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iGage iG9 User Manual
ARP HEIGHT: 0.0083 OVERALL RMS: 0.011(m)
REF FRAME: NAD_83(2011)(EPOCH:2010.0000) IGS08(EPOCH:2014.2452)
X: -2184137.494(m) 0.003(m) -2184138.362(m) 0.003(m)
Y: -3839941.381(m) 0.001(m) -3839940.177(m) 0.001(m)
Z: 4585410.516(m) 0.005(m) 4585410.529(m) 0.005(m)
LAT: 46 15 35.23578 0.005(m) 46 15 35.25052 0.005(m)
E LON: 240 22 8.47069 0.002(m) 240 22 8.40767 0.002(m)
W LON: 119 37 51.52931 0.002(m) 119 37 51.59233 0.002(m)
EL HGT: 208.861(m) 0.003(m) 208.444(m) 0.003(m)
ORTHO HGT: 230.163(m) 0.018(m) [NAVD88 (Computed using GEOID12A)]
UTM COORDINATES STATE PLANE COORDINATES
UTM (Zone 11) SPC (4602 WA S)
Northing (Y) [meters] 5126276.950 103343.987
Easting (X) [meters] 297235.684 566995.383
Convergence [degrees] -1.90148112 0.63125220
Point Scale 1.00010542 0.99993063
Combined Factor 1.00007268 0.99989789
Here are some general rules to help judge the quality of a solution:
The orbit [precise] should be precise or rapid (not-ultra rapid.)
> 90% observations used or > 80% # Fixed Ambiguities
> 50% Fixed Ambiguities or > 95% observations used
Overall RMS < 0.030(m)
Lat / Lon RMS < 0.030(m)
If you collect data under canopy or in an area where there are buildings or trees that obstruct the
view above 10° elevation, the number of observations used will be lower.
Make sure you use the left-hand column (NAD_83) results, not the right-hand column (IGS08.)
Be careful with heights. Both ellipsoid and orthometric heights are listed. The orthometric height is
NAVD88 GPS derived and typically is the elevation you need.
The RMS error estimate for the orthometric height includes an error estimate for the GEOID in
addition to the RMS value for the ellipsoid height.
US Survey Feet vs. International Feet, Scale Factors
The state plane coordinates are listed at the bottom in the right-hand column. They are in Meters. If
you need Feet, you can convert them, however be careful to convert to International Feet or U.S.
Survey Feet as required by your State and application:
US Survey Feet
= Meters * (3937/1200)
International Feet
= Meters / 0.3048
The misapplication of Ft/M scale factor can result in a 30-foot coordinate blunder! If you request an
‘Extended Format’ OPUS results, the state plane coordinates are computed and returned at the
bottom of the report.
If your survey is at a significant elevation (> 100 feet) you may need to apply the Combined Factor
(listed on the OPUS report for both UTM and State Plane Coordinates) to inversed distances to
match optical shots made at ground level.
Getting ready to use OPUS
OPUS is a great tool for grounding your survey. But OPUS is part of a larger toolset. Before you begin
a project take a moment to think about the ‘Big Picture’:
What are your GOALS?
Required accuracy
