2017 SUBARU BRZ Navigation Manual

Navigation 175
Further Information
Accuracy & error calculation
Regarding Precision Accuracy
Since the GPS satellites are controlled by the US Department of Defense
they do have a very high level of accuracy, however a multipath due to
reflections from buildings and so on could cause errors to occur.
Regarding the Properties of the GPS Electro-
Magnetic Waves and Signal Reception
If there are any obstacles between the GPS antenna and the GPS
satellite, electromagnetic-waves cannot be received from the satellite.
It is also impossible to use GPS positioning in the following locations as
at least three simultaneous electromagnetic-waves are necessary to
take measurements.
Also, if there are any obstacles around the GPS antenna,
electromagnetic-waves cannot be received from the satellite.
• In tunnels • If the immediate area is enclosed by
large objects such as skyscrapers

176 Navigation
Further Information
NOTE•Because the GPS satellite is in orbit around the earth, the reception status for
the electromagnetic waves changes depending on their position at that point
in time, even if your vehicle is in the 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 satellites or less, errors may occur in
the position. Modifying or adjusting the system will not prevent these
errors.
• In underground buildings 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

Navigation 177
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 position based on the most likely
road.
This unit uses information on the 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 accurate display of the current position
or route navigation may not be provided, however this is not an
indication of a malfunction in the unit, 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 behind when turning
right or left.• Shows the current position when
traveling up a steep hill.

178 Navigation
Further Information
• Shows the current position if the
road continues to curve around on
itself in the same direction.• Shows the current position after a
sudden change in lanes.
• Shows the current position when the
vehicle is on a parking garage
turntable and the ACC is off.• Shows the current position when
driving on snowy roads where the
vehicle may slip easily, or when
driving with snow chains.• Shows the current position in the last
confirmed position before moving
when using another means of
transport, such as a ferry, until the
GPS can determine the new position.• It actually navigates through roads
that cannot be driven (no entry and
so on).
• Shows the current position when
reversing.

Navigation 179
Further Information
Regarding Roads and Place Name Data
Because road and place names may change after the map data has
been created, there may be times when road and place names do not
match.
When no information is available in the map data, function such as
display of road names, searching for facilities, and route guidance
cannot be used.
When maps are created, land surveys are conducted and information
about roads improvement and opening is collected to provide the
most accurate information possible. However, modifications in roads,
place names and facilities may be carried out at any time.
Consequently, we cannot guarantee that map data contains no errors
in road positions, configuration and names, or in facility names.
The navigation system includes a function to read out names of roads,
intersections, and so on during guidance.
Depending on the selected language, names read out by the system
may not be exactly accurate due to missing information in map data.
Regarding Route Navigation
• It may deviate from the route
navigation when there is a turn at an
intersection etc., and a mistake in the
voice navigation.• When searching for the route, it may
take the long way around.
• The route may need you to make a
U-urn during navigation.• When driving on a straight road,
information may be displayed
indicating that you should go
straight ahead. ( When the
intersection shape is not clear and so
on.)
In six tenths
of a mile,
right turm.

180 Navigation
Further Information
•Performing a new search while traveling at high speeds may take
some time.
•The route may not change even after performing another search.
•When isolated locations or roads with no surrounding available
information are set as the current position/destination, you may not
be able to search for a route.
•A route may not be displayed when the current position is close to
the destination.
•Even if you select toll roads as a priority, the route may not guide you
through a toll road.
In a similar way, toll roads may be displayed even if you prioritize
other roads over toll roads.
( When it is possible to select a toll road or a normal road to create
the route, priority is given to the user's toll road preference - use toll
roads, or avoid toll roads.)
• The navigation may not indicate that
the road curves at an intersection.• The navigation may guide you back
to a waypoint if you search for the
route again after passing the
waypoint and are heading to your
destination.
• Many place names may be displayed
when navigating a district.• Always drive by following the actual
traffic regulations.
• When searching for a route, it may not be displayed quick enough for the next
left or right turn.
Transit point
Search
reinitiated
Route
search
complete

182 Audio and Visual
Before Using the Audio and Visual System
Precautions When Using the System
WA R N I N G
Read this manual first
Read this manual carefully before using the audio and visual
system. We are not liable for accidents or other problems
resulting from failure to follow the instructions in this
manual.
Avoid operating the audio and visual system while driving
You should stop the vehicle in a safe place before operating
the audio and visual system. For safety, some of the audio
and visual system's functions cannot be used unless the
vehicle is stopped.
If you stare at the display too much or operate the buttons of
the system while driving, the audio and visual system could
distract your attention from the current traffic conditions. Be
sure to enter as much information as possible into the
system before departing. Also, be sure to stop your vehicle
in a safe place if you need to enter information.
The touch button on the display screen that cannot be used
have their colors toned down. Buttons on the touch screen
that cannot be used have their colors toned down.
Operating the audio and visual system while driving could
cause your attention to be distracted from the current traffic
conditions. This could result in a severe or fatal accident. Follow
the descriptions of all operations and the instructions for
safety given in this manual without fail.
Look at the audio and visual system screen only when
necessary
When you need to look at the audio and visual system
screen, do so for the shortest time possible. Looking away
from the road for too long could lead to an accident.
Keep the volume low enough for you to hear outside sounds
Keep the system's volume level low enough for you to be
able to hear outside sounds while driving. Otherwise, you
may not be able to react appropriately to traffic conditions,
resulting in an accident.