JP3548014B2 - Map display device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a map display device that measures a current position using a GPS (Global Positioning System) satellite, displays a mark indicating the current position on a display, and displays map information overlapping the mark. In particular, the present invention relates to a map display device suitable for carrying.
[0002]
[Prior art]
As shown in FIG. 7, the so-called navigation system mounted on the vehicle has a basic configuration including a GPS antenna 1, a GPS receiver 2, a navigation control unit 3, a CD-ROM drive device 4, and a display device 5, Radio waves 7 from a plurality of GPS satellites 6 (three when performing two-dimensional positioning of latitude and longitude) are received by the GPS antenna 1, and the received signals are demodulated by the GPS receiver 2 to measure the current position. The navigation controller 3 combines the mark indicating the current position with the map information read from the CD-ROM drive 4 and sends it to the display 5 to provide visual route guidance to the driver or passenger. However, the device configuration was large and could not be carried and used as it was.
[0003]
On the other hand, there is also known a navigation system in which the large and bulky CD-ROM drive device of the above basic configuration is not required and can be carried. In this improved system, as shown in FIG. 8, a necessary range 8a is selected from the map displayed on the map server 8 (in the figure, the Kanto and Chubu districts are selected for convenience), and the range 8a is selected. Is downloaded (transferred) to the navigation system 9 and carried, and the map server 8 is, for example, a personal computer. The map disk 11 is set in the CD-ROM drive device 10 of the map server 8, and a predetermined application program is executed by the map server 8 to select a necessary map information range and transfer the information to the navigation system 9. . The transferred map information is stored in the semiconductor storage memory of the navigation system 9, and is thereafter provided for displaying the map when the navigation system 9 is carried.
[0004]
By the way, in any of the above navigation systems, the map stored in the map disk 11 is made with "North" facing upward, and the map projected on the screen of the navigation system 9 is also oriented with the top of the screen facing north. However, when using such a navigation system 9 outdoors, it is necessary to check the north with a compass (magnet), turn the top of the screen to the north, and then compare the displayed map with the surrounding terrain. In addition, it is inconvenient to use and there is an inconvenience that an erroneous judgment cannot be denied if the user does not have a compass.
[0005]
Therefore, it is known that the navigation system 9 is provided with azimuth position detecting means such as a geomagnetic sensor or a gyro sensor and corrects the direction of the display map based on the azimuth information of the system body detected by the azimuth position detecting means. I have. For example, as shown in FIG. 9, a technique is known in which when the direction is changed while holding the navigation system 9, the direction of the map display on the screen is changed according to the movement. In other words, when facing north, the display map is also pointing north (for example, the road 13 extending north and south is parallel to the north azimuth mark 14). Accordingly, the direction of the display map also changes (the tip of the road 17 extending to the northeast is on the top), and when the direction is changed to 90 degrees, the direction of the display map also changes (the tip of the road 18 extending to the east is changed). On).
[0006]
The user of the navigation system 9 may adjust the direction of the current position mark 12 on the screen to the road on which the user intends to go. For example, when it is desired to proceed on the road 18 heading east, the direction of the current position mark 12 indicates the road 18 when the direction is changed by 90 degrees, so that the foot may be moved forward as it is. Since the azimuth of the display map corresponds to the azimuth of the actual terrain, there is a target road 18 in the traveling direction.
[0007]
By the way, especially in the handheld navigation system 9, a delicate change in the direction of the system body due to the fine movement of the hand or body is inevitable. For this reason, the direction of the display map is corrected even with a very slight change in the direction, so that the screen is frequently rewritten and it is not easy to see, and the map cannot be used during the correction processing.
[0008]
Therefore, Japanese Patent Application Laid-Open No. 7-280582 discloses a technique in which the display map is not modified unless the azimuth change of the system body exceeds a predetermined angle. According to this technique, assuming that the predetermined angle is 45 degrees, as shown in FIG. 10, the map display does not change at all even if the body direction changes to 45 degrees. The orientation is corrected.
