Abstract:
The invention relates to a method and a device for combining an in-vehicle navigation system with a sound system in a vehicle. The combination permits the navigation system to project audible maneuver instructions to a driver. While projecting the audible maneuver instruction to the driver the vehicle navigation system moves the location of the projection of the maneuver instruction from a first location to a second location. The first location does not coincide with the content of the maneuver instruction and the second location does coincide with the content of the maneuver instruction. Thus, a system is provided wherein the driver perceives the audible maneuver instruction as moving in a direction which coincides with the content of the instruction.

Description:
BACKGROUND OF THE INVENTION 
     This invention generally relates to navigation or route guidance systems and, more particularly, to a navigation system that provides audible route guidance instructions to a user of the navigation system. 
     Navigation systems generally provide a recommended route from a starting point to a desired destination. Generally, the starting point and desired destination are selected from a large database of roads stored in a mass media storage, such as a CD ROM, which includes the roads in the area to be travelled by the user. The navigation system can be located in a personal computer or it can be installed in a vehicle. If the navigation system is installed in a vehicle, the starting point is typically the current position of the vehicle, which can be input to the navigation system by an associated position determining system that usually includes a GPS (Global Positioning System) receiver. 
     The navigation system determines a route from the starting point to the destination utilizing an algorithm well-known to those in the art and currently in use in many navigation systems. Usually there are many potential routes between the selected starting point and the desired destination. Typical navigation systems select a recommended route based upon certain “cost” values associated with each segment of road in the road database. These cost values include the length of the road segment and the estimated time of travel through the road segment. The navigation system selects the potential route with the lowest total cost to be the recommended route. Depending upon the predetermined algorithm of the navigation system, the navigation system will recommend the route with the shortest total length, the lowest total time, or some weighted average of length and time. 
     The recommended route is then displayed to the user as a map showing the starting point and desired destination and highlighting the recommended route. Preferably, if the navigation system is installed in a vehicle, the navigation system displays the current position of the vehicle and provides visual turn-by-turn instructions to the driver, guiding the driver to the selected destination. 
     Many navigation systems also provide audible turn-by-turn instructions to the driver. One such system is that disclosed in U.S. Pat. No. 5,406,492 wherein an instruction is perceived by the driver to be emanating from a fixed direction that is determined by the content of the instruction. One disadvantage of such a system is that drivers do not always correctly perceive the direction of the fixed source and thus any benefit derived by associating the source of the instruction with its content is lost. 
     Thus, it is desirable to provide a system for projecting audible instructions that enhances the ability of a driver to correctly perceive the content of the instruction. It is also desirable to provide a system that is readily adaptable to a typical vehicle audio system. 
     SUMMARY OF THE INVENTION 
     In general terms, this invention provides a vehicle navigation system in combination with a vehicle audio system that provides audible maneuver instructions to a driver, which the driver perceives as moving in a direction that corresponds to the content of the instruction. 
     The navigation system generally includes a database of a plurality of roads, a position determining system, an input device, and a route determination system. The position determining system determines a position of the vehicle relative to the plurality of roads. The user selects a destination from the database with the input device. The route determination system determines a route from the position of the vehicle to the selected destination via a plurality of maneuvers on the plurality of roads. The navigation system generates an audible maneuver instruction based on one of the plurality of maneuvers. The sound system, which is connected to the vehicle navigation system, is used by the navigation system to project the audible maneuver instruction. The audible maneuver instruction is generated from a first location and a second location and is moved from the first location to the second location during the output of the audible maneuver instruction. 
     The method of the invention comprises the steps of determining a route on a plurality of roads between a starting position and a destination. Selecting a first audible maneuver instruction from a database of audible maneuver instructions based on the determined route. The first audible maneuver instruction is initially projected from a first location and moved to a second location, which is based on the content of the first audible maneuver instruction, while projecting the first audible maneuver instruction. 
     This invention enhances the ability of a driver to perceive the content of an audible maneuver instruction using the audio system typically found in a vehicle. 
