Attending OPUS Projects class at OSU in Corvallis, OR. This is the third class, in on the ground floor!
SHG
I think this is the FIRST time that OPUS results are going to be good enough to take to the bank. Prior to this, I think too much trust has been put into an OPUS solution.
The idea that some individuals are performing COUNTY-WIDE Benchmark monumentation and "adjustments" with a collection of single-occupation (Rapid Static) sessions with simple OPUS solutions is in my opinion, poor professional practice.
OPUS Projects will solve that deficiency for those that have the insight to use this new tool. It likely will have little affect on the knuckle-draggers ...
Howdy,
Hope you enjoy the class.
As best I understand OPUS Projects, it provides what we used to call a "network" or "multi-baseline" solution for a set of simultaneously observed GPS sites. I have no doubt that this yields better results than the single baseline results of "regular" OPUS. Because the solution will include correlations between baselines the ellipsoidal (latitude, longitude and ellipsoid height) adjustment results should yield excellent results.
Unfortunately, the "real" difficulty occurs when fitting this set of observations to fixed control. Adjusting to CORS sites should not be much of a problem; ground monuments are the problem. Even more difficult is taking these ellipsoidal results and fitting them NAVD 88 benchmarks. This problem exists no matter how good the vectors are.
How does OPUS Projects deal with this issue?
The new adjustments and the improvements in geoid models will solve many of these problems. Achieving the best results fitting these new better vectors to the existing current monumented network of control remains the difficulty. This is not a new problem Dr. Charles Schwarz described it in his excellent article "The Trouble with Constrained Adjustments" linked here.
Cheers,
DMM