JP2000098883A - Map display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the frequent rewriting of a display map accompanying a delicate change in direction and to improve the ease of viewing by dividing the bearing measurement range by M and executing bearing correction when the output of a bearing detecting means changes beyond respective equally divided area. SOLUTION: The bearing measurement range of the bearing detecting means is devided by M and the bearing correction is executed when the output of the bearing detecting means changes beyond the respective equally divided areas. At the time of execution of the bearing correction, the bearing correction is so executed that the north, south, east and west of map information are aligned on the bisectors of the respective equally divided areas. The actual values of a display angle θi are 0 deg., 45 deg., 90 deg., 135 deg., 180 deg., 225 deg., 270 deg. and 315 deg.. The lines 66 of these angles passing a point P correspond to the bisectors of the equally divided areas. The bearing correction (rotation correction) of the map information is executed when the actual bearings detected in the bearing detecting section exceed a range of θi-Δθa or θi+Δθa' and further it is executed when exceeding the range of Δθb or Δθb'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a GPS (Global P
ositioning System) A map display device that measures the current position using a satellite, displays a mark indicating the current position on a display, and displays map information overlapping the mark, and is particularly suitable for portable use. The present invention relates to a map display device.

[0002]

2. Description of the Related Art As shown in FIG. 7, a so-called navigation system mounted on a vehicle has a GPS antenna 1, a GPS receiver 2, a navigation control unit 3, and a CD-ROM.
It has a ROM drive device 4 and a display device 5 as a basic configuration.
Radio signals 7 from the GPS satellites 6 are received by the GPS antenna 1, the received signals are demodulated by the GPS receiver 2, the current position is measured, and the navigation control unit 3 displays a mark indicating the current position and a CD. -ROM drive device 4
Is combined with the map information read from the device and sent to the display device 5 to provide a visual route guidance to the driver and the passenger. However, the device configuration is large and cannot be carried and used as it is. Did not.

On the other hand, there is also known a navigation system which can be carried without the need for a large and bulky CD-ROM drive device of the above basic configuration. This improved system, as shown in FIG.
Necessary area 8 from the map displayed on the map server 8
is selected (in the figure, the Kanto / Chubu district is selected for convenience), and the map information included in the range 8a is downloaded (transferred) to the navigation system 9 and carried. For example, a personal computer is used. Map server 8 CD-R
Set the map disk 11 in the OM drive device 10,
The map server 8 executes a predetermined application program to select a necessary range of map information 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 thereafter is used for map display when the navigation system 9 is carried.

[0004] In any of the above navigation systems, the map stored in the map disk 11 is created with "North" facing upward, and the map displayed on the screen of the navigation system 9 is also displayed on the screen. Although it is north, when using such a navigation system 9 outdoors, check the north using a compass (magnet),
The user must compare the displayed map with the surrounding terrain after turning the screen to the north, which is inconvenient. In addition, there is a disadvantage that if the user does not have a compass, the user cannot make a wrong decision.

Therefore, a navigation system 9 is provided with azimuth position detecting means such as a geomagnetic sensor or a gyro sensor, and corrects the direction of a display map based on azimuth information of the system body detected by the azimuth position detecting means. Are known. 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 in accordance with the movement. That is, 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). Further, 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). Above)
It has become.

[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, and therefore, the foot may be advanced forward as it is. Since the direction of the displayed map corresponds to the direction of the actual terrain, the target road 18
Exists.

By the way, especially in the hand-held navigation system 9, a delicate change in the direction of the system body due to fine movement of the hand or body cannot be avoided. For this reason, the direction of the display map is corrected even with a very small 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.

Therefore, Japanese Patent Application Laid-Open No. 7-280582 discloses a technique in which the display map is not corrected 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]

However, in the technology described in the above publication, a change in the azimuth within a predetermined angle is completely ignored. Of the terrain and the actual terrain direction at a maximum of 45 degrees, which hinders the determination of the azimuth 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-described 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.

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 this azimuth does not match the azimuth of the map, which makes it difficult to use. Or misunderstanding the direction. For example, although the azimuth is 16 azimuths, if the map rotates by 30 degrees or more, the azimuth is rotated to that azimuth. Furthermore, even in the rotation of the map, since the angle of the map rotation can take various rotation angles, various sin, cos necessary for the map rotation can be taken.
Must be stored in the navigation system, which increases the memory capacity and increases the cost.

