AV-324
< FUNCTION DIAGNOSIS >
[BOSE AUDIO WITH NAVIGATION]
NAVIGATION SYSTEM
GPS (Global Positioning System) is developed for and is controlled
by the US Department of Defense. The system utilizes GPS satel-
lites (NAVSTAR), sending out radio waves while flying on an orbit
around the earth at an altitude of approximately 21,000 km.
The receiver calculates the travel position in three dimensions (lati-
tude/longitude/altitude) according to the time lag of the radio waves
that four or more GPS satellites transmit (three-dimensional position-
ing). The GPS receiver calculates the travel position in two dimen-
sions (latitude/longitude) with the previous altitude data if the GPS
receiver receives only three radio waves (two-dimensional position-
ing). GPS position correction is not performed while stopping the
vehicle.
Accuracy of the GPS will deteriorate under the following conditions:
• In two-dimensional positioning, GPS accuracy will deteriorate when altitude of the vehicle position changes.
• The position of GPS satellite affects GPS detection precision. The position detection may not be precisely
performed.
• The position detection is not performed if GPS receiver does not receive radio waves from GPS satellites.
(Inside a tunnel, parking in a building, under an elevated highway etc.) GPS receiver may not receive radio
waves from GPS satellites if any object is placed on the GPS antenna.
NOTE:
• The detection result has an error of approximately 10 m even with a high-precision three dimensional posi-
tioning.
• There may be the cases that the accuracy is lowered and radio waves are stopped intentionally because the
GPS satellite signal is controlled by the US trace control center.
Component Parts Location
INFOID:0000000000964770
SEL526V