Abstract:
An improved navigation system that provides vehicle route navigation information in a more user friendly format than provided by commercially available navigation systems includes a processor coupled to a display, a location device and a memory subsystem. The memory subsystem stores a navigation database that the processor utilizes to display two-dimensional and three-dimensional models of a relevant highway intersection.

Description:
TECHNICAL FIELD  
       [0001]     The present invention is generally directed to route navigation for a motor vehicle and, more specifically, to intersection route navigation system for a motor vehicle.  
       BACKGROUND OF THE INVENTION  
       [0002]     A recent Federal Highway Administration (FHWA) report has indicated that intersection-related motor vehicle accidents consistently make up about 23 percent of the total number of fatal automobile crashes and more than 50 percent of combined fatal and injury automobile crashes. A relatively large number of these accidents result from a driver of a motor vehicle making an incorrect maneuver at a highway intersection, which may generally be attributed to geometric and topological complexities of the highway intersection. Such incorrect maneuvers tend to increase during heavy traffic density. In an effort to aid a driver of a motor vehicle to reach a desired destination, many motor vehicle manufacturers have installed route guidance navigation systems, such as map-based navigation systems and turn-by-turn route guidance navigation systems, within various motor vehicle models.  
         [0003]     A typical map-based route navigation system displays route guidance information on a map image, which has required a driver to devote a good deal of attention to extracting turn guidance information for a particular intersection from the map display. While these types of map displays are generally adequate for determining a current location of a motor vehicle, they are generally inadequate for allowing a driver to determine, in a short amount of time, where the driver needs to go as a typical map display contains a significant amount of information that is not directly relevant to navigation. Further, utilization of current map displays by a driver of a motor vehicle distracts the driver from current traffic situations as the driver must divert their eyes from the road for a relatively long time to accurately view the map display. As a result, navigation information is somewhat difficult for a driver to extract from a map-based navigation system, particularly during high traffic density.  
         [0004]     Furthermore, turn-by-turn route guidance navigation systems tend to be inadequate for highway intersections with complex geometrical and topological characteristics. In such situations, visual arrows and/or spoken instructions may also tend to confuse a driver, rather than allow a driver to safely exit a currently travelled highway. In general, turn-by-turn route guidance navigation systems provide additional non-relevant information and do not provide an adequate view of a relevant portion of an intersection.  
         [0005]     It would be desirable to provide an improved intersection route navigation system for a motor vehicle that limits display of non-relevant information.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention is directed to an improved navigation system that provides vehicle route navigation information in a driver friendly format. Various embodiments of the present invention are directed to a system and method for providing improved motor vehicle route navigation information. A three-dimensional model of a highway intersection, which is included within a selected route and corresponds to an exit point from a currently traveled highway, is displayed within a motor vehicle. Additionally, a two-dimensional model of a route-specific portion of the highway intersection is also displayed. The two-dimensional model includes route guidance indicators for providing maneuvering instructions to an occupant of the motor vehicle.  
         [0007]     In one embodiment, the route guidance indicators are directional arrows. In another embodiment, the two-dimensional model includes an entry node and an exit node connected by an appropriate ramp for the highway intersection. In general, a node defines the intersection of a motor vehicle&#39;s entry direction or one or more exit directions. In one embodiment, the ramp is arched and, in another embodiment, the ramp is straight. As a subset, the highway intersection may include a highway interchange.  
         [0008]     These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:  
         [0010]      FIG. 1  is an exemplary electrical block diagram of a navigation system implemented within a motor vehicle;  
         [0011]      FIG. 2  is an exemplary display of a highway intersection with turn guidance;  
         [0012]      FIG. 3  is a view of an exemplary highway intersection illustrating entry and exit intersection nodes that are connected by an arch ramp;  
         [0013]      FIGS. 4A and 4B  are exemplary displays of three-dimensional (3 D) and two-dimensional (2 D) views, respectively, of a highway intersection provided according to the present invention;  
         [0014]      FIGS. 5A and 5B  are exemplary displays of 3 D and 2 D views, respectively, of the highway intersection of  FIG. 4A  provided according to a different aspect of the present invention; and  
         [0015]      FIGS. 6A and 6B  are exemplary displays of 3 D and 2 D views, respectively, of another highway intersection provided according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     In general, a highway intersection turn guidance display, according to the present invention, may be implemented with three modules; a geometric model of the highway intersection; a data model of the highway intersection; and a three-dimensional rendering of the geometric model. The geometric model of the highway intersection emphasizes common geometric and topological characteristics. As used herein, the term “highway intersection” includes highway intersections and highway interchanges. According to the present invention, instead of modeling an entire highway intersection, only the routes relating to a travel destination, through the intersection, are provided with a 2 D model. In this manner, a 2 D highway intersection diagram  300  (see  FIG. 3 ) is modeled as two simple intersecting nodes, with an entry intersection node  302  and an exit intersection node  304  connected by an arch ramp  306 . As used herein, the term “node” defines an intersection of lines, with each line representing a motor vehicle entry or exit direction. In general, a node has one entry direction and at least one exit direction. A node also typically includes geometric information, such as exit and entry angles, and topological information, such as the number of node branches.  
