SAE TECHNICAL
`PAPERSER'ES
`
`920601
`
`Development of the New Toyota Electro-
`Multivision
`
`
`
`Yu ki h i ko U meda, H i rcs h i Morita, S h i getosh i Azu m.,
`f;1gotfi H J.il
`
`EAFJ. A. E.
`LIBRARY
`ilr/ru
`Reprinbd from : Etectronic OisdaV ff;Inoffi!
`(sP€04)
`
`
`
`Inbmational Congress & E eosition
`Defuoit, Michigan
`February 24-28, 1992
`
`GIEffi,
`
`4OO COiIMONWEALTH DRIVE, WARRENDALE, PA 15096.0001 U.S.A.
`
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`
`

`

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`rssN 0148-7191
`Copyright 1992 Society of Automotive Engineers, lnc.
`
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`

`

`920601
`Development of the NewToyota Electro-
`'
`Muftivision
`Yukihiko Umeda, Hiroshi Morita, Shige,toshiAzuma, and Tohru bh
`Toyota lilobrCorp.
`
`based on location using a CRT display. The system's
`development is traced in broad outline form in Fig.
`1 .
`
`The present upgraded system has map matching
`technology and dead reckoning using satellite'emitted
`waves, and far greater accuracy in displaying road
`networks. This technology has made it possible to
`offer navigation function (map display, location,
`route guidance) display based on detailed map data.
`
`'85
`
`'87
`
`'&l
`
`'91
`
`'!lil
`
`'&l
`'81
`ttttlll
`
`s t G t 4
`
`' f
`. IO nat-
`dtirB
`. GPS
`. L(D
`
`r f
`
`'Rcute
`g.ridarEo
`
`: .CRIT :
`
`r ( =
`
`' D i g i t a l
`map
`
`s€|rsor
`
`: : i
`
`Fig. 1. History of Toyotia Navigation System
`
`ABSTRACT
`
`This study introduces the most recent version of
`the Toyota Electro-Multivision system which was
`equipped on the 1991 Soarer. As in the previous
`is operated and
`version, the Electro-Multivision
`controlled by interactive inputs through touch-
`activated display panel switches. The key features
`of the system are its use of the state-of-the art
`5.9-inch thin film transistor (TFT) LCD and four
`improved navpation furdions.
`
`follows:
`1. Two CD-ROM disks incorporating map data on major
`cities (Scale: 10,000 to 1).
`2. Touch activated panel display of maps that can be
`scrolled with the touch of a finger.
`3. A location function that works off a global
`positioning system (GPS)and map matching.
`4. Route Guidance from the present position to a
`target destination.
`
`The new navigation-related functions are as
`
`BRIEF HISTORY 0F TOYOTA ELECTROI,IULTMSION
`
`Toyota developed the first "Electronic Compass"
`
`thefor automotive applications in 1983. Foreseeing
`
`demand for auto-related information, it developed a
`system called Toyota Electro-Multivision, equipped
`with a cathode ray tube (CRT) capable of multiple
`display of auto information. The in-vehicle system
`was equipped on the Toyota Soarer models in 1985.
`On the Toyota Crown in 1987, two new functions
`were added to the ElectroMultivision: a compact disk
`read-only memory (CD-ROM) to store digital map data
`covering the whole of Japan, and a navigation function
`displaying the vehicle's position using a self-
`navigation system. This car navigation system was the
`first step in providing drivers with key information
`
`2 9
`
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`

`

`LAYOUT
`SYSTEM COMPONENT
`
`The components of the in-vehicle Electro-
`Multivision system are shown in Fig. 2. As different
`from the previous configuration, the updated CRT
`features a thin film transistor (TFT)-type liquid
`crystal display (LCD). The display computer unit is
`
`accomodated in back of the display, with the computer
`unit housed in the space it was in the earlier CRT
`display unit. The weight of the unit is now less than
`half that of the earlier version.
`Connected to this display computer are the
`various system components: sensors, computers,
`
`audiovisualsystem computers and so on.
`The block diagram in Fig. 3 gives the bus design
`for the global positioning system (GPS), TV, radio,
`air conditioner, mr phone and other sutrcomputers and
`their communications network involved. Up to 10 sub-
`computers can be hooked up for more expandible
`functions. The compact disk read-only (CD-ROM) data
`are transfered by means of a separate high-speed bus
`line system.
`
`Cotpass
`sonsor
`
`CPS
`anternas
`
`TV
`mterna
`
`il/Ft
`antqna
`
`GPS mtqna
`
`Cqp6s
`
`GPS
`anterna Antsna
`c l i f i e r
`TV tupr
`
`Elmtro-
`f r l t i v i s i m
`Badio
`
`Carera
`cot|rrter
`
`player
`Rear via
`GPS nuritor cmra
`rmiver
`
`Fig. 2. Electro-Multivision System
`
`El EI EEE
`trt
`Ef
`EI
`
`l l l t i v i s i m
`
`display
`
`E
`
`Lrlt ivisiqr
`
`con/ter
`
`*itdrs
`&
`Sorsors
`
`g @
`
`Fig. 3. Block Diagram
`
`Rear vic rritor
`caFra
`
`3 0
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`

