US4757455A — Navigation system for a vehicle

Claim 1

Independent Claim 191 words

A navigation system for a vehicle, comprising: (a) first means for storing map data; (b) second means for detecting geomagnetic North; (c) third means for deducing the current position of the vehicle on the basis of the sensed output of the said second means; (d) fourth means for manually selecting a starting point and a destination; (e) fifth means for selecting a travel course of the vehicle between said starting point and said destination on the basis of said map data from said first means and displaying the travel course of the vehicle on a display with the current position of the vehicle deduced by said third means, and the starting point and the destination selected by way of said fourth means also displayed thereon; and (f) sixth means for comparing the current position of the vehicle deduced by said third means with said stored map data from said first means to determine if the vehicle is travelling on a freeway, said sixth means further changing the travel course display image on the display unit from a diagrammatic map to a road-name display while the vehicle is travelling on a freeway.

Claim 2

Dependent Claim 191 words

A navigation system for a vehicle, comprising: (a) first means for storing map data; (b) second means for detecting geomagnetic North; (c) third means for deducing the current position of the vehicle on the basis of the sensed output of the said second means; (d) fourth means for manually selecting a starting point and a destination; (e) fifth means for selecting a travel course of the vehicle between said starting point and said destination on the basis of said map data from said first means and displaying the travel course of the vehicle on a display with the current position of the vehicle deduced by said third means, and the starting point and the destination selected by way of said fourth means also displayed thereon; and (f) sixth means for comparing the current position of the vehicle deduced by said third means with said stored map data from said first means to determine if the vehicle is travelling on a freeway, said sixth means further changing the travel course display image on the display unit from a diagrammatic map to a road-name display while the vehicle is travelling on a freeway.

Claim 3

Dependent Claim 69 words

The navigation system according to claim 1, which further comprises a manual reset switch wherein when the reset switch is operated, the third means corrects the current position of the vehicle deduced on the basis of the sensed output using the map data stored in the first means and the sixth means is triggered to return the display of the road-name display to that of the diagrammatic map display.

Claim 4

Dependent Claim 59 words

The navigation system according to claim 2, wherein the fifth means displays a message on the display unit to inform an operator to operate the manual reset switch, said message being displayed in response to a comparison of the current position of the vehicle with said stored map data indicating a vehicle location at an exit of the freeway.

Claim 5

Independent Claim 172 words

A method for navigating a vehicle, comprising the steps of: (a) storing image data on roadmap; (b) displaying diagrammatically the map image stored in said step (a); (c) searching an optimum travel course of the vehicle according to data on a selected starting point and selected destination; (d) displaying the diagrammatic map image on which the searched optimum travel course of the vehicle in said step (c) is superposed; (e) displaying the current position of the vehicle along the optimum travel course on the basis of the detected output of a magnetic direction sensor for detecting a direction of the vehicle with respect to the geomagnetic North; (f) determining whether the vehicle has reached a junction to a freeway through which the vehicle will reach the destination on the basis of the current travel position of the vehicle; and (g) changing the travel course display image from the diagrammatic map displayed in said step (d) to a road-name display when determining that the vehicle has reached the junction in said step (f).

Claim 6

Independent Claim 172 words

A method for navigating a vehicle, comprising the steps of: (a) storing image data on roadmap; (b) displaying diagrammatically the map image stored in said step (a); (c) searching an optimum travel course of the vehicle according to data on a selected starting point and selected destination; (d) displaying the diagrammatic map image on which the searched optimum travel course of the vehicle in said step (c) is superposed; (e) displaying the current position of the vehicle along the optimum travel course on the basis of the detected output of a magnetic direction sensor for detecting a direction of the vehicle with respect to the geomagnetic North; (f) determining whether the vehicle has reached a junction to a freeway through which the vehicle will reach the destination on the basis of the current travel position of the vehicle; and (g) changing the travel course display image from the diagrammatic map displayed in said step (d) to a road-name display when determining that the vehicle has reached the junction in said step (f).

Claim 7

Dependent Claim 52 words

The method according to claim 4, which further comprises the steps of: (h) determining whether the vehicle has left said junction to the freeway; and (i) changing the travel course display image from the road-name display to the diagrammatic map when determining that the vehicle has left the junction to the freeway.

Claim 8

Dependent Claim 43 words

The method according to claim 4, wherein the current position of the vehicle when the vehicle travels on the freeway is determined only on the basis of the detected output of a travel distance sensor for detecting the travel distance of the vehicle.

Claim 9

Dependent Claim 87 words

The method according to claim 6, wherein said step (g) further comprises the steps of (h) determining whether the vehicle has reached a predetermined distance before the junction to the freeway at which the vehicle will leave the freeway and (i) displaying the road-name display indicating to exit the junction and push a start button at a tollgate to change the travel course display image from the road-name display to the diagrammatic roadmap display when determining that the vehicle has reached the junction in said step (h).

Claim 10

Dependent Claim 31 words

The method according to claim 7, wherein the current position data on the basis of the detected output of the magnetic direction sensor is cancelled when the start button is pushed.

Claim 11

Dependent Claim 32 words

The method according to claim 8, wherein the current position data of the vehicle is preset to the position data of the tollgate when the start button is pushed at the tollgate.

Claim 12

Dependent Claim 36 words

The method according to claim 8, wherein the current position data of the vehicle is preset to the position data of a first intersection after the travel through the tollgate when the start button is pushed.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-07-12	1992-01-11	1992-07-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-07-12	1996-01-11	1996-07-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-07-12	2000-01-11	2000-07-12	$7700.00	Window Closed / Lapsed

Navigation system for a vehicle

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