The following two OPUS-RS solutions are from a recent pool design project. The occupied points were concrete monuments at either end of the block. The precision is typical of my recent work in the PA-NJ area. I occaionally get better, like height as tight as position. Usually that occurs when I am snugly inside a triangle of CORS. This site was about midpoint on a line between LUMT and NJWC and a bit West of a line between PAMS and NJHC inside a diamond. These are my second day solutions and are 0.001m better than the day before. It was not due to a better orbit but rather getting certain CORS data and all matching stations.
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FILE: M0440961.13O OP1365382912078
NGS OPUS-RS SOLUTION REPORT
========================
All computed coordinate accuracies are listed as 1-sigma RMS values.
For additional information: http://www.ngs.noaa.gov/OPUS/about.jsp#accuracy
USER: lplopresti@enter.net DATE: April 08, 2013
RINEX FILE: m044096q.13o TIME: 01:08:51 UTC
SOFTWARE: rsgps 1.37 RS92.prl 1.87 START: 2013/04/06 16:05:00
EPHEMERIS: igr17346.eph [rapid] STOP: 2013/04/06 17:37:10
NAV FILE: brdc0960.13n OBS USED: 8721 / 9090 : 96%
ANT NAME: LEIAT502 NONE QUALITY IND. 57.09/ 81.92
ARP HEIGHT: 2.146 NORMALIZED RMS: 0.320
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2013.26220)
X: 1234334.861(m) 0.005(m) 1234334.046(m) 0.005(m)
Y: -4681372.367(m) 0.009(m) -4681370.930(m) 0.009(m)
Z: 4138522.567(m) 0.007(m) 4138522.514(m) 0.007(m)
LAT: 40 42 53.41135 0.003(m) 40 42 53.44382 0.003(m)
E LON: 284 46 15.49503 0.005(m) 284 46 15.47706 0.005(m)
W LON: 75 13 44.50497 0.005(m) 75 13 44.52294 0.005(m)
EL HGT: 78.052(m) 0.011(m) 76.807(m) 0.011(m)
ORTHO HGT: 112.112(m) 0.017(m) [NAVD88 (Computed using GEOID12A)]
UTM COORDINATES STATE PLANE COORDINATES
UTM (Zone 18) SPC (3702 PA S)
Northing (Y) [meters] 4507127.212 156437.132
Easting (X) [meters] 480655.513 812978.554
Convergence [degrees] -0.14939497 1.63558862
Point Scale 0.99960461 0.99997010
Combined Factor 0.99959237 0.99995786
US NATIONAL GRID DESIGNATOR: 18TVL8065507127(NAD 83)
BASE STATIONS USED
PID DESIGNATION LATITUDE LONGITUDE DISTANCE(m)
DJ8949 PASS SCHUYLKILL HAVEN CORS ARP N403820.925 W0760929.779 79011.5
DJ8947 PAMS STROUDSBURG CORS ARP N405944.024 W0751503.835 31231.1
DL6296 LUMT LEHIGH UNIVERSITY CORS ARP N403605.748 W0752127.133 16621.7
DK7751 NJWC WARREN COUNTY CORS ARP N404803.072 W0750452.530 15714.7
DK4430 NJHC HUNTERDON COUNTY CORS ARP N403005.804 W0745404.015 36480.5
DK4432 NJSC SUSSEX COUNTY CORS ARP N410331.676 W0744509.429 55419.1
DF5884 PARL PSU ARL NRDC CORS ARP N401146.224 W0750335.664 59354.3
DI3830 NJTP PISCATAWAY CORS ARP N403225.841 W0742804.135 67250.2
DJ6115 PAPH PHILADELPHIA WDPT CORS ARP N400047.348 W0751034.787 78044.8
NEAREST NGS PUBLISHED CONTROL POINT
KV2903 M 363 N404321. W0751331. 909.9
This position and the above vector components were computed without any
knowledge by the National Geodetic Survey regarding the equipment or
field operating procedures used.
*****************************************************************************
FILE: M0370961.13O OP1365382866072
NGS OPUS-RS SOLUTION REPORT
========================
All computed coordinate accuracies are listed as 1-sigma RMS values.