[0009]
[Problems to be solved by the invention]
However, in the technology described in the above publication, since the azimuth change within a predetermined angle is completely ignored, for example, when the predetermined angle is 45 degrees, the direction of the display map and the direction of the actual terrain Azimuth deviation of up to 45 degrees occurs between the two, and there is a problem in that the azimuth determination is hindered particularly at a complicated intersection where a multi-directional road is complicated.
It is to be noted that if the predetermined angle is reduced, the above-mentioned misalignment can be reduced, but this is not preferable because the above-described inconvenience (screen rewriting occurs frequently and it is difficult to see and the map cannot be used while the screen is being corrected) is caused.
[0010]
In such a navigation device, the azimuth measured as an electronic compass function is often displayed alone or together with a map. However, the display of the azimuth does not match the azimuth of the map, and it is difficult to use the azimuth. There is an inconvenience of misunderstanding. For example, the direction is 16 directions, but if the map is rotated by more than 30 degrees, the map is rotated to that direction. Furthermore, even in the rotation of the map, since the angle of the map rotation can take various rotation angles, it is necessary to store various sin and cos values required for the map rotation in the navigation system, and the memory capacity is reduced. This increases the cost.
[0011]
Therefore, the present invention suppresses rewriting of the display map due to subtle changes in the direction of the system body, and furthermore, makes it easy to match the direction of the display map with the direction of the actual terrain, for example, a multi-directional road is complicated. An object of the present invention is to provide a map display device that does not hinder azimuth determination at a complicated intersection.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a position detecting means for detecting its own current position, an azimuth detecting means for detecting its own azimuth, a storing means for storing map information, and a current position detected by the position detecting means. Searching means for searching the storage means for map information corresponding to, correction means for correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means, and output from the correction means. Display control means for synthesizing the map information and the mark indicating the current position to display on the display means, and displaying the azimuth detected by the azimuth detection means on the display means as real azimuth information, together performs the azimuth correction of the map information when the output of said azimuth detecting means the azimuth measurement range of the azimuth detection means beyond each equal area and equally divided into M is changed, said KuraiOsamu When performing the stomach line orientation modified as cardinal match the map information on the bisector of the equally divided areas, and, the actual azimuth information every time the azimuth detected by said azimuth detection means is changed Is updated .
According to a second aspect of the present invention, there is provided a position detecting means for detecting its own current position, an azimuth detecting means for detecting its own azimuth, an inclination detecting means for detecting its own inclination, and a storage means for storing map information. Searching means for searching the storage means for map information corresponding to the current position detected by the position detecting means, and correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means. A correcting means for combining the map information output from the correcting means with a mark indicating the current position and displaying the result on the display means, and displaying the azimuth detected by the azimuth detecting means on the display means as actual azimuth information. and display control means for causing the correcting means, wherein when the output of the inclination detecting means is within the reference value, the azimuth measuring range of the azimuth detection means beyond each equal area and equally divided into M wherein Performs azimuth correction of the map information when the output of the position detecting means is changed, when performing said position fix on the bisector of the equally divided areas of the azimuth modified as cardinal map information matches There row, and, while performing the display updating of the actual orientation information every time the azimuth detected by said azimuth detection means is changed, when the output of said inclination detecting means is not within the reference value, to issue the required warning It is characterized.
According to a third aspect of the present invention, in the first or second aspect of the invention, the correcting means changes the output of the azimuth detecting means beyond each of the equally divided areas and also crosses some dead zones. In this case, the azimuth of the map information is corrected.
According to a fourth aspect of the present invention, in the first or second aspect of the present invention, when the output of the azimuth detecting means changes over each of the equally-divided areas, the correcting means temporarily stops the output. In this case, the azimuth of the map information is not corrected.
According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the display control means is provided in any one of the equally divided areas in which the azimuth detected by the azimuth detecting means is equally divided by the M. At one time, the display of the azimuth along the direction of the bisector of this area is performed simultaneously with or independently of the map display.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings as an example in which the present invention is applied to a portable map display device integrated with a GPS antenna.
