Pioneer AVIC-F550BT - Manual (Page 113)

113
Appendix
Positioning technology
Positioning by GPS
The Global Positioning System (GPS) uses a
network of satellites orbiting the Earth. Each
of the satellites, which orbit at a height of
21 000 km, continually broadcasts radio
signals giving time and position information.
This ensures that signals from at least three
can be picked up from any open area on the
earth’s surface.
The accuracy of the GPS information
depends on how good the reception is. When
the signals are strong and reception is good,
GPS can determine latitude, longitude and
altitude for accurate positioning in three
dimensions. But if signal quality is poor, only
two dimensions, latitude and longitude, can
be obtained and positioning errors are
somewhat greater.
Handling large errors
Positioning errors are kept to a minimum by
combining GPS, dead reckoning and map
matching. However, in some situations, these
functions may not work properly, and the error
may become bigger.
When positioning by GPS is impossible
• GPS positioning is disabled if signals
cannot be received from more than two
GPS satellites.
• In some driving conditions, signals from
GPS satellites may not reach your vehicle.
In this case, it is impossible for the system
to use GPS positioning.
• If a car phone or mobile phone is used near
the GPS aerial, GPS reception may be lost
temporarily.
• Do not cover the GPS aerial with spray
paint or car wax, because this may block
the reception of GPS signals. Snow buildup
can also degrade the signals, so keep the
aerial clear.
❒ If a GPS signal has not been received for a
long time, your vehicle’s actual position and
the current position mark on the map may
diverge considerably or may not be
updated. In such case, once GPS reception
is restored, accuracy will be recovered.
Conditions likely to cause noticeable
positioning errors
For various reasons, such as the state of the
road you are travelling on and the reception
status of the GPS signal, the actual position of
your vehicle may differ from the position
displayed on the map screen.
In tunnels or
enclosed parking
garages Under elevated roads
or similar structures
When driving among
high buildings When driving through
a dense forest or tall
trees
13-MAN-AVICF550-EN.fm Page 113 Monday, April 8, 2013 3:02 PM