OS Net® infrastructure

The OS Net infrastructure is currently (as at January 2006) all of Great Britain except for the north-west of Scotland, the Scottish islands and the very tip of South West Cornwall – see map below. A business case that will look at providing complete GB-wide coverage in 2006 is being considered.

Black stations are current, yellow stations are to be installed in early 2006, red stations may be installed in 2006. Dark grey shading shows the area where 1-cm RTK (Real-Time Kinematic) corrections are possible; light grey shading shows where dGPS (differential GPS) corrections are possible.

The future of satellite navigation could mean that there are 60 to 80 usable positioning satellites in orbit by 2012, compared to the current crop of about 24 GPS satellites. This will mean much better availability in built-up areas as well as quicker and more accurate positioning. These extra satellites come from two sources:

• Galileo is the new European satellite system, which is due to launch up to 30 satellites from 2008 to 2010.
• GLONASS is the Russian equivalent of GPS. There are currently (January 2006) 9 working GLONASS satellites in orbit; new funding could mean that this is increased to 24.

Once dual GPS/Galileo receivers are fully available and Galileo satellites are starting to be launched,       Ordnance Survey® will plan to replace the OS Net base station infrastructure with GPS/Galileo receivers. These receivers may also be able to receive GLONASS signals. This is planned to happen in late 2006-07 and will mean that OS Net is able to generate corrections for whatever type of receiver a user has. A second re-equipping of the GNSS (Global Navigation Satellite System) infrastructure will probably occur in about 2013, but it is seen that there will be little change to the functionality of the receivers and the end-products that they could offer.