The popularity of satellite navigation – better known as sat nav – has sky-rocketed in recent years. Prices have come down and functionality has improved, as have screen sizes and touch screen technology.
If you are looking for a new sat nav – whether it’s an upgrade or your first one – what should you be looking for?
In this buyer’s guide, we explain the latest sat nav features and jargon, plus we take a look at what GPS is and how it works.
What’s A Sat Nav ?
A sat nav (satellite navigation device) is an electronic gadget that is used by motorists to provide them with directions to a destination.
Sat navs work by calculating the best route from your current location to your destination. The sat nav uses GPS to work out your current location and you enter your destination into the sat nav by typing in the address or postcode. Most sat navs now have touch screens, like the latest touch screen mobile phones.
Current model sat navs also offer a range of other functionality, including features that help you avoid traffic jams and calculate the fastest route for the time of day – which is not always the shortest route. We’ll look at these features in a bit more detail in a minute.
There are three main types of sat nav:
- Mobile phone (smartphone)
Portable sat nav units are the most common and are small, self-contained units that usually mount on your car’s windscreen using a sucker pad. You can plug them into your cigarette lighter to keep them charged on longer journeys, and they can be removed (and used in other vehicles) if needed.
Built-in (integrated) sat nav units are often found in upmarket cars and are permanently fitted into the dashboard – like the stereo.
These units have the advantage of offering larger screens and of being neatly fitted with no wires – but they cannot be removed from the car and are not always as easy to keep up to date as portable units.
Many smartphones have a built-in GPS receiver and allow you to run navigation software (navigation apps), transforming your smartphone into a sat nav.
Using your smartphone as a sat nav has the advantage of being portable and reducing the number of gadgets you need to carry around, although smartphone screens are not always as big or clear as some dedicated portable sat navs.
Buying the navigation software for your phone can also be nearly as expensive as buying a portable sat nav device.
How Do Sat Navs Work?
Sat navs use the Global Positioning System (GPS) to locate your position on the earth’s surface. Your position is then overlaid onto a digital map – and bingo! You can see your location, on a road map.
Routing software in your sat nav then calculates the best route between your current location and your destination. As well as calculating the shortest route, current sat navs can calculate the quickest route (not always the shortest) and sometimes the least congested or most fuel-efficient routes.
The GPS system is an American satellite network of 24 satellites. Sat navs all have a GPS receiver built into them and this will receive signals from all visible satellites to calculate your position – hence why GPS sat navs need a clear view of the sky to work properly.
The GPS system was developed by the Americans in the 1970s for military and civilian use and has been fully operational since 1994. It is free to use for everyone and will calculate your position to within a few metres: GPS positioning can actually be much more accurate than this, but only military users are allowed access to the most accurate positioning data.
Sat Nav Feature Guide
Widescreen: Rather like widescreen televisions and laptop screens, sat navs with widescreens have a bigger display that’s able to show more information at once.
Basic sat navs have 3.5″ screens (sat nav screens are measured diagonally) while widescreen models have 4.3″ or even bigger screens. Heavy users will probably find it worthwhile spending a little extra on a widescreen model.
Standard 3.5″ screen vs. 4.3″ widescreen
Mapping: If you only drive in the UK, then you need to look for a sat nav with UK mapping or perhaps ‘UK & ROI’ (UK & Republic of Ireland).
Extra maps cost money, so drivers who plan to drive on the continent will have to pay a little more. Different levels of European mapping are available, starting with Western Europe and extending up to all of Western, Eastern and Central Europe. Be warned – mapping detail in some Eastern & Central European countries is not as detailed as in Western Europe.
Updated maps are usually issued every three months or so – you will have to pay to do this.
Enter Your Destination: At the heart of sat nav functionality is routing. Most sat navs allow you to enter postcodes or addresses when setting up a destination and some units now have voice recognition, allowing you to tell the sat nav where you are going.
Sat navs normally have touch screens – a keyboard appears on the screen for you to enter data. To make it quicker and easier to type in addresses, many sat navs have systems similar to predictive text messaging on mobile phones, where they work out what you are typing in as you type it. Generally, these work very well and save a lot of time.
Most sat navs have a touch screen that allows you to enter your destination or browse the maps freely.
Routing & Directions: Routing is getting more sophisticated and intelligent each year. Some sat navs can now update your route in real time based on live traffic information received by the unit’s built-in mobile data unit.
Even more basic sat navs can now access databases of speed information collected from other sat nav users (e.g. TomTom’s IQ Routes). This is used to work out the fastest route for the time of day you are travelling – for example, some routes are fast at night but hopelessly slow in rush hour.
All sat navs can re-route automatically while you are driving – if you take a wrong turn, for example, the sat nav will calculate a new route to get you back on track and will issue new instructions for you to follow.
Some sat navs have text-to-speech feature that reads street names when giving directions, rather than just telling you to ‘take the next left’. Some units also have 3D mapping images for cities and other major destinations, which make it easier for you to recognise your surroundings and follow the sat nav’s directions.
Traffic Information: There are two types of traffic information system for sat navs. The most common is TMC, which is received over FM radio and is probably already available on your car’s stereo. This is free to use but is often out of date and not very useful (in our experience).
The best traffic information system uses the mobile phone network. Data is received by mobile phone as soon as it is available. This can be through your mobile phone or through a built-in phone unit in your sat nav. These services require a paid subscription, although the first year is often free (e.g. TomTom Live).
Points of Interest (POIs): POIs are stored in your sat nav and show up on your map when you are nearby. Examples of popular POIs include speed cameras, petrol stations, hotels, cash machines, restaurants and car parks.
You can normally add your own POIs, too. Note that speed camera POIs are illegal in some European countries.
Driving Aids: Other sat nav features aimed at making driving easier include displaying the current speed limit on the screen and lane guidance – telling you which lane you should be in when approaching multi-lane junctions.
Many sat navs also have built-in Bluetooth units, allowing you to use the sat nav as a hands free system with Bluetooth-enabled mobile phones.
Buying A Sat Nav
The two largest sat nav makers are TomTom and Garmin. Both of these companies make excellent units. Other respectable brands include Navigon, Mio and Navman.
Like most popular electronic equipment, prices are very competitive and often reduced – shop around.