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Yard Robot Glossary
Robot marketing runs on acronyms. Every technical term used anywhere on this site is defined here — spelled out, explained in plain English, and translated into what it actually means for your yard and your wallet.
Jump to: RTK · NetRTK · RTK Cloud · GNSS · GPS · LiDAR · SLAM · VSLAM · VIO · ToF · EPOS · AWD · GPH · IPX ratings · OTA updates · TOPS · No-go zone · Boundary wire · Mowing patterns · Reference station · Virtual boundary · IMU · Ah & Wh · dBA · Micron
RTK — Real-Time Kinematic
A way of supercharging satellite positioning. Plain satellite signals are only accurate to within a few yards; RTK adds a live correction stream that tightens accuracy to about an inch (a couple of centimeters).
What it means for you: RTK is how a mower cuts in straight, even rows and stops at your flower bed instead of in it. Traditional RTK needs a reference station in your yard — the newer network versions (below) don't.
NetRTK — Network RTK
Mammotion's name for RTK corrections delivered over the internet — via the mower's 4G (cellular) connection or Wi-Fi — from a network of fixed stations, instead of from a base station in your yard. Mammotion's service is called iNavi.
What it means for you: no antenna to install, but the mower depends on cellular or Wi-Fi coverage to stay inch-accurate. On the Luba 3 models that use it (3000 and up), Mammotion made the service free for the life of the mower.
RTK Cloud
Worx's name for the same idea as NetRTK: RTK (Real-Time Kinematic) correction data streamed from Worx's own network of reference stations over the internet, with no antenna installed at your home. Worx says the service is free for the life of the mower.
What it means for you: wire-free and antenna-free setup — but check that Worx actually has correction coverage at your address before buying, especially in rural areas.
GNSS — Global Navigation Satellite System
The umbrella term for all satellite positioning systems: GPS (American), Galileo (European), GLONASS (Russian), and BeiDou (Chinese). A "GNSS receiver" listens to several systems at once.
What it means for you: more satellite systems = more satellites overhead = better odds of holding a position fix. It helps at the edges of tree cover; it does not make satellites work under a dense canopy — nothing does.
GPS — Global Positioning System
The original American satellite navigation system. In everyday speech (and most marketing), "GPS" is used loosely to mean any satellite positioning, including the wider GNSS (Global Navigation Satellite System) family.
What it means for you: when a mower box says "GPS," read it as "satellite positioning" — and look for whether it's corrected by RTK (inch-accurate) or raw (yard-accurate, too sloppy to mow in rows).
LiDAR — Light Detection and Ranging
A sensor that spins (or sweeps) laser pulses and times their reflections to build a live 3D map of everything around it — trees, fences, furniture, people.
What it means for you: LiDAR mowers navigate the way you do — by seeing the yard. They work in the dark, under tree canopy, and anywhere else satellites can't reach. If your yard is heavily wooded, LiDAR is the technology that matters most.
SLAM — Simultaneous Localization and Mapping
The software trick of building a map of a place while simultaneously figuring out where you are inside that map. It's how a robot learns a new yard without being told where anything is.
What it means for you: SLAM is the engine inside LiDAR and camera mowers' "auto-mapping" features — the robot explores, builds the map, and then mows against it.
VSLAM — Visual SLAM
SLAM (Simultaneous Localization and Mapping) done with cameras instead of — or alongside — lasers. The robot recognizes landmarks visually and tracks its position against them.
What it means for you: camera-based positioning keeps working in shade and under light tree cover where satellite signals fade. It needs light, though — pure camera systems weaken at dusk and in the dark.
VIO — Visual-Inertial Odometry
Fusing camera images with motion-sensor data to track exactly how the robot has moved, step by step, between position fixes from other sensors.
What it means for you: VIO is the bridge across dropouts. When the satellite signal blinks out under a tree or beside the house, VIO keeps the mower on its line until the signal returns.
ToF — Time of Flight
A distance sensor that measures how long a pulse of light takes to bounce off an object and return. The ECOVACS GOAT's forward 3D ToF sensor is its close-range "eyes" for obstacles directly ahead.
What it means for you: precise, fast obstacle detection at close range — the sensor that stops the mower for the toy, the pet, or the garden hose right in front of it.
EPOS — Exact Positioning Operating System
Husqvarna's brand name for its satellite positioning system — its version of RTK (Real-Time Kinematic). Boundaries are drawn virtually in the Automower Connect app, and correction data is delivered free via the Husqvarna Cloud over cellular.
What it means for you: no boundary wire on a Husqvarna — as long as your yard has decent sky view and cellular coverage. Where it doesn't, Husqvarna sells an optional reference station (the RS1) to fill the gap, at extra cost.
AWD — All-Wheel Drive
Every wheel on the machine is powered. On four-wheeled mowers you'll also see it sold as 4WD (four-wheel drive) — in this category they mean the same practical thing: all four wheels pulling.
What it means for you: traction. An AWD mower climbs slopes and powers through rough, uneven ground that would leave a two-wheel-drive mower spinning its wheels and sending you a "come rescue me" alert.
GPH — Gallons Per Hour
For pool cleaners: how much water the machine pumps through its filter every hour — a measure of suction strength and cleaning speed.