Therefore, the present invention suppresses the rewriting of the display map due to a subtle change in the direction of the system body, and makes it easier to match the direction of the display map with the direction of the actual terrain. It is an object of the present invention to provide a map display device that does not hinder azimuth determination at a complicated intersection where the traffic is complicated.

[0012]

According to the first aspect of the present invention,
Position detecting means for detecting its own current position, azimuth detecting means for detecting its own azimuth, storing means for storing map information, and storing the map information corresponding to the current position detected by the position detecting means. Searching means for searching from the means, correcting means for correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means, and a mark indicating the map information output from the correcting means and the current position. And a display control means for displaying the result on the display means by synthesizing the data. The correction means divides the azimuth measurement range of the azimuth detection means into M equal parts and outputs the azimuth detection means over each equal area. Is changed, and when the azimuth is corrected, the azimuth is corrected so that the east, west, south and north of the map information coincide with the bisector of each equally divided area. 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. Correction means, and display control means for synthesizing the map information output from the correction means and a mark indicating the current position and displaying the combined information on a display means, wherein the correction means uses the output of the inclination detection means as a reference. When the value is within the range, the azimuth measurement range of the azimuth detecting means is divided into M equal parts and the azimuth correction is performed when the output of the azimuth detecting means changes beyond each equally divided area. Is While performing the azimuth modified as cardinal map information matches on the bisector of equal area, the output of said inclination detecting means when it is not within the reference value, characterized in that emit the required warning. According to a third aspect of the present invention, in the first or second aspect of the present invention, the correcting means changes the output of the azimuth detecting means beyond each of the equally-divided areas and also exceeds a slight dead zone. In this case, the azimuth 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 correction is not performed in a case where the target is a target. The invention according to claim 5 is the invention according to claim 1 or claim 2.
In the invention described in the above, when the azimuth detected by the azimuth detecting means is in any one of the equally divided areas of the M, the display control means follows the direction of the area on the bisector. The display of the azimuth is performed simultaneously with or independently of the map display.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be
An embodiment applied to a portable map display device integrated with a PS antenna will be described with reference to the drawings. 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 a small memory card 31 on the lower side.
Insertion slot 32 (referred to as “smart media” for convenience)
Is provided. Of course, the memory card 31
Flash memory may be used instead of
-A ROM drive or a DVD-ROM drive may be used.

FIG. 2 is an internal block diagram of the map display device 20. Reference numeral 40 denotes a GPS receiving section (position detecting means) for demodulating a received signal of the GPS antenna 21 to measure a current position, and 41 denotes a key switch group 23. The operation unit 42 includes an RO that stores programs and data necessary for map display.
M and 43 are CPUs (search means, correction means, display control means) for executing the program, 44 is a RAM used as a working area of the CPU 43, 45 is a display unit including the liquid crystal display 22, and 46 is a memory card 31
A memory I / O 47 that takes a signal interface with the terrestrial magnetism sensor (the map display device 20 that detects the magnetism of the earth and
Gyro sensor (for example, a device that measures a rotation angle applied to a loop-shaped optical fiber based on a time difference between a pair of optical signals that circulate clockwise and counterclockwise around the loop-shaped optical fiber) ), And 48 is a bus for connecting each unit.

The memory card 31 (storage means) stores, for example, map information appropriately downloaded (transferred) from the map server 8 shown in FIG. 8, and does not reach the storage capacity (540 MB) of the map disk. However, it has a 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, the entire map M1 (minimum scale map) of the Kanto-Chubu district is located on the first layer, and the section map M1 / 1 is shown. ~ M1 / n (middle scale map) is located in the second layer, and the detailed view M1 / 1 /
It has a hierarchical structure in which 1 to M1 / 1 / m (maximum scale map) are located in the third layer. According to this structure, for one entire view, n section views and m detailed views are stored.

The relationship between the scales is "overall view"<"sectionmap"<"detailedview". In the illustrated example, these three types of scale maps are stored, but this simplifies the description. It is only a convenience example for Actually, more 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.

FIG. 4 is a flowchart showing the main part 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 detection unit 47 (S0), and the presence or absence of an azimuth change is determined 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 in consideration of 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).

