JP2006226871A - Map display controller, and map display control controlling program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of correcting properly an error of a map data in the present position, when map precision is worse compared with present position measuring precision, in a device for displaying an image superposed on an image display with a present position mark on a map indicated by the map data. <P>SOLUTION: A navigation system for a vehicle shifts a display reference point for displaying the map (step 140) to bring an error between curved position coordinates and position coordinates of a curved corner in the map data into zero, based on the presence of the error within a reference range between a curved position and a position of the curved corner in the map (step 130, 135), every time when a vehicle advances in the curved corner to be turned (step 125), when a distance up to a destination comes to a reference distance or less during route guide processing (step 110) and when carrying out highly precise present position measurement by an RTK-GPS (step 120). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a map display control device and a map display control program for causing an image display device to display an image in which a current position mark is superimposed on a map indicated by map data.

  2. Description of the Related Art Conventionally, in an apparatus for displaying an image in which a current position mark is superimposed on a map indicated by map data, a technique has been proposed in which two types of measuring methods with different accuracy are used as the current position measuring method. For example, in a navigation apparatus, during route guidance, the current position is measured by a normal GPS method with an error of about 10 meters until the destination is approached, and the current position with higher accuracy such as RTK-GPS or D-GPS is used near the destination. Various techniques using a position measuring method have been proposed.

  Further, Patent Document 1 and Patent Document 2 describe techniques that focus on the fact that the accuracy of map data is relatively lowered when the current position measurement method becomes highly accurate.

The navigation devices described in Patent Document 1 and Patent Document 2 calculate an error correction value of map data around the destination before the start of route guidance, correct the position of the guide during guidance with the correction value, and display it on the map. It is displayed correctly.
JP 2002-340589 A JP 2002-340591 A

  However, the error between the map data and the actual topography varies from point to point. Therefore, the error correction performed on the destination is not always correct even at a location away from the destination.

  In view of the above points, the present invention provides a device that displays on the image display device an image in which a current position mark is superimposed on a map indicated by map data when the map accuracy is poor compared to the current position measurement accuracy. An object of the present invention is to provide a novel technique capable of appropriately correcting an error in map data.

  In order to achieve the above object, the invention according to claim 1 provides a current position mark on the map indicated by the map data based on the current position coordinates measured by the first current position measuring method. The superimposed image is displayed on the image display device. In another case, based on the current position coordinates measured by the second current position measurement method having higher measurement accuracy than the first current position measurement method, Map display control means for causing the image display device to display an image in which a current position mark is superimposed on a map indicated by the map data, and the map display control means are current positions measured by the second current position measurement method. Based on the coordinates, when the image display device displays an image in which the current position mark is superimposed on the map, the bending position coordinates and the map data are displayed based on the fact that the traveling route is bent. Correction means for correcting the relative position between the map in the image to be displayed on the image display device and the current position mark so as to reduce an error from the position coordinate of the corner in the screen. is there.

  As described above, the map display control device, based on the fact that it is bent, the coordinates of the bent position (that is, the position in the vicinity of the current position) measured by the second current position measuring method and the turning angle in the map data. Since the relative position between the map in the image display device and the current position mark is corrected so that the error with the position coordinate of the image is reduced, the image display after the error of the map data at the current position is properly corrected It can be performed.

  The invention according to claim 2 is the map display device according to claim 1, further comprising route guidance means for guiding a guidance route to a destination, wherein the route guidance means is route guidance. Based on the completion of the process, the modification made so far is discarded.

  Thus, the map display control device does not fail to correct the error so far after the end of the route guidance, so that the past correction does not affect the next route guidance or the like.

  Further, the invention according to claim 3 is the notifying device which warns of the fact based on the fact that the second current position measuring method cannot be used in the map display control device according to claim 1 or 2. It is characterized by having a notification control means for informing the user.

  As a result, the user can easily detect that detailed current position measurement cannot be performed.