What it means for you: higher GPH generally means stronger pickup of leaves and debris. But GPH says nothing about filter fineness — a high-GPH cleaner with a coarse filter can stir up fine dust instead of catching it. Read GPH and micron rating together.
IPX ratings — Ingress Protection (water resistance)
A standardized water-resistance score. IPX6 means the machine shrugs off powerful water jets — you can hose it down and it can sit out in the rain. IPX4 means splash-resistant only. The number after "IPX" is the protection level; higher is tougher.
What it means for you: IPX6 on a mower means "hose it off, leave it out in a storm, don't worry." It does not mean submersible — never dunk a mower. (Pool cleaners are the exception: they're built to go underwater, and their specs say so explicitly.)
OTA updates — Over-The-Air updates
Software updates delivered wirelessly (Wi-Fi) to the robot — no cable, no dealer visit. Mowers, like phones, get new features and bug fixes this way.
What it means for you: your robot can genuinely get better after you buy it — and occasionally get a buggy update. It's also why "the app and software at launch" isn't the whole ownership story.
TOPS — Tera Operations Per Second
Trillions of calculations per second — a measure of how much raw computing muscle a robot's AI (artificial intelligence) chip has. The Luba 3's chip is rated at 10 TOPS.
What it means for you: mostly a spec-sheet number. More TOPS can mean faster obstacle recognition, but what matters is whether the mower actually avoids the hose in your yard — judge that from owner reports, not the chip rating.
No-go zone
A keep-out area you draw on the map in the mower's app — around flower beds, a fire pit, a septic lid, the kids' sandbox. The mower treats it as if a fence were there.
What it means for you: the digital replacement for physically fencing things off. Draw them generously — a few inches of buffer beats fishing the mower out of the mulch.
Boundary wire
The cable that older robot mowers require you to bury or peg around the edge of your lawn (plus a guide wire back to the dock). The mower senses the signal in the wire and stays inside it.
What it means for you: it's the chore the entire wire-free generation exists to eliminate: hours of installation, and a dead mower whenever an aerator, shovel, or frost heave breaks the wire. If a product still needs one, that's last-generation technology.
Mowing patterns — systematic vs. random
Systematic mowing means planned, parallel passes — stripes, checkerboard, triangles — like a person mowing carefully. Random mowing means the mower bounces around the yard at angles, pinball-style, and relies on enough hours to eventually cover everything.
What it means for you: systematic looks better and finishes faster, but it demands precise positioning (RTK, LiDAR, or both). Random is simple and forgiving but slower to full coverage and leaves a less uniform finish. Every flagship we cover mows systematically.
Reference station (base station)
A fixed antenna unit installed at your home that receives satellite signals and radios RTK (Real-Time Kinematic) corrections to the mower. Older RTK mowers included one in the box, and you had to find it a spot with open sky.
What it means for you: extra hardware to site, mount, and power. Network RTK designs (NetRTK, RTK Cloud) exist specifically to eliminate it — a reference station is now mostly a fallback for properties with poor coverage.
Virtual boundary
The edge of the mowing area, drawn on a map in the app instead of marked by a physical wire in the ground. The mower holds the line using its positioning system.
What it means for you: rearrange the garden by editing a map, not re-digging a cable. The trade-off: the boundary is only as reliable as the positioning behind it — satellite-based virtual boundaries can drift or drop out under heavy tree cover.
IMU — Inertial Measurement Unit
A cluster of motion sensors (accelerometers and gyroscopes) that feel acceleration, tilt, and rotation — the robot's inner ear.
What it means for you: the IMU feeds VIO (visual-inertial odometry) tracking, helps the robot sense slopes and bumps, and notices if it's been picked up — part of theft and safety systems.
Ah & Wh — Amp-hours & Watt-hours
The two ways battery size is quoted. Amp-hours (Ah) measure charge; watt-hours (Wh) measure total energy. Wh = Ah × voltage, so a 5 Ah battery at 32 volts (160 Wh) stores more energy than a 5 Ah battery at 20 volts (100 Wh).
What it means for you: compare Wh, not Ah, when brands use different voltages — otherwise you're comparing apples to oranges. Bigger Wh generally means longer runtime between charges.
dBA — A-weighted Decibels
Loudness measured the way human ears perceive it. Rough anchors: 60 dBA is conversation level; 80+ dBA is loud-power-tool territory.
What it means for you: a mower at ~62 dBA is neighbor-friendly at any hour. Watch for add-ons that break the peace — the GOAT A3000's edge trimmer runs ~82 dBA even though the mower itself is quiet.
Micron (µm)
A millionth of a meter — the unit for filter fineness, mostly on pool cleaners. The smaller the micron number, the finer the particles the filter can trap. A 150 µm mesh stops leaves and bugs but lets fine dust and pollen straight through.
What it means for you: if your pool problem is fine dust, silt, or pollen, the micron rating matters more than suction (GPH — gallons per hour). Pleated cartridge filters beat flat mesh here.
Missing a term? If a review anywhere on this site uses a word that isn't defined here, that's a bug, not a feature. The reviews are a good place to start: the five-flagship mower comparison or the pool cleaner comparison.