RTK, vision or boundary wire: which guidance fits your yard

Boundary wire: old, cheap, and still the most reliable under trees

A wire pegged or buried around the lawn carries a signal the mower follows. It does not care about trees, sheds, tall fences or a neighbour's house because it needs no sky and no camera. Installation is the cost: a few hours of pegging on a simple lawn, a full day with a spade on a complex one, and a break in the wire means finding it with a detector.

Wire is the right answer for heavily wooded lots, lawns hemmed in by tall buildings, and anyone who wants the mower to work the same way in year three as in week one.

RTK: centimetre positioning from satellites, with one condition

RTK mowers use satellite positioning corrected by a small base station in your yard, giving position to a couple of centimetres. You draw the lawn in the app, the mower drives it in neat stripes, and moving a boundary takes a minute. The condition is sky view: both the mower and the base station need to see enough satellites. Dense tree canopy, a two-storey house on the south side, or a lawn tucked between buildings causes dropouts.

Manufacturers have answered with hybrid systems that switch to vision or wheel odometry when the signal drops, and some now sell a longer antenna mast for the base. Our rule: under 15 percent canopy over the lawn, RTK is the best experience available; between 15 and 35 percent, pick a model with a vision backup; over 35 percent, lean to wire or vision.

Vision: cameras that learn the edge of the grass

Camera-guided mowers recognise grass versus everything else and need neither wire nor satellites. They handle trees well and set up fastest of all. Their weak spots are edges that look like grass but are not, such as a wildflower bed or a gravel path in shade, and low light. They also tend to mow in less tidy patterns than RTK.

How the fit engine decides

The advisor measures tree cover over your lawn from imagery and weighs it against each mower's guidance. It also counts separate lawn areas: RTK and vision mowers cross between areas on their own if there is a gap, while wire mowers need a wire corridor or a hand carry. If your yard is a single open lawn with light tree cover, most systems work and the choice comes down to price; if it is shaded, split or walled in, guidance is the decision.