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iG5 User Manual
1 foot above your GNSS antenna, the beam width is 1.6’ in
diameter. 20 feet above the rover antenna (perhaps the
midpoint of tree canopy), the 1
st
Fresnel beam diameter is 7
feet! A clearing in t
he treetops 100’ above your antenna
needs to be 16’ in diameter.
At the midpoint between your receiver and the satellite, the
Fresnel beam is over 6,000 feet in diameter! And that is for
the signal for a single satellite, multiply this by the number of
tracked satellites and there is signal energy everywhere.
Conclusion
There are lots of things that can go wrong with OPUS
occupations. Some you can control, some you can’t.
If you stack multiple problems:
Bad Constel Short Occu Moderate
Bad HI => FAILURE
