JP2011191065A - Navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a navigation system capable of performing route search in a lower-ranking layer, in a more appropriate way. <P>SOLUTION: A route search unit 43 calculates an area Sn of a region for re-search needs determination which is surrounded by an intermediate route Rmn, searched for in an upper layer Hn and by the shortest straight line L, and performs re-search for an intermediate route Rmn+1 in a lower-layer Hn+1, when the area Sn of the region for re-search needs determination is a prescribed reference value Sthn or more. An area of a semicircle the diameter of which is the distance between intersections, i.e. the distance between intersections C10 and C20, in this case, is adopted as the prescribed reference value Sthn. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a navigation apparatus for guiding a route from a departure place to a destination.

  In general, in a navigation device, map information necessary for searching for a route from a departure place to a destination is stored in a hierarchy corresponding to the level of detail of the road. The upper hierarchy stores road information of major roads such as expressways, metropolitan expressways, toll roads, and national roads. The lower hierarchy includes all roads including general roads in addition to these major roads. Road information is stored. When performing a route search from the departure point to the destination, the navigation device performs a detailed route search at a lower hierarchy for the vicinity of the departure point and the vicinity of the destination, For intermediate points between them, a rough route search is performed in the upper hierarchy.

  Such a general technique searches for a route that passes through the main road at a higher level at an intermediate point, and therefore searches for a roundabout route from the starting point to the destination. You may be guided.

  Therefore, the technique described in Patent Document 1 detects the current location of the vehicle on which the navigation device is mounted, and searches for a route from the current location to the destination every predetermined time or every predetermined distance. The search for a roundabout route is reduced.

JP 2002-107164 A

  However, in the technology described in Patent Document 1, without determining the possibility that there is a route having a lower route cost than the current route (intermediate route) searched for in the upper hierarchy, every predetermined time, Alternatively, an intermediate route is searched for in a lower hierarchy for each predetermined distance. Therefore, if there is no possibility that a closer route exists, an intermediate route that is the same as the intermediate route searched in the upper layer is searched in the lower layer, and the route search is performed in the lower layer. It has been carried out in vain.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a navigation device that can more appropriately perform a route re-search in a lower hierarchy.

  In order to achieve such an object, in the invention described in claim 1, the departure point setting unit for setting the departure point, the destination setting unit for setting the destination, and the map information in a hierarchy corresponding to the degree of detail of the road In a navigation device comprising: a map information storage unit stored in memory; and a route search unit that searches for a route from the departure point to the destination using the map information stored in the map information storage unit. Searches for the route near the departure point and the route near the destination for an intermediate route that connects the route near the departure point and the route near the destination. A search is performed at a higher level where the level of detail of the road is lower than the level, and the area of the re-search necessity determination area, which is an area surrounded by the searched intermediate route and the shortest straight line connecting the current position and the destination, is calculated. , Need to search again When the area of the cross-sectional area is equal to or greater than the predetermined reference value, characterized in that the re-search an intermediate route of detail of the road than the hierarchy of searching the last intermediate route with high lower hierarchy.

  If the area of the re-search necessity determination area, which is the area surrounded by the shortest straight line and the intermediate route, is large, expect the existence of an intermediate route whose route cost is lower than the intermediate route searched in the upper hierarchy. Can do. In the first aspect of the invention as the navigation device, the route search unit calculates the area of the re-search necessity determination area, and the area of the re-search necessity determination area is equal to or larger than a predetermined reference value. In addition, since the intermediate route is re-searched in the lower hierarchy where the level of detail of the road is higher than the hierarchy in which the previous intermediate route was searched for, there is a closer route with a lower route cost than the intermediate route searched in the upper hierarchy. When there is a high possibility of existing, the intermediate route can be re-searched in the lower hierarchy. As a result, the same intermediate route searched for in the upper layer is reduced from being searched again in the lower layer, and the route can be re-searched more appropriately in the lower layer. It becomes like this.

