NRI Grazing Land On-Site Data Collection
(03/23/20011) B-27
Shows location of satellites in sky relative to location (in center) of receiver.
Satellites that are displayed in the plot are being tracked.
Satellites used for navigation (positioning) will be highlighted in black.
The center dot is directly overhead of the receiver.
The inner ring depicts the sky from 45 to 90 degrees off the horizon.
The outer ring depicts the sky from the horizon to 45 degrees.
The sky view is a good indicator of terrain masking – it provides a user perspective
of the GPS constellation geometry.
Satellite strength indicators
- bars that display which satellites are being tracked and
what their relative signal strengths are. Satellites used for navigation will be solid
black. A “D” in any given bar indicates presence of differential corrections.
You can toggle between a set coordinate system, such as UTM, and
degrees/minutes/seconds by toggling the ROCKER key up/down.
Using the GPS Information Page to determine quality of position
Quality of Position refers to how well your receiver is computing positions at your
particular location.
The quality of position depends on several variables being optimal:
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Ionospheric interference is below modeled tolerances.
°
There is minimal multipathing (reflectance of GPS signals from objects and from
the ground surface).
°
You have a relatively unobstructed view of the sky.
There is little masking of the horizon (less than 15 degrees).
You are not standing in a depression, canyon, or gully.
You are not standing under canopy.
You are not standing in an area with many tall buildings.
You can get a sense of your positional quality by monitoring:
°
The satellite sky plot – this tells you what GPS satellites the receiver is using and
where they are in the sky relative to your position.
°
The Accuracy field. This field provides a horizontal accuracy estimate.
The estimate is based on the satellite geometry, time ranging errors, and
modeled ionospheric error.
