On 5/10/12 9:33 AM, Attila Kinali wrote:
On Thu, 10 May 2012 17:01:48 +0200
[email protected] wrote:
On Thu, 10 May 2012 22:50:15 +1000
swingbyte<[email protected]> wrote:
Hope this isn't too chat roomy, however, I have need of a survey precise
geolocation type gps. I was wondering if the precise timing abilities
extend to its precision in position output? I have a thunderbolt and
one of those conical white aerials from china and would like to know if
this combination will give me accurate height data.
How fast do you need it?
One project i'm involved with uses a LEA6-T with its phase data output
and averaging over several hours to get x/y resolutions in the 2-4mm
range.
I'm quite sure you can do something similar with altitude as well.
That is relative positions over a baseline of ca 100m. Not absolute
positions.
The "Baseline" is definitly larger than just 100m. the current testing
field is spread over the side of a mountain... I haven't looked at the
scale of the map, but i'd say it was somewhere in the range of 2-5km.
I do not know whether they use fixed reference stations. I am not aware
of any.
There are "virtual" reference stations available in a lot of places,
where they use data from carefully surveyed geodetic quality receivers
to create a synthetic reference. A common acronym is HARN (High
Accuracy Reference Network). Some are free, others have a user fee of
some sort(depends on where they are, and who set it up.)
And, of course, if you can post process, then things like GIPSY can
help. I believe the GIPSY folks ingest data from all over the world.
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