  In the configuration according to claim 1, in calculating the area of the re-search necessity area, an approximate curve that approximates the intermediate path is obtained, and the area surrounded by the approximate curve and the shortest straight line is calculated by integration. May be. Alternatively, as in the second aspect of the present invention, the intermediate path is composed of a plurality of links, and the path search unit is parallel to sides and parallels parallel to the meridian for each of the plurality of links. A rectangle having sides may be set, and the total sum of the set rectangle areas may be calculated as the area of the re-search necessity area. Alternatively, as in the invention described in claim 7, the intermediate path is configured by a plurality of links, and the path search unit has, for each of the plurality of links, a side parallel to the shortest straight line and an orthogonal straight line. Alternatively, a rectangle having sides parallel to each other may be set, and the total area of the set rectangles may be calculated as the area of the re-search necessity determination region. According to the calculation method using the approximate curve, although the calculation load necessary for obtaining the approximate curve and the calculation load necessary for integration are large, according to the calculation method according to claim 2 or 7, Since a rectangle is set for each individual, the calculation load can be reduced.

  More specifically, in the configuration according to claim 2, as in the invention according to claim 3, the route search unit includes a parallel straight line that passes through the end point on the end point side of the link and is parallel to the meridian and the shortest straight line. A rectangle having a diagonal line connecting the intersection and the end point on the link start point side is set. In the configuration according to claim 2, as in the invention according to claim 4, the route search unit It is preferable to set a rectangle having a diagonal line connecting an intersection of a parallel straight line passing through the end point on the start point side and parallel to the meridian and the shortest straight line and an end point on the end point side of the link.

  Alternatively, in the configuration according to claim 2, as in the invention according to claim 5, the route search unit includes an intersection between a parallel straight line that passes through the end point on the end point side of the link and is parallel to the latitude line, and a link. In the configuration according to claim 2, the route search unit is configured such that the path search unit includes the end point on the start point side of the link, as in the invention according to claim 6. It is preferable to set a rectangle having a diagonal line connecting the intersection of the parallel straight line parallel to the latitude line and the shortest straight line and the end point on the end point side of the link.

  Alternatively, in the configuration according to claim 7, as in the invention according to claim 8, the route search unit includes an intersection of an orthogonal straight line passing through the end point on the end point side of the link and orthogonal to the shortest straight line, and the shortest straight line. A rectangle having a diagonal line connecting the end point on the start point side of the link is set, or in the configuration according to claim 7, the route search unit is connected to the start point side of the link as in the invention according to claim 9. It is preferable to set a rectangle having a diagonal line connecting an intersection of an orthogonal straight line that passes through the end point of the link and an orthogonal straight line orthogonal to the shortest straight line and an end point on the end point side of the link.

  In the configuration according to any one of claims 1 to 9, as in the invention according to claim 10, the route search unit includes an intermediate route searched for in a higher hierarchy as a predetermined reference value. A value determined based on the distance between the intersection points with the shortest straight line may be used. Such predetermined reference values include, for example, a square area with the distance between the intersection points as one side, a semicircle area with the distance between the intersection points as a diameter, and an equilateral triangle area with the distance between the intersection points as one side. In this way, it is preferable to employ the area of the figure determined using the distance between the intersections.

It is a block diagram which shows the whole structure about one Embodiment of the navigation apparatus which concerns on this invention. In the navigation apparatus of this Embodiment, it is a schematic diagram which shows collectively the intermediate route searched in the upper layer, and the intermediate route re-searched in the lower layer. It is a figure for demonstrating the calculation method which calculates the area of the area | region for necessity of re-searching. It is a flowchart which shows an example of the process sequence about the route search process performed by the navigation apparatus of this Embodiment. It is a figure for demonstrating the modification about the calculation method which calculates the area of the area | region for necessity of re-searching.

  Hereinafter, an embodiment of a navigation device according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the navigation device 1 includes a map information storage unit 10, a GPS reception unit 20, an operation input unit 30, a control unit 40, a display unit 50, and an audio output unit 60. The control unit 40 is a computer having a known CPU and a built-in memory, and the CPU implements various functions by executing programs stored in the built-in memory. In the following description, for the sake of convenience, the control unit 40 will be described as having a current location detection unit 41, a destination setting unit 42, a route calculation unit 43, and a route guide unit 44. The navigation device 1 is mounted on a vehicle (not shown).

