The boundary wire is finally gone

For twenty years, buying a robot mower meant buying an afternoon with a spade. Two hundred metres of wire around the lawn, around the beds, around the pond, buried deep enough to survive the scarifier and shallow enough to be findable when a mole cut it.

RTK satellite positioning has ended that. A base station on the house corrects the satellite signal to about two centimetres, which is accurate enough to define a lawn by walking its edge once and then drawing the rest on a phone. Beds, trees and the trampoline become no-go zones you can move in seconds when the trampoline moves.

The mowing changes as well. A wire-guided mower bounces around at random and hopes to cover the lawn eventually. A machine that knows where it is mows in parallel lines, which cuts the running time roughly in half and leaves the stripes people actually want.

Two caveats worth knowing before you buy. RTK needs a view of the sky, so a garden under heavy tree cover can still confuse it - most manufacturers now pair it with vision or wheel odometry for exactly that reason. And an obstacle sensor is not a substitute for supervision: hedgehogs are nocturnal, so keep the schedule to daylight.