[bsder]

And yet, funnily enough, your phone needs a more thorough understanding of gravity than you do. The GPS system must correct for relativistic effects that cause the atomic clocks to shift relative to ground.

[saagarjha]

Isn’t this corrected by the satellites themselves?

[bsder]

Mostly, but there are still correlations between the satellites that are corrected by the receiver.

The Earth's gravity field is not deterministic.