Vehicle navigation system having inferred user preferences

Abstract: A vehicle navigation system for providing route guidance in response to an input destination. The navigation system comprises a position sensing unit (12) for sensing the location of the vehicle, a user input device (14) for entering preferred route criteria and the desired destination, a display (16) for outputting route guidance information, a controller (18), and a machine learning unit. The machine learning unit communicates with the controller (18) and the user input, and monitors the user-selected preferred route criteria during a learning phase. Once the preferred route criteria have been learned, the machine learning unit enters an intervention phase whereby inferred user-preferred route criteria is transmitted directly to the controller (18). In this manner, users need not enter preferred route criteria upon each navigation sequence.

Description: The present invention relates to a vehicle navigation system having inferred user preferences. Vehicle navigation systems are well-known. A typical vehicle navigation system searches for a route from the present position of the vehicle to the destination, and provides route guidance based upon the route found. Such systems reduce the burden on the driver when the vehicle is travelling on unfamiliar roads. To accomplish this, typical vehicle navigation systems include a function by which a route from the present position to the destination is retrieved in response to entry of the destination by the user, or other user inputs. A preferred route is then calculated and displayed to the driver. Typical vehicle navigation systems also include functions for detecting the present position of the vehicle and displaying the present position along with the desired route, thereby providing route guidance. Conventional vehicle navigation systems allow the vehicle driver to choose among several route calculation criteria such that the navigation system can generate different routes to the desired destination point. For example, the vehicle driver can command the navigation system to determine the shortest distance between the present vehicle location and the destination address. Alternatively, the driver could command the navigation system to determine the shortest route traversal time between the present vehicle location and destination address. This may or may not correspond to the shortest distance route determination. In addition, user preferences could include route determinations such as the most freeway segments possible, or least use of freeways possible. Likewise; the navigation system may include a user preference for toll roads or avoidance of toll roads. WO 93/09511 employs such a system, requiring the user to input preferences with an associated importance, it then uses a fuzzy logic processor in order to determine the most preferred route available based on the criteria and the relative importance assigned to each by the user. Regardless of the type of user preference inputs available, conventional navigation systems require a destination address entry as well as user preferred route calculation criteria each time the navigation system is activated. There are several drawbacks to requiring users to repeatedly input preferred route calculation criteria. Obviously, it is cumbersome and less "user friendly" to require users to input preferred route calculation criteria upon every new navigation experience. Such inconvenience can lead to diminished navigation system use and decreased operator benefit. According to a first aspect of the present invention there is provided a navigation system for automatically providing an automotive vehicle with route guidance in response to an input destination comprising: a position sensing unit for sensing the location of the vehicle; an information storage unit containing map and route information; a user input device for entering preferred route criteria and said destination; a display for outputting route guidance information; and a controller arranged in communication with said position sensing unit, information storage unit, user input and display, said controller including a route calculator for performing a route search from the sensed vehicle location to said destination in accordance with said preferred route criteria and said information storage unit, and displaying route guidance information to said display; characterised by a machine learning unit in operative communication with said controller and said user input, said machine learning unit monitoring said preferred route criteria input from said user input during a learning phase and transmitting inferred user-preferred route criteria to said controller during an intervention phase. According to a second aspect of the present invention there is further provided A method of inferring user preferences for a vehicle navigation system comprising a position sensing unit, a user input device, a display, a controller and a machine learning unit, the method comprising the steps of monitoring, with said machine learning unit, preferred route criteria input from said user input and transmitted to said controller during a learning phase; and, thereafter, entering an intervention phase wherein inferred route criteria is transmitted to said controller in response to an input destination. An advantage of the present invention is enhanced user friendliness as compared to conventional vehicle navigation systems. The present invention will now be described further, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a schematic diagram of a vehicle equipped with a navigation system according to the present invention; FIGURE 2 is a block diagram of one embodiment of a vehicle navigation system according to the present invention; FIGURE 3 is a more detailed block diagram of the navigation system of Figure 2 during the learning phase of operation; and FIGURE 4 is a more detailed block diagram of the navigation system according to Figure 2 during the intervention phase of operation. An embodiment of the invention will