     These and other features and advantages of this invention will become more apparent to those skilled in the art from the following detailed description of the presently preferred embodiment. The drawings that accompany the detailed description can be described as follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic of a navigation system connected to a sound system installed in a vehicle; 
     FIG. 2 is a schematic of a processor connected to a sound system and a plurality of loud speakers; and 
     FIG. 3 is a cross-sectional view of the vehicle with the navigation system and sound system of the present invention installed within the vehicle. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The navigation system  20  of the present invention is shown schematically in FIG.  1 . The navigation system  20  includes a CPU  22  (Central Processing Unit) connected to a display device  24 , such as a high resolution LCD or flat panel display. The CPU  22  is also connected to an input device  26 . The navigation system  20  further includes a database  28  connected to the CPU  22 . The database  28  is a mass media storage device, such as a CD ROM or hard drive, which includes a map of all the roads in the area to be travelled by the user. Each road in the database is divided into road segments, each having an associated set of cost values, which indicate the “cost” of traveling that road segment. For example, the cost values may include the length of the road segment, the estimated time to travel the road segment, and the type of road (i.e., highway, secondary road, toll road, one way, etc.). 
     The navigation system  20  can, but need not, be installed in a vehicle  32 . The navigation system can be used in conjunction with position determining devices, such as a GPS receiver  34 , a gyroscope  36 , a compass  38 , an orthogonal multi-axis accelerometer  40 , and a vehicle speed sensor  42 , all connected to the CPU  22  (connections not shown for simplicity). Such position determining devices are well-known and are commercially available. Preferably, a combination of these position determining devices is utilized. A sound system  44  is also connected to the CPU  22 . 
     FIG. 2 is a schematic of the CPU  22  connected to the sound system  44 . The CPU  22  further includes a database of audible maneuver instructions  50 , a route determination system  52 , and a future position calculator  54  all preferably implemented in software in the CPU  22 . The sound system  44  includes a sound amplifier  56 , a three dimensional (“3-D”) sound generator  57  and a volume regulator  58 . A plurality of loud speakers  60   a - 60   d  are connected to the sound system  44 . Preferably, the audible maneuver instructions are voice commands, but they could also be tones or other sounds. The 3-D sound generator  57  is of a conventional type known in the art. The 3-D sound generator  57  creates the impression that the sound is coming from a specific location, which may not coincide with the location of any of the plurality of loud speakers  60   a - 60   d.  The spatial impression created by the 3-D sound generator  57  enables the sound system  44  to project an audible maneuver instruction from any point within a 360° radius of the driver and also from a location either above or below the driver. 
     In FIG. 3 the CPU  22  and sound system  44  are shown installed in the vehicle  32 . The vehicle  32  includes an engine compartment  62 , a passenger compartment  64 , and a trunk  66 . Each of the loudspeakers  60   a - 60   d  is placed in one of the four comers of the passenger compartment  64 . 
     By way of illustration, the method of the present invention and the use of the navigation system  20  in combination with the sound system  44  will be described as it would be used to instruct a driver to make a right turn. As will be understood by one of ordinary skill in the art, the method and system would be similarly utilized to provide other route guidance instructions to the driver. 
     First, a user selects a destination from the database of roads  28  with the input device  26 . Then the route determination system  52  in the CPU  22  determines a route from the current position of the vehicle to the selected destination on the database of roads  28 . The CPU  22  then displays at least a portion of the route on the display device  24  including the first maneuver, which is generally displayed as a directional arrow having a shape that corresponds to the first maneuver. In addition, the CPU  22  selects a first audible maneuver instruction from the database of audible maneuver instructions  50  based on the first maneuver on the determined route. In our example, this first audible maneuver instruction might be the following: “Turn right at the next intersection.” 
