[chrissmithuk]

Yes but that somewhat limits the practicality because you need two receivers, a clear signal path between them and one has to be relatively static.

It's fine for surveying but for dynamic applications which are far more common, it's a pain.

[toomuchtodo]

You can receive RTK corrections over IP (via a cellular connection). Government bodies across the US push the data over IP to you if you register for a free account.

http://igs.bkg.bund.de/ntrip/index

http://en.wikipedia.org/wiki/Networked_Transport_of_RTCM_via... nternet_Protocol

[Nrsolis]

Then you engineer another source of correction and incorporate that into your project.

The US Navy has been doing accurate position determination using ZERO satellite availability. How do you think a submarine knows where it is?

http://www.liveleak.com/view?i=aba_1332656862

[randomdata]

In agriculture, it is not uncommon to get correction data over mobile data connections, where the static receiver is provided by a third-party service provider.