  According to a fourth aspect of the present invention, in some cases, an image obtained by superimposing a current position mark on a map indicated by map data is displayed based on the current position coordinates measured by the first current position measuring method. The map data is displayed based on the current position coordinates measured by the second current position measurement method having a higher measurement accuracy than that of the first current position measurement method. Map display control means for displaying an image with a current position mark superimposed on a map on the image display device, and the map display control means based on the current position coordinates measured by the second current position measurement method In the case where an image with the current position mark superimposed on the map is displayed on the image display device, the bending position coordinates and the song in the map data are based on the fact that the traveling route is bent. So as to reduce the error between the position coordinates of the corner, as correction means for correcting a map and relative positions of the current position mark in an image to be displayed on the image display apparatus, a map display control program causing a computer to function.

  In this way, the present invention can be understood as a program.

  Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows a hardware configuration of a vehicle navigation apparatus 1 according to this embodiment. The vehicle navigation device 1 includes a position detector 11, an operation switch group 12, an image display device 13, a speaker 14, a RAM 16, a ROM 17, an external storage medium 18, and a control circuit 19.

  The position detector 11 includes sensors such as a GPS receiver 11a, a gyroscope 11b, a vehicle speed sensor 11c, and the like, and measurement information for specifying the current position and orientation of the vehicle based on the properties of each of these sensors. Is output to the control circuit 19.

  The GPS receiver 11a measures the current position by a normal GPS method (corresponding to the first current position measurement method) that specifies the three-dimensional position of the host vehicle based on navigation data transmitted from a plurality of GPS satellites. In addition, the current position is measured by the well-known RTK-GPS method (corresponding to the second current position measuring method), and the three-dimensional current position coordinates (latitude, longitude, altitude) of the measurement result are output to the control circuit 19. To do. The error of the position measurement by the normal GPS method is about 10 meters, and the error of the position measurement by the RTK-GPS method is about 1 centimeter.

  The GPS receiver 11 a switches which of these two measurement methods is used based on a control signal from the control circuit 19. However, when a sufficient number of GPS satellites cannot be received or communication with the reference station cannot be performed, even if a control signal requesting to use the RTK-GPS method is received from the GPS receiver 11a, the RTK- A signal indicating that the GPS system cannot be used is returned, and the current position measurement by the normal GPS system is continued.

  The gyroscope 11 b detects the turning angle, roll angle, etc. of the host vehicle and outputs the detected angles to the control circuit 19. The vehicle speed sensor 11c outputs a pulse signal to the control circuit 19 at a cycle inversely proportional to the vehicle speed.

  The operation switch group 12 includes a plurality of mechanical switches provided in the vehicle navigation device 1 and an input device such as a touch panel provided so as to overlap the display surface of the image display device 13. A signal based on the touch is output to the control circuit 19.

  The image display device 13 displays a video based on the video signal output from the control circuit 19 to the user. Examples of the display image include a map centering on the current location. Specifically, the image display device 13 has a plurality of pixels arranged in two dimensions (for example, horizontal 640 dots × vertical 480 dots), and the control circuit 19 determines which pixel in which position in the image display device 13. A signal indicating whether to display such luminance and color is received, and color development of each pixel is controlled based on this signal. Each pixel is assigned a unique two-dimensional coordinate (hereinafter referred to as pixel coordinate) based on its position. For example, the pixel coordinates at the lower left of the screen as viewed from the user are (0, 0), the pixel coordinates at the lower right of the screen are (640, 0), and the pixel coordinates at the upper left of the screen are (0, 480). The pixel coordinates on the upper right are (640, 480).

  The external storage medium 18 is a non-volatile storage medium such as an HDD, and stores a program read and executed by the control circuit 19, map data for route guidance, and the like.

  The map data includes road data and facility data including position coordinates (latitude, longitude) and type of road pieces (links) and intersections (nodes), information on connection relations between intersections and road pieces, and the like. The facility data has a plurality of entries for each facility, and each entry has data indicating name information, location coordinates (latitude, longitude), facility type information, and the like of the target facility.

  A control circuit (corresponding to a computer) 19 executes a program for the operation of the vehicle navigation apparatus 1 read from the ROM 17 and the external storage medium 18, and in executing the program, the RAM 16, the ROM 17, and the external storage medium 18. The information is read from the RAM 16 and the information is written to the RAM 16 and the external storage medium 18, and signals are exchanged with the position detector 11, the operation switch group 12, the image display device 13, and the speaker 14.

