This one seems appropriate for the stuff coming down the pike at an alarming pace. 
But I'm partial to this one.
dp
How about:
"My shrink says I have an OPUS complex."
my wife has RINEX envy
Deral that first one is nuts!
Quit looking at my shape files!
it's all my fault. I distorted the geoid with my rover pole and now they have to do a whole new datum to account for that. 🙁
¿Poor PDOP? Your Ephemeris may be to blame! Consult your Geodeticoigst!
CV 😉
Spelling police have at me, I took my best SWAG on this one!
Deralski
I would characterize NAD83(CORS96a) [aka “96-alpha”] as a refinement as opposed to a “shift.” NAD27 to NAD83 could be called a “shift” I suppose (Datum CHANGE), but I don't visualize NAD83(CORS96) to 96_alpha that way.
It is a “new” realization to be sure, but the mathematical definition is in fact an identity function that is STILL based on the relationship of NAD83 to ITRF_1996 (combined with ITRF_1996 to ITRF_1997 to ITRF_2000 to ITRF_2005 to ITRF_2008). When you look at the 14 parameter Helmert Similarity Transformation between NAD83(CORS96) and ITRF_1996, you will see that the geocentric origin of both systems was coincident over time (the Tx/Ty/Tz, and Scale RATES were zero). That was NOT the case between NAD83(CORS96) and ITRF_1997, ITRF_2000, ITRF_2005, OR between CORS96_alpha and ITRF_2008, where we see relative movement of the geocentric origins AND a Scale Rate.
Personally, I would have preferred a more robust “update” at this time, but as a practical matter, it doesn't really effect what I do one way or the other. One can make the argument (with certain caveats) that the “update” (shift) is primarily a function of time (Epoch 2002.0 to 2010.0). There ARE [many] other considerations (newer models, antenna calibration format, Tx,Ty,Tz,Scale RATEs) involved, but one can (I believe) think of it as a temporal UPDATE/refinement.
Now obviously the FACT that all of the CORS Coordinate estimates ARE going to CHANGE, and we will also need to adopt Absolute Antenna Calibration models, means that we have to “shift gears” a little, but the new realization is really more of a refinement than a “shift.”
I have run some informal (and preliminary) tests down in Tooele County Utah this winter, which indicate that a “simple” transformation (ITRF_2005 to ITRF_2008) and epoch 2008.0 (which we have been using in Tooele County) to 96_alpha Epoch 2010.0 should match up at or about the 1-2mm threshold. I was able to do this because the IERS/ITRF published a couple of ITRF_2008 coordinates in and around Tooele County already. A [VERY] slight tweak of our Projection Parameters (zone constants), and ALL of our TCCS-2008 coordinate estimates, will match the new TCCS-2010 Coordinate estimates, at or BELOW our signal to noise threshold. In other words, NONE of our North/East Coordinate estimates will change!
Now you are sorry that you brought it up aren't you?
BTW...It was Lew Lapine that I first heard refer to NAD83(CORS96a) as “96_alpha,” and I thought that it was so “catchy” that I have used the term ever since.
🙂
Loyal
Deralski
you really should say, if you want to be totally correct...
Niner-six, Alpha.
I got chewed out by an air traffic controller over the frequency for not using niner instead of nine. It sounded like he was in a cranky mood but I get the point.
Deralski
Maybe so...BUT, it's not as catchy as "96-alpha."
🙂
Loyal