now be described in detail herein with reference to the drawings. Figure 1 shows a vehicle 2 with a navigation system 10 according to one embodiment of the present invention. The basic navigation system 10 is shown in greater detail in Figure 2. The navigation system 10 includes sensors 12, a user input 14, output display 16, and a central controller 18. Sensors 12 provide data to the controller 18 to determine the present vehicle location and its relation to a desired destination address. The sensors 12 are conventional and can include a global positioning system (GPS) which communicates with the existing GPS satellite network to provide highly accurate, real-time vehicle location data. The GPS satellite network includes a constellation of radio-navigation satellites which continuously transmit precise timing and location information to substantially the entire surface of the earth. Position sensors 12 located on the vehicle acquire transmissions from the corresponding plurality of GPS satellites. This allows the navigation system 10 to determine the location of the vehicle, velocity, and direction of motion. The GPS data in the sensor set 12 is augmented by dead-reckoning sensors. Dead-reckoning sensors include an absolute heading sensor such as a geomagnetic sensor or the like; a relative heading sensor such as a wheel sensor, steering sensor or a gyroscope; and a distance sensor for sensing travelling distance from the number of revolutions of a wheel. All of the positioning data gathered from the sensors 12 is supplied to the system controller 18. User inputs 14 are similarly supplied to the system controller 18. User inputs 14 are supplied by way of an input apparatus comprising a keyboard or the like for generating various commands to the system controller 18. User inputs 14 can be supplied to the controller 18 using any known methods including keyboard entry, voice input, light pen, and touch screen. Using the input apparatus, the user supplies to the system controller 18 a desired destination address, and a preferred method of calculating the navigation route to the desired destination address. Many possibilities exist for preferred route calculations. These can include: a route which makes the least use of freeway segments; a route which makes the most use of freeways; the shortest route as measured by traversal time; the shortest route measured by distance; and a preference to avoid or use toll roads. Depending upon the communication capabilities of the navigation system 10, such user preferences could also include routes with the least amount of road construction, or the least amount of congestion. These latter two options would require data input from an area-wide traffic monitoring system such as are known in the art. The display apparatus 16 comprises a display such as a CRT or colour liquid-crystal display device or the like; graphic memory comprising VRAM or the like; a graphic controller for drawing map data sent from the system controller 18 as image data in the graphic memory and for outputting the image data; and a controller for displaying the map on the display 16 on the basis of the image data generated from the graphic controller. The display 16 outputs, as a colour display, all screens necessary for navigation such as a route setting screen and screens of interval views of map data. The display 16 can also include the user inputs 14 for setting route guidance as well as inputs for changing over guidance and screens during the route instruction. The display 16 and user inputs 14 are preferably provided as part of, or attached to, the instrument panel in the vicinity of the vehicle operator seat. The controller 18 will now be described in greater detail with reference to Figures 3 and 4. Referring to Figure 3, the navigation controller 18 comprises several regions designated in the block diagram as: machine learning program 20, navigation preference data 22, route calculation criteria 24, route calculator 26, route database 28, and manoeuvre list 30. Machine learning program 20 comprises any known machine learning algorithms to process user inputs 14 to infer user preferences for the navigation system 10. Thus, for example, the machine learning program 20 could include a fuzzy logic system, a neural network, a genetic algorithm, or an expert system. The machine learning algorithms encompassed by machine learning program 20 fall into two categories: symbolic and connectionist. The symbolic methods used are statistical inferencing and ruled based inferencing. These symbolic methods generally depend on string inputs from the user. The connectionist methods employed are neural networks and fuzzy logic systems. Connectionist methods depend on numerical inputs. Thus, string inputs from the user must be transformed into numerical inputs before presenting information to the machine learning algorithms. The operation of the machine learning program 20 to infer user preferences for the navigation system 10 will be described in further detail below. The navigation preference data 22 is derived from the user inputs 14 and presented to the machine learning program 20 as well as the route calculation criteria 24. Navigation preference data includes the user input preferences for the desired route calculation such as: least/most use of freeways, shortest time route, shortest distance route, and toll road avoidance/preference. Such navigation preference data 22 is then stored as route calculation criteria 24. Route calculator 26 is the actual processor of the navigation controller 18. Accordingly, the route calculator 26 comprises an interface for receiving the detected outputs of the sensors 12. A central processing unit (CPU) for executing various image data processes and arithmetic operations, a read only memory (ROM), and random access memory (RAM). The route calculator 26 uses known methods to calculate a route to the desired destination address. Typically, the route calculator will use an algorithm incorporating a breadth-first search employing heuristics at each position node to help determine which