For additional information: http://www.ngs.noaa.gov/OPUS/about.jsp#accuracy
USER: lplopresti@enter.net DATE: April 08, 2013
RINEX FILE: m037096p.13o TIME: 01:13:11 UTC
SOFTWARE: rsgps 1.37 RS43.prl 1.87 START: 2013/04/06 15:47:30
EPHEMERIS: igr17346.eph [rapid] STOP: 2013/04/06 17:27:20
NAV FILE: brdc0960.13n OBS USED: 8154 / 9333 : 87%
ANT NAME: LEIAT502 NONE QUALITY IND. 57.24/ 81.38
ARP HEIGHT: 2.146 NORMALIZED RMS: 0.307
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08 (EPOCH:2013.26217)
X: 1234125.459(m) 0.006(m) 1234124.644(m) 0.006(m)
Y: -4681449.859(m) 0.013(m) -4681448.423(m) 0.013(m)
Z: 4138500.147(m) 0.013(m) 4138500.094(m) 0.013(m)
LAT: 40 42 52.40480 0.002(m) 40 42 52.43725 0.002(m)
E LON: 284 46 6.02666 0.005(m) 284 46 6.00868 0.005(m)
W LON: 75 13 53.97334 0.005(m) 75 13 53.99132 0.005(m)
EL HGT: 79.760(m) 0.019(m) 78.516(m) 0.019(m)
ORTHO HGT: 113.824(m) 0.023(m) [NAVD88 (Computed using GEOID12A)]
UTM COORDINATES STATE PLANE COORDINATES
UTM (Zone 18) SPC (3702 PA S)
Northing (Y) [meters] 4507096.758 156399.757
Easting (X) [meters] 480433.284 812757.302
Convergence [degrees] -0.15110973 1.63388222
Point Scale 0.99960471 0.99997008
Combined Factor 0.99959220 0.99995757
US NATIONAL GRID DESIGNATOR: 18TVL8043307096(NAD 83)
BASE STATIONS USED
PID DESIGNATION LATITUDE LONGITUDE DISTANCE(m)
DJ8949 PASS SCHUYLKILL HAVEN CORS ARP N403820.925 W0760929.779 78787.3
DJ8947 PAMS STROUDSBURG CORS ARP N405944.024 W0751503.835 31249.7
DL6296 LUMT LEHIGH UNIVERSITY CORS ARP N403605.748 W0752127.133 16453.4
DK7751 NJWC WARREN COUNTY CORS ARP N404803.072 W0750452.530 15910.3
DK4430 NJHC HUNTERDON COUNTY CORS ARP N403005.804 W0745404.015 36630.1
DK4432 NJSC SUSSEX COUNTY CORS ARP N410331.676 W0744509.429 55601.3
DF5884 PARL PSU ARL NRDC CORS ARP N401146.224 W0750335.664 59378.5
DI3830 NJTP PISCATAWAY CORS ARP N403225.841 W0742804.135 67454.5
DJ6115 PAPH PHILADELPHIA WDPT CORS ARP N400047.348 W0751034.787 78026.9
NEAREST NGS PUBLISHED CONTROL POINT
KV2903 M 363 N404321. W0751331. 1035.2
This position and the above vector components were computed without any
knowledge by the National Geodetic Survey regarding the equipment or
field operating procedures used.
******************************************************************************
The difference in OPUS-RS heights is 5.63'. My field D&R ties difference was 5.61'.
Good enough to build a pool?
We are blessed with many CORS in this area and I could probably find 9 different ones a bit farther away.
Paul in PA
The difference in the ortho height is 113.824 - 112.112 = 1.712 meters
1.712 x 3937 / 1200 = 5.617 feet. How'd you get 5.63'?
looks like he did better than he thought... good work Paul
Switched Field And GPS Differences
1123.824m x 3.28 = 373.343 I rounded to 373.34'
112.112m x 3.28 = 367.727 I rounded to 367.73'
373.34' - 367.73' = 5.61'
My field traverse difference was 5.63', swapped those two numbers lat night.
I expect 0.02' and consider anything better just luck because of rounding and height measurement errors.
It has nothing to do with my ability. It has everything to do with CORS abundant and close.
Paul in PA
That's quite good for a 1-sigma solution.
The thing that has puzzled me in reading this is the apparent error limits given at the side of a computation. It that a plus/minus or the full range of error? Just curious.
Switched Field And GPS Differences
> 1123.824m x 3.28 = 373.343 I rounded to 373.34'
>
> 112.112m x 3.28 = 367.727 I rounded to 367.73'
>
> 373.34' - 367.73' = 5.61'
>
> My field traverse difference was 5.63', swapped those two numbers lat night.
>
> I expect 0.02' and consider anything better just luck because of rounding and height measurement errors.
>
> It has nothing to do with my ability. It has everything to do with CORS abundant and close.
>
> Paul in PA
3.28 is a pretty crude conversion factor from meters to feet. 113.824 meters would be closer to 373.438 feet, say 373.44. That's a full 0.10' difference from your 373.34'. Similarly 112.112 meters would be 367.82 feet. The difference is 5.62, rounding each result to the hundredth.
But, I agree with your general suggestion that anything less than 0.02' is just likely to be luck....
Al