In FIG. 1, reference numeral 20 denotes a portable map display device. The map display device 20 has a GPS antenna 21 mounted on an upper end surface thereof, and a liquid crystal display 22 (22a is a mark indicating a current position) and a key switch group 23 (for example, up / down / left / right direction keys 24 to 27 and an OK key 28). And a cancel key 29), a slide-type power switch 30 on the right side, and an insertion slot 32 for a small memory card 31 (referred to as “smart media” for convenience) on the lower side. I have. Of course, a flash memory may be used instead of the memory card 31, or a CD-ROM drive or a DVD-ROM drive may be used.
[0014]
FIG. 2 is an internal block diagram of the map display device 20. Reference numeral 40 denotes a GPS receiving unit (position detecting means) for demodulating a received signal of the GPS antenna 21 to measure a current position, and 41 denotes an operation including the key switch group 23. , A ROM storing programs and data necessary for map display; 43, a CPU (search means, correction means, display control means) for executing the program; 44, a RAM used as a working area of the CPU 43; A display unit including the liquid crystal display 22, a memory I / O 46 for taking a signal interface with the memory card 31, a geomagnetic sensor (detecting the magnetism of the earth to detect the direction of the map display device 20) and a gyro sensor 47 (For example, based on a time difference between a pair of optical signals circulating clockwise and counterclockwise around a looped optical fiber, Azimuth detecting unit, including those) for measuring the angle of rotation applied to the-loop-shaped optical fiber (direction detecting means), 48 denotes a bus for connecting the respective units.
[0015]
The memory card 31 (storage means) stores, for example, map information appropriately downloaded (transferred) from the map server 8 in FIG. 8, and does not reach the storage capacity (540 MB) of the map disk, but it is for the time being. It has sufficient storage capacity to store only necessary map information.
FIG. 3 is a diagram showing map information stored in the memory card 31. For example, an entire map M1 (minimum scale map) of the Kanto-Chubu area is located on the first layer, and the section map M1 / 1 is shown. Hierarchical structure in which M1 / n (middle scale map) is located in the second layer and the detailed maps M1 / 1/1 to M1 / 1 / m (maximum scale map) are located in the third layer have. According to this structure, for one whole view, n section views and m detailed views are stored.
[0016]
The relationship between the scales is “Overall view” <“Segmented view” <“Detailed view”. In the illustrated example, these three types of scale maps are stored, but this is a convenience for simplifying the description. It is only an example. Actually, many types of reduced scale maps are stored, and accordingly, the hierarchical structure of the memory card 31 is complicated to three or more layers.
The map information includes road data, intersection data, map drawing data, character data, and the like, and these data are used alone or in combination.
[0017]
FIG. 4 is a main part flowchart of the “display map rotation processing program” executed by the CPU 43. This program is executed at predetermined time intervals or in response to an output interrupt from the azimuth detecting unit 47. When the program is started, first, an azimuth detection signal is read from the azimuth detecting unit 47 (S0), and it is determined whether or not the azimuth has changed based on the signal (S1). This determination is made by taking the difference between the output of the azimuth detection unit 47 at the time of the previous execution and the output of the azimuth detection unit 47 this time, and when this difference value exceeds a threshold value considering a margin margin such as noise. It is determined that the direction has changed. If there is no azimuth change, the program is terminated. If there is azimuth change, "azimuth display update processing" is executed (S2).
[0018]
Here, the azimuth display update processing is processing for updating the display of the azimuth mark 50 shown in FIG. Such an azimuth mark 50 can be displayed in a large size on the screen with a design as shown in FIG. 5 and used like an electronic compass, or can be displayed small in a corner of the screen and used together with a map display. It is switchable so that you can do it. When used together with the map display, the azimuth mark 50 is displayed at an appropriate position on the liquid crystal display 22 that does not interfere with the map display (for example, at a corner of the screen). The design of the azimuth mark 50 may be appropriately determined in consideration of the resolution, display color, and the like of the liquid crystal display 22, but it is preferable that the azimuth mark 50 includes at least the following objects.
[0019]
(1) Message objects 51 to 54 indicating east, west, north and south:
In the figure, message objects 51 to 54 corresponding to 2-byte characters of "North" in the 45-degree direction, "East" in the 135-degree direction, "South" in the 225-degree direction, and "West" in the 315-degree direction are displayed. May be an initial letter of the direction of English notation (NWES). The display position of each of the message objects 51 to 54 on the drawing is an example in the case where the north direction detected by the azimuth detecting unit 47 is assumed to be 45 degrees (0 degrees above the liquid crystal display 22).