  The map information storage unit 10 includes, for example, a hard disk drive device, a DVD (digital versatile disc) device, a CD (compact disc) device, a flash memory, and the like, and stores map information. Specifically, as shown in FIG. 2, the map information storage unit 10 includes an upper layer H0 including road information of major roads such as expressways, capital expressways, toll roads, and national roads, and these major roads. In addition to the above, map information is stored in two layers with a lower layer H1 including all road information including general roads. The road information includes link costs such as required time, distance, and toll, and the route cost of the route R from the current location P to the destination T is the sum of the link costs of the links constituting the route R. is there. The map information storage unit 10 is connected to the control unit 40, and the map information and the like are appropriately read by the control unit 40. For convenience of explanation, it is assumed that map information is stored in the map information storage unit 10 in two layers of layers H0 and H1.

  The GPS receiving unit 20 is configured with, for example, a GPS antenna (not shown), and receives GPS signals emitted from a plurality of GPS satellites (not shown). The GPS receiving unit 20 is connected to the control unit 40, and outputs the received GPS signal to the control unit 40.

  The operation input unit 30 is configured by an appropriate input device such as a touch panel or a voice input device, and is connected to the control unit 40. The user of the navigation device 1 can input the destination to the control unit 40 by operating the operation input unit 30.

  The current location detection unit 41 is connected to the map information storage unit 10 and the GPS reception unit 20, acquires a GPS signal received by the GPS reception unit 20, and stores the map information stored in the map information storage unit 10. read out. The current location detection unit 41 is connected to the route search unit 43, and detects the current location of the vehicle using these GPS signals and map information. Further, in the detection of the current location of the vehicle, an error in the current location determined based on the GPS signal is corrected by executing known map matching based on the travel locus of the vehicle on which the navigation device 1 is mounted and the map information. . And the present location information which is the information of the present location S of the vehicle detected in this way is output to the route search part 43.

  The destination setting unit 42 sets a destination on the route guidance based on the destination input from the operation input unit 30. Note that the present destination is not limited to the destination input from the operation input unit 30, and the present destination may be estimated from the history of the current location and the destination, and the estimated destination may be set as the destination on the route guidance. .

  The route search unit 43 is connected to the map information storage unit 10, the destination setting unit 42, and the current location detection unit 41. When the destination information is acquired from the destination setting unit 42, the acquired destination information, current location The route R from the current location P of the vehicle to the destination T is calculated using the current location information input from the detection unit 41 and the map information acquired from the map information storage unit 10. The route search unit 43 is connected to the route guide unit 44. When a route R from the current location P of the vehicle to the destination T is searched, route information that is information on the searched route R is sent to the route guide unit 44. Output.

 In the present embodiment, the route search unit 43 sets the current location P of the vehicle as the starting point of the route R, and searches for the route R from the current location P of the vehicle to the destination T. Therefore, the route search unit 43 corresponds not only to the route search unit described in the claims but also to the departure point setting unit. Not only the current location P of the vehicle is set as the departure location of the route R, but also the point input by the operation input unit 30 may be set as the departure location of the route R.

  The route guide unit 44 is connected to the map information storage unit 10, the route search unit 43, a display unit 50 configured by, for example, an LCD, and an audio output unit 60 configured by, for example, a speaker. When route information is input from the route search unit 43, the route guide unit 44 draws a map image based on the input route information, and causes the display unit 50 to display the drawn map image. Further, the route guide unit 44 outputs a voice guidance or a warning sound from the voice output unit 60 to guide the route to the user.

  Hereinafter, the route search unit 43 and the route guide unit 44 will be further described with reference to FIGS. 2 and 3.

  Among the routes R from the current location P to the destination T, the route search unit 43 uses the layer H0 for the current neighborhood route Rp that is a route near the current location P and the destination neighborhood route Rt that is a route near the destination T. Are searched in a lower layer (not shown in FIG. 2), and an intermediate route Rm0, which is a route connecting these current location neighborhood route Rp and destination neighborhood route Rt, is searched in the upper layer H0.

  However, if the area S0 of the re-search necessity determination area, which is an area surrounded by the shortest straight line L that is a straight line connecting the current position P and the destination T, and the intermediate route Rm0 is large, the intermediate layer searched in the upper layer H0 Presence of an intermediate route having a route cost lower than that of the route Rm0 can be expected.

