. Signage and TVs etc can emit ultrasonic beacons your devices can hear, with applications like tracking your viewing habits and your location.

Ditto the proximity sensor: it's just a photocell and a simple room light could comprise a beacon. Flashing over, say 30hz would be invisible to us.

[guessbest]

A lot of the cheap wifi security cameras already use sound to transmit data such as for pairing.

https://setup.smartlink.pitneybowes.com/advancedTroubleshoot...

[ourmandave]

We demonstrate that PinMe can accurately estimate the user’s location during four activities (walking, traveling on a train, driving, and traveling on a plane).

Wonder if they can track someone who is "lost in remote area without hope of being rescued."

Maybe if the phone is set on Survival Mode?

[Nasrudith]

Even traveling on a plane has a transponder to piggy back on IIRC. Remote area implies a spotty network at best. The best that could be done is noting when and where contact with a network of some sort is lost or regained.

[thdrdt]

When you have a location you can also use the gyroscope to track where the device is going after the starting point.

Almost like a video stream. Once in a while a keyframe and a stream of changes in between.

[pbhjpbhj]

Maybe also compass and step counting (accelerometer) data?