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GPS on Bench Marks 2015 ???
Posted by standing-on-the-corner on October 1, 2014 at 2:41 pmI did not get a chance to participate in March 2014, but I do wish to perform some observations this coming March.
Is anyone planning to organize any efforts?
Here is the link to the NGS page: http://www.ngs.noaa.gov/heightmod/GPSonBM.shtml
and PSLS: http://www.psls.org/ReachingNewHeights
Steve Corley replied 9 years, 5 months ago 6 Members · 10 Replies- 10 Replies
NGS is accepting GPS on bench marks at any time now; 52 were added using the NGS OPUS “share” option in September alone.
There is also early talk of staging a major simultaneous nationwide observation just before NGS updates GEOID12A; that not might take place for another few years.
Here is a quick CONUS view of the 3,700+ GPS bench mark ties shared with NGS since 2012, with red/yellow highlighting areas most needing such ties:
I would strongly encourage going through the OPUS Projects seminar put on by NGS. They spend some time on this exact topic. A day and 1/2 of very well spent time.
I have researched 3 benchmarks in NW Arkansas that are in one of those voids that geocachers have posted pictures of that appear to be suitable for GPS. I hope to be able to do OPUS DB observations on them before Christmas this year. If every surveyor with GPS would do one BM per month, concentrating on the areas that need help, we would really help with the GEOID Model. I have probably submitted GPS on benchmarks on 20 different Benchmarks in the last few years. All of it except weekend boondoggles was incorpated into projects. If you a re running RTK, set your base on a Benchmark and record the data then submitt it to OPUS DB.
For the last 9 days, I have had an OPUS X90 running 24 hours per day on a 1st Order BM. The only problem is that the GEOID is good in that area. I also did 12+ hours of observations on a BM about 20 miles NW of Little Rock that has not had a recovery filed on it since 1935. If find one file a recovery. If you can swing, do a 4+ hour session on it and submitt it to OPUS DB.
I talked to our NGS advisor the other day and he is planning another height mod push in southern Arkansas in the next 6 to 9 months. The last time he did this there were about 25 GPS receivers in the mix from a varity of private and public surveyors
good to hear from you again. I am currently trying to resurrect a dual frequency. not much luck yet, but hope is not lost.
I DO have a pair of single frequency receivers for the other research endeavor we were talking about.
Is there a way to get a list of the BM already observed? A sortable spreadsheet perhaps?
> Is there a way to get a list of the BM already observed? A sortable spreadsheet perhaps?
Nice! Thanks.
I just noticed that from the first link, you can navigate to a download of your state’s data, where you can view a county-by-county “wish list” where the BMs are prioritize by need.
I attended the OPUS Project Managers training course back in May with Dan Martin.
I already went out on some recon, uploaded over 100 recovery reports (granted not all reports were for NGS requested marks) and established a re-prioritized version the NGS recommended marks in my area.
A very rough concept of this is shown on a Draft map here: https://mapsengine.google.com/map/u/0/viewer?mid=zW9ywN3-cDuc.kUGhA4Xw7Ecc
The problem I’m running into is managing the data for a state-wide effort.
In Maryland, we happen to already have a strong geoid model and this is more as a PR exercise for our State Society.
I think I’m going into the KML/KMZ format to host the data and organize the effort.
> NGS is accepting GPS on bench marks at any time now; 52 were added using the NGS OPUS “share” option in September alone.
>I was under the impression that March was the favored month for this project, due to seasonal variability in soils at the CORS as well as opening up the sky for more observables.
I have some third order marks that wouldn’t really “help” the model but it would be nice to assign a new horizontal position to. Maybe these marks could be observed between now and March?
My Latest GPS On Benchmarks
This is an OPUS Reprot from a BM I did on September 24, 2014:
FILE: Q_712670.14o OP1412609158615
NGS OPUS SOLUTION REPORT
========================All computed coordinate accuracies are listed as peak-to-peak values.
For additional information: http://www.ngs.noaa.gov/OPUS/about.jsp#accuracyUSER: steve.c.corley DATE: October 06, 2014
RINEX FILE: q_71267m.14o TIME: 15:26:33 UTCSOFTWARE: page5 1209.04 master53.pl 022814 START: 2014/09/24 12:07:00
EPHEMERIS: igr18113.eph [rapid] STOP: 2014/09/24 20:29:30
NAV FILE: brdc2670.14n OBS USED: 20713 / 22632 : 92%
ANT NAME: LEIAT502 NONE # FIXED AMB: 126 / 134 : 94%
ARP HEIGHT: 2.667 OVERALL RMS: 0.016(m)REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2014.7306)
X: -239199.121(m) 0.004(m) -239199.921(m) 0.004(m)
Y: -5225389.522(m) 0.016(m) -5225388.094(m) 0.016(m)
Z: 3637350.864(m) 0.009(m) 3637350.723(m) 0.009(m)LAT: 34 59 38.19323 0.002(m) 34 59 38.21534 0.002(m)
E LON: 267 22 44.54241 0.004(m) 267 22 44.50832 0.004(m)
W LON: 92 37 15.45759 0.004(m) 92 37 15.49168 0.004(m)
EL HGT: 60.084(m) 0.018(m) 58.865(m) 0.018(m)
ORTHO HGT: 88.120(m) 0.035(m) [NAVD88 (Computed using GEOID12A)]UTM COORDINATES STATE PLANE COORDINATES
UTM (Zone 15) SPC (0301 AR N)
Northing (Y) [meters] 3872436.936 73468.154
Easting (X) [meters] 534590.623 343310.501
Convergence [degrees] 0.21737749 -0.36133634
Point Scale 0.99961475 0.99998864
Combined Factor 0.99960532 0.99997921US NATIONAL GRID DESIGNATOR: 15SWU3459072436(NAD 83)
And the Pictures
This mark has not had a recovery filed on it since the 1930’s until I did one about a year ago.
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