  Specific processing performed by the control circuit 19 executing the program includes current position specifying processing, map display control processing, guidance route search processing, route guidance processing, and the like.

  The current position specifying process is a process of specifying the current position coordinates (latitude, longitude, altitude) and direction of the vehicle based on the signal from the position detector 11. In the current position specifying process, the control circuit 19 performs a control signal for causing the GPS receiver 11a to perform a current position measurement by the normal GPS method and a current position measurement by the RTK-GPS method, as necessary. The control signal to be performed is output.

  The map display control process causes the image display device 13 to display a map image composed of roads and facilities indicated by the map data according to the arrangement of the position coordinates of the roads and facilities, and further causes the image display device 13 to display the map in the displayed map. The current position mark is superimposed on the position corresponding to the current position coordinates specified by the current position specifying process. Specifically, it is determined which part of the map in the map data is to be displayed on the image display device 13, and the correspondence between the position coordinates in the map determined by this determination and the dots in the image display device 13 is determined. Based on the above, it is determined which brightness and color are to be displayed on which dot, and a signal based on the determination is output to the image display device 13.

  Determining which part is to be displayed on the image display device 13 corresponds to determining the position coordinates (latitude, longitude) in the map corresponding to the display reference point and the scale of the map. Hereinafter, the position coordinates in the map are referred to as map coordinates. FIG. 2 shows the relationship between the map 31 indicated by the map data and the view window 32 indicating the range of the display screen of the image display device 13. The display reference point 33 is fixed with respect to the view window 32. For example, the display reference point 33 is a point fixed at the upper left coordinate position (5,475) in the pixel coordinates fixed in the view window 32. Therefore, when the map coordinate position of the display reference point 33 is determined, it is determined at which position in the image display device 13 the map coordinate position is displayed. Further, when the scale of the map is determined, the ratio for associating the map coordinates with the pixel coordinates is determined, so that the range in the map that can be accommodated in the view window 32 is determined. Note that the map coordinates and scale of the display reference point are set to values that allow the current position coordinates specified by the current position specifying process to be within the view window.

Further, based on this determination, which brightness and color are displayed on which dot is determined as follows. That is, on the basis of the map coordinate position and scale of the display reference point 33, for each component such as a road or a facility within the map range within the view window 32, the relative position on the map coordinate with respect to the display reference point of the component Then, the pixel coordinate position of the component is specified, and the luminance and color for the graphic of the component are assigned to a predetermined range of dots including the pixel coordinate position. For example, the facility 34 in FIG. 2 is located at a position shifted from the display reference point 33 by longitude + x ₀ and latitude −y ₀ in map coordinates. Thus, the pixel coordinates of the facility _34, the _{(x r + px 0, y} r -py 0). Here, (x _r , y _r ) is the pixel coordinate position of the display reference point 33, and p is a coefficient based on the determined scale. For the current position mark, the pixel coordinate position is specified from the relative position on the map coordinate with respect to the display reference point of the current position based on the map coordinate position and scale of the display reference point 33, and the pixel coordinate position is included. Assign brightness and color for the current position mark to a predetermined range of dots. Specifically, the current position mark 35 in FIG. 2 is at a position shifted from the display reference point 33 by longitude + x ₁ and latitude −y ₁ in map coordinates. Thus, the pixel coordinates of the current position mark 35 _{becomes (x r + px 1, y} r -py 1).

  The guidance route search process is a process of receiving an input of a destination by the user from the operation switch group 12 and calculating an optimum guidance route from the current position to the destination.

