[stefantalpalaru]

It is, using RTK (real time kinematic) and 2 different receivers: http://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-g...

[Nrsolis]

And there you have it.

This is from the datasheet of the Trimble R10 surveying receiver:

real time Kinematic surveying

Single Baseline <30 km

Horizontal ...................................... 8 mm + 1 ppm RMS

Vertical ....................................... 15 mm + 1 ppm RMS

Network RTK3

Horizontal ..................................... 8 mm + 0.5 ppm RMS

Vertical ...................................... 15 mm + 0.5 ppm RMS

RTK start-up time for specified precisions4 .....................2 to 8 seconds

Trimble CenterPoint RTX

Horizontal .................................................. 4 cm

Vertical .................................................... 9 cm

RTX convergence time for specified precisions12 ........... 30 minutes or less

RTX QuickStart convergence time for specified precisions12 .... 5 minutes or less Trimble xFill5

Horizontal ................................. RTK6 + 10 mm/minute RMS

Vertical ................................... RTK6 + 20 mm/minute RMS

[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.