Interesting NGS paper

[Bill93]

http://www.ngs.noaa.gov/2010Summit/Improving_the_NSRS.pdf

 

We had already heard about the GRAV-D plan that will drastically reduce the reliance on benchmarks. There will be a NAD83 and NSRS2007 replacement also.

 

This paper is a nice summary of the problems NGS people have to worry about in staying up with the technology. You might learn a little more about the underlying reference systems, also.

 

I have a concern that I hope is based on unfounded fears. What if, through war, economic priorities (space shots are expensive), or who knows what, GPS and the other satellite systems cannot be maintained at some point in the future? There needs to be a program of re-collecting up-to-date and accurate data on the passive marks as a backup to total reliance on satellites.

[+billwallace]

...

I have a concern that I hope is based on unfounded fears. What if, through war, economic priorities (space shots are expensive), or who knows what, GPS and the other satellite systems cannot be maintained at some point in the future? There needs to be a program of re-collecting up-to-date and accurate data on the passive marks as a backup to total reliance on satellites.

(Enter Stage Left - The Intrepid Amateur Benchmark Hunter)

[Bill93]

We can report what is still there, but most of them only have data in the old systems and do not have the accuracy expected of the recent updated systems.

 

Only a fraction of the horizontal mark positions were measured for NSRS2007 and probably perhaps fewer of them will have updated vertical values after GRAV-D.

Edited May 19, 2010 by Bill93

[+billwallace]

I haven't read that paper yet but what I got out of their Ten-Year-Plan was that while they were phasing out the use of passive marks, they were still going to maintain ties from the new datums to the passive marks AND maintain easy public access to the information for the passive mark networks - maybe with current computing power and information technology a bit of mathemagics, its not too hard to adjust all the passive control by making only a relatively few observations??

 

(That was a doozy of a run-on sentance )

[DaveD]

NGS does not intend to do away with passive marks. What is described in the 10 year plan is our ability to deliver access to the reference system through active stations (CORS) and to provide models such as improved geoid model -- GRAV-D, and tools such as OPUS and OPUS-DB (database) that will allow surveyors to set passive marks when and where they want them, easily connect them to the National Spatial Reference System and be able to archive and share their data. We believe strategy laid out in the plan will allow us to meet these goals.

[Allison Wunderland]

I heard just the other day that the US is launching new, updated, more accurate GPS satellites. Technology is nice, but I really like looking for the metal markers out in the field.

[DaveD]

The first of the next generation GPS Block 2F-1 was launcher last Thursday (May 27). Among other things this is the first operational SV to provide the 3rd dedicated civil frequency L5. While it will take several years to repopulate the constellation to a point where this enhancement will be noticeable, the not-so-distance future of space-based positioning is looking very exciting.