  The route guidance process is a process for displaying the current position of the host vehicle and the map along the guidance route specified by the guidance route search process by executing the above-described current position specification process and map display control process. Further, in the route guidance process, the control circuit 19 indicates that the normal GPS method is used for the current position specifying process while the current position of the host vehicle is at a distance exceeding the reference distance (for example, 100 meters) from the destination. A signal is output to the GPS receiver 11a, and after the current position of the host vehicle is less than the reference distance from the destination, a signal indicating that the RTK-GPS method is used for the current position specifying process is output to the GPS receiver 11a. Let

  Further, the control circuit 19 repeatedly executes an error correction processing program 100 shown as a flowchart in FIG. In the execution of the error correction processing program 100, the control circuit 19 first determines in step 110 whether or not the current position of the host vehicle is within the reference distance to the destination. The reference distance here is the same as the reference distance used for switching between the normal GPS method and the RTK-GPS method in the route guidance process. Therefore, the case of being within the reference distance corresponds to the case where the current position measurement should be performed by the RTK-GPS method. The reference distance is a distance that satisfies a predetermined proximity standard (for example, a standard that is within 100 meters, a standard that is within a distance randomly selected between 200 meters and 300 meters). If the reference distance is exceeded, step 110 is executed again. If the reference distance is within the reference distance, step 115 is executed subsequently.

  In step 115, it is determined whether or not high-precision positioning, that is, current position measurement by RTK-GPS is possible. Specifically, it waits for a certain period, and if it does not receive a signal indicating that the RTK-GPS system cannot be used from the GPS receiver 11a within that period, it determines that high-precision positioning is possible, and RTK-GPS system. If a signal indicating that the device cannot be used is received, it is determined that high-precision positioning is impossible. If high-precision positioning is possible, step 125 is subsequently executed. If not, then in step 120, the user cannot perform high-precision positioning, and thus no more route guidance can be performed. Are notified to the image display device 13 and the speaker 14 respectively, and then the execution of the error correction processing program 100 is terminated.

  In step 125, it is determined whether or not the vehicle has turned a corner. Specifically, when the trajectory of the current position specified by the current position specifying process is immediately after (for example, within 10 meters of driving) a turn of a reference angle (for example, 45 °) or more, the host vehicle turns a corner. It is determined that the vehicle has been turned. Otherwise, it is determined that the host vehicle has not turned the corner. If the vehicle has turned a corner, then step 130 is executed, and if not, step 145 is executed.

  In step 130, the apex of the bent portion (for example, the center position of the bent portion, the position having the smallest radius of curvature, etc.) of the trajectory determined to be bent in step 125 is specified as the bent position, and the bent portion. The center of the intersection (or the vertex of the curve) on the map closest to is specified as the corner position, and the position error between the coordinates (latitude and longitude) of this corner and the map coordinates (latitude and longitude) of the corner It is determined whether or not there is. FIG. 4 shows a map 31 having the same format as FIG. 2 and a view window 42 showing a map area displayed by the image display device 13 in this case. Here, the map coordinates (X, Y) of the display reference point 43 fixed to the view window 42 and the scale of the map are determined so that the current position mark 45 and the destination 44 enter the view window 42. Here, when the turning position of the host vehicle is the position of the current position mark 45 and the turning corner position is the center point 46 of the intersection, the position errors are latitude + α and longitude −β (where α and β are positive numbers). ). If there is a position error, step 135 is subsequently executed, and if not, step 145 is subsequently executed.

  In step 135, it is determined whether or not the position error calculated in step 130 is within the reference range (for example, the distance error is within 50 meters). If it is within the reference range, step 140 is executed. If it is outside the reference range, step 145 is executed.

  In step 140, the display reference position of the map is corrected so that the position error calculated in step 130 is eliminated. FIG. 5 shows the view window 42 and display reference point 43 before correction, and the corrected view window 52 and display reference point 51 on the map 31 as in FIGS. 2 and 4. As shown in this figure, the display reference point is corrected in order to translate the map on the image display device 13 so that the calculated position error is eliminated and the current position mark 45 and the corner position 46 coincide. Therefore, the display reference point 51 after correction is deviated from the display reference point 43 before correction in the same direction as the position error in the opposite direction, that is, by latitude-α and longitude + β. However, after the display reference point is corrected, the pixel coordinate position of the current position mark 45 is at a relative position between the current position coordinate of the current position mark 45 and the original display reference point 43 that has not been corrected. Come to decide based on. Thus, as shown in FIG. 5, the facilities 47 and the like, which are constituent elements of the map, determine the pixel coordinates based on the relative position with respect to the display reference point 51, and the current position mark 45 is the display reference point. Since the pixel coordinates are determined based on the relative position with respect to 43, as a result, the current position mark 45 is obtained by moving the map in parallel while the current position mark 45 is fixed on the display screen 52 of the image display device 13. And the corner position 46 coincide with each other.

