User's Manual

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viewed from the Data View page. Most GPS applications require that
your unit’s GPS receiver be set to output NMEA messages. There are
some specialized GPS applications which require the SiRF Binary
output mode. Please consult the documentation of your GPS
application to see which output format you should use and then
choose that option via this setting.
Static Navigation: This feature keeps your unit’s GPS receiver from
showing the normal erratic positions when standing still. When
checked, small changes in your position are interpreted as GPS error
and your computed position will remain unchanged. For applications
where you will be mapping or navigating at walking speed or slower,
it is recommended to disable this feature, so even small changes in
position will be shown.
Smooth Tracking: This feature smoothes the track generated by your
unit’s GPS receiver. When checked, movement is smoothed
mathematically to reduce the seemingly jagged movement resulting
from GPS error. For unfiltered, raw GPS readings, you should leave
this box unchecked. However, if you want to see a smoother overall
position (e.g. while navigating), then turn this feature on via the
checkbox.
NOTE: Both the Static Navigation and Smooth Tracking features
modify your true GPS positions mathematically so these features
should not be used when you need the most accurate GPS positions
available.
Masks: These define limits that determine when a satellite will be
used or not used.
• Elevation: This is the minimum angle above the horizon that a
satellite must be located before it is used. A value of zero
would essentially turn off the elevation mask. A value of
ninety would mask all satellites. A typical elevation mask
setting is between five and fifteen degrees to block tracking of
those satellites potentially affected by multipath error due to
obstructions (e.g. buildings or trees). Multipath error is error
to the GPS position from the satellite signal bouncing off of
objects before reaching the GPS receiver.