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Automotive navigation
system
An automotive
avigation
system is
a satellite
navigation
system designed
for
use
in automobiles. It
typically uses a GPS navigation device to acquire
position data to locate the
user on a
road in the unit's map database. Using the road
database, the unit can give directions
to other locations along roads also in
its database. Dead reckoning using distance data
from
sensors
attached
to the drivetrain,
a
gyroscope and
an accelerometer can
be
used
for
greater
reliability, as GPS
signal loss and/or multipath can occur due to
urban canyons or tunnels.
Some sorts
can be taken out of the car and used hand-held
while walking.
History
Automotive navigation systems were the
subject of extensive experimentation, including
some efforts to reach mass markets,
prior to the availability of commercialGPS.
Most major technologies required for
modern automobile navigation were already
established
when the microprocessor
emerged in the 1970s to support their integration
and enhancement
by computer software.
These technologies subsequently underwent
extensive refinement, and
a variety of
system architectures had been explored by the time
practical systems reached the
market in
the late 1980s. Among the other enhancements of
the 1980s was the development
of color
displays for digital maps and of CD-ROMs for
digital map storage.
However, there is
some question about who made the first
commercially available
automotive
navigation system. There
seems to be little room for doubt that Etak was
first to make
available a digital
system that used map-matching to improve on dead
reckoning instrumentation. Etak's
systems, which accessed digital map information
stored on
standard cassette tapes,
arguably made car navigation systems practical for
the first
time.
[2]
However,
Japanese efforts on both digital and analog
systems predate Etak's founding.
Steven
Lobbezoo developed the first commercially
available satellite navigation system for
cars. It was produced in Berlin from
start 1984 to January 1986. Publicly presented
first at the
Hannover fair in 1985 in
Germany, the system was shown in operation on the
evening news
from the first German
television channel in that year. It used a
modified IBM PC, a large disc
for map
data and a flat screen, built into the glove
compartment. It was called Homer
Alpine
claims to have created the first automotive
navigation system in 1981. However,
according to the company's own
historical timeline,
[3]
the
company claims to
have
co-
developed an analog
automotive navigation product called the Electro
Gyrocator,
working with Honda. This
engineering effort was abandoned in 1985. Although
there are
reports of the Electro
Gyrocator being offered as a dealer option on the
Honda Accord in
1981, it's not clear
whether an actual product was released, whether
any customers took
delivery of an
Electro Gyrocator-equipped Accord, or even whether
the unit appeared in any
dealer
showrooms; Honda's own official history appears to
pronounce the Electro Gyrocator
as not
practical.
Honda claims
[4]
to have created the first navigation system
starting in 1983, and culminating
with
general availability in the 1990 Acura Legend. The
original analogElectro Gyrocator
system
used an accelerometer to navigate using inertial
navigation, as the GPS system was
not
yet generally available. However, it appears from
Honda's concessions in their own
account of the Electro Gyrocator
project that Etak actually trumped Honda's analog
effort
with a truly practical digital
system, albeit one whose effective range of
operation was limited
by the
availability of appropriately digitized street map
data.
Technology
Visualization
Navigation systems may (or may not) use
a combination of any of the following:
?
?
top view for the map
top
view for the map with the map rotating with the
automobile (so that
map always
corresponds to
bird's-eye view for the
map or the next curve
linear gauge for
distance, which is redundant if a rotating map is
used
numbers for distance
schematic pictograms
?
?
?
?
?
voice prompts
Road database
Contents
The road database is a vector map of
some area of interest. Street names or numbers and
house numbers are encoded as geographic
coordinates so that the user can find some desired
destination by street address .
Points of interest will also be stored
with their geographic coordinates. Point of
interest
specialties include speed
cameras, fuel stations, publicparking, and
Contents can be produced by the user
base as their cars drive along existing streets
and
communicating via the internet,
yielding a free and up-to-date map.
Physical Storage Format
The
Physical Storage Format (PSF) initiative is an
industry grouping of car manufacturers,
navigation system suppliers and map
data suppliers whose objective is the
standardization of
the data format used
in car navigation systems, as well as allow a map
update capability.
Standardization
would improve interoperability, specifically by
allowing the same navigation
maps to be
used in navigation systems from 19 manufacturers.
Companies involved
include BMW,
Volkswagen, Daimler,Renault, ADIT, Aisin AW,
Alpine