Abstract: According to the present invention, methods and apparatus are provided to generate notification about condition changes behind a vehicle. Information about a first set of conditions behind a vehicle is gathered at a first point in time. Information can be gathered using imaging devices, infrared detectors, distance meters, light intensity sensors, and timing devices. At a later point in time, information about a second set of conditions behind the vehicle is gathered. The information gathered at a first point in time is compared to the information gathered at the later point in time to determine differences between the conditions behind the vehicle. If the differences meet a notification criterion, a notification is generated conveying information about the changed conditions behind the vehicle.

Abstract: The present invention provides a computer implemented method and apparatus for providing a directional arrow to intermediate locations to aid a user of a vehicle navigation system. According to one aspect of the present invention, a vehicle navigation system is provided and includes a processor configured to determiner the vehicle location from location data generated by a plurality of sensors. Where the location data does not correspond to map data in a map database, a directional indicator is generated on the display to indicate a first location corresponding to the map data. In one embodiment, the first location corresponds to a road segment in the map database nearest the vehicle location. In another embodiment, the processor is configured to identify an intermediate location on the route and generate a directional indicator on the display which indicates the direction to the intermediate location.

Abstract: The present invention provides a computer implemented method and apparatus for providing a directional arrow to intermediate locations to aid a user of a vehicle navigation system. According to one aspect of the present invention, a vehicle navigation system is provided and includes a processor configured to determiner the vehicle location from location data generated by a plurality of sensors. Where the location data does not correspond to map data in a map database, a directional indicator is generated on the display to indicate a first location corresponding to the map data. In one embodiment, the first location corresponds to a road segment in the map database nearest the vehicle location. In another embodiment, the processor is configured to identify an intermediate location on the route and generate a directional indicator on the display which indicates the direction to the intermediate location.

Abstract: The present invention enables a vehicle navigation system to automatically compensate for odometer measurement errors due to changes in tire size and/or slip, and to avoid odometer recalibration when slip is present. These capabilities improve the accuracy and reliability of the vehicle navigation system. Slip of a vehicle, e.g., a loss of traction, can occur when a road is wet or covered with snow or ice. It can occur when a road is dry, and a vehicle is accelerating or decelerating rapidly. It can occur rounding a sharp corner. Because an odometer is typically hooked up to a driven wheel, the engine or transmission, there may be large sources of error in the distance estimates derived from the odometer. Utilizing conveniently derived slip signals from an anti-lock brake system (ABS) or from a traction control system (TCS), the slip of the vehicle can be accounted for, even absent a GPS signal to recalibrate the system.

Abstract: Methods and apparatus are described for providing route guidance to a user of a vehicle navigation system. In response to selection of a destination by the user, a route is generated from a first position to the destination. The route includes a plurality of maneuvers. A plurality of maneuver instructions are generated corresponding to the plurality of maneuvers. An audio representation of each of the maneuver instructions is presented prior to execution of a corresponding one of the maneuvers. In response to a first signal generated when the vehicle is at a first location on the route, all remaining maneuver instructions corresponding to maneuvers on the route after the first location are sequentially presented. According to another embodiment, a most recently presented maneuver instruction is presented in response to the first signal. According to yet another embodiment, the audio level associated with at least one instruction is adjusted in response to the first signal.

Abstract: The present invention discloses an improved vehicular inertial guidance navigation system, a.k.a. a dead reckoning system for navigation of a vehicle. The inertial guidance navigation system which may be used alone or in combination with other position determination means, such as GPS and map databases, to determine the location of a vehicle. The dead reckoning system has several advantages over existing systems. First, it can be easily mounted to the chassis of any vehicle. Second, it does not require any interface with existing sensors on the vehicle. Third, the system contains logic for removing errors in the position and heading determinations, brought about by angulation/rotation of the chassis and inertial guidance sensors, brought about by inclination or tilt of the chassis, with respect to an inertial/quasi-inertial frame of reference, such as the earth. The inertial guidance system includes: an inertial guidance sensor, a translation unit, and a logic unit.

Abstract: A method for selecting a destination in a vehicle navigation system is described. A plurality of options are provided for designating the destination in the system's user interface. A first option employs at least one street name to designate the destination. In response to selection of the first option, a list of cities is provided for display in the user interface. The list of cities includes a first plurality of cities for which no street names are available for display and a second plurality of cities for which only a few street names are available for display. In response to selection of one of the first plurality of cities from the list of cities, a first location associated with the selected city in the map database is selected as the destination.

Abstract: An apparatus and method for more accurately determining the position of a moving object by using an azimuth detector distinct from an angular speed detector to correct the gain error and the offset error of the angular speed detector. The position of the moving body is determined using the offset error- and gain error-corrected angular speed. The correction of the offset error includes checking the azimuth and movement of the moving object for three predetermined periods of time; then checking whether the moving object was moving in a straight line each of the three predetermined periods of time. If the object was moving in a straight line each of the three predetermined periods of time, then an offset error correction value is computed using data from the second of the three predetermined periods of time.

Abstract: Methods and apparatus are described for displaying information corresponding to a current vehicle position on a display of a vehicle navigation system. After the current vehicle position is determined by a separate process, the system determines the road on which the vehicle is currently located. The system then refers to a map database to construct a current road database corresponding to the current road. A current road segment corresponding to the current vehicle position is then determined. The system then refers to the current road database to determine a first geographical location based on the current vehicle road segment. The system then displays a text representation of the current vehicle position relative to the first geographical location.

