For geodetic survey we have identified the best in differential mode GPS available for this task - the Ashtech Z-Surveyor dual frequency, 12 channel, differential mode GPS. This is a successor the well known P12 and Z12 systems.

This dual frequency system compensates for ionosphere irregularities. It also embodies two key features which mark it out as the market leader:

Ashtech use a patented tracking receiver (Z-tracking) which provides a 13 dB signal-to-noise advantage over the more normal cross-correlation receivers. This, in effect, creates a much more powerful antenna and so reduces signal ambiguities - and hence spatial ambiguities - over other, competitive systems.

The second differentiating feature is the use of a carefully tuned antenna. This technology maintains a phase centre stability of better than 1 mm in the presence of adverse signal conditions.

We have carried out a project to densify a national geodetic network to sub-centimetric accuracy under very arduous conditions - including temperatures of - 27º Celsius.  Our staff suffered but the results were excellent!

For further information, please contact Geo Strategies at:
	Geo Strategies Ltd			Geo Strategies SA
	St John's Innovation Centre			Str G-ral V. Milea, 10A
	Cowley Road			Sibiu 550331
	Cambridge  CB4 0WS			Romania
	United Kingdom
	Tel:	+44 (0)1223 205080		Tel:	+40 (0)269 210832
	Fax:	+44 (0)1223 205081		Fax:	+40 (0)269 211165
	Email:	maps@geo-strategies.com		Email:	maps@geo.strategies.ro