New NAP pub ƒ??Evolving the Geodetic Infrastructure to meet New Scientific Needsƒ? pdf free download

The way I see it, the Geodetic Infrastructure has evolved adequately to include more precise measurements in all areas. I would say it is time for scientists to evolve their thinking to deal with the reality of measurements. If the geodetic community is not meeting their needs they are free to do it themselves at their expense.

It is totally possible to measure the caliber inside a rifle barrel using mutiple GPS receivers, from satellites 11,000 miles away, but why would you do it?

Paul in PA

I do not agree. The document is interesting reading. Especially for those engaged in more challenging work.

From Chapter 8, I copy the following:

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@geeoddmike

That article is not asking for a technology need, but a political need. The Coast Guard had a ground based GNSS system that could have easily been enhanced by available technology, instead the system was shut down and the lands assets not even set in reserve but instead disbursed to the wind. Because that signal was delivered 100% within the atmosphere it would have needed multiple frequency layers so that better atmospheric corrections could be calculated, just as L5 now makes GPS even more precise (other GNSS constellations have multiple frequency layers also). 

Paul in PA

@paul-in-pa

You have obviously not read the book (at 141 pages it is hardly an “article).

This book highlights the need for a more robust infrastructure to support the Terrestrial Reference Frame through multiple sensors. GNSS is only one component. As can be seen in the graphic below, VLBI and SLR are essential to the ITRF. Note as well that the distribution of sites is deficient with large portions of the Southern Hemisphere without sensors.

 The need for better distribution and higher quality sites is highlighted in the US by the Foundation CORS initiative. Anyone arguing that the old Coast Guard sites were the best basis for a national network is unaware of their many deficiencies in terms of stability, site operation and spatial distribution. Guy-wired skeletal-steel tower mounted antennas hardly provide the stability to monitor the geophysical phenomena the book discusses. 

Improvements in the TRF benefit all users. This summary of the Foundation CORS might be of interest. See also the poster on the topic shown at the 2018 AGU meeting linked below:

For those interested in NGS activities and their relationship to the TRF see the following:

Discussion of the Fortaleza, Brazil site:

https://www.ngs.noaa.gov/CORS/Articles/brft-gpssoln.pdf

For those unaware, the NGS operated VLBI sites until 1995:

https://www.ngs.noaa.gov/GRD/VLBI/VLBI-END.html

Article on various sensor systems and need to tie them together:

https://www.ngs.noaa.gov/CORS/Articles/ties-jog.pdf

Describes components of the TRF:

https://www.ngs.noaa.gov/CORS/Articles/igs-refframe.pdf

Project Report for a multi-sensor survey in Washington state:

https://www.ngs.noaa.gov/corbin/iss/reports/BrewsterWA_SiteSurveyV2.pdf

NGS Foundation CORS poster AGU 2018

http://www.igs.org/assets/pdf/IGSWS-2018-PS05-08.pdf

Cheers,

DMM