`

`The various sensors are connected up in parallel
`to the display computer: the previous geomagnetic
`sensors for calculating the vehicle's position and the
`distance sensors, plus the wheel sensors, steering
`sensors and GPS receiver. The special CD-ROM player
`is equipped with two CD-ROM disks that store the
`digital map data, and it is equipped in the trunk
`room. There is a diversity-type GPS antenna system.
`The two antennas are equipped in trays in the front
`and back of the vehicle interior so as not to
`interfere with the smooth lines on the exterior. The
`audiovisual system is basically the same as before.
`The four TV antenna are glass print types. A CCD
`camera is carried in the air spoiler in back for rear
`vision when backing up.
`
`SYSTEM FUNCTIONS
`
`The main functions of the Electro-Multivision
`system and display examples are listed in Table 1.
`The system functions incorporating new technology are
`herewith explained in comparison with the previous
`technology.
`DISPLAY INFORMATIOI+-An automotive display must be
`readily visible while driving, not to mention
`arranged for easy recognition, safety and comfort.
`An in-vehicle display, compared to one for
`conventional use, must be built to withstand severe
`environmental conditions such as temperature
`fluctuations (high and low), vibration and other
`factors in the in-vehicle environment. The display
`construction is shown in Fig. 4, while Table 2
`indicates the differences with the earlier version.
`The construction and functional features are outlined
`in what follows.
`In-vehicle Color LCD Panel--The present display
`employs a diagonal LCD of about 6 inches. This is
`approximately one inch larger than the previous model
`(see Table 2). Resolution and brightness are
`virtually the same.
`(1) The position for mounting the display and the
`Light control filter(LCF) selection were arranged to
`assure sufficient contrast for good visibility by the
`driver (see Fig. 5).
`(2) For better response characteristic at low
`temperatures (under 20 degrees celsius), the back of
`the LCD was stripped with a transparent film heater
`(see Fig. 6).
`In-vehicle backlit-The same as with the previous
`version-(W shape;, the new color LCD panbt has a
`backlit screen using a high-luminance cold-cathode
`tube(Ref. 3.).
`
`INPUT OPERATIONS-There are muftiple displap
`accessible with the touch-sensitive panel depending
`on the operation mode used. Since all kings of
`information can be displayed, they must be instantly
`accessible to the driver. Thus, as with the former
`system, a hierarchy of functions is provided with
`touch-activated switches (see
`access by mechanicaland
`Table 3).
`
`Table 1. Outline of Function
`
`Type of Screen
`
`Function
`
`(1) Basic screen
`
`(2) Geographical
`information
`screen
`
`(3) Vehicle
`information
`screen
`
`r Air conditioner status
`I Calendar (cunent month
`day and day of the week)
`r Audio equipment stafus
`
`r Map
`r Cunent location With
`GPS)
`r Place name index
`r Route gukJane
`r Memory poinb
`rStoring point
`
`r Maintenan@ information
`(Engin oil, filter, tyre
`e t c , )
`r Fuel economy information
`rTrip information
`(dairy trip and fuel
`consumption)
`r Monthly calender
`
`(4) Audio screen
`
`r Audio equipment status
`
`(5) Air conditioner
`screen
`
`r Air conditioner status
`
`(6) W screen
`
`r TV broadcast
`
`(7) Diagnosis screen r System diagnosis
`
`(8) Rear view monitor r Rear view while backing
`up
`
`(9) Mobile telephone
`screen
`
`r Mobile telephone status
`
`3 1
`
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`

