Porcini mushrooms

Offline GPS localization in the woods: how it works

Updated on August 7, 20262 min read

In the woods the signal disappears, but the GPS location does not. It seems like a contradiction: how does the phone know where you are without reception? The answer separates two things that we often confuse.

Offline GPS tracking works because it uses satellites, not the telephone network. The field is used for calling and downloading data, not for calculating the position.

The field is used for making telephone calls. Not knowing where you are.

In short

  • GPS uses satellites, not the cellular network: it works even without reception.
  • What is missing offline are the maps: they must be downloaded first.
  • Satellite chip plus offline maps equals car route and return anywhere.

Two different signals (and here is the misunderstanding)

The cell phone signal

It's the one with the notches. It is used for making calls and surfing the internet. Under the branches, in the valley or far from the repeaters, it disappears.

The satellite signal (GNSS)

It's something else. The phone's chip receives satellite signals — GPS, Galileo, GLONASS — directly from the sky. He doesn't need any network.

Mathematics: trilateration

The phone measures how long it takes for each satellite's signal to arrive. From that time he derives the distance from each. By crossing the distances from at least four satellites, it calculates where you are, with precision of a few meters.

What's really missing offline: maps

You know the position even without the field. What you can't download on the fly is the cartography beneath you. For this reason, maps of the area must be taken before leaving.

  • Download the maps of your area first.
  • The path is still recorded, even at zero field.
  • The return to the car works with an arrow and distance, without signal.
Mappa satellitare di MushScout con tracciato GPS offlineGPS trackEven without a field
Selezione delle mappe offline in MushScoutOffline mapsSatellite, mouse, trails

The time I understood the difference

The first time I found myself at a loss with my one-bar phone, I learned the difference between field and GPS firsthand.

The dot knew very well where I was. The map was missing, which I hadn't downloaded. Since then I always unload it before entering.

— Federico, Mush Scout

Download the maps before leaving

MushScout records the track via satellite and takes you back to the car even at ground zero. The important thing is to download the maps of the area first: satellite, topographic and paths.

Tracks and routes remain on your phone, like your finds. Download it on Google Play.

Frequently asked questions

Yes. It uses satellites, not the cellular network. The field is of no use to the position.
Usually the downloaded maps are missing, or the first connection to the satellites is slow under the foliage.
Offline maps of your area: satellite, topographic and trails.
GPS has an impact. It is best to start with a full charge and keep the screen off during the route.
No. They stay on your phone, like your finds.
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