Glossary
• Wide area map, detailed map
The wide area map is a map of a large area, and the detailed map is a
map of a small area. The scales of the maps are 1/20,480,000,
1/10,240,000, 1/5,120,000, 1/ 2,560,000, 1/1,280,000, 1/640,000,
1/320,000, 1/160,000, 1/80,000, 1/40,000, 1/20,000, 1/10,000, and
1/5,000.
• Positioning
• 2D positioning and 3D positioning
Actual position
Signals do not cross at one point
Position determined by 2D positioning
The quality of the GPS positioning is displayed in the top right of the
menu screen. The greater the number of displayed symbols, the
higher the precision of the GPS positioning.
168 Navigation
GPS calculates positions using triangulation.
The distance to the satellite can be determined when the radio wave
from that satellite is received, and the current location can be
measured by receiving radio waves from 3 satellites.
However, because there is a margin of error in the GPS satellites and
navigation unit, positioning is performed in only the 2 dimensions of
latitude and longitude when radio waves from only 3 satellites can
be received. The precision will be lower in this case. When radio
waves from 4 or more GPS satellites are received, positioning is
performed in the 3 dimensions of latitude, longitude, and altit