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Sat nav systems and OS data

Our role in the sat nav (satellite systems) market

We support the sat nav industry by making our detailed mapping data available to all sat nav manufacturers and suppliers. We do not develop or manufacture sat nav systems or software ourselves, nor do we create the travel instructions that are displayed on your device.

Instead, we supply a range of products, both premium, such as the OS MasterMap Integrated Transport Network Layer, and free, via our OS OpenData portfolio, to satnav manufacturers and suppliers. Our data is fully maintained and current and as roads are built or changed, we map these changes and make them available in our data.

Third-party system and software customers may use our data as just one component of their products, which might also feature information, such as, known congestion blackspots and safety camera locations – this information comes from other sources. It is this portfolio of data, overlaid with your device or service provider's own inferences from it, that is used to generate the suggested routes and prompts which your device provides during your journey.

Some devices or services do not contain our mapping information at all. Their developers either conduct their own surveying work or license map data from other suppliers.

If you would like more information on how Ordnance Survey works with navigational technology, GPS and the national positioning infrastructure, please visit the OS Net pages for more details.

Data capture

We aim to capture significant change to the landscape within six months of completion to maintain the currency of our national geographic database (NGD). From this we can produce a range of products, including OS MasterMap Integrated Transport Network Layer with over 340 000 miles of network lines depicting all road carriageways and some 980 000 associated Road Routing Information (RRI) features.

We only capture physical features within our data. For example, if there is a motorway in the landscape, we will call it a motorway – but we do not record how busy it is at different times of day. Sat nav manufacturers add any extra information to make their routing applications work or to attribute routes with a weighting of importance that determines the order in which the navigation software will route the user.

Update cycles for all our datasets are published and known by the satnav industry.

Who recommends the route you should take

We supply both free and premium, paid for, data on road networks to a range of users associated with routing and navigation, including some satnav system manufacturers and component suppliers.

However, these businesses then decide how to use this information in their systems – and how often they update the mapping data. Users can then choose the equipment that suits their needs – whether commercial, fleet or for private use – and decide how often they update their system and the level of detail they want.

Some sat nav suppliers use their own revisions of routing data and do not take any updates from us.

We do not recommend particular routes or say any particular route is faster or slower than another, since we do not create the routing software.

It is important to note that the definition as to whether a road is public or private is defined by the local authority, not by us.

We would encourage customers with a satellite navigation query relating to the above to contact their manufacturer/supplier.

Satnav accuracy

Satnavs use the Global Positioning System (GPS), positions have an accuracy of around 5-10 metres on the ground and 10-20 metres in height. There are many factors that can lead to the distortion of GPS signals, such as orbital errors, physical obstructions (tall buildings, trees and so on) and bad reception.

Satnav devices for walking

Although most in-car satellite navigation systems are designed specifically for navigation whilst driving, hand-held GPS systems are also available that are designed for walking and some systems are a combination of the two. You can buy a range of hand-held GPS systems by our partners from us.

How to report errors in satnav maps

Please report all errors to the private mapping companies direct; these are HERE, formerly Navteq and TomTom, formerly Tele Atlas. Both companies provide reporting systems on their websites, which allow you to report problems.

Postcodes in your satnav

Postcodes often include several different addresses and a satnav may only direct you to the centre of the postcode area, rather than an individual property within it. We can verify if a postcode is contained within our products and if it is correctly located.

However, if a postcode is missing from your device, please contact your device manufacturer. It may be that you need to buy an update for the device.

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© Ordnance Survey 2018