How car GPS tracking works, from satellite to phone
The short answer
A GPS tracker works out its position from satellites, then sends it over the mobile network through its own SIM card, about every 10 seconds. You see the result live on the NavUp platform and app, and if the network drops, the tracker stores its positions and sends them later.
A car GPS tracker does two jobs. First, it works out where the car is by listening to satellites. Then it sends that position over the mobile network, through its own SIM card, to a tracking platform. With NavUp, the position updates about every 10 seconds and you see it live on the web platform and in the phone app. If the network drops, the tracker keeps recording and sends everything once the signal returns.
Here is each step in plain words.
How does a tracker know where the car is?
Satellite navigation systems, such as the American GPS, the European Galileo and others, keep dozens of satellites in orbit. Each one constantly broadcasts its position and the exact time.
The tracker in your car has a small antenna that picks up these signals. By comparing how long the signals from several satellites take to arrive, it calculates its own position, its speed and its direction. It needs at least four satellites to do this properly. Out in the open, it usually sees many more.
This part is passive. The tracker only listens to the satellites. It does not send anything back to them, and the satellites have no idea your car exists.
How does the position get from the car to your phone?
Knowing its position is not enough. The tracker has to tell someone. That is where the mobile network comes in.
Inside the tracker there is a SIM card, just like the one in your phone. Every few seconds, the tracker packs its position, speed, ignition status and a few other details into a tiny data message. It sends that message over the mobile network to a server.
The server stores every message and passes the latest one to the tracking platform. When you open the NavUp app, you are looking at those messages drawn on a map. It uses very little data.
With NavUp, the SIM card and the data are included. You never have to top up a card or watch a balance.
How often does the location update?
On NavUp, the position refreshes about every 10 seconds while the vehicle is moving. That is frequent enough to follow a car street by street on the map, and to replay a trip later with every turn and stop.
When the car is parked with the ignition off, the tracker slows down to save power and goes into a light sleep. It wakes up instantly if the car moves, starts or is towed, and that is when movement alerts reach your phone.
How accurate is GPS tracking?
In normal conditions, out in the open, a GPS tracker is accurate to within a few metres. That is enough to see which street the car is in, and usually which side of the road.
Accuracy can drop in a few situations:
- In underground car parks or closed garages, where satellite signals do not reach.
- Between tall buildings, where signals bounce off walls.
- Right after the tracker wakes up, while it locks onto the satellites again.
In these cases, the platform shows the last good position until the signal returns. A tracker fitted properly, with its antenna facing the sky behind the dashboard, gives the best results. This is one reason fitting matters as much as the tracker itself.
What happens when there is no network?
In some parts of Tunisia, especially on long roads in the south or in the mountains, mobile coverage can be weak or missing for a while.
The tracker does not need the mobile network to know where it is, because the satellites are always there. So it keeps calculating its position and stores each point in its memory. As soon as the network comes back, it sends the stored positions in one go.
On the platform, the trip appears complete, with no gap. You might see the live position arrive a little later than usual, but the history is not lost.
Where do you see the location?
Every NavUp tracker comes with access to the NavUp platform. You can use it in two ways:
- On the web platform, from any browser on a computer or tablet, with no software to install.
- In the NavUp app for iPhone and Android, made for one-handed use on a phone.
Both show the same things: your vehicles live on the map, trips you can replay, alerts for movement, speed or leaving a zone, and reports. Both work in English, French and Arabic. The technician sets up your account and installs the app on your phone on the day of fitting, then shows you how it all works.
What can you do with the location?
For a private car, the location is mainly about peace of mind and theft. You know where the car is, you get an alert if it moves without you, and with the Anti-theft plan you can cut the engine remotely once the car is going slower than 20 km/h. Our anti-theft GPS page explains this in detail.
For a company, the same data becomes a management tool: rounds, mileage, driving hours, speeding and fuel. The platform turns the raw positions into reports you can read in a minute.
If you still have questions, our FAQ covers fitting, battery, network and more. Or simply ask for a free quote and we will call you back within the hour.
In short
- A GPS tracker finds its position from satellites, then sends it over the mobile network through its own SIM card.
- On NavUp, the location updates about every 10 seconds while the vehicle moves.
- Accuracy is a few metres in the open, less in underground car parks or between tall buildings.
- With no network, the tracker stores its positions and sends them later, so trips stay complete.
- You follow everything live on the NavUp web platform and phone app, in three languages.