Andre Fuegner,        Oct 30, 2013

Do have any idea what would cause the strange
motion in the north component of the time-series
for TXGE?  The behavior repeats every two years.

The plot txge_13330.gif starts at 2011:220 and ends
at 2013:300, nearly covering our data holdings for
TXGE.  (The ASCII site log says that the site was
established 07:322, but our data holdings don't begin
until 11:073.)

The same behavior is seen in two methods of
coordinate computations and therefore is not
an artifact of the software but is physical.  (Plot
txge_13270.gif shows a single baseline computation
method.)

Does the soil dry out and crack?  Is there massive
water withdrawal nearby?  What would cause
one of your standard concrete monuments (4m deep)
and masts (1.8m tall) to wobble two inches north
to south in October every two years?
http://www.ngs.noaa.gov/CORS/SitePhotos/Required/txge/txge_ant_000.jpg

--M Cline

____________________________________________________________

Mike,    Nov 20, 2013

That is indeed strange. I can only think that it has to do with the ground soil moisture. 
We are in draught in Texas for the last year at least, if not longer. We have received quite 
some rainfall this fall, but are still in draught. Yes the soil does dry out and crack in summer in Texas.
I would think that is what is going on with TXGE.

We recently visited the site for the GNSS receiver and antenna upgrade and did not see anything 
strange on the antenna tower, but there is a drainage ditch close by. Attached are a few pictures 
of our recent visit.

Thank you,
Andre Fuegner
NTT DATA
GPS RTN support
3712 Jackson Avenue, Building 6
Austin, TX 78731
512 465 7769
andre.fuegner@nttdata.com