A caution to those wanting to use VRS in GNSS Solutions. Not every GNSS Solutions allows VRS to work. I first used VRS in 2009, and since then have jumped around with GNSS Solutions that work and don't work. Last night I found that it does not work in Version 3.70.5 so today I am downloading 3.71.1.
I mentioned the other day that one can submit a RINEX file from VRS to OPUS. Following is a OPUS-RS report from a 21 minute file from 2009.
" FILE: VRS1219Q.09O OP1341362616337
1009 WARNING! No antenna type was selected. No antenna offsets or
1009 pattern will be applied. Coordinates with reduced accuracy
1009 will be returned for the antenna phase center.
1009
1008 NOTE: Antenna offsets supplied by the user were zero. Coordinates
1008 returned will be for the antenna reference point (ARP).
1008
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.html#accuracy
USER: lplopresti@enter.net DATE: July 04, 2012
RINEX FILE: vrs1219q.09o TIME: 05:19:08 UTC
SOFTWARE: rsgps 1.37 RS40.prl 1.73 START: 2009/08/07 16:09:30
EPHEMERIS: igs15435.eph [precise] STOP: 2009/08/07 16:30:30
NAV FILE: brdc2190.09n OBS USED: 2025 / 2124 : 95%
ANT NAME: NONE QUALITY IND. 14.58/ 28.54
ARP HEIGHT: 0.0 NORMALIZED RMS: 0.314
REF FRAME: NAD_83(CORS96)(EPOCH:2002.0000) ITRF00 (EPOCH:2009.59912)
X: 1259746.366(m) 0.005(m) 1259745.622(m) 0.005(m)
Y: -4656572.695(m) 0.014(m) -4656571.261(m) 0.014(m)
Z: 4158754.980(m) 0.017(m) 4158754.889(m) 0.017(m)
LAT: 40 57 18.52180 0.006(m) 40 57 18.55311 0.006(m)
E LON: 285 8 16.50421 0.004(m) 285 8 16.48952 0.004(m)
W LON: 74 51 43.49579 0.004(m) 74 51 43.51048 0.004(m)
EL HGT: 141.121(m) 0.021(m) 139.870(m) 0.021(m)
ORTHO HGT: 174.131(m) 0.032(m) [NAVD88 (Computed using GEOID03)]
UTM COORDINATES STATE PLANE COORDINATES
UTM (Zone 18) SPC (2900 NJ )
Northing (Y) [meters] 4533786.901 235629.884
Easting (X) [meters] 511606.963 119518.527
Convergence [degrees] 0.09040083 -0.23733509
Point Scale 0.99960166 0.99991143
Combined Factor 0.99957953 0.99988930
US NATIONAL GRID DESIGNATOR: 18TWL1160633786(NAD 83)
BASE STATIONS USED
PID DESIGNATION LATITUDE LONGITUDE DISTANCE(m)
DK4432 NJSC SUSSEX COUNTY CORS ARP N410331.676 W0744509.429 14741.8
DK7751 NJWC WARREN COUNTY CORS ARP N404803.072 W0750452.530 25197.5
DJ8947 PAMS STROUDSBURG CORS ARP N405944.024 W0751503.835 33046.5
DH3768 NJMT NJMT CORS ARP N404747.350 W0742859.339 36479.2
DK4430 NJHC HUNTERDON COUNTY CORS ARP N403005.804 W0745404.015 50472.8
DI3830 NJTP PISCATAWAY CORS ARP N403225.841 W0742804.135 56823.4
DI0600 NYMD MIDDLETOWN CORS ARP N412424.522 W0742634.078 61268.6
DH3766 NJDY NJDY CORS ARP N402252.073 W0742756.301 72020.0
AJ4872 LAMT LAMONT EARTH OBS CORS ARP N410016.233 W0735432.057 80407.8
NEAREST NGS PUBLISHED CONTROL POINT
KV5834 GIBBS N405644.231 W0745247.326 1829.4
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. "
This file bounced back yesterday so I had to edit it. It seems the VRS created observations for satellite PRN 00, i.e. G00 in the Rinex file. Once I removed satellite 00 I got pleasing results. Amazing, an OPUS solution out of thin air. I was not sure I would get a solution since the VRS RINEX file had 0,0,0 for the X,Y,Z coordinates. OPUS-RS uses the supplied X,Y,Z to select the surrounding CORS for processing and I did not have time last night to dig out the 2009 data to calculate them.
In the past I have also gotten OPUS-RS solutions for a ProMark 2 L1 only observation. I mathematically created L2 and P2 observations from my L1 and C1 data. It was a bit of work but it can be done.
I test with OPUS-RS because it is more particular with the quality of RINEX data it processes. That plus when you are working from scratch it takes that mudh longer to create a 2 hour long file.
Happy Independance Day to all independant thinking Americans.
Paul in PA
Thank you!
And a happy 4th!
Someone sent me some Promark2 data and some static L1/L2 data collected on HiPer Ga receivers that I processed in GNSS Solutions 3.71.1 using the VRS function. The resulting positions corresponded very well with the OPUS solutions obtained from the OPUS reports on those same files.
I had GNSS Solutions create the VRS point and held that to see how the results processed with the HiPer files to the same points.
Perhaps the most interesting thing was the GNSS Solutions appeared to process dual frequency solutions between the two HiPer Ga files without fussing that I do not have a dual frequency key for the software. I don't know if it would do that if I had not included the VRS point. I have not played with it very much.
Jerry S ?
As I said a short distances the L1 only solution can be as good or better than an L1/L2 solution. Does the vectors tab show them as L1/L2 solutions?
Paul in PA
Jerry S ?
Actually I was just revealing my ignorance. I couldn't find the L1/L2 solution information in the Vector tab display so I looked at the project history window at the bottom of the GNSS window and it says in there that the L2 is not processed.
Previous versions warned you about that but this one does not. No big deal but thanks for helping me to avoid giving erroneous information in the future.
