[Talk-GB] accurate GPS

Simon Ritchie simonritchie.uk at gmail.com
Wed Oct 9 13:40:53 UTC 2019

> The real question, really, is why you're aiming for that level of precision

That's what the emerging equipment does.  I'm just planning on showing how
it can be put together, but I'd like to be able to say with confidence that
it works properly.

As to who will use it, there's the readers of this forum, or some of them,
and surveyors and architects, of course.  There's also archaeologists,
because they are required to log where they find objects, and they use GPS
trackers to do it.  They often leave objects in the ground to protect them,
and then come back a few years later to have another look using new
techniques.  It would be nice if they knew precisely where their target is.
They would only have to dig a small hole to find it.

I note your point about plate techtonics.   My local archaeology group
recently re-excavated a site that was first excavated a hundred years
earlier.  The records they had turned out to be quite misleading.  That was
due to poor record keeping, but I guess over that time, the UK might have
moved around a bit.  I recall that one end is rising and the other is

However, when new equipment comes along, people find new uses for it.  We
moved house a few years ago and I saw our Land Registry documents.  I was
quite surprised at the rudimentary map that is the legal definition of our
property.  I'm supposed to resolve a boundary dispute with this? Now that
land is so valuable, I can see people demanding better, so the estate agent
will walk around the boundary with a GPS device and the result will be
logged with your land registry records.

In the future I can also see architects putting GPS coordinates on plans,
and builders using accurate GPS devices to do the initial  layout of the
site.  At 2 cm accuracy, they will probably have to tweak the positions
using better instruments, but if GPS speeds up the process or makes it more
reliable, they will use it.

> Relative accuracy (i.e. consistency of measured points
> within a reasonably sized area) is much easier to achieve than
> absolute accuracy (which is not even an especially well-defined
> concept in this case).

Given the inaccuracy of the trig point locations, I can't even do that :(

Regards, Simon
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