`

`Cold=cattrdo
`tLbo
`F$o
`
`Backl it
`
`)R
`
`oo
`5o.
`
`oo
`
`J
`
`id cmtal panl
`
`Lidrt ontro
`
`Fig. 4. Display Construction
`
`Table 2. Comparison of LCD and CRT
`(New and Earlier Version)
`
`\qo"r
`\-
`Item
`
`Type
`
`Resolution
`
`Brightness
`(Luminane)
`
`'91 Soarer
`
`'88 Crown
`
`5.9" LCD
`
`220 N)
`x 882 (H)
`
`5.1" CRT
`
`Dot pitch:
`031rm
`
`150 od/m2
`
`150 od/m2
`
`hntrast ratio
`
`60"
`
`00
`Arsle
`
`60"
`
`Fig 5. Horizontal Contrast Viewed at Eye Level
`
`32
`
`t80
`lm
`Elosod tim(sc)
`
`Fig. 6. Relation Between Elapsed Tlme and LCD
`Response at -20"C(100% response means he response at
`normal temperature)
`
`Table 3. Comparison of Display Hienarchy
`
`Display added
`on'91 Soarer
`
`Rear view moni-
`tor
`
`Air conditioner
`
`None
`
`'88 Crown
`
`\{odel
`Hierarch\
`Superior Car phone call-
`in system
`
`Basics
`
`Detail
`
`Maps, vehicle
`information, TV
`radio, display
`adjustment
`
`More detailed
`displays of
`conditions at
`each level of
`display
`hierarchy
`
`MAP DISPLAY-In addition to the various map
`displays, the system offers overall display of TV
`broadcast reception, vehicle information (e.9., fuel-
`related, time for maintenance), air conditioner
`operating conditions, audio operating conditions, car
`phone operating conditions and the like. Map display
`information is provided in hierarchical array of data
`(expressway, national highway, main trunk and other
`road data). Map information is given in terms of
`scale to al low easier reading. Thus, one has a
`choice of 1/2-step increments/decrements
`in a scale
`range of 5.12 million to one up to 10,000 to 1.
`
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`
`

`

`NIAP OPEMTION€esides he earlio'rfixed rnap nnde,
`the present position can be set in the center on the
`screen while driving, and the map may be scrolled as
`the vehicle moves toward its destination.
`The southern mode can also be selected when
`proceeding south.
`A "one-touch scroll" function has been added,
`which permits the driver to simply touch a point in a
`desired direction to be explored, and the map is
`automatically scrolled accordingly. This is a
`breakthrough feature that does not employ the earlier
`cursor system.
`
`NAVIGATION FUNCTIONS
`
`The navigation functions of the new system are
`diagrammed in Fig. 7. Using the independent self-
`navigation method and radio wave approach, the present
`system features a high-accuracy location function
`making map matching of anywhere in Japan feasible.
`The special feature of this self-navigation method is
`that, unlike the earlier system equipped on the '90
`Crown, this one provides map matching technology
`using CD-ROM map data. The radio wave method is
`called the global positioning system (GPS).
`Another feature newly added is the route guidance
`function, whereby the projected routes are displayed
`from the present position to the target destination.
`Herewith is presented a broad outline of the main new
`technologies using position feedback.
`
`Cq|E
`
`Sr€d
`
`fa
`
`HS
`
`a-t,re
`
`S-rao.
`
`/a\_\z
`
`Fig. 7. Navigation System Construction
`
`POSITION FEEDBACK TECHNOLOGY-Dead Reckoninq
`
`
`Technoloqv-Numerous sensors have been reported (Ref .
`4.) for use in dead reckoning technology. As in the
`previous system, the present one employs 3 sensors:
`the cost-effective geomagnetic sensor for detection of
`
`33
`
`Sizing of map is possible in 10 stages. See Table. 4
`for a comparison of the present with the previous
`syatem sizing.
`Also, as shown in Table. 5, additional
`information is provided by way of detailed maps
`including the names of metropolitan and other
`prefectures, municipalities, public institutions and
`facilities and intersections. Each map carries much
`more information.
`As a result, the total data capacity is more than
`500-bytes.
`
`Table4. Comparison of Road Map Data (Pages)
`on New and Earlier Svstems
`
`Model
`
`'90 Crown
`
`'91 Soarer
`
`Scale
`
`5.12 million to 1
`
`2.56 million to 1
`
`1.28 million to 1
`
`
`
`6110,000 to 1
`
`
`
`320,000 to 1
`
`
`
`160,000 to 1
`
`80,000 to 1
`
`40,000 to 1
`
`20.000 to 1
`
`
`
`10,000 to 1
`
`2,500 to 1
`
`16
`
`No
`
`207
`
`No
`
`698
`
`No
`
`3846
`
`No
`
`No
`
`No
`
`No
`
`10
`
`40
`
`67
`
`261
`
`687
`
`2681
`
`1 0997
`
`42890
`
`601 1
`
`23443
`
`2956
`
`Table 5. Detailed Road Map Data
`
`Scale
`
`Map
`
`40,000 to 1
`
`All Japan
`
`10,000 to 1
`
`2,500 to 1
`
`Main cities
`in Japan
`
`Tokyo-area
`intersections
`
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`
`

