This article finally answered a question I've had for a while: how they can do decent triangulation with just two towers.

> "We said that a tower covers a radius around it. In practice, this is sub optimal so that’s not how it’s done.

> Instead, a station is usually split in 3 independent beams of 120 degrees."

So it's not the intersection of two circles anymore, it's the intersection of two arcs, which will likely only have one intersection point, unlike circles.