  Since the control circuit 19 stores the map coordinates of the original display reference point, the position of the display reference point is changed to the map coordinate of the original display reference point and the relative map coordinate displacement corresponding to the correction to the original. Is stored in the RAM 16, and the current display reference point is obtained by adding the relative map coordinate displacement to the map coordinates of the original display reference point. Each time the display reference point is corrected in step 140, the value of the relative map coordinate displacement is shifted by the change. Also, in the map display process, if you want to scroll to prevent the current position mark from appearing outside the view window, rather than correcting the display reference point, the map coordinates of the original display reference point are shifted by that amount. It is like that.

  Subsequent to step 140, in step 145, it is determined whether or not the vehicle has reached the destination and the route guidance process has been completed. If the route has been reached, step 155 is subsequently executed. Continues with step 150. In step 150, it is determined whether or not the route guidance processing has been interrupted due to a guidance end operation or the like on the user operation switch group 12, and if there is any interruption, step 155 is executed. If there is no interruption, step 125 is executed. To do.

  In step 155, the correction value is reset. Specifically, the relative map coordinate displacement value in the RAM 16 is set to zero. After step 155, one execution of the error correction processing program 100 ends.

  By executing the error correction processing program 100 as described above, the vehicle navigation apparatus 1 becomes less than the reference distance to the destination during the route guidance processing (see step 110), and the current accuracy with RTK-GPS is high. When position measurement is being performed (see step 120), each time the host vehicle enters the turn and makes a turn (see step 125), a reference is made between the turn and the turn on the map. Based on the fact that there is an error within the range (see steps 130 and 135), the display reference point for displaying the map is shifted so that the error between the bending position coordinates and the position coordinates of the turning corner in the map data becomes zero (see FIG. (See step 140).

  As described above, the vehicle navigation apparatus 1 determines the bent position (that is, the current position) measured by the current position measurement method with high accuracy based on the fact that the vehicle navigation apparatus 1 is bent when approaching the destination during route guidance. The vehicle turns the corner of the relative position between the map in the image display device 13 and the current position mark so that the error between the coordinates of the nearby position) and the position coordinates of the corner in the map data is reduced. Since the correction is repeatedly performed each time, it is possible to display an image after the error of the map data at the current position is appropriately corrected in real time. Therefore, it is possible to perform accurate route guidance to the destination in accordance with the current position measurement with high accuracy.

  In addition, the vehicle navigation device 1 corrects until the route guidance ends when the host vehicle reaches the destination (see step 145) or the route guidance process is interrupted (see step 150). Is discarded (see step 155). Since this is the case, the navigation apparatus 1 for a vehicle does not affect the error correction up to that point after the end of the route guidance, so that the past correction does not affect the next route guidance or the like.

  In addition, when the vehicle navigation device 1 cannot use the current position measurement method with high accuracy (see step 115), the vehicular navigation device 1 informs the notification device of a warning to that effect (step 120). It becomes possible to easily detect that the route guidance based on the current position measurement cannot be received.

  In addition, when there is an error that exceeds the reference range between the bent position and the position on the map (see step 135), the vehicle navigation device 1 determines the bent position coordinates and the turn angle in the map data. No correction is made to make the error from the position coordinate zero. Therefore, when an abnormal current position measurement is performed, such as when there is a failure in the GPS receiver 11a, the possibility of performing correction based on the abnormal measurement is reduced.

  In the above embodiment, the vehicle navigation device 1 corresponds to a map display control device. Further, a program for map display control processing, a program for route guidance processing, and an error correction processing program 100 correspond to a map display control program. The control circuit 19 functions as map display control means by executing a program for map display control processing, and functions as route guidance means by executing a program for route guidance processing. The control circuit 19 functions as a correction unit by executing the error correction processing program 100.