Abstract: A technique for determining a gyro zero voltage is provided. A gyroscope ("gyro") is installed in an automobile as a component of an on-board navigation system. The gyro outputs a voltage representing an angular velocity of the vehicle. The gyro output voltage representing zero angular velocity ("gyro zero voltage") is determined by first determining when the vehicle is stationary based upon the amount of noise in the output voltage of the gyro. When the vehicle is determined to be stationary, the gyro zero voltage is measured.

Abstract: A method for selecting a destination in a vehicle navigation system is described. A plurality of options are provided for designating the destination in the system's user interface. A first option employs at least one street name to designate the destination. In response to selection of the first option, a list of cities is provided for display in the user interface. The list of cities includes a first plurality of cities for which no street names are available for display and a second plurality of cities for which only a few street names are available for display. In response to selection of one of the first plurality of cities from the list of cities, a first location associated with the selected city in the map database is selected as the destination.

Abstract: A method for transmitting data from a navigation system to a vehicle controller in a vehicle having a plurality of systems controlled by the vehicle controller is described. The plurality of systems includes a user interface and the navigation system. A request is received from the vehicle controller for interface data of a particular data type to be presented in the user interface. A first transmission protocol is selected from a plurality of transmission protocols for transmitting the interface data to the vehicle controller. The first transmission protocol is selected based, at least in part, on the data type of the interface data. The interface data are then transmitted to the vehicle controller according to the first transmission protocol.

Abstract: Methods and apparatus are described for selecting an entry from a list of entries in a vehicle navigation system. First and second objects are presented on the system display. The first object includes the list of entries and the second object includes a character slot and a selection window comprising a plurality of adjacent character spaces. The second object is operable to present a sequence of characters in the character slot and to enter one of the characters in each of the character spaces in response to manipulation of an input device associated with the navigation system. An arrangement of the characters is presented in the adjacent character spaces of the selection window and the character slot in response to manipulation of the input device. For each of the characters entered in the selection window, a first entry in the list of entries is highlighted, the first entry corresponding to the arrangement of characters in the selection window and the character slot.

Abstract: A method of using a DOS file system to access a file in a database is provided. In one embodiment implemented in an on-board vehicle navigation system, the file includes map data for a given geographic area. A file access table (FAT) is associated with the file system and references the file. The FAT has a plurality of locations, each location including a reference to one of the data clusters of the file and to another location in the FAT, forming a linked list of the references. The logical order in which the data clusters occur within the file is determined by following the linked list in the FAT for that file. A cluster table is then constructed for the file. The references to the data clusters are stored in consecutive locations of the cluster table according to the logical order of the data clusters within the file. The file is then accessed by sequentially accessing the consecutive locations in the cluster table to retrieve the data clusters.

Abstract: A method and apparatus provide access to an interactive product to a passenger of a vehicle while limiting access to the interactive product to the driver of the vehicle. At least one control device is provided for allowing user interaction with the interactive product. Interaction with the interactive product via the at least one control device is inhibited while the vehicle is moving. An access device is provided which must be employed in conjunction with the at least one control device to enable user interaction with the interactive product while the vehicle is moving.

Abstract: A method and apparatus for selecting a destination in a vehicle navigation system are described. The vehicle navigation system includes a display and a selection control. A first destination is selected from a primary list of destinations in response to a selection signal generated by the selection control. The first destination is placed on a secondary list of destinations in response to its selection. The secondary list includes previously selected destinations from the primary list. For subsequent destination selections, the primary and secondary lists are presented on the display thereby facilitating selection of destinations from both the primary and secondary lists. A feature by which the system may search for a destination across categories is also described.

Abstract: A method of enabling an on-board vehicle navigation system to compute a route from a current position of the vehicle to a desired destination is provided. A user of the navigation system in a vehicle utilizes a cellular telephone or any other wireless, two-way audio communications link to contact an operator in a remote communications center. The user informs the operator of his desired destination. The operator in the communications center accesses a computer database to determine the exact location of the desired destination in terms of latitude/longitude, street address, or other similar information. The operator then causes the information specifying the exact location to be transmitted from the communications center to the on-board vehicle navigation system over a data link. The on-board vehicle navigation system receives the location information and uses it to compute a route from the vehicle's current position to the desired destination.

Abstract: Methods and apparatus for generation of a route from a source location to a final destination are described. According to one embodiment, a two-ended search is performed based on the principles of the A* algorithm. That is, two routes are simultaneously generated, one from the source to the destination, and one from the destination to the source. According to another embodiment, a route generation algorithm determines when to stop searching for route candidates. The algorithm searches a map database for a first number of iterations thereby generating a first route candidate. After generation of the first route candidate, searching of the map database is terminated after a second number of additional iterations. A best route candidate is then selected as the route.

Abstract: A method and apparatus for determining an alternate route from a new source location located on an original route to a subsequent location on the original route using a vehicle navigation system are described. A portion of the original route to be avoided by the alternate route is determined which begins at the new source location. The portion of the original route includes a plurality of segments each of which has an original parameter associated therewith. Selected ones of the original parameters are adjusted thereby resulting in a plurality of adjusted parameters. The alternate route is then determined based in part on the adjusted parameters.

Abstract: An on-board automobile navigation system provides route guidance instructions to a user. The system detects a power-down of the vehicle and, in response, determines whether to resume route guidance in response to the next start-up of the vehicle. This determination is made prior to powering down the system. The determination is based on the current position of the vehicle and the computed route. If a determination was made to resume guidance after start-up, the selected destination and the computed route are saved in memory before powering down the system. If a determination was made to resume guidance, then in response to the next start-up of the vehicle, the selected destination and the computed route of the vehicle are recalled from memory, and route guidance is resumed from the current position of the vehicle.