  Therefore, when the area S0 of the re-search necessity area is equal to or larger than the predetermined reference value Sth0, the route search unit 43 has a lower layer having a higher level of road detail than the layer H0 searched for the intermediate route Rm0. When the intermediate route Rm1 is re-searched at H1, and the area S0 of the re-search necessity determination region is less than the predetermined reference value Sth0, the road detail level is higher than the layer H0 that searched for the intermediate route Rm0. The intermediate route Rm1 is not searched again in the higher lower layer H1.

  In addition, the route guide unit 44 determines that the route cost of the intermediate route Rm1 re-searched in the lower layer H1 is lower than the route cost of the intermediate route Rm0 searched in the upper layer H0. The intermediate route Rm1 re-searched in H1 is guided by the display unit 50 and the voice output unit 60, and the route cost of the intermediate route Rm1 re-searched in the lower layer H1 is searched in the upper layer H0. When the route cost is equal to or higher than the route cost of the intermediate route Rm0, the display unit 50 and the voice output unit 60 guide the intermediate route Rm0 searched for in the upper layer H0.

  The route guiding unit 44 uses a value determined based on the distance between the intersections C10 and C20 between the intermediate route Rm0 and the shortest straight line L as the predetermined reference value Sth0. Specifically, the route search unit 43 employs, for example, the area of a semicircle whose diameter is the distance between the intersection points C10 and C20 as the predetermined reference value Sth0. However, the distance between intersections C10 and C20 is not limited to a semicircle, such as an area of a square having a distance between the intersections C10 and C20 as one side, and an area of an equilateral triangle having a distance between the intersections C10 and C20 as one side. You may employ | adopt the area of the figure defined using.

  Further, if the area for searching for the current vicinity route Rp and the destination vicinity route Rt is narrowed, the area for searching for the intermediate route Rm0 is widened, and the amount of calculation necessary for searching for the route R from the current position P to the destination T is large. Less. On the other hand, if the area for searching for the current vicinity route Rp and the destination vicinity route Rt is widened, the area for searching for the intermediate route Rm0 is narrowed, and the amount of computation required for searching for the route R from the current position P to the destination T is large. Become more. Therefore, ranges near the current location and the destination are determined in advance according to the computing ability of the CPU constituting the control unit 40. By the way, in this embodiment, an area up to a predetermined distance (for example, “10 km”, etc.) centered on the current location (ie, the departure location) is adopted as the neighborhood of the current location, ie, the neighborhood of the departure location. An area up to a predetermined distance (for example, “10 km”, etc.) centered on the ground is employed. In addition to this, for example, an area up to a predetermined linear distance from the current position to the destination (for example, “1/10” or the like) around the current position is adopted as the vicinity of the current position, that is, the vicinity of the departure place. Alternatively, as the vicinity of the destination, an area from the current position to the predetermined distance (for example, “1/10”) centered on the destination may be adopted.

  In FIG. 3, the intermediate route Rm0 searched in the layer H0 in the orthogonal coordinate system having the intersection C10 between the intermediate route Rm0 and the shortest straight line L as the origin and the latitude and longitude as the X axis and the Y axis, respectively, It consists of a total of “12” links of ˜l12. A method for calculating the area S0 of the re-search necessity determination area by the route search unit 43 in this case will be described in detail.

  First, the route search unit 43 calculates intersections C10 and C20 between the intermediate route Rm0 and the shortest straight line L. Here, the intersection points C10 and C20 are end points of the link straddling the shortest straight line L.

  Next, the route search unit 43 calculates the area S0 of the re-search necessity determination region surrounded by the line segment C10-C20 connecting the intersections C10 and C20 and the intermediate route Rm0. Specifically, the route search unit 43 sets the rectangles A1 to A12 for each of the links 11 to 112 constituting the intermediate route Rm0 searched in the layer H0, and the areas of the set rectangles A1 to A12. Is calculated as the area S0 of the re-search necessity determination region.

