Navigation 185
Further Information
NOTE•Because the GPS satellite is in orbit around the earth, the reception status for
the electromagnetic waves changes depend ing on their position at that point
in time, even if your vehicle is in th e same place. Also, electromagnetic-waves
from satellites near the horizon can be easily influenced by surrounding
obstacles.
• At times, satellites under the control of the US Department of Defence will
intentionally drop positioning accuracy.
Regarding Errors in Current Position Display
The system displays the vehicle current position based on GPS
information and data from various sensors and road maps. However,
when the radiowave signals from GPS satellites are weak or when
signals are received only from two sate llites or less, errors may occur in
the position. Modifying or adjusting the system will not prevent these
errors.
• In underground buil dings and indoor
parking lots • In places with a lot of overgrown
trees and so on
• Under elevated roads • Roads at the base of cliffs and caves
186 Navigation
Further Information
Regarding Vehicle Position Detection
Correction Using Map Matching
Map matching is a method of comparing information on the current
position acquired by GPS and so on, with the road driven up to that
point, and correcting the current po sition based on the most likely
road.
This unit uses information on th e current position combined with
independent navigation and satellite navigation and matches it to the
shape of the road to create the correction.
However, as it cannot avoid the error margins at the current position,
the current position may shift away from the actual position even when
correcting using map matching.
Also, the vehicle marker may shift if the map data and the shape of the
road being driven on differ.
NOTE
Because it takes a short time for operations to stabilize just after turning on the
unit, the vehicle mark may not immediately match the vehicle as it moves. After
driving for a while, operations stabilize, and the marker should match the actual
driving position.
Regarding the Accuracy of the Current Position
and Route Navigation
As in the following images, an accura te display of the current position
or route navigation may not be pr ovided, however this is not an
indication of a malfunction in the un it, but is due to road conditions or
driving conditions.
Actual Vehicle Swept Path
Vehicle swept path acquired from each sensor
Corrected using map matching on the screen
• Shows the current position on roads
running in parallel. • Shows the current position on the
other road when there is a narrow
fork in the road.
• Shows the current position on the road ahead or behi nd when turning
right or left. • Shows the current position when
traveling up a steep hill.
