Offline GPS, can it work?

You don’t have your phone with you, maybe it’s in for a broken screen repair and you need to Sat-Nav somewhere important. Will the GPS work offline?

GPS

G.P.S. is the Global Positioning System. This system of pinpointing your location on the globe right down to which side of the street you are on is provided by satellites. These special satellites orbit Earth about 20Km above it sending signals back to the planet. The GPS receiver, which may be a phone, an android headunit or some handheld GPS device can interpret these signals. When there are enough different satellites signals being received and decoded at the same time a position on the globe can be calculated.

No Data

The GPS does not need an internet connection or 3G/4G/5G or any mobile phone masts to work. The GPS (US) and its spin-off systems employed by other countries, like GLONASS (RU), BeiDou (CN), Galileo (EU), NavIC (IN) and even QZSS do not need any mobile data to fix your position.

Offline Maps

GPS is much improved by adding a map, and route planning to give you a GPS powered Sat-Nav. With your actual location provided by GPS, a map to plot your location on and an algorithm to plan a route we have the familiar system of satellite-navigation we know so well. Google Maps is a well known Sat-Nav mapping and routing system that uses this exact system. Maps are loaded into the device when there is an internet connection but other systems can use maps stored on an SD card that is attached to the device. Either way the GPS system can map and route offline.

Add Data

Adding a data connection to the GPS Sat-Nav brings many benefits to the system. While the GPS can function offline the experience is massively improved with a mobile data connection.

  • Up-to-date maps, an internet connection can allow for more up-to-date maps than those supplied, say yearly on an SD card.
  • Quicker location pinpointing. A problem with offline GPS is the time it takes to calculate your initial position after a ‘cold boot’. The receiver needs to ‘see’ many satellites and get enough data to reliably work out where you are in the world. Adding a data connection by being on-line can offload some of this initial calculation and data collection, it can even get a rough fix by identifying which mobile phone mast you are near. There are several tricks employed to assist the GPS lock on your position with an internet connected Sat-Nav that speed up location pinpointing, massively.
  • Real-Time route planning. Traffic information from the internet can be fed into the mapping and routing algorithm which can route you around a real time road closure or build up of traffic. Google maps and waze both utilise information provided by other travellers apps to report back their progress (or lack of progress) to build up a picture of the congestion on routes. Other GPS Sat-Nav system connect to their internet servers to download real time traffic information to plan and re-route around problems.

Overall

Offline GPS and Sat-Nav works very well. In some locations this is the only option.

Adding data to GPS Sat-Nav to make it ‘online’ is a big improvement in many areas of its usefulness and speed at getting a precise location.

Tips

If you don’t have your phone with you, see if you can download the map area from your home wifi. Google maps has a option to download a map, at home, of the areas of your choosing. This is for times when there is no data, the map can be read from the download. Online will also help the head unit get a quicker fix on your location if the GPS aerial has a clear view of the sky and access to your broadband wifi, particularly with a cold boot.

Pie-Man
Pie-Man
Android guy who loves his android head units as much as he loves his cherry pie.

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