Why does the mocked point jitter slightly and drift off the route?

Question

Accepted Answer

That is intentional: a real GPS is never perfectly still, and a point that moves exactly along the line looks artificial. In other apps it smoothly drifts a meter or two off the route and comes back; the map in Mock Location itself draws it exactly on the line.

The drift is smooth, not jerky: the point slowly “floats” aside over a couple of seconds and comes back, like with a real receiver. The heading wobbles slightly, and the reported accuracy changes within 1–2.5 m. A point standing still jitters slightly too. With the “City GPS accuracy” route option, episodes of poor reception take the point several meters away.

With Premium this is adjusted in the “GPS realism” section: the “Perfect accuracy” profile keeps the point exactly on the line and holds it still, while “Weak signal”, on the contrary, increases the jitter. Details are in the guide on GPS realism.