Navigation System Information; Limitations Of The Navigation System - Toyota Prius 2012 User Manual

6. NAVIGATION SYSTEM INFORMATION

1. LIMITATIONS OF THE NAVIGATION SYSTEM

This navigation system calculates the
current vehicle position using satellite
signals, various vehicle signals, map
data, etc. However, an accurate posi-
tion may not be shown depending on
satellite condition, road configuration,
vehicle condition or other circumstanc-
es.
The Global Positioning System (GPS) de-
veloped and operated by the U.S. Depart-
ment of Defense provides an accurate
current vehicle position, normally using 4
or more satellites, and in some case 3 sat-
ellites. The GPS system has a certain level
of inaccuracy. While the navigation system
will compensate for this most of the time,
occasional positioning errors of up to 300
feet (100 m) can and should be expected.
Generally, position errors will be corrected
within a few seconds.
The GPS signal may be physically ob-
structed, leading to inaccurate vehicle po-
sition on the map display. Tunnels, tall
buildings, trucks, or even the placement of
objects on the instrument panel may ob-
struct the GPS signals.
The GPS satellites may not send signals
due to repairs or improvements being
made to them.
66
Even when the navigation system is re-
ceiving clear GPS signals, the vehicle po-
sition may not be shown accurately or
inappropriate route guidance may occur in
some cases.
NOTICE
● The installation of window tinting may
obstruct the GPS signals. Most window
tinting contains some metallic content
that will interfere with GPS signal recep-
tion of the antenna. We advise against
the use of window tinting on vehicles
equipped with navigation systems.
Accurate current vehicle position may not
be shown in the following cases:
• When driving on a small angled Y-
shaped road.
• When driving on a winding road.
• When driving on a slippery road such as
in sand, gravel, snow, etc.
• When driving on a long straight road.
• When motorway and surface streets run
in parallel.
• After moving by ferry or vehicle carrier.
• When a long route is searched during
high speed driving.
• When driving without setting the current
position calibration correctly.
• After repeating a change of direction by
going forward and backward, or turning
on a turntable in the parking lot.
• When leaving a covered parking lot or
parking garage.
• When a roof carrier is installed.
• When driving with tire chains installed.
• When the tires are worn.
• After replacing a tire or tires.
• When using tires that are smaller or
larger than the factory specifications.
• When the tire pressure in any of the four
tires is not correct.