If you get 2 hour occupations on marks, NGS will use it, just not the same way as 4+ hour occupations.?ÿ See page at web address below.
https://www.ngs.noaa.gov/OPUS/about.jsp#sharing
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Edit: the website does say 4 hour minimum.?ÿ I was convinced that I heard a presenter at the PLSO conference say that 2 hour sessions would be used, but not with the same weight as 4 hour.?ÿ Maybe I heard wrong.?ÿ It seems like 2 hours of good data would be better than no data....
NGS OPUS-S will process sessions of 2 hours or more and give you the results, but I don't see anything that says NGS will use your results for?ÿ their purposes if it is less than 4 hours.
The doc says for GPS on BM: must be 4 hrs.
I would??ve thought that in areas with many CORS sites, 2+ hrs be useful. Particularly with precise ephemerides. And the solutions weighted by the residuals, data quality, etc. I have geodetic antennae and the venerable Z12s. I don??t believe a newer receiver has much better phase resolution, which is the critical part.?ÿ
So if I post the data, next day, and get an opus shared solution, with 4 hr, will NGS reprocess with precise ephemeris, or should I upload AFTER the precise eph is available??ÿ
I wish they would issue some sort of warm fuzzy that the 4-hour session I did in April, 2021 and reprocessed in early January, 2022 is actually being used. ?ÿI log onto the nifty GIS application and still see the same blue 10km hexagon. ?ÿNo indication that my data has been used, beyond the OPUS results email and the successful receipt of the data sheet update email with one question about a photo but no follow up to my response, and no official update of the hexagon or the data sheet. ?ÿI guess they are just as overwhelmed as the rest of us.
should I upload AFTER the precise eph is available??ÿ
In one of their webinars I heard that they don't recommend submitting when only "Ultra rapid" results are available, but "Rapid" is sufficient and you don't need to wait for "Precise", which can take up to 2 weeks.?ÿ They may or may not reprocess before the final conversion tool is finished.
Next day may not be good enough - Rapid is usually available in the USA afternoon on the day after your session, unless your session went past UTC midnight.
As I recall the process, you check Share when submitting the data file, and get a screen to enter description and pictures.?ÿ After you do that there should be an email (usually withing the hour) with a link to an approval page, where you can either edit or approve the submission.?ÿ After that, usually within the day, an email sent notice that it was approved.?ÿ It's been a while since I submitted any, though.
Look for it in the Share list to see if that process was completed.
I realize that reprocessing with precise eph makes small to no difference with OPUS CORS, and slight difference in error estimate. And only a little difference with PPP solutions.
For GPS on BM I would think for those solutions precise eph processing would be beneficial.?ÿ
In my neighborhood there??s plenty of CORS. so 1 hr solutions, or 3hr, are only mm ?ÿdifferent. I could do 2 hr GPS on BM.
I realize that reprocessing with precise eph makes small to no difference with OPUS CORS, and slight difference in error estimate. And only a little difference with PPP solutions.
For GPS on BM I would think for those solutions precise eph processing would be beneficial.?ÿ
In my neighborhood there??s plenty of CORS. so 1 hr solutions, or 3hr, are only mm ?ÿdifferent. I could do 2 hr GPS on BM.
Oh my, you are trying to apply common sense. Stop it.
Basically NGS doesn??t deal with data shorter than 4 hours and they like 12 hours for their data. Once time gets to 12 hours, calculations settle down.
well in crowd sourcing gps on bm, and more than enough obs at 4+ hrs is collected, then I guess more 2 hr data is a filter.?ÿ
I realize that reprocessing with precise eph makes small to no difference with OPUS CORS, and slight difference in error estimate. And only a little difference with PPP solutions.
For GPS on BM I would think for those solutions precise eph processing would be beneficial.?ÿ
In my neighborhood there??s plenty of CORS. so 1 hr solutions, or 3hr, are only mm ?ÿdifferent. I could do 2 hr GPS on BM.
Oh my, you are trying to apply common sense. Stop it.
To be fair, while we might think "anything is better than nothing", in their world, they are (understandably) hesitant to mix data types. As state above, 4 hours is probably not a random requirement. As I am not an expert in what they do, it seems non-sensical, but my comment above was part real, part sarcastic. Common sense applies to our own world and experiences, and isn't always true when we move outside our area of expertise.?ÿ
We may measure stuff on the earth, but as a surveyor, most of us are not doing the work that a scientist at NGS is doing.
You do an ALTA, run a traverse and balance, know your precision and accuracy, and ready to go...then your crew goes out and runs an open traverse to pick up a monument.?ÿ What then? Can you just use the info because it is better than nothing??ÿ It needs to be checked. So, we apply the same concepts to our own work.
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4 hours is an old standard, the GPS world has moved on and it's not something that needs to be done anymore for accuracy. I suppose those areas with 250 miles between CORS would still be valid, if there are any of those left (Alaska?). But 2 hours should suffice.?ÿ
I was convinced that I heard a presenter at the PLSO conference say that 2 hour sessions would be used, but not with the same weight as 4 hour.?ÿ
That is how I heard it, also. Perhaps he just misspoke. But more than likely the website needs updating.
4 hours is an old standard, the GPS world has moved on and it's not something that needs to be done anymore for accuracy. I suppose those areas with 250 miles between CORS would still be valid, if there are any of those left (Alaska?). But 2 hours should suffice.?ÿ
This is about data for NGS use, not for business use
