Hemisphere GPS LiteStar II Air, User Manual

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7: Setting Advanced Features
Swapping SLX Applications
The Swap SLX Applications function allows you to switch between
two differential correction signals if you are using a Hemisphere
GPS receiver, such as WAAS and OmniSTAR or WAAS and e-Dif.
To swap SLX applications:
1. Select DGPS > Swap SLX Apps from the Main menu. A
WARNING will tell you that you may temporarily lose
guidance while swapping.
2. Press to confirm you wish to swap applications.
3. Reboot LiteStar II Air to begin receiving data.
Using e-Dif
- e-Dif (extended-Differential) is a proprietary Hemisphere GPS
technology that provides precision guidance with accuracy similar
to that achieved with a broadcast differential solution. e-Dif
monitors the standard GPS signals over several minutes to
generate an internal model consisting of differential corrections.
These corrections are then applied to the GPS positions to improve
its accuracy. Typically, e-Dif maintains less than a 3 foot drift over
40 minutes in relation to the original reference point. However,
pass-to-pass accuracy typically remains as accurate as if you were
using a broadcast differential signal.
e-Dif can be used anywhere in the world as it does not operate
using a broadcast differential signal. So, e-Dif is an ideal solution in
areas where SBAS (WAAS, EGNOS, MSAS, etc.) and beacon
coverage is not available or is unreliable, or where the cost of an L-
band differential subscription is cost-prohibitive.
For example, ideal locations for e-Dif would include the fringe areas
of North America (Hawaii, Alaska, and extreme southern or
northern latitudes), South America, Australia, Asia, and Europe.
LiteStar II Air.book Page 100 Thursday, June 7, 2007 4:02 PM