[0020]
(2) Direction pointer objects 55 to 62:
In the figure, eight direction pointer objects 55 to 62 indicating directions at every 45 degrees are displayed, but the number is not limited to this. 2 ^N (where N is an integer of 2 or more) may be used. Note that the direction pointer object indicating the north direction and the direction pointer object indicating the south direction (direction pointer objects denoted by reference numerals 55 and 59 in the figure) should be distinguished from other direction pointer objects by changing the color and fill pattern. .
[0021]
(3) Real direction objects 64 and 65:
This is an object for displaying the real azimuth (the azimuth on the upper end side of the map display device 20, in other words, the azimuth on the upper side of the liquid crystal display 22) detected by the azimuth detecting unit 47. For example, assuming that the current real direction is 300 degrees, in the figure, a graphical inverted triangular real direction object 64 is displayed outside a ring-shaped scale 63 provided around the direction pointer objects 55 to 62, and further, a direction mark is displayed. A real direction object 65 for reading a numerical value is displayed below 50. Of these two real azimuth objects 64 and 65, the inverted triangular real azimuth object 64 is particularly indispensable. This is because the real azimuth object 64 is used as an upper index of the display map, as described later.
[0022]
The eight direction pointer objects 55 to 62 are provided at equal intervals (in the figure, at 45 degree intervals), and four of them always point to the upper, lower, left, and right sides of the liquid crystal display 22. For example, in the illustrated example, the azimuth pointer object 62 in the 0-degree direction points on the liquid crystal display 22, the azimuth pointer object 56 in the 90-degree direction points to the right of the liquid crystal display 22, and the azimuth pointer object 58 in the 180-degree direction is The azimuth pointer object 60 in the 270 degree direction points to the lower side of the liquid crystal display 22.
[0023]
Since the current north direction is indicated by the azimuth pointer object 55 in the 45-degree direction, the azimuth pointer object 62 pointing above the liquid crystal display 22 indicates northwest (315 degrees in azimuth). The azimuth angle (315 degrees) is incorrect because it includes a misalignment. The correct azimuth angle without azimuth deviation is 300 degrees indicated by the real azimuth objects 64 and 65. Therefore, in actual use, as will be described later, the direction indicator object 62 is used as a tentative guide, and the upward direction of the drawing is regarded as the direction of the real direction object 64 in the shape of an inverted triangle. And so on.
[0024]
Next, rotation display processing of map information will be described. When the azimuth display updating process is completed, first, it is determined whether or not the change in azimuth is equal to or more than a “predetermined angle” (S3). A determination is made (S4). If the angle is equal to or greater than the predetermined angle and the dead zone is exceeded, the azimuth of the map information is corrected by the azimuth change and the display on the liquid crystal display 22 is updated (S5).
[0025]
FIG. 6 is a conceptual diagram showing “predetermined angle” and “dead zone”. In FIG. 6, θi is the display angle of the azimuth pointer objects 55 to 62, and its actual value is 0 degree, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, or 315 degrees. The line 66 of these angles passing through the point P corresponds to the bisector described in the summary of the invention.
Δθa and Δθa ′ provided on both sides of θi correspond to the predetermined angle (Δθa + Δθa ′ is an equal area described in the gist of the invention), and the actual direction detected by the direction detection unit is θi−Δθa or θi + Δθa ′. When the value exceeds the range, the determination result of step S3 becomes YES. Further, Δθb and Δθb ′ correspond to the above-mentioned dead zone. When the actual direction detected by the direction detecting unit exceeds the range of θi−Δθa or θi + Δθa ′, and further exceeds the range of Δθb or Δθb ′, the determination in step S4 is made. The result is YES, and the azimuth correction (rotation correction) of the map information is performed.
