Robot lawn mowers: what wire-free navigation actually changed

For twenty years a robot mower meant a boundary wire pegged around every bed, tree and path, and a spring spent finding the break that stopped the machine leaving its dock. Wire-free navigation has become the default selling point of new models, and the installation genuinely is shorter. What changed is which part of the garden decides whether the machine works.

The three navigation systems on sale

• Boundary wire: a buried or pegged perimeter loop the mower senses. Unaffected by tree cover or weather, but physically laid once and repaired by hand.
• RTK satellite: a fixed reference antenna corrects the mower's satellite position to centimetre accuracy. No wire, but the antenna and the mower both need sky visibility.
• Camera vision: on-board cameras read grass edges and obstacles. No wire and no antenna, but performance depends on light, contrast and how clearly the lawn edge is defined.

The practical consequence is that garden shape now selects the technology. An open suburban lawn suits RTK. A garden under mature trees, or one broken up by a house wall on two sides, will lose the satellite correction exactly where the machine is hardest to retrieve — and a wired install remains the reliable answer there.