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An RTK robot mower steers by navigation satellites — and holds a position to about an inch by doing it. This is that sky, live. Tap for your own location, then drag the slider to watch it change across the next 24 hours.
✓ Nothing saved ✓ No account ✓ Public orbit data, computed on your device
Live positions from public CelesTrak orbits, computed in your browser.
The dial is the sky drawn the way an antenna sees it: the centre is straight up, the outer ring is the horizon, and every dot is a real navigation satellite plotted by its compass direction and how high it sits. The colours are the four systems your mower tracks at once — GPS (United States), Galileo (Europe), GLONASS (Russia) and BeiDou (China).
Tracking four constellations instead of one is why a robot mower can lose a dozen satellites behind a tree line and still know exactly where it is. Satellites below about 10° of elevation are left out of the count, because a signal that shallow has crossed too much atmosphere and bounced off too much ground to be worth trusting — the same rule the receiver on a mower applies.
Plain GPS is accurate to a few metres, which would put a mower in the flower bed. RTK fixes that with a second receiver: an antenna somewhere fixed on your house that knows precisely where it is, watches the same satellites, measures how wrong they're reading right now, and streams that correction to the mower continuously. The shared error cancels and the mower lands on about an inch.
Which means the sky matters twice — both receivers need the same satellites at the same time. A mower with a clear view and an antenna tucked under an eave is a mower with no fix. A base antenna reaches roughly 600 ft with clear line of sight and about 300 ft through trees and buildings; past that an extension antenna adds around 600 ft and lifts the signal above whatever is in the way.
The sky above you is the same for your whole town, and it's free to work out — that's this page. What it can't see is what's around you: your maple, your roof line, the neighbour's garage. That half is specific to your yard, it's usually the half that decides whether an install is easy or fussy, and it takes a scan of your actual property to answer.
We run that scan free when you map your lawn — reading the tree and roof line from satellite surface data to work out how much open sky each part of your property really has, and which side of the house the antenna wants.
🌱 Map my lawn — free → 🛰️ Open the full tool (enter an address)
Between about 30 and 45 usable navigation satellites, for most of the continental United States. The dial on this page works out the exact number over your location from published orbital data — GPS, Galileo, GLONASS and BeiDou — and updates as they move.
About 5 shared between the mower and its base antenna to hold an RTK fix, and 15 or more at every corner for a comfortable install. Since most open properties see 30 to 45, the raw count is rarely the limit — what your trees and roof block is.
A signal arriving at a shallow angle crosses far more atmosphere and bounces off more ground before it lands, so it carries more error than it's worth. RTK receivers typically ignore anything below about 10 degrees of elevation, which is why a tree line on one side costs you more satellites than its height suggests.
Yes. Navigation satellites orbit roughly twice a day, so the count over any fixed address rises and falls by ten or more across 24 hours. Drag the time slider on this page to see your own curve. The dips are short and a healthy install rides through them, but on a marginal lawn, mowing outside the daily low is a free improvement.
Completely. There's no account and nothing is saved. Your browser computes the satellite positions itself from public orbital elements published by CelesTrak, so there's no service to pay for.
It answers half the question honestly. The sky above you is the same for your whole town, and this page shows it. What it cannot see is your own tree canopy and roof line, which is usually the half that decides whether an install is easy — two houses on the same street can differ. That takes a scan of your property, which we run free when you map your lawn.
On the side of the house with the clearest sky, mounted high and rigidly. A base antenna reaches the mower about 600 feet with a clear line of sight and roughly 300 feet once trees and buildings are in the way; past that, an extension antenna adds about 600 feet. Mapping your lawn tells you which side of your own house that is.