Jump to the following:

Ordnance Survey logo

Discover Ordnance Survey

Skip primary navigation
Site Search
Skip secondary navigation

Product definitions

We expect that there will be three primary products offered by OS Net® partners. Other markets could be through providing data to ‘inverse GPS’ applications or 'aGPS' service providers (please see glossary), but these are considered out of the initial scope of the product launch.

The only data sent to partners is the raw GPS data stream that is received from the OS Net base stations. No manipulation is done to the data before it is sent out and the partner generates the entire service portfolio.

Raw GPS positions have an accuracy of around 5 to 10 meters in plan, 10 to 20 meters in height. This inaccuracy is caused by the errors in the GPS, summarised below:

Error source

Description

Potential magnitude of positional error (m)

Orbit errors

Our inexact knowledge of where the satellites are in their orbit.

2.5

Satellite clocks

The small inaccuracy in the satellite clocks means the distance measurement is not precise.

1.5

Ionosphere

The atmospheric layer from 50 to 500 km disturbs  the GPS signal, leading to inexact range measurements.

5.0

Troposphere

The atmospheric layer which includes the Earth’s weather disturbs the GPS signal, leading to inexact range measurements.

0.5

Receiver noise

Internal receiver errors.

0.1

Multipath

The effect of indirect GPS signals arriving at the GPS antenna.

0.6

 

 OS Net corrects the orbital, atmospheric and satellite clock errors.

 

Skip supplementary navigation

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