  For convenience of explanation, the case where the rectangle A5 is set for the link 15 will be described. The route search unit 43 draws a parallel straight line parallel to the meridian from the end point e5t on the end point side of the link 15 and intersects with the shortest straight line L i5t. And a rectangle A5 having a diagonal line connecting the intersection point i5t and the end point e5p on the start point side of the link l5 is set. In FIG. 3, since the links l8 to l12 are parallel to the meridian, the route search unit 43 does not set the rectangles A8 to A12 for the links l8 to l12, and the links l1 to l4, l6 to l7. Then, the rectangles A1 to A4 and A6 to A7 are set in the same manner as the link l5. Then, when the rectangles A1 to A7 are set, the route search unit 43 calculates the total area of the set rectangles A1 to A7 as the area S0 of the re-search necessity area.

  In the present embodiment, the route search unit 43 calculates an intersection point i5t with the shortest straight line L by drawing a parallel straight line parallel to the meridian from the end point e5t on the end point side of the link 15 and calculates the intersection i5t and the link 15 Although the rectangle A5 having the diagonal connecting the straight line connecting the end point e5p on the start point side is set, the present invention is not limited to this. The route search unit 43 draws a parallel straight line parallel to the meridian from the end point e5p on the start point side of the link l5 to calculate an intersection point i5p with the shortest straight line L, and connects the intersection point i5p and the end point e5t on the end point side of the link l5. A rectangle A5 whose diagonal is a straight line may be set.

  The path search unit 43 also includes an unshown intersection of an end point e5p on the start point side of the link 15 and a straight line parallel to the meridian passing through the intersection point i5p and a parallel line parallel to the meridian passing through the end point e5t on the end point side of the link 15. Alternatively, a rectangle A5 having a diagonal line may be set. Further, the route search unit 43 intersects the end point e5t on the end side of the link 15 with a straight line parallel to the parallel line passing through the intersection point i5t and a parallel straight line parallel to the meridian line passing through the end point e5p on the start point side of the link 15 (see FIG. A rectangle A5 having a diagonal line (not shown) may be set.

  The navigation device 1 configured as described above executes the route search process S1 shown in FIG. Up to this point, for convenience of explanation, it is assumed that the map information storage unit 10 stores map information in two layers of layer H0 and layer H1, but in the following, the map information storage unit 10 is not limited to two layers and includes a plurality of layers. Map information is stored. The subscript n attached to the intermediate path Rmn, the intersection C1n, the intersection C2n, the area Sn, and the reference value Sthn means that it is calculated in the layer Hn.

  When the current position P is detected and the destination T is set, the control unit 40 starts executing the route search process S1. When the route search process S1 is started, a route R from the current location P to the destination T of the vehicle is calculated using the current location information, the destination information, and the map information as the processing of step S11. At this time, the route searching unit 43 determines the layer H0 for the current neighborhood route Rp that is the route near the current location and the destination neighborhood route Rt that is the route near the destination among the routes R from the current location P to the destination T. The intermediate layer Rm0, which is a route connecting the current location route Rp and the destination neighborhood route Rt, is searched for in the higher layer H0.

  When the route R from the current location P to the destination T is calculated, the control unit 40 calculates the shortest straight line L that is a straight line connecting the current location P and the destination T as the processing of the subsequent step S12.

  When the process of step S12 is completed, the control unit 40 calculates the intersections C1n and C2n between the intermediate route Rmn and the shortest straight line L as the process of the subsequent step S13, and the line segment C1n-C2n as the process of the subsequent step S14. An area Sn surrounded by the intermediate route Rmn is calculated. Specifically, the control unit 40 draws a parallel straight line parallel to the meridian from the end point on the end point side of the link for each of the plurality of links constituting the intermediate route Rmn searched for in the layer Hn, and generates the shortest straight line L. Is calculated, and a rectangle whose diagonal is the intersection point and the end point on the link start point side is set. Then, the route search unit 43 calculates the sum of the set rectangular areas as the area Sn of the re-search necessity determination region.

  When the process of step S14 is completed, the control unit 40 proceeds to the subsequent determination process of step S15, and determines whether the area Sn calculated in the process of step S14 is equal to or greater than a predetermined reference value Sthn. In the present embodiment, the predetermined reference value Sthn is the area of a semicircle whose diameter is the distance between the intersection points C1n and C2n.

