sensor SUBARU LEGACY 2008 4.G Navigation Manual

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The vehicle’s mark could also deviate even after the
vehicle has exited the parking area.
(9) The vehicle’s mark could deviate from its actual position
if the vehicle is driven using tire chains or snow tires on
a snow-covered road or on a mountainous road.
(10) The vehicle’s mark could deviate from its actual position
after the tires have been replaced.
■How the vehicle position is detectedDetecting the vehicle’s position through the GPS
GPS stands for “Global Positioning System”, which is a
system used for detecting an object’s position through the
use of satellites of the U.S. Department of Defense.
Radiowave signals from three or more satellites are received
by the navigation system, which utilizes the principle of
triangulation to detect the position at which the radiowave
signals are received.
When the navigation unit is receiving the GPS radiowave
signals, a “GPS” mark will appear on the map screen.Detecting the vehicle’s position through self-containednavigation
Self-contained navigation is a system that detects the
vehicle’s position by calculating the vehicle’s driven distance
and turning angle though the use of various types of sensors
that are mounted on the vehicle.Through the use of self-contained navigation, the vehicle’s
position can be detected even in an area where the GPS
radiowave signals cannot be received.
Making corrections to the detection of the vehicle’sposition through map matching
• In map matching, the position information resulting from
the detection of the vehicle’s position and the locus of the
travel of the vehicle up to the present are constantly
compared to the shape of the roads on the map in order to
correct the vehicle’s position mark to the most appropriate
road.
• If the vehicle is driven on a road whose actual shape
differs from its map data, the vehicle’s position mark on
the map could deviate from its actual position.
Occasionally, the correction of the vehicle’s position mark
to the actual road on the map can be observed, particularly
after the vehicle has turned at an intersection or has exited
from a parking area.
General Information