Network RTK and 4G: signal, subscriptions and coverage in the UK

What network RTK is

Satellite-guided robot mowers use RTK (real-time kinematic) positioning to know where they are to within a few centimetres. RTK needs a stream of correction data from a reference receiver at a known location. Traditionally that's a base station you mount in the garden. Network RTK replaces it with corrections sent over the internet from a network of permanent reference stations, so there's nothing to install except the charging station. Brands use different names for it, such as NetRTK, RTK Cloud, cloud RTK or RTKn.

National networks of reference stations already exist for surveying and mapping; in Great Britain, for example, Ordnance Survey runs OS Net. Mower makers generally don't say which correction service they use, so judge a model on the coverage it needs in your garden rather than on the network behind it.

For a wider comparison with vision and LiDAR, read RTK vs vision vs LiDAR.

How the corrections reach the mower

There are three set-ups in the UK market:

1. Built-in 4G. The mower has its own SIM and mobile connection. Most network RTK mowers work this way, including the Stiga A v range and the Navimow i2 AWD.
2. Your Wi-Fi. Husqvarna's newer V-range Automowers, such as the Husqvarna Automower Aspire R6V, get their corrections over Wi-Fi, and Husqvarna says Wi-Fi needs to cover the whole lawn. A dealer-fitted cellular kit or a base station are the alternatives if it doesn't.
3. Via the charging station or a hub. Some systems relay data through the charging station or a separate gateway rather than directly to the mower. Check the manufacturer's coverage requirements, because they differ.

Whichever route, the mower still needs a good view of the sky for the satellite part. Network RTK removes the base station, not the need for open sky; trees and tall buildings affect it just as much.

Checking coverage in your garden

Mobile coverage in UK gardens varies more than you might think. Rural areas, valleys, houses with thick stone walls and the far end of long gardens can all be patchy. Before buying a 4G-dependent mower:

• Check the official maps. Ofcom's mobile coverage checker shows predicted outdoor 4G coverage by postcode for each network. Look at all the main networks, because you may not know which one the mower's SIM uses.
• Use the manufacturer's checker if there is one. Navimow, for example, offers a postcode checker on its UK site.
• Walk the lawn with your phone. Stand at the far corners and in shaded spots, and try loading a web page. It's not a perfect test, since your network may differ from the mower's, but a dead spot for your phone is a warning sign.
• For Wi-Fi-based systems, check your signal at the furthest edge of the lawn. An outdoor access point or a mesh node near a back door or window can extend it.

Correction data doesn't need much bandwidth, so you don't need fast speeds, but the connection should be steady. Remote features such as live camera view use more data.

What happens when the signal drops

Short gaps are normal and most mowers ride them out. Longer gaps mean the corrections go stale and positioning accuracy falls. What the mower does next depends on its design:

• RTK-only mowers typically slow down, pause or head home until the fix returns.
• Hybrids that also use cameras or LiDAR can keep going on those sensors for a while. Worx, Husqvarna and Mammotion all describe their hybrid systems as carrying on through weak satellite signal.

A connection can matter even when there's a base station in the garden. Stiga's first-generation A-series comes with its own reference station, yet Stiga says the mowers can't start without their 4G link, because the corrections are relayed through its cloud. So check coverage for any mower with built-in 4G, not just those sold as network RTK.

If part of your lawn has no coverage at all, a hybrid, a base station fallback, or a different navigation type is safer.

Subscriptions and data plans

This is where the small print matters. Three questions to ask about any 4G mower:

1. How long is data included?
2. Is a paid plan required to keep mowing, or only for remote features?
3. Is the RTK correction service itself free for life?

Here's what manufacturers state for some current models:

• Mammotion YUKA mini 2: 36 months of data included; subscription required: No. Mammotion says its NetRTK service is free and 4G is optional after the included period.
• Navimow i2 AWD: 12 months included; subscription required: No.
• Stiga A v range: 120 months included; subscription required: No.
• Stiga A 4 and A 8 (older range with its own reference station): 24 months included; subscription required: Yes.
• Sunseeker X3 Gen 2: 24 months included; subscription required: Yes.
• Kress EyePilot RTKn: Kress says connectivity is included with no additional fees. It doesn't make the same statement on its older Mission RTKn pages.

Terms change, so check the manufacturer's current data terms before buying, and note the renewal price if there is one. You can add any subscription cost to our running-costs calculator to see the yearly total.

What 4G gives you besides corrections

Even where it isn't needed for mowing, 4G adds useful features: controlling the mower from anywhere, alerts if it's stuck, and GPS tracking if it's stolen. That last one is often the strongest argument for keeping a plan. See robot mower theft and security.

Older connected mowers and the 2G switch-off

Some older connected mowers use 2G mobile networks. The government says UK operators will switch off their 2G networks between 2029 and 2033. Bosch's manuals, for example, describe the cellular link in the discontinued Indego S+ and M+ as GSM (2G). If you're buying second-hand or a run-out model with a cellular module, check which network generation it uses; its remote features may stop working when 2G goes, even if the mower still mows.

If your signal isn't good enough

• Add a base station. Several brands sell an RTK base or reference station as a fallback. It needs mains power and a clear view of the sky; see RTK station accessories.
• Choose a hybrid that can navigate with cameras or LiDAR when the connection drops.
• Choose vision or LiDAR, which don't need a connection to navigate.
• Choose a wired mower. See perimeter wire vs wire-free.

For a shortlist based on your lawn and signal, use our mower finder, or browse all wire-free robot mowers.