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iGage iG9 User Manual
No radar or radio paths that cross over the top of the receiver
No chain link fences nearby
Locations under busy landing paths are undesirable
No large ‘GPS reflective’ surfaces (metal roofs) nearby: avoid multipath
Receiver facing correct direction: usually MMI (Man-Machine-Interface AKA the push
buttons), antenna connector or North fiduciary pointing to the North.
Receiver mounted very securely on well braced, fixed-height tripod
No chance of giant birds sitting on your antenna during occupations:
This picture is an actual GIANT crow sitting on an actual CORS antenna!
No chance of trucks higher than your antenna passing nearby during occupation
Yes, users get great results in challenging locations all the time. And you may be lucky, but these are
real rules and you should consider respecting them.
Worst Case Scenarios
All of the sites presented below are actual customer sites (or in some cases slightly obfuscated
locations to save embarrassment.)
Remember that during times of low DOP (see the mission planning section of this document) you
may get reasonable OPUS-Static and OPUS-RS solutions at these challenging locations. Longer (3-
hour) and very long occupations (over 8-hours) may be dependable because the high-DOP
conditions are bridged with times of good coverage. However, in general, you should avoid the
following scenarios.
Semi-Trucks and Trains
This bench mark is 3 feet north of the eastbound edge-of-pavement of I80 near Green River
Wyoming:
It has fantastic views in all directions, unfortunately a semi-truck drives by every 20-seconds and
completely obscures a receiver’s view of the southern sky. This forces the receiver (and OPUS) to
lose lock. This is a
BAD
location and will greatly increase the RMS error estimates and drop the
percentage of observations used.