  Here, when it is not determined that the area Sn is equal to or larger than the predetermined reference value Sthn (“No” in the determination process of step S15), the intermediate route cost is lower than the intermediate route Rmn searched in the previous higher layer Hn. The possibility that the route Rmn + 1 exists in the lower layer Hn + 1 is low. Therefore, the control unit 40 ends this route search process S1.

  On the other hand, when it is determined that the area Sn calculated in the process of step S14 is equal to or larger than the predetermined reference value Sthn (“Yes” in the determination process of step S15), the route is more than the intermediate route Rmn searched in the previous upper layer Hn. There is a possibility that the low-cost intermediate route Rmn + 1 exists in the lower layer Hn + 1. For this reason, the control unit 40 proceeds to the subsequent determination process of step S16.

  In step S16, the control unit 40 determines whether or not a lower layer Hn + 1 than the layer Hn searched for the previous intermediate route Rmn is stored in the map information storage unit 10. Here, when it is determined that the lower layer Hn + 1 is not stored (“No” in the determination process of step S16), the control unit 40 cannot search for the intermediate route Rmn + 1 in the lower layer Hn + 1. This route search process S1 is completed.

  On the other hand, if it is determined that the lower layer Hn + 1 is stored (“Yes” in the determination process of step S16), the control unit 40 proceeds to the process of the subsequent step S17 and sets the intermediate route Rmn + 1 in the lower layer Hn + 1. Search again.

  When the process of step S17 is completed, the process proceeds to the subsequent determination process of step S18, and the control unit 40 determines that the route cost of the intermediate route Rmn + 1 re-searched in the lower layer Hn + 1 this time is the intermediate route Rmn searched in the previous upper layer Hn. It is determined whether it is smaller than the route cost. Here, when it is not determined that the route cost of the intermediate route Rmn + 1 re-searched in the lower layer Hn + 1 this time is lower than the route cost of the intermediate route Rmn searched in the previous upper layer Hn (in the determination process of step S18, “ No "), since the route cost of the intermediate route Rmn + 1 re-searched in the lower layer Hn + 1 is equal to or higher than the route cost of the intermediate route Rmn searched in the previous upper layer Hn, the control unit 40 performs this route search processing S1. Exit.

  On the other hand, when it is determined that the route cost of the intermediate route Rmn + 1 re-searched in the lower layer Hn + 1 this time is lower than the route cost of the intermediate route Rn searched in the previous upper layer Hn (“Yes” in the determination process in step S18) Then, the control unit 40 proceeds to the processing of the subsequent step S19, and changes the intermediate route Rmn searched in the previous upper layer Hn to the intermediate route Rmn + 1 searched again in the current lower layer Hn + 1. And the control part 40 transfers to the judgment process of previous step S13, and performs a series of processes of step S13-S19 again. Thus, the route search unit 43 sequentially searches for the intermediate route Rmn.

  In the present embodiment described above, the route search unit 43 calculates the area Sn of the re-search necessity determination region, which is a region surrounded by the intermediate route Rmn searched in the upper layer Hn and the shortest straight line L, When the area Sn of the re-search necessity determination region is equal to or larger than the predetermined reference value Sthn, the intermediate route Rmn + 1 is re-searched in the lower layer Hn + 1. Further, the route guide unit 44 determines that the route cost of the intermediate route Rmn + 1 re-searched in the lower layer Hn + 1 is lower than the intermediate route Rmn searched in the upper layer Hn. The intermediate route Rmn + 1 re-searched in the layer Hn + 1 is guided. When there is a high possibility that a near intermediate route having a lower path cost than the intermediate route Rmn searched in the higher layer Hn is present, the intermediate route Rmn + 1 can be re-searched in the lower layer Hn + 1. As a result, the intermediate route Rmn + 1 identical to the intermediate route Rmn searched for in the upper layer Hn is reduced from being searched again in the lower layer Hn + 1, and the route search in the lower layer Hn + 1 is performed more appropriately. Will be able to.

  In the present embodiment, the route search unit 43 sets a rectangle for each of a plurality of links constituting the intermediate route Rmn, and re-searches necessity determination area for the sum of the set rectangular areas. The area Sn was calculated. According to this calculation method, the calculation load can be reduced as compared with a calculation method in which an approximate curve that approximates the intermediate path Rmn is obtained and the area surrounded by the approximate curve and the shortest straight line L is calculated by integration. Become.

