RTK vs LiDAR Robot Lawn Mowers

RTK and LiDAR are often presented as competing answers to the same question. They are not really competing at all — they answer two different questions, and the better one depends entirely on what your garden looks like.

What each one actually does

RTK stands for Real-Time Kinematic positioning. The mower receives satellite signals, as any navigation device does, but it also receives a correction stream from a reference station that knows exactly where it is standing. That station measures the current error in the satellite signal and the mower subtracts it, giving positioning accurate to a few centimetres instead of a few metres.

The station can be a small antenna fixed on your own property, or it can be part of a permanent network reached over a mobile data connection — "Network RTK", which puts nothing in your garden at all. Both kinds are on this site: Segway Navimow models use the network kind, while the Mammotion Luba 2 AWD series includes its own reference station.

LiDAR does not care about satellites. A laser scanner sweeps the surroundings many times a second and measures how long the light takes to return, building a live three-dimensional map of what is actually around the mower — fences, walls, trees, furniture, the shape of the garden itself.

The distinction in one line: RTK tells the mower where it is. LiDAR tells the mower what is around it.

Where RTK is strong

On an open lawn with a clear view of the sky, RTK is excellent. Knowing its position to a few centimetres lets a mower cut in tidy parallel lines rather than wandering randomly, which means it covers the lawn faster, with less repetition and less wear on the grass.

It also makes virtual boundaries genuinely practical. You can draw a no-go zone around a flower bed in an app and expect the mower to respect it closely.

Where RTK struggles

Anything between the mower and the sky weakens the signal: mature trees, a tall hedge, the side of a house, a narrow passage between two buildings.

When the correction is lost, an RTK mower typically slows down, pauses, or reverts to a less accurate mode until reception recovers. In a garden with one large tree this is a minor annoyance. In a garden with a dozen, it can mean the mower spends much of its time waiting.

Where a model uses a local reference antenna, it also has to go somewhere with a clear view — usually a roof, a wall or a post — and that is not always convenient. Network RTK avoids that entirely, but depends instead on mobile coverage at the garden.

Where LiDAR is strong

LiDAR is unaffected by tree cover, because it never looks up. Under a canopy that would stop an RTK mower, a LiDAR mower simply carries on.

It is also inherently good at obstacles. A system that is already building a map of its surroundings can see the garden chair you left out and drive around it, rather than bumping into it and turning away.

Where LiDAR struggles

LiDAR needs features to navigate by. A very large, very open, very flat lawn with few landmarks gives it comparatively little to work with — the opposite of the situation RTK likes.

It is also generally the more expensive technology, and heavy rain, fog or snow can scatter the laser light and reduce reliability.

Why many mowers now use both

Once you see that the two systems fail in opposite circumstances, combining them is the obvious move. A mower with both can navigate by satellite across the open middle of a lawn and switch to its own sensing under the trees at the edge.

If your garden is mixed — some open lawn, some tree cover — a combined system is usually the more robust answer, and it is worth paying attention to whether a model genuinely has both or simply mentions both in its marketing.

Choosing between them

• Open lawn, clear sky, want tidy lines — RTK is a strong fit.
• Mature trees, tall buildings, narrow shaded areas — LiDAR, or a combined system.
• Mixed garden — combined, if the budget allows.
• Small, simple, heavily shaded lawn — do not rule out a boundary wire. It is unglamorous, but it is entirely immune to the problem that defeats RTK.

What to check before you buy

• Does the model confirm which technologies it actually uses, or just imply them?
• If it uses RTK, is the correction from a network service or from an antenna you must mount — and if the latter, where would it go?
• How does the model behave when the signal is lost — does it stop, or fall back to another system?
• If the garden is heavily shaded, has the manufacturer said anything specific about tree cover?