`

`RadioWave Method -The new system uses GPS for
`the radio wave method for the following reasons:
`(1) Initial positioning
`is unnecessary
`( 2 ) E l i m i n a t i o n o f p o s i t i o n e r r o r d u e t o
`accumulatedenor of the distance sensor when
`driving long distances.
`OCPS antennas and receivers
`Two antennas and receivers were used for the
`design with the following in mind.
`(a) Reception performance when installed inside
`the vehicle.
`ln order to mount the system inside the vehicle, a new
`high-performance microstrip flat antenna with a low-
`noise pre-amp had to be developed to be equipped
`below. The outside dimensions are 72 mm (L) x 72 mm
`(W) x 20 mm (H). See Fig. 9. The concern in
`the pre-amp and antenna unit was radio wave
`designing
`reflection and transmittance within the vehicle
`interior in relation to glass and other materials. A
`diagram of the reception area is shown in Fig. 10.
`(b)A block diagram of the receiver channels is
`given in Fig. 11. The internal processing system has
`a 2-channel, diversity-switchable
`arrangement making
`reception possible from up to 7 satellites. Thus,
`high performance
`is assured even when driving through
`the center of cities where radio wave conditions show
`great fluctuation.
`(DPosition data
`The GPS receiver output contains the fix on
`position together with the error radius calculated on
`the basis of satellite conditions. The position fix
`is output by a WGS-84 system, so it must be converted
`to a Tokyo geodetic system. The conversion data are
`
`incorporated in the CD-ROM map data. For the two-
`dimensional fix, a high degree of accuracy is
`achieved, thanks to sophisticated datia among the CD-
`ROM rnap data.
`Sensor conection-
`tDCeornanetic sensor
`Depending on the magnetism of the vehicle body
`itself, there must be consistent correction to the
`geomagnetic zero point on the geomagnetic sensor.
`This is done with the wheel sensors and GPS fix
`results.
`@Wheel sensor conection
`Correction must be made for the distance and
`peculiar tendency for either wheel to turn in on the
`wheel sensors. This correction is made using the map
`matching and GPS results together with the
`geomagnetic sensor output.
`
`the absolute derection; the wheel sensors which can
`detect the relative direction and the steering
`sens0r.
`The improvement over the previous system lies in
`the addition of a means to use the direction of the
`steering sensor, which outputs its pulse at about
`every 4.5 ' when the wheel sensor output is not
`obtainable at low speed and the direction cannot be
`calculated due to the number of pulses of the right
`and left wheels that output a pulse about every 4.1
`cm. Still another new feature is the determination of
`the most certain status of each sensor, the weighting
`of an integrating position. Figure 8 presents the
`results from integrating data ftom the geomagnetic and
`wheelsensors.
`
`0
`
`300
`100
`200
`Arrival error(n)
`raagptic ssmrs * n+ natdtirg
`
`{00
`
`cFs
`
`,.t
`
`*
`
`Es
`
`r.i
`
`0
`
`300
`r00
`200
`Arrival error(n)
`magetic + *teel sqsors I n4 natdriru
`
`400
`
`Fig. 8. Effects of Geomagnetic + Wheel
`(Average drive d istance :25000km )
`
`34
`
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`
`