  The navigation device according to the present invention is not limited to the configuration illustrated in the above embodiment, and can be implemented with various modifications without departing from the spirit of the present invention. In other words, for example, the following embodiment can be implemented by appropriately changing the above embodiment.

  In the above embodiment, the route search unit 43, for each of a plurality of links constituting the intermediate route Rmn, passes through the end point on the end point side of the link and is parallel to the meridian and the shortest straight line, A line connecting the end point on the start point side is set as a diagonal line, and a rectangle having sides parallel to the meridian and sides parallel to the parallel is set, and the total area of the set rectangles is set in the area for determining whether to search again. Although the area Sn is calculated, the present invention is not limited to this.

  In addition, for example, the route search unit 43, for each of a plurality of links constituting the intermediate route Rmn, passes through the end point on the link start point side and is parallel to the meridian and the shortest straight line, and the link end point side. A rectangle connecting a line connecting the end points of the rectangle and having a side parallel to the meridian and a side parallel to the latitude is set, and the total area of the set rectangles is determined as the area Sn of the re-search necessity determination area. May be calculated as

  Alternatively, the route search unit 31 may, for each of a plurality of links constituting the intermediate route Rmn, an intersection of a parallel straight line passing through the end point on the end point side of the link and parallel to the parallel and the shortest straight line, and an end point on the start point side of the link A rectangle having a side parallel to the meridian and a side parallel to the latitude line is set as a diagonal line, and the total area of the set rectangles is calculated as the area Sn of the re-search necessity determination area. May be.

  Alternatively, the route search unit 31 may, for each of the plurality of links constituting the intermediate route Rmn, pass through the end point on the link start point side and the intersection of the parallel straight line parallel to the parallel and the shortest straight line, and the link end point side. A line connecting the end points is set as a diagonal line, and a rectangle having sides parallel to the meridian and parallel to the parallel is set, and the total area of the set rectangles is set as the area Sn for the re-search necessity determination region. It may be calculated.

  In addition, for example, the route search unit 43 uses an orthogonal coordinate system having an intersection C1n between the intermediate route Rm and the shortest straight line L as an origin, and a parallel and a meridian as X and Y axes, respectively. In the Cartesian coordinate system rotated by an angle θ formed by, an intersection of an orthogonal straight line passing through an end point on the start point side of the link and orthogonal to the shortest straight line L and the shortest straight line L for each of a plurality of links constituting the intermediate path Rmn And a straight line connecting the end point on the end point side of the link as a diagonal line, a rectangle having a side parallel to the shortest straight line L and a side parallel to the orthogonal straight line is set, and the total sum of the areas of the set rectangles is set It may be calculated as the area Sn of the re-search necessity determination region.

  This will be described in detail with reference to FIG. 5 shown as a diagram corresponding to FIG. As shown in FIG. 5, the route search unit 43 sets rectangles A1 to A12 for each of the links 11 to 112 constituting the intermediate route Rm0 searched in the layer H0, and sets the set rectangle A1. The total area of .about.A12 is calculated as the area S0 of the re-search necessity determination region.

  The case where the rectangle A5 is set for the link 15 will be described. The route search unit 43 calculates an intersection i5p with the shortest straight line L by drawing an orthogonal straight line orthogonal to the shortest straight line L from the end point e5p on the start point side of the link 15. Then, a straight line connecting the intersection point i5p and the end point e5t on the end point side of the link l5 is set as a diagonal line, and a rectangle A5 having a side parallel to the shortest straight line L and a side orthogonal to the shortest straight line Lni is set. When the coordinates of the end point e5p on the start point side of the link 15 are (a, b) and the coordinates of the end point e5t on the end point side are (a ′, b ′), the area of the rectangle A5 is “(a′− a) × b ′ ”. When the path search unit 43 sets the rectangles A1 to A4 and A6 to A12 for the links l1 to l4 and l6 to l12 in the same manner as the link l5, the route search unit 43 needs to search again for the total area of the set rectangles A1 to A12. It is calculated as the area S0 of the non-judgment area.