position node to. visit next. Navigation preference data 22 in the form of route calculation criteria 24 is added to the heuristics. Route database 28 comprises map data stored as a CD-ROM or other non-volatile memory medium such as DAT, IC card, or the like. The manoeuvre list 30 is the output of the route calculator 26. The manoeuvre list 30 comprises a sequence of manoeuvres that the navigation system presents to the user by way of the display 16. In operation, the navigation system 10 operates in a learning phase (Figure 3) and an intervention phase (Figure 4). During the learning phase, the machine learning program 20 collects and processes preference information entered by the user via signal line 40. Depending upon the machine learning algorithm employed, a pattern of user preference behaviour is determined. Thus, for example, the machine learning program 20 may come to learn that a particular user always prefers that the navigation system present the shortest distance route to the desired destination address. When this pattern of preference behaviour is determined, the machine learning program exits the learning phase and enters the intervention phase. Referring to Figure 4, during the intervention phase, the machine learning program 20 intervenes on behalf of the user. In other words, the machine learning program 20 presents the navigation preference data 22 inferred from the learning phase to the route calculation criteria 24 via signal line 42. This preference data is then passed along with the desired destination address to the route calculator 26. Thus, once in the intervention phase, there is no need for the user to provide route preference criteria. Rather, the user need only input a preferred destination address. Once in the intervention phase, however, the user can override the machine generated preferences by modifying the user inputs 14. To allow the machine learning program 20 to distinguish among different users of the vehicle, user inputs preferably additionally include an input for a user identification such as a password or passcode. This user identification can be tied to the operator identification system of some vehicles which allows the vehicle to store in memory such things as radio pre-sets and seat positions for various users. Such identification can occur by inputting a user code into the navigation system, selecting a user "pre-set" button within the vehicle, entering a user-specific vehicle entry code or the like. From the foregoing, it will be seen that there has been brought to the art a new and improved vehicle navigation system which overcomes the need for the user to repeatedly input route preference criteria such as is typical in conventional vehicle navigation systems.

Claims: A navigation system for automatically providing an automotive vehicle with route guidance in response to an input destination comprising: a position sensing unit (12) for sensing the location of the vehicle; an information storage unit containing map and route information; a user input device (14) for entering preferred route criteria (22) and said destination; a display (16) for outputting route guidance information; and a controller (18) arranged in communication with said position sensing unit, information storage unit, user input and display, said controller including a route calculator (26) for performing a route search from the sensed vehicle location to said destination in accordance with said preferred route criteria and said information storage unit, and displaying route guidance information to said display; characterised by a machine learning unit (20) in operative communication with said controller and said user input, said machine learning unit monitoring said preferred route criteria input from said user input during a learning phase and transmitting inferred user-preferred route criteria to said controller during an intervention phase. A vehicle navigation system as claimed in claim 1, wherein said machine learning unit (20) is an expert system, a genetic algorithm, a connectionist-type machine learning unit, a neural network, a fuzzy logic-based system, or a symbolic-type machine learning unit. A vehicle navigation system as claimed in claim 1, wherein said preferred route criteria (22) includes at least one of the following criteria: the shortest distance route, the shortest time route, the route using the most freeways, the route using the least freeways, routes preferring toll roads, and routes avoiding toll roads. A vehicle navigation system as claimed in claim 1, wherein said preferred route criteria (22) includes routes with the least congestion. A vehicle navigation system as claimed in claim 1, wherein said position sensing unit (12) includes a global positioning system. A vehicle navigation system as claimed in claim 1, wherein said user input (14) includes a touch-screen and/or a voice input device. A method of inferring user preferences for a vehicle navigation system comprising a position sensing unit, a user input device, a display, a controller and a machine learning unit, the method comprising the steps of: monitoring, with said machine learning unit, preferred route criteria input from said user input and transmitted to said controller during a learning phase; and, thereafter, entering an intervention phase wherein inferred route criteria is transmitted to said controller in response to an input destination. A method as claimed in claim 7 further comprising the step of identifying the user of said vehicle navigation system. A method as claimed in claim 7 further comprising the steps of detecting a user-input route preference criteria and, if in the intervention phase, overriding the inferred route criteria and transmitting said user-input route preference criteria to said controller.

Inventors: FECHER DANA BRIAN, STEFAN JEFFERY MICHAEL, WILLIAMS GREGORY HOWARD, FECHER, DANA BRIAN, STEFAN, JEFFERY MICHAEL, WILLIAMS, GREGORY HOWARD
Applicants: FORD MOTOR CO, FORD MOTOR COMPANY
Application year: 2000
Main classification: G01C21
IPC codes: G08G1, G09B29, G06N5, G06F9, G01C21