-
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
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
Electronics, Navigon, Bosch, DENSO,
Mitsubishi, Harman Becker, Panasonic,
PTV, Continental AG, Clarion, Navteq,
Tele Atlas and Zenrin.
Media
The road database may be stored in
solid state read-only memory (ROM),
optical media (CD or DVD), solid state
flash memory, magnetic media (hard
disk), or a combination. A common
scheme is to have a base
map
permanently stored in ROM that can be augmented
with detailed
information for a region
the user is interested in. A ROM is always
programmed at the factory; the other
media may be
preprogrammed, downloaded
from a CD or DVD via
a computer or
wireless connection (bluetooth, Wi-Fi), or
directly used utilizing
a card reader.
Some navigation device makers provide
free map updates for their customers.
These updates are often obtained from
the vendor's website, which is
accessed
by connecting the navigation device to a PC.