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OS Net frequently asked questions

What is OS Net?

OS Net® is a national Global Navigation Satellite System (GNSS) correction network. Ordnance Survey® has established a network of around 110 permanent GNSS stations around the country. From the observations made by these stations errors can be calculated to provide a range of correction services. 

OS Net as a service is not available commercially, however, our partners are utilising this network data to develop and provide a basket of real-time and post-process GNSS correction services to customers within a wide range of markets.

What is a correction service?

A correction service seeks to rectify the majority of errors caused by the satellite orbits, clocks and the atmosphere.

What does Ordnance Survey use OS Net for?

OS Net is currently used by 150 of our surveyors to collect field data for the production of our various mapping products.

How much do the partner services cost to use?

End-user pricing is decided by partners.

Does OS Net support DNF principles?

Yes. We require all use of OS Net services to be coordinated to primary coordinate reference frame (ETRS89). This means that all data collected through the use of OS Net will use a common framework and can therefore be shared and interchangeable.

Where can I get current information?

The 2012 guidance notes for “Network RTK GNSS Report” can be downloaded from The Survey Association (TSA) website.

Europe is developing its own GPS called Galileo. Why doesn’t Ordnance Survey use that?

OS Net base stations are ready to receive signals from Galileo once they are publically available.

Some OS Net services are ‘free to air’ through the GPS website. Will this continue now that commercial services are available

Yes. A free service for post-process applications will be maintained (using readings every 30 seconds) and this will continue to be available on our website.

What are RTK, dGPS and RINEX?

These are the three key positional services available via OS Net (see the GNSS glossary document for descriptions):

RTK (Real-Time Kinematic) GNSS gives accuracy at the few centimetre level in real-time.

DGNSS (Differential GNSS) gives sub-metre accuracy in real-time.

RINEX (Receiver INdependent EXchange Format) refers to data for post- process applications.

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For general enquiries, complaints, feedback or suggestions, email: customerservices@ordnancesurvey.co.uk or call us on 08456 05 05 05