     The content of the first audible maneuver instruction and the direction associated with it coincides with the location of loudspeaker  60   a  in FIG.  3 . The CPU  22  through the sound system  44  would initially begin projecting the instruction through loudspeaker  60   d,  which is in a location that does not coincide with the direction associated with the instruction. While projecting the instruction the CPU  22  would also begin projecting the instruction through loudspeaker  60   a.  The CPU  22  would then complete projecting the first maneuver instruction entirely from loudspeaker  60   a.    
     Changing the location that the first audible maneuver instruction is projected from while projecting the first audible maneuver instruction will cause the driver to perceive the first audible maneuver instruction as moving from loudspeaker  60   d  to  60   a  during projection of the instruction. This movement of the instruction will create a “whooshing” effect that will enhance the ability of the driver to perceive the content of the first audible instruction maneuver. As will be understood by one of ordinary skill in the art, this could also be accompanied by the CPU  22 , through the volume regulator  58 , increasing the volume of the instruction as it is projected. 
     As should be understood, this whooshing effect could also be achieved by volume biasing. In such a method, the CPU  22  would initially project the first audible maneuver instruction from both loudspeaker  60   d  and loudspeaker  60   a  with the volume of the instruction projected from loudspeaker  60   d  being significantly higher than the volume of the instruction as projected from loudspeaker  60   a . Then, while projecting the first audible maneuver instruction the CPU  22  would increase the volume at loudspeaker  60   a  while decreasing the volume at loudspeaker  60   d  during the projection of the first audible maneuver instruction. This volume biasing would also create a whooshing effect perceived by the driver of moving the instruction from loudspeaker  60   d  to loudspeaker  60   a.    
     When the sound system  44  includes the 3-D sound generator  57 , the whooshing effect that is created may include additional spatial characteristics that are perceived by the driver. For example, projecting the first audible maneuver instruction for a right turn, the 3-D sound generator  57  would create a first audible maneuver instruction that the driver would perceive as whooshing along a pathway in the passenger compartment  64  that coincides with the shape of the directional arrow displayed by the CPU  22  on the display device  24  as noted above. As an additional benefit, when the maneuver actually also involves an upward or downward component such as when exiting onto an off ramp of a highway or entering an on ramp of a highway, respectively, the 3-D sound generator  57  would generate an audible maneuver instruction that is perceived by the driver as whooshing not only in the direction of the right hand turn but also either upwardly or downwardly in a direction that coincides with the actual maneuver being performed. 
     A second feature of the method of the present invention is to repeat an audible maneuver instruction a plurality of times prior to the position where the maneuver is to be executed. The CPU  22  in conjunction with the GPS receiver  34  accurately determines its current position on the database of roads  28 . Utilizing the vehicle speed sensor  42  and a direction of travel indicator such as the compass  38  the future position calculator  54  of the CPU  22  determines a future position of the vehicle  32 . At predetermined distances between the current position and a calculated future position the CPU  22  repeats the first audible maneuver instruction. In addition, the volume of the first audible maneuver instruction increases as the distance between the current position and the calculated future position, which coincides with the position of the first maneuver, decreases. 
     If a user should fail to execute the next required maneuver on the determined route, the CPU  22  projects the first audible maneuver instruction from one of the rear loudspeakers  60   c  or  60   d . In the example described above, if a driver had failed to make the right turn, the CPU  22  would project the first audible maneuver instruction from the right, rear loudspeaker  60   c.    
     A third feature of the method of the present invention is that the sound system  44  can also be used to cue a driver as to the relative location of a icon on the display device  24 . Such a cue would be a sound projected from a location that coincides with the location of the icon on the display device  24 . For example, an icon located in the upper right quadrant of the display device  24  would be cued to the driver by projecting a sound that the driver would perceive as emanating from a location ahead and to the right of the driver. The sound cue could either be a tone or voice command. 
     As will be understood by one of ordinary skill in the art other maneuvers such as a left-hand turn would be projected in an appropriate fashion as described above to provide to the driver a perception that the audible instruction maneuver is moving in a direction coinciding with the content of the audible maneuver instruction. 
     The foregoing description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of this invention. Accordingly, the scope of legal protection afforded this invention can only be determined by studying the following claims.