Chapter 2 - Introducing the 961/962
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Figure 3: GPS satellites communicating with vessel
Absolute and
repeatable accuracy
GPS’s major advantage over all other commercially-available
navigation systems, including loran, is its all-weather,
worldwide availability, and its
absolute accuracy
. (Those
readers interested in loran should see “Understanding
Loran-C” starting on page 5-7.) Absolute accuracy refers to the
ability of a navigation device to determine your actual lat/lon
coordinates on the surface of the earth, as compared to
position data determined from a paper chart or other
reference.
Repeatable
accuracy, on the other hand,
refers to the
ability of a particular navigation device to
return
to a position
whose lat/lon coordinates were previously recorded by this
same navigation device.
Selective availability
The Department of Defense developed a system of built-in
errors, called Selective Availability (SA), which was introduced
as a national defense strategy to intentionally degrade the GPS
solution. (The Department of Defense wanted to avoid the
possibility that its precision could be used by hostile forces as
Summary of Contents for 961
Page 6: ...Page viii 961 962 Operations and Reference Manual Rev A ...
Page 8: ...Page x 961 962 Operations and Reference Manual Rev A ...
Page 14: ...Page xvi 961 962 Operations and Reference Manual Rev A ...
Page 92: ...Chapter 3 Using the Controls Page 3 34 961 962 Operations and Reference Manual Rev A ...
Page 160: ...Chapter 6 Creating Waypoints Page 6 18 961 962 Operations and Reference Manual Rev A ...
Page 176: ...Chapter 7 Creating Avoidance Points Page 7 16 961 962 Operations and Reference Manual Rev A ...
Page 202: ...Chapter 8 Creating Routes Page 8 26 961 962 Operations and Reference Manual Rev A ...
Page 380: ...Glossary Page G 8 961 962 Operations and Reference Manual Rev A ...