[0026]
Therefore, according to the above embodiment, the rotation correction of the map information is not performed unless the actual bearing detected by the bearing detecting unit exceeds the range of θi−Δθa−Δθb or θi + Δθa ′ + Δθb ′. , Θi = 315 degrees, Δθa = Δθa ′ = 22.5 degrees, Δθb = Δθb = 3 degrees, and if the actual azimuth detected by the azimuth detecting unit is in the range of 289.5 degrees to 340.5 degrees, Since the rotation correction of the map information is not performed, frequent rewriting of the display map due to a subtle change in direction of the map display device 20 can be suppressed, and the visibility can be improved.
[0027]
By the way, although the top, bottom, left and right of the display drawing are represented by θi, this θi does not exactly correspond to the actual azimuth. There is a possibility that a misalignment of up to 22.5 degrees + 3 degrees (Δθa + Δb or Δθa + Δb) will occur. However, in the present embodiment, the real azimuth is displayed on the liquid crystal display 22 by the two real azimuth objects 64 and 65, so that a correct azimuth can be grasped. There is no hindrance in matching the data with the actual terrain. This is because, as described above, it is sufficient to interpret the real direction object 64 of the inverted triangle as the upward direction in the drawing and interpret the traveling direction.
[0028]
The embodiment of the present invention is not limited to the above example. Various deformations are possible within the range of the idea. For example, even when the actual azimuth detected by the azimuth detecting unit exceeds the range of θi−Δθa−Δθb or θi + Δθa ′ + Δθb ′, it is temporary. If so, the correction of the azimuth of the displayed map may not be performed.
In addition, if the geomagnetic sensor is used at an angle, it may not operate properly. Therefore, a tilt sensor is attached to the map display device 20. A warning (for example, “Please level”) may be displayed at 22.
In the above embodiment, the number of the direction pointer objects is eight (therefore, eight directions), but this number is a convenience value. The measurement accuracy can be increased as the number is increased. In practice, 16 to 32 suffices. In other words, it is necessary to obtain the necessary and sufficient measurement accuracy and also to have the values of sin and cos for calculating the rotation angle of the map by the above number, and to have all the expected values as in the conventional example. Requires much less memory capacity.
[0029]
【The invention's effect】
According to the first aspect of the present invention, the azimuth measurement range of the azimuth detecting means is divided into M equal parts, and when the output of the azimuth detecting means changes beyond each equal area, the azimuth correction is performed. When performing, the direction is corrected so that the east, west, south and north of the map information coincide with the bisector of each bisector, so the direction of the display drawing is always M bisectors. If one of them matches, for example, M = 8, the bisector is “north”, “northeast”, “east”, “southeast”, “south”, “southwest”, “west”, “northwest” , It is easy to intuitively grasp the direction of the display map, and it is easy to adjust the direction even if there is a slight misalignment.
Therefore, rewriting of the display map due to subtle changes in the direction of the system body is suppressed, and the direction of the display map and the direction of the actual terrain are easy to match, so for example, at a complex intersection where multiple directions are complicated. A map display device that does not hinder azimuth determination can be provided.
Further, since the direction of the map is adjusted to the direction of the area divided into M equal parts in advance, the values of sin and cos required for the rotation display of the map can be reduced, and the memory capacity can be reduced and the cost reduction can be measured.
In addition, the azimuth detected by the azimuth detecting means can be displayed as "real azimuth information", and the display of the "real azimuth information" is updated every time the azimuth detected by the azimuth detecting means changes. Therefore, even when the orientation of the display drawing does not match any of the bisectors of the M equal areas, the fine orientation change of the display screen is always displayed based on the actual orientation information. You can continue.
According to the second aspect of the present invention, when the output of the inclination detecting means is not within the reference value, the azimuth of the map information is not corrected and a required warning is issued. (It may not operate properly when used at an angle).
According to the third aspect of the present invention, in the first or second aspect of the invention, the azimuth correction is performed when the output of the azimuth detecting means changes over each equally divided area and also exceeds a certain dead zone. Therefore, the azimuth correction execution operation can be provided with a hysteresis characteristic, and frequent correction operations at the equally divided area boundary can be avoided.