Here, the azimuth display updating process is a process of 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 it can be done. When used in combination with the map display, this direction 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 desirable that the azimuth mark 50 includes at least the following objects.

(1) Message objects 51 to 54 indicating north, south, east and west: "North" in the direction of 45 degrees, "east" in the direction of 135 degrees, "south" in the direction of 225 degrees, and "west" in the direction of 315 degrees. Although the message objects 51 to 54 corresponding to the two-byte characters are displayed, they may be initial letters (NWES) in the direction of English notation. The display position of each of the message objects 51 to 54 on the drawing is 45 degrees in the north direction detected by the direction detection unit 47 (the liquid crystal display 2).
2 is assumed to be 0 degrees).

(2) Orientation 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 number. ^{Any number of} 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. .

(3) Real azimuth objects 64 and 65: objects for displaying the real azimuth detected by the azimuth detecting unit 47 (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). It is. 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 orientation 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.

Eight direction pointer objects 55 to 62 are provided at equal intervals (45 degrees in the figure).
Four of them always point to the top, bottom, left and right 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 Pointing below the liquid crystal display 22, 27
The direction indicator object 60 in the 0-degree direction points to the left of the liquid crystal display 22.

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 is displayed.
Indicates northwest (315 degrees in azimuth), but this azimuth (315 degrees) is incorrect because it includes misalignment.
The correct azimuth without azimuth deviation is the real azimuth object 6.
It is 300 degrees indicated by 4, 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.

Next, the rotation display processing of map information will be described. When the azimuth display update processing is completed, first, it is determined whether or not the change in azimuth is equal to or more than a “predetermined angle” (S
3) If the angle is equal to or greater than the predetermined angle, it is further determined whether the angle exceeds the "dead zone" (S4). If the angle is equal to or greater than the predetermined angle and also exceeds the dead zone, the azimuth of the map information is changed by the azimuth change. The display is corrected and the display on the liquid crystal display 22 is updated (S5).

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, the actual value of which is 0 degree,
45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 27
0 degrees or 315 degrees. Line 6 at these angles passing through point P
Reference numeral 6 corresponds to a bisector described in the gist of the invention. Δθa and Δθa ′ provided on both sides of θi are equal to the predetermined angle (Δθa
a + Δθa ′ corresponds to the equal area described in the gist of the invention), and the determination result in step S3 becomes YES when the actual azimuth detected by the azimuth detecting unit exceeds the range of θi−Δθa or θi + Δθa ′. Δθb and Δθb ′ correspond to the dead zone, and the actual azimuth detected by the azimuth detector is θ
i−Δθa or θi + Δθa ′, and Δ
When it exceeds the range of θb or Δθb ′, the determination result of step S4 becomes YES, and the azimuth correction (rotation correction) of the map information is performed.

Therefore, according to the above embodiment,
The actual azimuth detected by the azimuth detecting unit is θi−Δθa−Δθb
Or unless it exceeds the range of θi + Δθa ′ + Δθb ′
Since rotation correction of map information is not performed, for example, θi =
315 degrees, Δθa = Δθa ′ = 22.5 degrees, Δθb = Δ
Assuming that θb = 3 degrees, if the actual azimuth detected by the azimuth detecting unit is in the range of 289.5 degrees to 340.5 degrees, rotation correction of the map information is not performed. Frequent rewriting of the display map due to the direction change can be suppressed, and the visibility can be improved.

By the way, the upper, lower, left and right sides of the display drawing are represented by θi, but the θi does not exactly correspond to the actual azimuth. 22.5 degrees + 3 degrees at maximum (Δθa + Δb or Δθa + Δ
There is a possibility that the misalignment of b) 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 only necessary to regard the real orientation object 64 of the inverted triangle as the upward direction in the drawing and to interpret the traveling direction.

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, the actual azimuth detected by the azimuth detecting unit is θi−
Even if it exceeds the range of [Delta] [theta] a- [Delta] [theta] b or [theta] + [Delta] [theta] a '+ [Delta] [theta] b', the orientation of the display map may not be corrected if it is temporary. Also, if the geomagnetic sensor is used at an angle, it may not operate properly. Therefore, an inclination sensor is attached to the map display device 20,
A warning is issued to the liquid crystal display 22 when the tilt sensor is used to such an extent that the operation of the geomagnetic sensor becomes unstable (for example,
“Please level” may be displayed. In the above-described embodiment, the number of 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 to have the values of sin and cos for calculating the rotation angle of the map by the above-mentioned number, and to have all the expected values as in the conventional example. It requires much less memory capacity than.