  In addition, the route search unit 43 sets an orthogonal coordinate system having an intersection C1n between the intermediate route Rm and the shortest straight line L as an origin, and a latitude line and a meridian as X and Y axes, respectively, and an angle θ between the meridian and the shortest straight line L. In the Cartesian coordinate system rotated by a distance, for each of a plurality of links constituting the intermediate path Rmn, the intersection of the orthogonal straight line passing through the end point on the link start point side and orthogonal to the shortest straight line L and the shortest straight line L, A straight line connecting the end points on the end point side is set as a diagonal line, and a rectangle having a side parallel to the shortest straight line L and a side parallel to the orthogonal straight line is set, and the total sum of the set rectangular areas is required to be searched again You may calculate as area Sn of the area for judgment.

DESCRIPTION OF SYMBOLS 1 ... Navigation apparatus, 10 ... Map information memory | storage part, 20 ... GPS receiving part, 30 ... Operation input part, 40 ... Control part, 41 ... Present location detection part, 42 ... Destination setting part, 43 ... Route search part, 44 ... Route guidance unit, 50 ... display unit, 60 ... audio output unit

Claims (10)

A departure point setting section for setting a departure point;
A destination setting section for setting a destination;
A map information storage unit in which map information is stored in a hierarchy according to the degree of detail of the road;
In a navigation device comprising a route search unit that searches for a route from the departure place to the destination using map information stored in the map information storage unit,
The route search unit
For the intermediate route that connects the route near the departure point and the route near the destination and the route near the destination, the hierarchy for searching the route near the departure point and the route near the destination In the upper hierarchy where the level of detail of the road is low,
Calculate the area of the re-search necessity area, which is an area surrounded by the searched intermediate route and the shortest straight line connecting the current location and the destination,
When the area of the re-search necessity determination area is equal to or larger than a predetermined reference value, the intermediate route is re-searched in a lower hierarchy with a higher level of road detail than the hierarchy in which the previous intermediate route was searched. Navigation device. The navigation device according to claim 1, wherein
The intermediate path is composed of a plurality of links,
The route search unit sets, for each of the plurality of links, a rectangle having a side parallel to the meridian and a side parallel to the latitude line, and determines the total area of the set rectangles for determining whether the re-search is necessary. A navigation device that calculates the area area. The navigation device according to claim 2, wherein
The route search unit sets a rectangle having a diagonal line connecting an intersection of a parallel straight line passing through an end point on the end point side of the link and parallel to the meridian and an end point on the start point side of the link. Navigation device. The navigation device according to claim 2, wherein
The route search unit sets a rectangle having a diagonal line connecting an intersection of a parallel straight line passing through an end point on the link start point side and parallel to the meridian and an end point on the end point side of the link. Navigation device. The navigation device according to claim 2, wherein
The route search unit sets a rectangle having a diagonal line connecting an intersection of a parallel straight line passing through an end point on the end point side of the link and a parallel line parallel to a latitude line and an end point on the start point side of the link. Navigation device. The navigation device according to claim 2, wherein
The route search unit sets a rectangle having a diagonal line connecting an intersection of a parallel straight line that passes through an end point on the link start point side and parallel to the latitude line and the shortest straight line, and an end point on the end point side of the link. Navigation device. The navigation device according to claim 1, wherein
The intermediate path is composed of a plurality of links,
The route search unit sets, for each of the plurality of links, a rectangle having a side parallel to the shortest straight line and a side parallel to the orthogonal straight line, and determines whether or not the re-search is necessary for the total area of the set rectangles. A navigation device characterized in that it is calculated as the area of a judgment area. The navigation device according to claim 7,
The route search unit sets a rectangle having a diagonal line connecting an intersection of an orthogonal straight line that passes through an end point on the end point side of the link and is orthogonal to the shortest straight line, and an end point on the start point side of the link. A navigation device characterized by the above. The navigation device according to claim 7,
The route search unit sets a rectangle having a diagonal line connecting an intersection of an orthogonal straight line passing through an end point on the link start point side and orthogonal to the shortest straight line and the shortest line and an end point on the end point side of the link. A navigation device characterized by the above. In the navigation device according to any one of claims 1 to 9,
The navigation device according to claim 1, wherein the route search unit uses a value determined based on a distance between intersections of an intermediate route searched in a higher hierarchy and the shortest straight line as the predetermined reference value.

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