(Other embodiments)
In the above embodiment, the error between the current position measured by the RTK-GPS method and the map is eliminated by shifting the map in the image display device 13. The same effect can be achieved by shifting the mark in the reverse direction.

  In the above embodiment, the second current position measurement method is based on the RTK-GPS method, but the second current position measurement method may be D-GPS, for example. In addition, the first current position measurement method and the second current position measurement method may not necessarily use the GPS satellite, but may use another satellite navigation system. Further, the first current position measuring method and the second current position measuring method do not necessarily need to use a satellite navigation system. For example, a low-precision gyroscope may be used as the first current position measurement method, and a high-precision gyroscope may be used as the second current position measurement method. Further, a low-precision acceleration sensor may be used as the first current position measurement method, and a high-precision vehicle speed sensor may be used as the second current position measurement method. That is, the display based on the map is performed such that the first current position measurement method has lower measurement accuracy than the second current position measurement method and the error is larger than the error of the second current position measurement method. As long as this is the case, any of the first current position measuring method and the second current position measuring method may be used.

  Moreover, in said embodiment, although the vehicle navigation apparatus 1 is shown as an example of a map display control apparatus, as a map display control apparatus, the navigation apparatus which a person can carry may be sufficient, A device that does not perform route guidance and simply causes the image display device to display an image with the current position superimposed on the map may be used.

It is a hardware block diagram of the vehicle navigation apparatus 1 which concerns on embodiment of this invention. It is a figure which shows the relationship between the map which map data shows, and the display part 32 to the image display apparatus 13 in the map. 3 is a flowchart of an error correction processing program 100 executed by a control circuit 19; It is a figure which shows the difference | error between the position 45 of the own vehicle at the time of a turn, and the corresponding turning angle 46. FIG. It is a figure which shows a mode that the display part to the image display apparatus 13 in a map is correct | amended based on an error.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle navigation apparatus, 11 ... Position detector, 11a ... GPS receiver,
11b ... Gyroscope, 11c ... Vehicle speed sensor, 12 ... Operation switch group,
13 ... Image display device, 14 ... Speaker, 16 ... RAM, 17 ... ROM,
18 ... External storage medium, 19 ... Control circuit, 31 ... Map,
32, 42, 52 ... view window, 33, 43, 51 ... display reference point,
34, 47 ... Facility, 35, 45 ... Current position mark, 44 ... Destination,
46: Turn angle position, 100: Error correction processing program.

Claims (4)

In some cases, on the basis of the current position coordinates measured by the first current position measurement method, an image in which the current position mark is superimposed on the map indicated by the map data is displayed on the image display device. Is based on the current position coordinates measured by the second current position measurement method, which has higher measurement accuracy than the first current position measurement method, and an image in which the current position mark is superimposed on the map indicated by the map data. Map display control means for displaying on the image display device;
When the map display control unit displays an image in which a current position mark is superimposed on a map based on the current position coordinates measured by the second current position measuring method on the image display device, The map of the image displayed on the image display device and the current position mark are reduced so as to reduce an error between the position coordinates of the turn and the position coordinates of the turn corner in the map data. A map display control device comprising: correction means for correcting the relative position; Provide route guidance means to guide the guidance route to the destination,
The map display device according to claim 1, wherein the correction unit discards the corrections made so far based on the fact that the route guidance unit has finished the route guidance. 3. The map display control according to claim 1, further comprising notification control means for informing a notification device of a warning to that effect based on the fact that the second current position measurement method cannot be used. apparatus. In some cases, on the basis of the current position coordinates measured by the first current position measurement method, an image in which the current position mark is superimposed on the map indicated by the map data is displayed on the image display device. Is based on the current position coordinates measured by the second current position measurement method, which has higher measurement accuracy than the first current position measurement method, and an image in which the current position mark is superimposed on the map indicated by the map data. Map display control means for displaying on the image display device; and
When the map display control unit displays an image in which a current position mark is superimposed on a map based on the current position coordinates measured by the second current position measuring method on the image display device, The map of the image displayed on the image display device and the current position mark are reduced so as to reduce an error between the position coordinates of the turn and the position coordinates of the turn corner in the map data. A map display control program for causing a computer to function as correction means for correcting a relative position.

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