OPUS Projects
User Instructions
and Technical Guide
NOAA | National Geodetic Survey
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103
8a. RMS by baseline: smaller is better. See note 4 for additional information.
8b. OBS by baseline: bigger is better. The number of observations used depends upon conditions at the
observing site. Obstructions and unusual conditions should have been noted in the field report and used
in evaluating these values. In the absence of this type of information, a v
ery broad range of expected
values can be computed. For the minimum of this range, assume 4 observations per 30
second epoch;
for the maximum, assume 11 observations per epoch. In this example, the assumed duration for each
baseline is the span of the session, i.e. 5.5 hours (CORS to CORS baselines should be 24 hours regardless
of the session span). 5.5 hours per baseline 120 epochs/hour = 660 epochs per baseline. So, using 4
observations per epoch as the minimum and 11 observations per epoch as the maximum, the expected
range is 2640 OBS 7260. The numbers reported in this example, ~3500,
are at the lower end of this
range, but do not explicitly indicate a problem.
8c. OMITTED by baseline: smaller is better. The accepted range is implied by the “Minimum Observations
Used” project preference. In other words the percentage of maximum observations omitted = 100 –
“Minimum Observations Used”. Generally, experience has shown that values < 10% are typical. Values
substantially larger than this may indicate an obstruction or other issue – issues of the type often noted
in the field report. Substantially larger values do not absolutely indicate
a poor result, but the data and
processing should be scrutinized.
8d. FIXED by baseline: bigger is better. The project’s preference for the “Minimum Ambiguities Fixed” should
supersede the general guidance given here. Also be aware that the percentage of integers fixed can
have weather and baseline length dependencies. Experience indicates that values 90% are typical for
baselines < 10 km under almost all weather conditions. Values 80% are typical for baselines out to a
few hundred kilometers. Beyond a few hundred kilometers, percentages could drop into the 60’s.
Values significantly outside these ranges, do not absolutely indicate a poor result, but indicate that
additional scrutiny is justified. Information in the field report can be useful in such investigations, as can
correlating these values with other reported values such as the number of observations omitted for
example.
⋮
BASELINE LENGTH RMS
OBS OMITTED FIXED
-----------------------------------------------------------------
0012-0014 2.8 km 1.4 cm 3496 1.1% 94.4%
fmyr-0014 146.0 km 1.2 cm 3552 1.0% 93.8%
⋮
8a, b, c, d
User Instructions and Technical Guide
OPUS Projects
104 |
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NOAA |
National Geodetic Survey
9. The four-character mark ID.
10a. Derived coordinates in the requested reference frame and epoch appear on the left. These will only be
reported if it is meaningful to do so. For example, NAD 83 coordinates are only meaningful in the United
States and its territories; therefore, NAD 83 coordinates will not be reported outside the United States.
In these cases, only the computed coordinates, see note 10b, will be reported. Similar limitations can
exists for some other requested reference frames.
10b. Computed coordinates in the global reference frame at the mean data epoch appear on the right. These
are taken directly from the processing results. The geographic coordinates are computed using the
GRS−80 ellipsoid.
11. Adjusted monument coordinates are reported along with their formal uncertainties.
12a. Derived orthometric height, if possible, using the indicated gravimetric geoid or hybrid geoid model.
12b. The gravimetric geoid or hybrid geoid model used in the computation of the derived orthometric height.
13. Derived Universal Transverse Mercator and State Plane Coordinates. Like NAD 83 coordinates, State
Plane Coordinates are not defined and won’t be reported outside the United States and its territories.
⋮
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
UNCONSTRAINED MARKS
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MARK: 0012
REF FRAME: NAD_83(2011) (2010.0000) IGS08 (2011.8154)
X: 941989.040 m 0.003 m 941988.317 m 0.003 m
Y: -5607369.113 m 0.011 m -5607367.521 m 0.011 m
Z: 2880032.721 m 0.006 m 2880032.534 m 0.006 m
LAT: 27 01 06.53888 0.001 m 27 01 06.55840 0.001 m
E LON: 279 32 10.13680 0.001 m 279 32 10.12050 0.001 m
W LON: 80 27 49.86320 0.001 m 80 27 49.87950 0.001 m
EL HGT: -16.455 m 0.013 m -18.044 m 0.013 m
ORTHO HGT: 10.214 m 0.019 m (H = h – N WHERE N = GEOID12A HGT)
UTM COORDINATES
STATE PLANE COORDINATES
UTM (Zone 17) SPC ( 901 T FL E)
NORTHING (Y) [meters] 2988595.457 297565.003
EASTING (X) [meters] 553185.894 253204.047
CONVERGENCE [degrees] 0.24356643 0.24356643
POINT SCALE 0.99963492 0.99997611
COMBINED FACTOR 0.99963750 0.99997869
US NATIONAL GRID DESIGNATOR: 17RNK5318688595(NAD 83)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MARK: 0014
REF FRAME: NAD_83(2011) (2010.0000) IGS08 (2011.8154)
X: 940017.051 m 0.003 m 940016.328 m 0.003 m
Y: -5606734.742 m 0.010 m -5606733.150 m 0.010 m
Z: 2881901.988 m 0.006 m 2881901.801 m 0.006 m
LAT: 27 02 14.69392 0.001 m 27 02 14.71346 0.001 m
E LON: 279 31 03.39024 0.001 m 279 31 03.37393 0.001 m
⋮
9
10a, b
13
12a, b
11