`

`Map matching technology -The map matching
`technology automatically conects the vehicle position
`so that it takes the route predicted to be the most
`certain. lt does this by comparing CD-ROM map data
`road configurations with the route obtained by dead
`reckoning (Ref. 4. ). The key to this map matching
`is, of course, the algorithm and the CD-ROM data. In
`this system, highly accurate map matching is possible
`because of the broad data base consisting of urban
`roads and streets over 3.0 m wide and outlying roads
`over 5.5 m wide.
`Determining vehicle position-ln what follows, we
`describe the method used to establish the vehicle
`position consistently using position output from GPS
`and map matching. In map matching we ctrn obtain the
`actual road position of the vehicle, but the absolute
`position is unknown since the calculation is made
`from the starting point to a relative point. GPS, on
`the other hand, can provide the absolute position but
`cannot display it. To display a detailed map (10,000
`to 1) with this system, the vehicle's position must
`be accurately displayed at its actual road position.
`Therefore, the results of map matching must be
`utilized in order to display the present position
`Figure 12 illustrates the overall vehicle
`positioning as determined by map matching. In this
`illustration are a number of possible positions (Ml-
`M4), with a prediction accuracy in the order of Ml -
`M2-M3-M4. Ml and M2, which are within the circle R
`calculated with the estimated error radius where the
`GPS fix coordinate G is the center, emerge as
`candidates. Ml is chosen because of its high map
`matching certitude. M3 and M4, located outside circle
`R, are the least likely positions, so the road traces
`
`Fig. 9. GPS front antenna
`
`Lofuard dirctim
`
`. .
`
`\ Forrard
`I
`i 0rrsilm
`-----l--
`I,
`
`I
`
`t
`
`u " \
`
`R@tim aroa
`(frmt anterma)
`
`Rmptim area
`(rear antnra)
`.'7f\
`
`' i t \
`
`Reamard
`dirctim
`
`IIItt
`
`t
`
`t\\\
`
`Ridtrard dirctim
`
`Fig. 10. Antenna receptorarea demarcations
`
`f rql
`# l
`A N T .
`+
`
`frm
`# l
`A N T .
`ci
`
`# t # 2
`
`M T R X
`sw
`
`data
`calculatim
`C P U
`
`to
`data
`hts
`c+
`
`M T R X S W : m t r i x s i t d r
`SS:spstrur srlarffirt
`
`Fig. 1 1. Diversity-type GPS receiver construction
`
`35
`
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`
`

`

`are stopped. The selection is made on and
`elimination basis so that the most effective road only
`is left. Should there be no candidate within the
`circle when map matching, all road tracing is stopped,
`and a new search is launched for a road with G as the
`center of the circle.
`
`Road networks -The map data base construction and
`updated contents are critical to assure reliable route
`guidance. The nationwide road network is broken down
`into 3 stiages, any of which may be selected in terms
`of one's point of departure and the distance to one's
`destination. The 3 networks are presented in Table 7.
`
`
`
`Table 7. Road Networks for Route Guidance use
`
`Wid+zone
`network
`
`Standard
`network
`
`Detail
`network
`
`Region
`Item
`
`Whole of
`Japan
`
`Whole of
`Japan
`
`Tokyo 23
`wards
`
`Network
`area
`
`Road
`type
`
`300 km x
`
`9 0 k m x
`
`1 4 k m x
`
`. Major
`.Expresway
`'National
`local roads
`roads and
`and larger
`major joint
`roads
`
`. Secondary
`local roads
`and larger
`
`Route search algorithm (path-finding) -The
`Dijk
`route
`calculation for the system. The various intersections
`are searched from the point of departure and the
`shortest distance is calculated to each of the
`intersections. The network cost items serving as the
`basis for the path-finding process are shown in Table
`8.
`
`Table 8. Network Cost
`
`Cost ltem
`
`\
`A Road link length
`
`B RighV left turn cost
`c Traffic regulation cost
`
`D Road classification
`
`E Road width cost
`
`F Expressway priority
`
`G: CSmrrdritiat
`ll{: F Etdrirg projctd pitiqr
`Fig. 12. Vehicle Position Determination
`
`ROUTE GUIDANCE-The other requirement in
`
`automotive navigation is some kind of support system
`that can guide one safely, swiftly, effectively and
`comfortably to a desired destination. In the new
`Electro-Multivision system for navigation, we
`incorporated for the first time and automotive "route
`guidance' function. Some display examples are shown
`in Fig. 13. Route guidance is the function which
`calculates recommended route to be taken from the
`present position to the target destination on the
`basis of the CD-ROM map data. Here we present the
`road networks for the route guidance along with the
`search (path-finding) algorithm.
`
`tEBtrTOlm
`u
`\
`
`+4 1
`f$lt\
`
`:
`
`o . o
`
`r-oJr ...
`l ^ T '
`i
`\
`-L
`HP
`
`Fig. 13. Screen of Route Guidance Function
`
`The calculation is made with the following
`formula
`based upon the various cost coefficients:
`C o s t = ( A + A + C ) r D t E r F
`
`36
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`Google Ex. 1024
`
`

