[c22]

You could use some smart heuristics to make corrections without a gps lock, like resetting the location to "home" if it is near enough and sits motionless over night, or making an adjustment whenever the location drifts too far from the known locations of currently connected cell towers.

[maym86]

You won't get close to GPS accuracy with these. The uncertainty from cell tower triangulation is huge (relatively). But yes, some kind of beacon that works like GPS on a local scale or detection of known mapped landmarks could be used for corrections but there are issues with these too. These could assist GPS location rather than replace it entirely.

[c22]

> These could assist GPS location rather than replace it entirely.

Of course, that was the proposal. There's more datapoints if you're willing to get creative, wifi networks (already used for this), cooperative comparison with other mobile devices in a local meshnet, acoustic cues from the environment, machine analysis of captured images, etc. Obviously dead reckoning without gps is going to require a multi-pronged approach.

[maym86]

> cooperative comparison with other mobile devices in a local meshnet

Please explain how this will work?

[natosaichek]

I could imagine a secure location service that allows your phone to compare its current expected position with other nearby phones' expectations of their positions. If it's over bluetooth or wifi, the positions should be within meters of each other. This could provide an input to a kalmann filter type position estimator to help reduce drift as you (for example) walk down the street.

[maym86]

This doesn't make a lot of sense tbh.

[natosaichek]

What do you mean?

You don't think such a system is practical, or you don't think such a system is technologically feasible?

Or you just don't understand the system I'm describing?