         [0017]     With reference to  FIG. 2 , a 2 D highway intersection diagram  200  shows an exemplary view of a relevant highway intersection. In a location-enabled motor vehicle, whose position is, for example, tracked by a global positioning system (GPS) receiver, information on an upcoming intersection can be retrieved from an in-motor vehicle navigation database. In general, geometric modeling of an intersection of interest may include the number of exits in the intersection and the angle, e.g., relative to true North, of each exit, as well as the entry intersection node and exit intersection node, all of which are obtained from a navigation database. In addition, other properties of the exit classify the geometric or topological characteristic of the exit, such as a fork, a ramp, a merge and a straight exit, may be determined based on information retrieved from the navigation database.  
         [0018]     According to the present invention, providing and relating a two-dimensional representation of a relevant portion of an intersection to that of a three-dimensional representation of the intersection allows a driver of a motor vehicle to more readily understand complex intersections and navigate therethrough.  
         [0019]      FIG. 1  depicts a block diagram of an exemplary navigation system  100  that may be implemented within a motor vehicle (not shown). As shown, the system  100  includes a processor  102  coupled to global positioning system (GPS) receiver  140 , an AM/FM tuner  124 , audio sources  130 , e.g., including a compact disk (CD) player, a digital versatile disk (DVD) player, a cassette tape player and an MP3 file player, and a display  120 . The processor  102  controls the display of route guidance information on the display  120 , as dictated by manual and/or voice input supplied by a user of the system  100 . In systems that include voice recognition technology, different users can be distinguished from each other by, for example, a voice input or a manual input, and the guidance information may be customized for the user.  
         [0020]     The processor  102  may also control audio provided to a listener, via the speaker  112 , and may also supply various navigation information to a user, via the display  120  and/or the speaker  112 . As used herein, the term processor may include a general purpose processor, a microcontroller (i.e., an execution unit with memory, etc., integrated within a single integrated circuit), an application specific integrated circuit (ASIC), a programmable logic device (PLD) or a digital signal processor (DSP). The processor  102  is also coupled to a memory subsystem  104 , which includes an application appropriate amount of memory (e.g., volatile and non-volatile memory), which may provide storage for one or more speech recognition applications, as well as a navigation database and an application that accesses the navigation database and renders the 3 D and 2 D highway intersection diagrams.  
         [0021]     As is also shown in  FIG. 1 , an audio input device  118  (e.g., a microphone) is coupled to a filter/amplifier module  116 . The filter/amplifier module  116  filters and amplifies the voice input provided by a user through the audio input device  118 . The filter/amplifier module  116  is also coupled to an analog-to-digital (A/D) converter  114 , which digitizes the voice input from the user and supplies the digitized voice to the processor  102  which may execute a speech recognition application, which causes the voice input to be compared to system recognized commands and/or may be used to identify a specific user. In general, the audio input device  118 , the filter/amplifier module  116  and the A/D converter  114  form a voice input circuit  119 .  
         [0022]     The processor  102  may execute various routines in determining whether the voice input corresponds to a system recognized command and/or a specific operator. The processor  102  may also cause an appropriate voice output to be provided to the user through an audio output device  112 . The synthesized voice output is provided by the processor  102  to a digital-to-analog (D/A) converter  108 . The D/A converter  108  is coupled to a filter/amplifier section  110 , which amplifies and filters the analog voice output. The amplified and filtered voice output is then provided to audio output device  112  (e.g., a speaker).  
         [0023]     With reference to  FIG. 4A , a three-dimensional representation of an exemplary relevant highway intersection  400  is depicted.  FIG. 4B , shows a two-dimensional representation  402  of a relevant portion of the intersection  400 . As is shown, the representation  402  includes directional arrows  404  that aid a driver in understanding how to navigate through the highway intersection  400 . As is discussed above, the intersection  400  and its two-dimensional representation  402  are both displayed on the display  120  and provide information that is readily deciphered in heavy traffic conditions.  
         [0024]      FIG. 5A  depicts a three-dimensional representation of another relevant exemplary highway intersection  500 . With reference to  FIG. 5B , a two-dimensional representation  502  of a relevant portion of the intersection  500  is shown. The representation  502  includes directional arrows  504  that aid a driver in understanding how to navigate through the highway intersection  500 . The intersection  500  and its two-dimensional representation  502  are both displayed on the display  120  and provide information that is also readily decipherable in heavy traffic conditions.  
         [0025]      FIG. 6A  shows a three-dimensional representation of another exemplary highway intersection  600 .  FIG. 6B  depicts a two-dimensional representation  602  of a relevant portion of the intersection  600 . As is shown, the representation  602  includes directional arrows  604  that aid a driver in understanding how to navigate through the highway intersection  600 . As above, the intersection  600  and its two-dimensional representation  602  are both displayed on the display  120  and provide information that is readily deciphered in heavy traffic conditions.  
         [0026]     Accordingly, a number of displays and a system for providing the displays have been described herein that allow a driver to more readily navigate an intersection of interest.  
         [0027]     The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the doctrine of equivalents.