Since the 1970's, when?ÿ NGS began work on NAD 83, they have been constantly engaged in supporting that datum and it's many realizations. With the '27 datum there were no regular new realizations because there was no jump in technology big enough to trigger it. The introduction of GPS into the NAD83 network made periodic new realizations necessary until 2011, when we reached a vanishing point. Since then the focus has been on preparing the 2022 datum.?ÿ
I suspect that once the 2022 datum is released there will be little need for readjustment until, and unless, there is some new quantum leap in measurement technology.?ÿ
So what, then, will be on the NGS agenda??ÿ ?ÿ
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They have said they plan to monitor movement and provide updates as warranted.
Another big push to improve user accuracy could be work on stabilizing all the CORS stations that aren't necessarily the most important ones.?ÿ?ÿ OPUS isn't going to get you to ultimate accuracy until all the CORS it uses are tweaked in. There are some that seem to drift or have drifted a significant amount in their plots.
Their 10-year plan and blueprints describe many ‘high bar’ goals that won’t be reached right away. Improvements to tools and crowdsourcing of both passive and active control data plus gravity to give localities more control over the resolution of NGS models.
Geoid and Velocity Models will of course continue to evolve and improve. I believe that the biggest improvement to the NSRS will be the evolution of HTDP from a 2 dimensional proposition (N, E) to a 3 dimensional model (N,E,U). Obviously the 4th dimension (time) is the big T in HTDP. I know that this has been in the works for quite some time (no pun intended), but I don't recall what the proposed initialism is.
Loyal
I am reminded of the assertion (incorrectly attributed to Lord Kelvin) that the start of the 20th century would see the ??end of physics.???ÿ
??... years earlier, Albert Michelson ??whose famous experiment with Edward Morley refuted the existence of the luminiferous ether?? said at the inauguration of the Ryerson Physics Laboratory at the University of Chicago that the great principles had already been discovered, and that physics would henceforth be limited to finding truths in the sixth decimal place.??ÿ
While the scale and resources devoted to the effort to bring about the original NAD 83 project will never be repeated See:?ÿ https://www.ngs.noaa.gov/PUBS_LIB/NAD1983_Collection_of_Papers.pdf ?ÿ there remain numerous and many unforseeable challenges for the greatly reduced ranks of the NGS.
In my opinion the work of the NGS is diminished by its inability to move beyond relying on the kindness of others for its observation data. The piece wise, state-by-state approach which led to great variations in monument densities and time periods of observations (with a number of years separating state-wide surveys.?ÿ
?ÿGiven declines in the the willingness of nations to cooperate on all many of activities, I wonder how long the international cooperation represented by the IGS and similar components of international geodesy will continue?
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