GPS Drift Explained: Dilution of Precision

Your GPS drifting off the road isn't a glitch, it is actually a geometry problem

called Dilution of Precision. Engineers call this DOP, and it is the invisible

score deciding if your location is pinpoint accurate or total garbage. You have specific

scores for everything, like HDOP for horizontal spots and VDOP for your height. But the final boss

is GDOP. This combines your position, elevation, and even time errors

into one massive calculation. When satellites are bunched up too close,

you get Poor GDOP. Basically, if the math looks bad, your map thinks

you are driving inside a building.