Wednesday 18 December 2013

Mapping Mountains - Trimble GeoXH 6000 Surveys - Introduction



The Trimble Company was formed in 1978 by three employees from Hewlett-Packard and coincided with the first Global Positioning System (GPS) satellite, the NavStar, being launched.  The company concentrates on developing positioning and navigation products.

One of these products is the Trimble GeoExplorer 6000 Series.  The 6000 is an innovative piece of equipment and comes as either the Geo XH or Geo XT.  The advantage of the XH is its Floodlight technology.  This is standard in this model and delivers improved positioning accuracy in challenging mountain environments when part of the view is obstructed, such as under trees or beside trig pillars.

One of the major advantages of the Trimble is that it can function without an external antenna as one is built into it.  This enables the surveyor to gather accurate data and use the Trimble without the need to carry additional heavy equipment.  The instrument itself is compact, only weighs 2lb and appears to need only 2 – 5 minutes data collection to produce acceptable levels of accuracy (+/- 0.1m).   However, operating the Trimble as a stand-alone instrument does have its drawbacks.  The major drawback is how to accurately determine bwlch or summit positions if not visually obvious, as is often the case. This then has to be carried out by instrumental methods, for example via level and staff, Abney level or RTK (Real Time Kinematic) GNSS measurements.

The Trimble GeoXH 6000 on the summit of Cyrniau (SJ 063 251) a Pedwar and marginal HuMP above Llangynog in mid Wales
 
Although I have a pole, tripod, bipod and external antenna I envisage the majority of the surveys conducted under the moniker of Mapping Mountains will be carried out with just the Trimble.  Because of this I need to differentiate the surveys I conduct from those carried out by G&J Surveys.  As a member of G&J Surveys, I know that we follow a rigorous protocol to determine both summit and col positions and follow guidelines set out by the Ordnance Survey.  When operating the Trimble for Mapping Mountains I will usually do so as a single surveyor, and as described above, this does have limitations.  However, that is not to say that the data I will produce with the Trimble will not be accurate, but it does mean that sometimes the quoted margin of uncertainty will be greater than we usually quote within G&J Surveys.

Although the Trimble will be used extensively to look at hills within listings I have produced, it is also accessible to the team of G&J Surveys.  Because of this we plan to test its capabilities over the next year in all environments over different time periods of data collection with external antenna and without, and by doing so we can build up a greater understanding of its functions and capabilities. 





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