According to a fourth aspect of the present invention, in the first or second aspect of the present invention, when the output of the azimuth detecting means changes over each equally divided area, the time of the change is temporary. In this case, since the azimuth correction is not performed, unnecessary azimuth correction can be avoided.
According to a fifth aspect of the present invention, in the first or second aspect of the invention, the display control means is any one of the equally divided areas in which the azimuth detected by the azimuth detecting means is equally divided by the M. When, the display of the azimuth along the direction of the bisector of this area is performed at the same time as the map display or independently from the map display. The direction of the display map in a certain case can be correctly recognized.
Further, since the direction of the azimuth display coincides with the azimuth of the rotated and displayed map, it is easy to read the azimuth, and misunderstanding of the azimuth does not occur.
[Brief description of the drawings]
FIG. 1 is an external view of a map display device.
FIG. 2 is an internal block diagram of the map display device.
FIG. 3 is a diagram showing a storage structure of map information in a memory card.
FIG. 4 is a flowchart of a display map rotation processing program.
FIG. 5 is a layout diagram of an azimuth mark.
FIG. 6 is a conceptual diagram of a predetermined angle and a dead zone.
FIG. 7 is a configuration diagram of an in-vehicle navigation system.
FIG. 8 is a conceptual diagram when downloading map information from a map server to a portable map display device.
FIG. 9 is a rotation correction diagram of a display map.
FIG. 10 is a rotation correction diagram of a display map according to the technique described in the publication.
[Explanation of symbols]
Δθa + Δθa 'Equal area Δθb, Δθb' Dead zone 31 Memory card (storage means)
40 GPS receiver (position detection means)
43 CPU (search means, correction means, display control means)
45 Display (display means)
47 azimuth detecting unit (azimuth detecting means)
66 lines (bisector)

Claims (5)

Position detecting means for detecting its own current position;
Azimuth detecting means for detecting its own azimuth,
Storage means for storing map information;
Search means for searching the storage means for map information corresponding to the current position detected by the position detection means,
Correcting means for correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means,
Display control means for synthesizing the map information output from the correction means and a mark indicating the current position to display on the display means and displaying the azimuth detected by the azimuth detection means on the display means as real azimuth information With
The correcting means corrects the azimuth of the map information when the output of the azimuth detecting means changes by dividing the azimuth measuring range of the azimuth detecting means into M equal parts and beyond each equally divided area. when performing the stomach line orientation modified as cardinal match the map information on the bisector of the equally divided areas, and, the actual azimuth information every time the azimuth detected by said azimuth detection means is changed A map display device for updating the display of a map. Position detecting means for detecting its own current position;
Azimuth detecting means for detecting its own azimuth,
Inclination detection means for detecting its own inclination,
Storage means for storing map information;
Search means for searching the storage means for map information corresponding to the current position detected by the position detection means,
Correcting means for correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means,
Display control means for synthesizing the map information output from the correction means and a mark indicating the current position to display on the display means and displaying the azimuth detected by the azimuth detection means on the display means as real azimuth information With
The correcting means includes:
When the output of the inclination detecting means is within a reference value, the azimuth measuring range of the azimuth detecting means is divided into M equal parts, and when the output of the azimuth detecting means changes beyond each equally divided area, the map information orientation performs azimuth modification, when performing the said position fix have line orientation modified as cardinal match the map information on the bisector of the equally divided areas, and, detected by said azimuth detection means While the display of the real direction information is updated each time is changed ,
When the output of the inclination detecting means is not within a reference value, a required warning is issued. 2. The method according to claim 1, wherein the correcting means corrects the azimuth of the map information when the output of the azimuth detecting means changes over each of the equally divided areas and when the azimuth detecting means also crosses some dead zone. Item 3. The map display device according to Item 2. When the output of the azimuth detecting means changes over each of the equally-divided areas, the correcting means does not correct the azimuth of the map information if the time over which the azimuth is detected is temporary. The map display device according to claim 1 or 2, wherein When the azimuth detected by the azimuth detecting means is located in any of the M equally divided areas, the display control means displays the azimuth along the direction of the bisector of this area. The map display device according to claim 1 or 2, wherein the step (c) is performed simultaneously with or independently of the map display.

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