[0029]

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 the azimuth is corrected when the output of the azimuth detecting means changes beyond each equally divided area. When the azimuth correction is performed, the azimuth correction is performed so that the east, west, south, and north of the map information coincide on the bisector of each equally divided area. If any of the bisectors match, for example, M = 8, the bisectors are "north", "northeast", "east", "southeast", "south", "southwest", " Since it is "west" or "northwest", it is easy to intuitively grasp the direction of the displayed map, and it is easy to adjust the direction even if there is a slight misalignment. Therefore, it is possible to suppress the rewriting of the display map due to subtle changes in the direction of the system itself, and it is easy to match the direction of the display map with the direction of the actual terrain, so for example, at a complex intersection where multi-directional roads are complicated. A map display device that does not hinder azimuth determination can be provided. Further, since the orientation of the map is adjusted to the orientation 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. 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 correction of the map information is not performed and a required warning is issued. (It may not operate properly if 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. So do
Hysteresis characteristics can be given to the azimuth correction execution operation, and frequent correction operations at the equally divided area boundary can be avoided. According to the invention described in claim 4, claim 1 is provided.
Or, in the invention according to claim 2, if the output of the azimuth detecting means changes over each equally divided area, the azimuth correction is not performed if the output time is temporary,
Unnecessary azimuth correction can be avoided. According to a fifth aspect of the present invention, in the first or second aspect of the present 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 into M. Is displayed in the direction of the area along the bisector, the display of the azimuth is performed simultaneously with or independently of 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 map displayed by rotation, reading of the azimuth is easy 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 illustrating 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 a vehicle-mounted 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 official gazette.

[Explanation of symbols]

Δθa + Δθa ′ Equal area Δθb, Δθb ′ Dead zone 31 Memory card (storage means) 40 GPS receiver (position detection means) 43 CPU (retrieval means, correction means, display control means) 45 Display section (display means) 47 Direction detection section (Azimuth detection means) 66 lines (bisector)

Claims (5)

[Claims] 1. A position detecting means for detecting a current position of the own device, an azimuth detecting device for detecting an azimuth of the own device, a storing device for storing map information, and a position corresponding to the current position detected by the position detecting device. Searching means for searching map information from the storage means, correcting means for correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means, and map information output from the correcting means. Display control means for combining and displaying the mark indicating the current position on the display means, and the correction means sets the azimuth measurement range of the azimuth detection means to M
When the output of the azimuth detecting means changes over each equally divided area and the direction of the azimuth detecting means changes, the azimuth correction is performed. A map display device that corrects the azimuth so as to match. 2. Position detecting means for detecting the current position of the vehicle, azimuth detecting means for detecting the azimuth of the vehicle, inclination detecting means for detecting the inclination of the vehicle, storage means for storing map information, Searching means for searching the storage means for map information corresponding to the current position detected by the detecting means; correcting means for correcting the direction of the searched map information based on the azimuth detected by the azimuth detecting means; A display control unit that combines the map information output from the correction unit and a mark indicating the current position and displays the combined information on a display unit, wherein the correction unit is configured to output the inclination detection unit within a reference value. When the azimuth measurement range of the azimuth detecting means is divided into M equal parts and the output of the azimuth detecting means changes over each equally divided area, the azimuth correction is performed. A map display device, which performs azimuth correction so that east, west, north and south of map information coincides with a bisector of an area, and issues a required warning when an output of the inclination detecting means is not within a reference value. . 3. The azimuth correcting means, wherein the azimuth correction is performed when the output of the azimuth detecting means changes over each of the equally-divided areas, and when a slight dead zone is exceeded. The map display device according to claim 2. 4. The method according to claim 1, wherein the correcting means does not correct the direction when the output of the direction detecting means changes beyond the equal area and when the output exceeds a temporary time. The map display device according to claim 1 or 2, wherein 5. The display control means, when the azimuth detected by the azimuth detecting means is located in any of the M equally divided areas, along the direction of the area on the bisector. 3. The map display device according to claim 1, wherein the display of the azimuth is performed simultaneously with or independently of the map display.