`

`provision of useful information. there is also the
`n e e d t o f u r t h e r r e f i n e d i s p l a y a n d o p e r a t i o n
`technologies while pursuing matters related to human
`interfacing.
`
`REFEREI{CES
`
`1 . S . A z u m a , T . S a i t o u , N . l z u a n d A . K a w a h a s h i ,
`'Development of Toyota Electro-Multivision' Paper
`860175 presented at SAE Int. International Congress
`and Exposition, Detroit, Michigan, February, 1986.
`
`2. Y. Shoji, T. Horibe and N. Kondo, 'Toyota Electro
`Multivision' Paper 880220 presented at SAE
`Int.
`lnternational Congress and Exposition, Detroit,
`Michigan, February, 1988.
`
`3 . Y . l m a i , H . l t o , Y , H a g i s a t o a n d N . K o n d o ,
`Development of a New Electronic Analog Meter' Paper
`900874 presented at SAE Int. International Congress
`and Exposition, Detroit, Michigan, February, 1990.
`
`4. T. ltoh, S. Tunoda, K. Hirano and J. Tanaka,
`'Navigation System with Map Matching Method' Paper
`900471 presented at SAE Int. International Congress
`and Exposition, Detroit, Michigan, February, 1990.
`5. K. lshikawa, M. Ogawa, S. Azuma, and T. ltoh, 'Map
`Navigation Software of the Electro-Multivision of the
`'91 Toyota Soarer ' Paper 912790 presented at SAE
`I n t . V e h i c l e N a v i g a t i o n & I n f o r m a t i o n S y s t e m
`Conference Proceeding, Dearborn, Michigan, October,
`1 9 9 1 .
`
`Once the point of departure and destination have been
`decided, the area to be found lying between these
`points must be determined with the grid maps. lt is
`common to employ the "elliptic approximation" method
`b e t w e e n t h e p o i n t o f d e p a r t u r e a n d t h e t a r g e t
`destination. In the present system, however the "map
`grid approximation" approach is utilized by effective
`use of the path-finding road network so as to save
`processing time.
`From the foregoing, we calculated the route of
`minimum cost, and the processing flow may be stated
`roughly as follows.
`Step 1: The route (path) data file is determined for
`the path from the point of departure and the distance
`to the destination.
`Step 2: The detailed network file (or at least the
`s t a n d a r d n e t w o r k f i l e ) i n c l u d i n g t h e t a r g e t
`destination.
`Step 3: New labeling is performed using the upper
`network level while raking into account node costs
`enroute.
`Step 4: New labeling is performed using the lower
`network level while taking into account node costs
`enroute.
`Step 5: The routing to the target destination is
`obtained by pursuing the low-cost links in order
`beginning with the point of departure.
`Regulation information on roads processed by the
`route guidance function is regarded to be virtually
`error-free. The route determined from the path-
`f i n d i n g p r o c e s s i s c o n s i d e r e d t o b e , g e n e r a l l y
`speaking, the one most certain to lead to the target
`destination no matter who the driver may be.
`
`C O N C L U S I O N
`
`The aim in developing this particular navigation
`system was to lessen the difficulties associated with
`driver uneasiness and lack of information. The result
`was realization of the following new techniques.
`1.
`ln-vehicle application of a mass-produced 5.9-
`inch TFT LCD display, the very state of the art.
`2 One-touch map scrolling display with the touch-
`sensitive panel switch system.
`3 . L o c a t i o n f u n c t i o n u s i n g C D - R O M d i s k
`incorporating 10,000-to-1 scale map data on main
`c i t i e s a n d G P S p l u s t h e i r i n t e g r a t e d p o s i t i o n
`determination technology.
`4. Route guidance from the current position to a
`desired target destination.
`A GPS navigation system of this kind is also
`equipped on Toyotia '92 Crown Models.
`In forthcoming
`d e v e l o p m e n t i n t h e n a v i g a t i o n f i e l d , t h e k e y i n
`product development will be how to incorporate the
`highly diversifying expectations of the user. The
`effect input of extravehicular information, and the
`
`37
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