The GPS device has become one of the World’s most popular gadgets, with millions of units being sold over the last ten years. Two companies lead the way in terms of sales, which are TomTom and Garmin, which hold the lion’s share of the market. There are typically three different styles of GPS products that can be used in the car there are standalone devices (for example, Garmin), built-in factory-installed models, and now even Smartphone navigation. But how does GPS work to get you routed from A to B when driving? If you have ever wondered, then read our guide to GPS and satellite navigation below.
Global Positioning System (GPS)is formed by 24 Satellites
In total, twenty-four satellites are orbiting the Earth, which form the basis for the Global Positioning System, from which is where the GPS term comes. These were put in place by the US military as a defense project, but were then made commercially available at the beginning of the 1980s so companies could start to use the technology themselves.
Satellites Send Signal Transmissions to Earth’s Surface
The satellites all transmit GPS signals to the Earth’s surface, and each signal contains information on the satellite’s position and ID – each satellite does this at the same time which means the GPS in your car will be able to receive signals as long as it has a clear sight to the sky and is not blocked, for example by a tunnel or underground car park.
Trilateration for Accurate Positioning
When your GPS receives signals, there is a delay in time from being sent to being received, and because of this delay, the product can calculate the distance back to the satellite. It will take signals from at least three satellites, which then let the GPS determine your position due to a method called trilateration. This allows for accurate positioning and almost determines the pinpoint location of your car.
Showing the Car’s Location on the GPS Digital Map
But how does the product then route you along your journey? Well, it’s quite simple after this point, because each GPS device has digital maps stored on it. Because of this mapping software, the device can overlay your vehicle’s position onto the map and then give you the directions that you need. Because the GPS device is constantly receiving signals sent to it from the satellites, it can display the location of your car, and you will see the visual effect of the vehicle moving along the digital map on the screen.
Updating the Maps on Your GPS Device
As you can see from the guide to GPS above, the device that you own will only ever be as good as the actual maps that are stored on it. Contrary to popular belief, the maps are not beamed down from the satellites – only the car’s position and location. Because of this, the maps on a GPS will need to be updated frequently to accommodate road changes and new highways being built.
How to Update Factory-Installed Devices
Cars that come with a GPS pre-installed at the factory need to be updated via new mapping software discs. For example, Nissan GPS products will need to be updated using a Nissan Navigation DVD. (Additional manufacturers and options can be seen on the independent www.GPSNavigationDVD.net, which lists all categories.) The main supplier of maps to car manufacturers is a company called Navteq, so if you are in any doubt about how to update your GPS, make sure you check online for Navteq update discs.
How to Update Standalone GPS Devices
If you instead own a standalone product from Garmin or TomTom, then updating the maps is easier, as you can download new software directly from the manufacturer. Both brands offer schemes where you can pay for lifetime maps or opt for a one-off upgrade, and some newer models even come with the option of having lifetime maps bundled with the purchase, so you can continually download updates over the time you own the GPS device.
How to Update Smartphone GPS Apps
For those people who use a Smartphone device for navigation then you will need to visit the iTunes Store to purchase app upgrades, or your relevant Android online store. Please be aware, though, Smartphone navigation does not offer true turn-by-turn navigation, and they are not as reliable as factory-installed or standalone products and should be seen as a cheap alternative rather than a premium product.
