iGage iG5, Руководство пользователя

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65 iG5 User Manual
This is a bad location because the structure completely blocks
the anten na’s view to the South and East.
Huge Trees to the South
BAD : This site is not suitable for GPS observation because of
large trees to the south:
Southern sky is fully blocked and trees obscure view
directly overhead.
We can debate:
•
leaves on, leaves off
•
pine needles vs. broad leaves
•
length of pine needles
•
size of tree-trunks
•
size of branches
But trees above 10° to the East, South or West are bad and
100% canopy is really bad.
Huge Trees Overhead
Trees (with or without leaves) directly above the antenna
prevent the receiver from having a clear view of the sky. Even
though this location has open water to the South, it is directly
underneath large trees. Water can also be a source of
significant multipath (see the next section). This is a
BAD
location: