JPH04125418A - Processing apparatus of information on position of moving body - Google Patents

Abstract

PURPOSE:To make it possible to compute a distance from the current position to a destination accurately in a short time by determining a correction coefficient for the latitude of an intermediate point between the latitude of a target position and that of the current position. CONSTITUTION:A processing apparatus of information on position has a GPS receiver detecting the latitude and longitude of the current position, an antenna inputting at least one target position and ECU computing a straight-line distance between the current position and the target position and outputting information on a distance. ROM of the control means ECU holds correction coefficients for various latitudes on a map. The control means ECU finds out from the ROM the correction coefficient for the latitude of an intermediate point between the latitude of the target position and that of the current position, computes the distance between the current position and the target position in the direction of the longitude by using the correction coefficient found out, and further computes the distance between the current position and the target position in the direction of the latitude. Based on the distance in the direction of the latitude and that in the direction of the longitude, then, the distance between the current position and the target position can be computed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a position information processing device for a moving body, and in particular to outputting a straight-line distance between two points whose latitude and longitude are known.

[Prior Art] Various people have been working on the development of so-called navigation systems, which are location information processing devices that display the current location on a map and the distance from the current location to the destination, for example in automobiles. There is.

The applicant has already developed a navigation system as shown in FIG. This system uses a combination of a display device AG called an atlas gauge and an atlas (pre-specified commercially available one). This atlas gauge AG is equipped with a U-shaped frame 1 and a rectangular transparent thin plate 2 held inside the frame. A large number of indicators 3 are incorporated at intervals. Furthermore, black lines BL are added as scales to the thin plate 2 in the vertical and horizontal directions in a grid pattern at positions facing each of the indicators 3. In use, as shown in Fig. 2, a predetermined atlas MP is opened, the atlas MP is attached to the atlas gauge AG with the thin plate 2 in between, and the necessary pages of the atlas are placed under the thin plate 2. The scale and map are viewed from above the thin plate 2. Each page of the atlas has its end point MPo at the corner 1° of frame 1 and -
position to match.

Therefore, in this system, each position on the map combined with the atlas gauge AG can be expressed as a distance in the horizontal and vertical directions from a 1° corner of the frame, and the display 3H on the top side and the display on the vertical side Any location on the map can be indicated using the device 3v. Actually, if the latitude, longitude, and scale of the reference point Po on the map are known, the reference point P at any position Px on the map. Since the latitude and longitude of Px can be determined based on the distance (vertical and horizontal directions) to the reference point P on the map. If the reference point on the atlas gauge AG coincides with the reference point on the atlas gauge AG, the display 3 on the atlas gauge can be lit based on the latitude and longitude of the current position to indicate the current position on the map. For example, the current location can be determined using GPS (Global Positioning).
It can be detected by receiving radio waves from satellites of the System.

For example, the latitude and longitude of the destination can be entered into the device by sequentially changing the indicated position on the display 3 and having the device read that position as the destination when an arbitrary position is specified. can.

[Problems to be Solved by the Invention] Incidentally, this type of system is preferably provided with a function of displaying, for example, the distance from the current position to an arbitrary destination. In order to realize this function, the applicant's system needs to calculate the distance based on the latitude and longitude of the current location and the latitude and longitude of the destination (or waypoint).

The problem with this calculation is that the coefficient (m/degree 9 minutes 1 second) used to convert the longitude difference into distance varies greatly depending on the latitude. Note that the coefficient when converting the latitude difference into distance is constant.

For this reason, a coefficient corrected according to the latitude of the current location may be used to convert the longitude difference into distance, but if the latitude difference between the current location and the destination is large, the error will be quite large. occurs.

To perform accurate calculations, divide the distance between the current position and the destination into minute sections, find the corrected coefficient for each minute section, use it to find the distance of the minute section, and calculate. The total distance can be calculated from the sum of the distances of each section. However, in this method, as the minute interval is made smaller to reduce the error, the number of calculations increases, so it is not possible to accurately calculate the distance in a short time.

Therefore, an object of the present invention is to enable accurate calculation of the distance between the current position and a destination (or a route value) in a short time.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a position detection means for detecting the latitude and longitude of the current position.

In a position information processing device comprising means for inputting at least one target position, and a control means for calculating a straight-line distance between the current position and the target position and outputting distance information: Correction that holds correction coefficients at various latitudes. comprising a table means, wherein the control means obtains a correction coefficient from the correction table means for the latitude of an intermediate point between the latitude of the target position and the latitude of the current position, and uses the obtained correction coefficient to determine the current position in the longitudinal direction; Calculate the distance to the target position, further calculate the distance between the current position and the target position in the latitude direction, and calculate the straight-line distance between the current position and the target position based on the distance in the latitude direction and the distance in the longitude direction. Configure it to do so.

[Effect] Coefficient for converting longitude difference to distance (m/degree 2 minutes.

seconds) changes depending on latitude, but the direction of change is constant, increasing in low latitude regions and decreasing in high latitude regions. Therefore, for example, if the current position is at a low latitude and the destination is at a high latitude, the coefficient at the intermediate point (the center between the current position and the destination) is smaller than the coefficient at the current position.
It is large compared to the destination coefficient. Therefore, when calculating the distance between the current position and the destination using the coefficient of the waypoint,
An error appears in the negative direction in the area between the intermediate point and the current position, and an error appears in the positive direction in the area between the intermediate point and the destination, so the errors in a hundred directions cancel out and the error is small overall. Become. In this way, there is no need to repeat the calculation many times, so the distance can be determined in a short time with sufficient accuracy for practical use.

[Example] FIG. 1 shows the appearance of an automobile navigation system embodying the present invention, and FIG. 7 shows an outline of the configuration of the electric circuit. This will be explained with reference to FIGS. 1 and 7.

This system uses GPS, which is a wide area positioning system, to detect the latitude and longitude of the current location. An antenna ANT is provided to receive radio waves from GPS satellites.

The radio waves received by the antenna ANT are sent to the electronic control unit EC.
The information is input to a dedicated receiver installed inside the U and decoded into latitude and longitude information. The electronic control unit ECU is connected to a display DSP, and an atlas gauge AG is connected to the SP via a predetermined electric cable. R
The MT is a remote control unit equipped with various switches, and in response to switch operations, transmits a remote control code to the display device DSP by infrared rays.

The calculation board in the electronic control unit ECU is equipped with a microcomputer (MPU), ROM, and RAM. Various information such as area information corresponding to a map is stored in advance on the ROM.

RAM is used for temporary data storage.

This microcomputer also has a small internal capacity of R.
Equipped with AM. A backup battery (not shown) is provided in the power supply section so that the data on the built-in RAM will not be erased even if the main power supply is cut off.

The display device DSP is also provided with a microcomputer, which executes processing 1 display processing of signals received from the remote control unit RMT and data transmission processing with the ECU.

As described above, the atlas gauge AG holds the atlas MP and indicates the position on the map held by the display 3. It is also used to enter the location of a destination, etc. This system comes standard with a national road atlas that covers the entire country in one volume, but it also includes pre-specified commercially available local road atlases (in this example, the prefecture-based version of the Jinbunsha edition). You can also use it by purchasing a wide-area road atlas.

In this system, various information is stored in R as a database.
Although it is registered on the OM, ultimately the position on the map is calculated and determined by referring to the individual map data that has a one-to-one correspondence with each member's map on the atlas. Instruct on display 3.

Examples of individual map data are shown in Figures 6a and 6b.

Referring to FIGS. 6a and 6b, in this system, each individual map data includes a map data number,
Latitude and longitude of the map coordinate origin (EO1No = seconds),
Map size in latitude and longitude directions (x, y), offset amount of origin (Xolf.

Yoff), adjacent map data, page number 2 of the map, left and right divisions, scale, presence/absence of detailed drawings, and irregular map data.

Assuming that the map is positioned so that the end point MPo of the map coincides with the corner 1o of the frame, the offset amount of the origin is calculated from a predetermined position on the atlas gauge AG (actually, in the case of the right page, the rightmost edge of the display 3H). map reference point (the position of the upper right end point P (R) for the page on the right, the upper left end point PO (L) for the left page) The amount of deviation (mm) is shown.

This is because the amount of deviation of the map reference point from the end point MPO differs depending on the page, and by making corrections using the offset amount during calculation, the positional deviation between pages can be reduced. .

Adjacent map data is to the right of the map on the page.

Map data numbers of adjacent maps corresponding to the upper right, upper, upper left, left, lower left, lower, and lower right positions are shown. The data number is 0 for maps for which there is no adjacent map. As will be described later, this adjacent map data is useful for shortening the time it takes to search for the next map when the current location is outside the range of the currently selected map.

The atlas contains detailed maps showing special enlarged and detailed maps of major and complex areas, such as urban areas. The presence or absence of a detailed map in individual map data indicates the presence or absence of a detailed map that shows the area included in the same area as the map in detail, and if there is no detailed map, it is O, and if there is a detailed map, it is O. , its map data number is retained.

In addition, in atlases, for example, in maps where the ocean occupies a large area, multiple maps are written on one page in the form of cutaway diagrams in order to eliminate wasted space and save space. (See Figures 11a and 11b). Even for maps with special shapes of this kind, in order to make it possible to accurately identify the area for each map within one page, in the case of such maps, the shape etc. of the map is stored as irregular map data. Retain information.

The above-mentioned individual map data exists for each page of the atlas, so in this system that covers all of Japan and is compatible with the national version and all local versions of the atlas, a huge amount of individual map data exists. Therefore, in order to display a location using this system, it is first necessary to search for the necessary individual map data from a huge amount of data. In reality, individual map data in an area including the current position is searched, but if the process is simply performed, it is necessary to compare each area for all individual map data, which takes an enormous amount of time.

Therefore, in this embodiment, by performing the processing described below, the amount of data actually referred to during a search is reduced and the search time is shortened.

First, we will limit the scope to all of Japan. As shown in FIG. 5a, the entire country of Japan is divided into a grid (matrix) according to latitude and longitude, and it is determined which of the divisions the current position belongs to. Then, set the latitude of the current position as the latitudinal partition boundary N02Nl, N2. ..., the X coordinate (Mn) of the section is detected, and the longitude of the current position is determined from the boundaries of the section in the longitudinal direction EO, El, E2, .
By comparing with each of..., the X coordinate of the parcel (
Me) and obtain the participation of the corresponding partition from these coordinates. As a result, there is no need to search for map data of areas outside the detected area, and the amount of data to be processed is significantly reduced.

In addition, the latitude data of the boundary of the division No., Nl, N2゜...
- and longitude data EO, El, E2. ... is ROM
This is provided as fixed data in Table 1 above. Further, a table 2 showing the correspondence between detected coordinates (Mn, Me) and partition numbers is also registered as fixed data on the ROM. Therefore, this process is executed while referring to the contents of Tables 1 and 2.

FIG. 5b shows the positional relationship between each of the divided sections as shown in FIG. 5a and the actual prefectural area (the area indicated by the dotted line is the prefectural border). As can be seen in Figure 5b, each of the compartments contains several units. Therefore, in the worst case,
Data for all prefectures included in the detected area must be processed.

However, if prefectures that are most likely to include the current location are processed preferentially, search results will be obtained more frequently before data for all prefectures are processed, and the search speed can be increased.

Therefore, in this embodiment, as shown in FIG. 5C, a table 3 is provided which stores the priority order of the prefectures included in each division. In FIG. 5c, matrix No. corresponds to the division number, and Dn in each column corresponds to the prefecture division. In reality, three types of tables are provided as shown in FIG. 12, and which table to use can be switched by a switch (not shown). In FIG. 12, in the upper table, each prefecture is prioritized in descending order of area occupied by the corresponding section. In other words, the larger the area within a section, the more likely that prefecture will be a search result, so the prefectures are prioritized in that order. In the middle table, priority is assigned to each prefecture included in the division in descending order of population density. In other words,
Since people tend to gather in areas with high population density, there is a high possibility that prefectures with high population density will be search results. In the lower table, priority is assigned to each prefecture in the division in descending order of the number of trunk roads. In other words, since there is a high probability that cars will travel on main roads, prefectures with a large number of main roads have a high probability of being included in search results.

Therefore, for example, when using table 3 in FIG. 5c, if the detected partition number (matrix number) is 3,
First, the prefecture corresponding to the DB is selected as a candidate. Next, the search process after the prefecture is specified will be explained.

In this example, in order to search the map area within the prefecture, the fifth d
A table 4 as shown in the figure and a table 5 as shown in Fig. 5f (one for each prefecture) are provided as fixed data. Table 4 assumes a rectangular area that includes the entire prefecture as shown in Figure 5e, and maps each area divided into a mesh pattern to each member's location on the map. . Of course, each prefecture is not rectangular, so some of the divided areas may not actually belong to that prefecture.
This can be determined by referring to Table 5.

First, referring to Figure 5d, this table 4 shows the latitude No' at the origin of the prefecture area (lower left of the rectangular area).
and longitude Eo', the size of the prefectural area in the longitude and latitude directions x, y (unit: 2 seconds), the number of divisions in the latitude direction Nn, the total number of divisions Nt, and the division unit length in the longitude and latitude directions x,
9 (unit: 2 seconds) is held. In the example of Aichi Prefecture in Figure 5d, Nn is 9 and Nt is 126, so
For each division that divides the prefecture (corresponding to each member's map),
Numbers are assigned in order as shown in Figure 5e.

The latitude and longitude range of each of the sections shown in Figure 5e can be specified by the coordinates of the section and Eo', No', x and y, so compare that range with the latitude and longitude of the current location. For example, it is possible to specify the section (ie, map) that includes the current location.

Table 5 shown in Figure 5f is the table 5 (for Aichi prefecture) in Figure 5e.
It shows the correspondence between the section number and the map data number. Regarding plots that do not actually belong to the atlas,
A special code is assigned to identify it as being outside the atlas. In FIG. 5f, the block number in each column is determined as vertical coordinate×8+horizontal coordinate. For example, section No. 10 is located at a position indicated by a vertical coordinate of 1 and a horizontal coordinate of 2, and 86 is registered as a map data number in that section. In other words, if the current position is within block number 10, the number of map data to be searched for is 86. If a non-atlas code is detected, the current location is not in the selected atlas, so it is necessary to refer to Table 3 shown in Figure 5c again and continue searching for the prefecture with the next highest priority. be.

By referring to Table 6 (FIGS. 6a and 6b) using the map data number retrieved in this way, it is possible to obtain individual map data for the area of the current location.

Next, the actual operation of the device will be explained. The contents of the processing by the electronic control unit ECU are shown in FIGS. 8a to 8f.

First, explanation will be given with reference to FIG. 8a. When the power is turned on,
First, initialization is performed, and then the information output by the GPS receiver is read and the latitude N and longitude E of the current location are input.

In the next step A3, it is detected which of the national divisions shown in FIG. 5a the current position belongs to by the method described above.

In step A4, table 3 (FIG. 5c) is referred to using the detected block number to obtain priority order data of the prefectures belonging to the block, and this data is stored in a buffer on the RAM. For example, if the partition number is 3, DB-D7-DB-D9
-DI. -Write the data sequence of D1□ onto the buffer.

By the way, when the system is activated, each time a map search is successful, the search results are stored in the non-volatile memory in step AI5. Therefore, by referring to the contents of the nonvolatile memory, the previous search results can be known even immediately after the power is turned on. Step A5 refers to the contents of the non-volatile memory and retrieves the prefecture code (
The presence or absence of Dn) in FIG. 5c is determined. Since a prefecture code normally exists, the process then proceeds to step A6. Step A
In step 6, it is checked whether or not the same prefecture code as the detected prefecture code exists among the priority pigs stored on the buffer. If the same prefecture code exists, the process proceeds to step A7. In step A7, the order of priority data on the buffer is changed so that the prefecture of the previous search result has the highest priority. For example, if the priority data on the buffer is D
6D7 Da D9 If the detected previous prefecture code is D8 when DIODl+, D8-D6D7
-D9-D, o-D, etc., change the priority order.

The priority order data in Table 3 used from step A7 onwards is the data on the buffer whose priority order has been changed.

The various processes in steps A8 to A21 are repeatedly executed in a loop until the power to the system is shut off.

In this system, all the numbers of local atlases owned by the user can be registered in the table 7 on the non-volatile memory. When registering this number, the display DSP processes the signal from the remote control unit RMT,
The results (map registration data) are sent to the ECU. E
When the CU receives the map registration data in step A8,
The data is registered in table 7 in step A9.

Furthermore, in this system, the map to be used can be switched between the national version and the local version by operating the remote control unit RMT. When a signal instructing this switching is received,
The display device DSP transmits a corresponding signal (map change data) to the ECU. In the ECU, step AIO
When the map change data is received in step All, the national/regional flag is inverted and the display mode is switched.

In step A12, the information output by the GPS receiver is read and the latitude N and longitude E of the current location are input.

In Step A]3, search and calculation processing is executed for the data corresponding to the local version of the atlas, and the next step A14
Then, search and calculation processing is executed for the pigs corresponding to the national version of the atlas. The results of steps AI3 and Al1 are stored in non-volatile memory in step A15.

In step A16, check the state of the national/regional flag,
Identify whether the national or local version of the map is selected. When the national version map is selected, the process advances to step AI8, and when the local version map is selected, the process advances to step A17. Step A] In 7, step A
It is checked whether the map book number of the search result obtained in the process I3 is registered in the table 7. If the atlas is registered, proceed to step A19, but if the atlas is not registered, proceed to step A as in the case of the national version.
Proceed to step 18.

In step A18, the processing results for the national atlas obtained in step AI4 (location data of the current location, etc.) are displayed on the display D.
In step A19, the processing result for the local atlas obtained in step AI3 is transmitted to the display device DSP. Therefore, even if the user has selected a mode that uses the local version of the atlas, when the user moves to an area of the local version of the atlas that the user does not own, the national version of the atlas will be automatically used. mode.

In step A20, processing for the user's destination input is executed. In the next step A21, the straight-line distance from the current position to the destination is calculated as the remaining distance.

Next, the local map processing in step AI3 will be explained in detail. Note that the national map processing in step A14 is not significantly different from the local map processing, so illustrations and explanations thereof will be omitted.

The contents of the local map processing are shown in Figure 8b. In this process, step B1 is first executed.

In step B1, it is checked whether the search results obtained in the previous process remain in the memory. If there is a previous search result, use the map data number included in it, that is, the number of the map used last time, and proceed to step B.
2. Immediately refer to individual map data. If there are no previous search results, it is necessary to search for the necessary individual map data, so the process proceeds to step B8 and executes a nationwide search process.

The contents of the nationwide search process will be explained with reference to FIG. 8c.

In step C1, as described above, it is detected to which of the national divisions in FIG. 5a the latitude and longitude of the current position belong. In step C2, the prefecture code of the data to be retrieved is determined by referring to the priority order data on the buffer (Table 3, see Figure 5c). If it is the first, select the prefecture with the highest priority. In step C3, search data for the prefecture is loaded from table 4 (Figure 5d).

In step C4, the latitude and longitude of the origin in table 4 (E
o', No') and the area size (X, Y) to determine the range of the prefecture, and determine whether the current position is within that range. If it is within the range, the process proceeds to step C5, and if it is outside the range, the process returns to step C2 to search for another prefecture.

In step C5, E on table 4.

No' Using the data of Nn, Nt, x and y, the fifth
As shown in figure e, the divisions on the map within the prefecture are calculated, and it is detected which division the current position belongs to. In step C6,
Referring to Table 5 (Fig. 5f), the number of the individual map data corresponding to the detected block number is checked. As a result of referring to Table 5, if the individual map data number is found, the process proceeds to step C8, and if the area does not have a map, the process returns to step C2.

In step C8, table 6 is selected according to the searched number.
Refer to the above individual map data (Figures 6a and 6b). In the map position calculation in step C9, the individual map data is used to calculate to which position within the selected map range the latitude and longitude of the current position correspond. The specific contents of this process are shown in FIG. 8d. Next, the process shown in FIG. 8d will be explained.

In step D1, based on the longitude E of the current position and the longitude Eo of the origin on the individual map data, calculate the longitude difference E between them, and further calculate the latitude N of the current position and the latitude No of the origin on the individual map data. The latitude difference ΔN between them is determined based on .

In step D2, various parameters used for calculation are input. The constant Cx is a coefficient when converting a longitude difference into a distance in the horizontal direction on the map, and since it has a different value depending on the latitude N, use N to refer to the constant table and select an appropriate constant C.
Find x. The constant cy is a coefficient for converting the latitude difference into a distance in the vertical direction on the map, and is a constant value. RATE is the map scale and is obtained from individual map data.

In step D3, the distance of the current position on the map from the origin is determined in both the horizontal direction (ΔX) and the vertical direction (ΔY). In steps D4 and D5, it is checked whether the current position does not extend beyond the map. In other words, the horizontal range of the map has a distance from the origin of O”-Xsize
(corresponding to X' on the map data by gJ),
The vertical range of the map is the distance from the origin from 0 to Ysize
(corresponding to Y on the cut map data), ΔX and ΔY are compared with those ranges.

When ΔX and ΔY are both within the range, step D6
, and add the offset amount (X
Add olf, Yof[) and get atlas gauge AG
Find the X and Y coordinates (X, Y) of the current position above. If the current position is outside the range on the map, proceed to step D7 and set error values (-1) to X and Y.
Substitute.

Returning to FIG. 8c, the explanation will be continued. At step CIO,
It is checked whether the calculation result in the map position calculation process is normal, that is, whether X and Y are not error values (-1).

If it is normal, the process proceeds to step C11, and if there is an error, the process proceeds to step C14.

In step C1l, it is determined whether the map being referred to is a variant map. That is, the determination is made with reference to the information included in the irregular map data column of the individual map data. In the case of an irregularly shaped map, the process proceeds to step CI2 to calculate the actual map range.

For example, if the shape code (pattern G) is 010XXOXO (X is O or 1), the map belongs to either area 1 or area 2 shown in Figure 11a, and the function Y = (b / a) By comparing the magnitudes of X and Y at the current position with X 10c, it is possible to determine whether the position is within the map area or outside the area. The direction of the fourth bit of the shape code, that is, the inequality sign, changes depending on the region division. The shape code is the parameter (a+l)+C
+ d) signs (10, -) are also shown.

If the current position is not within the range of the map, the process advances from step C13 to C14. In step C14, the presence or absence of an adjacent map is checked by referring to the adjacent map data column included in the individual map data. If an adjacent map exists, the data number of that map is input and the process returns to step C8.

If there is no adjacent map, the process returns to step C2.

Returning to FIG. 8b, the explanation will be continued. When the nationwide search process is completed, the process proceeds to step B9. In step B9, the individual map data is referred to to check whether there is a detailed map. When there is a detailed map, the process proceeds to step BIO, and the current position on the detailed map is calculated by referring to the individual map data of the detailed map.

On the other hand, if there is a previous search result, the individual map data is referred to using the result and a map position calculation is executed in step B3. As a result of the calculation, if the current position is outside the range of the map, the process advances to step B8 and a nationwide search process is executed. In addition, in the case of an irregularly shaped map, the range of the map is calculated in more detail. In that case as well, if the current position is outside the range of the map, the process proceeds to step B8.

Next, the contents of the destination input process will be explained with reference to FIG. 8e. In the destination input mode, an X coordinate update key, a Y coordinate update key, and a position input key (not shown) provided on the remote control unit RMT are used. When the X-coordinate update key is operated, the process proceeds from step E14 to Ei5, where the value of the X-coordinate counter is updated once and the corresponding display (3H) on the atlas gauge AG is displayed.
Move the lighting position of 1 step to the left. When the position exceeds the left end of the display row 3H, it returns to the right end position.

Similarly, when the Y coordinate update key is operated, step E1
6 to E17, the value of the Y coordinate counter is updated, and the lighting position of the display (3v) on the atlas gauge AC associated with it is moved down by one step.

When the position exceeds the bottom end of display row 3■, it returns to the top position.

When the position input key is operated, the position is calculated based on the state at that time. First, in step E2, the number of the atlas and the page of the map currently being used.

Input the value of the X coordinate counter and the value of the Y coordinate counter.

In the next step E3, individual map data for the relevant page is input.

In steps E4 to E8, it is determined whether the designated position is an area on the map. That is, in step E4, it is checked whether the X coordinate of the designated point is within the range of the X coordinate on the map, and in step E5, it is checked whether the Y coordinate of the designated point is within the range of the Y coordinate on the map. investigate. Further, in step E6, it is checked whether the map is an irregularly shaped map, and if it is an irregularly shaped map, the exact range of the map is checked in step E7, and it is checked whether there is a designated point within it.

If the coordinates of the designated point are outside the range of the map, first step E
Proceed to step 12 to check whether another map exists within the page. If another map exists, individual map data for the map is input in step Ell, and the process returns to step E3.

When it is confirmed that the coordinates of the specified point are within the range of the selected map, steps E9 and EIO are executed. In step E9, based on the X coordinate (X) of the designated point, the scale (RATE) on the individual map data, and the constant (Cx),
Longitude point Δ of the X coordinate (X) of the specified point relative to the origin on the map
Calculate E, and calculate the latitude difference ΔN between the Y coordinate (Y) of the designated point and the origin on the map based on the scale (RATE) and constant (Cy) on the 9 individual map data. demand. In step EIO, the latitude difference ΔN obtained in step E9 is subtracted from the latitude number of the map origin on the individual map data. Furthermore, the latitude and longitude (Ni, Ei) of the designated point are determined by adding or subtracting the longitude go of the map origin on the individual map data to the longitude difference ΔE.

Next, the content of the distance calculation process will be explained with reference to FIG. 8f. In this process, the straight-line distance between the current position and a pre-designated destination is determined. In this calculation, it is necessary to convert the latitude difference and longitude difference between two points into a distance, but the coefficient ExVAL when converting the longitude difference into a distance varies greatly depending on the latitude. For this reason, with normal calculation methods, calculation errors become large or processing takes a long time. Therefore, in this embodiment, the conversion coefficient EXVAL corrected for the latitude of the midpoint between the current location and the target location is used for the entire calculation between the current location and the target location. In this way, there is no need to repeat calculations many times, and the errors occurring in areas with high latitudes and those occurring in areas with low latitudes relative to the intermediate point cancel each other out, and the calculation errors are reduced to a level sufficient for practical use. reduced.

In step F1, the latitude N c a l at the intermediate point is determined based on the latitude of the current position and the destination.

In the next step F2, the conversion coefficient ExVAL corresponding to the latitude Ncal of the intermediate point is determined by referring to the table. In this example, the conversion coefficient ExVAL corrected at each 6-minute latitude position is provided as a table, and accurate conversion coefficients at each latitude can be obtained.

In step F3, the longitude difference E between the two points is calculated from the longitudes of the current position and the destination, and the latitude difference ΔN between the two points is calculated from the latitudes of the current position and the destination.

In step F4, the longitude difference ΔE is converted into a distance ΔX in the longitude direction, and the latitude difference ΔN is converted into a distance ΔY in the latitude direction.

During this conversion, conversion coefficients EXVAL and NYVAL are used. The conversion coefficient NyVAL is a constant value.

In step F5, the straight line distance between the two points is determined using the distance ΔX in the longitude direction and the distance ΔY in the latitude direction. This distance data L is output to the display device DSP in the next step F6.

Microcomputer (MPU) in display device DSP
An outline of the processing is shown in FIG. This will be explained with reference to FIG.

When the power is turned on, initialization is first performed, and then processing is performed in response to code input from the remote control unit RMT and data input from the electronic control unit ECU. When a map registration key (not shown) on the remote control unit RMT is operated, the map book registration mode is entered. When the atlas registration mode is entered, the process passes through step 2 and proceeds to step 3. When the atlas number is entered here, in the next step 4 it is checked whether the number is a valid value (within the range of values assigned to the atlas), and if it is, the next In step 5, the input number is sent to the ECU. After this, the atlas input mode is automatically canceled.

In addition, if the wide area/detail switch key on the remote control unit RMT is operated, the process advances to steps 7 to 8, the state of the internal wide area/detail flag is reversed, and if the wide area mode is in the detailed mode, the detailed mode is changed. If so, switch to wide area mode.

If the national/local switching key on the remote control unit RMT is operated, the process proceeds from step 9 to step 10, and the state of the internal national/local flag is reversed. Furthermore, in step 11, the contents of the national/regional flag are transmitted to the ECU.

In the normal operating mode, data sent by the ECU is input in step 15. In the next step 16, the type of map that can be used is identified, such as the presence or absence of detailed maps. If there is a detailed view, the "details" display is turned on in the next step 17.

In practice, steps 16 and 17 perform more complex processing as explained below.

A portion of the front panel of the display DSP includes an atlas number display 51. as shown in FIG. 13b. Map page display 52.
Wide area display 53. A city indicator 54 and a detail indicator 55 are provided. The display 51 displays a number previously assigned to the currently selected atlas, and the display 52 displays the page number and position (L, R) of the currently selected map. Wide area display 53. City display 54 and detail display 55
are controlled as shown in FIG. 13a, depending on the presence or absence of various maps at the time and whether the selected atlas is a national version or a local version. O shown in FIG. 13a indicates that a map is present or the display is lit, and x indicates that there is no map or the display is turned off. For example, if a national version of the atlas has a wide area map that includes the current location but no detailed map, and a local version of the atlas has a city map that includes the current location but no detailed map, the user may When selected, the wide area display 53 and city display 54 are lit, and the detailed display 55 is turned off. In regions where detailed maps exist, the detail indicator 55 lights up due to the presence of detailed maps, so that the user can know that detailed maps are also available when selecting a wide area map.

Returning to FIG. 9, the explanation will be continued. In step 18, by checking the wide area/detail flag, it is determined whether the display mode is wide area mode or detailed mode. If the display mode is wide area mode, the process proceeds to step 19, and if it is detailed mode, the process proceeds to step 12. In step 12, it is checked whether or not detailed diagram data exists in the data sent from the ECU. If it exists, the process proceeds to step 13; if it does not exist, the process proceeds to step 19. In other words, even when the user selects the detailed mode, if there is no detailed view at the current position, the same processing as in the wide area mode is executed.

In step 13, the detailed map data is stored in a display buffer, and in step 19, the wide area map data is stored in a display buffer.

In step 14, the data stored in the display buffer is processed and necessary information is displayed. This display also includes control of the lighting positions of the display rows (3H, 3V) on the atlas gauge AG. By looking at the coordinates of the lighting positions of the indicators 3H and 3V, the user can read the current position on the map attached to the atlas gauge AG.

By the way, in an actual atlas, each map of a wide area divided into a mesh pattern is not accurately described on each page, and there are some positional deviations.

For example, the longitudes of the upper right end of the left map and the upper left end of the right map of sections that are adjacent to each other in the longitude direction may not match. There is no problem if the position shifts in the direction that the areas of both maps overlap, but if the position shift occurs in the direction that creates a gap between both maps, if you use the data as is, A point (gap) that does not appear on the map occurs, and when passing through that point, the current location cannot be displayed on the map.

Therefore, in this embodiment, R of the electronic control unit ECU is
The contents of the individual map data group held on the OM are subjected to a correction process in advance, and are configured so that there are no gaps between adjacent maps. The contents of this correction process are shown in FIG. 10, and changes in the map area before and after correction under various conditions are shown in FIGS. 4a to 4f. The map data correction process will be described below with reference to these drawings.

In FIG. 10, in step 31, one piece of individual map data is input. In this correction process, among the data,
Longitude E1 at the map origin. Latitude N1. Map size in the longitude direction: 5I7EX, , Map size in the latitude direction: 5IZEY
, , scale RATEI, and adjacent data.

In the next step 32, individual map data of a map adjacent to the map of the data input in step 31 is input. The data to be entered here is the longitude E2 at the origin of the map.
．． Latitude N2. Longitudinal map size 5IZEX2. The map size in the latitude direction is 5IZEY2 and the scale RATE2.

In the following step 33, the gap ΔEs in the longitudinal direction or the gap ΔNs in the latitude direction between the map of the data input in step 31 and the map of the data input in step 32 is calculated. This calculation will vary depending on the conditions of each map.

That is, as shown in FIGS. 4a and 4b, if the right side of the map (right page) Ml whose origin is in the upper right is adjacent to the left side of the map (left page) M2 whose origin is in the upper left , E
2-E is the gap ΔEs.

In addition, as shown in Figures 4c and 4d, if the left side of the map (left page) Ml whose origin is in the upper left is adjacent to the left side of the map (page 1/[2 on the right) whose origin is in the upper right (E2 5IZEX2) (E]+5IZEXI)
is the gap ΔEs.

Furthermore, as shown in Figures 4e and 4f, when two maps are vertically adjacent, (N+ 5IZEY
I) Let N2 be the gap ΔNs.

In step 34, the gap ΔEs or ΔNs is checked to see if there is a gap. That is, if ΔEs or ΔNs is a positive value, there is a gap between the two maps, and the process proceeds to step 35 for correction. If there is no gap, proceed to step 37.

In step 35, the amount of the gap ΔEs or ΔNs to be distributed to each map is determined. That is, for example, if the scales of the two maps are the same as in Figure 4a, it is sufficient to correct the origins of the two maps by the same amount, but if the scales of the two maps are different as in Figure 4b, the scales may be corrected. The smaller the size, the less the effect of the correction will occur, so the correction amount is distributed to the two maps as follows according to the ratio of the scales of the two maps.

ΔE, = ΔE s −RATE2/ (RATE
I+RATE2)ΔE2=ΔEs−RA
TEI/ (RATEI+RATE2)ΔN□=ΔN
s −RATE2/ (RATE1+RATE2)ΔN
2-ΔNs-RATEI/ (RATE1+RA
TE2) In the next step 36, the data is actually corrected.

The content of this correction also differs depending on the conditions of each map.

That is, in the case of FIGS. 4a and 4b, the following correction process is executed.

E1'←E1+ΔE1 SIZEX4←5IZEX, 10ΔE1 E2'←E2−ΔE2 SIZEX2←5IZEX2+A E 2 Also, in the case of FIG. 4c and FIG. 4d, the following correction process is executed.

5IZEX14-3IZEX1+ΔE1SIZEX2←
5IZEx2+ΔE2 In the case of FIGS. 4e and 4f, the following correction process is executed.

5IZEY1←5IZEY□10ΔN1 N2'4-N2+ΔN2 5IZEY2←5IZEY2+ΔN2 Since the data corrected in this way is registered as individual map data, even if there is a gap between adjacent maps in the atlas, However, there are no gaps in the data registered on the ROM, so the current position can be displayed virtually continuously on the map at any position.

[Effect] As described above, according to the present invention, the conversion coefficient (EX
Since the distance between 2A is calculated using 2A (VAL), the calculation error is small and the calculation can be completed in a short time.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the appearance of the entire system of the embodiment. FIG. 2 is a plan view showing the atlas gauge AG of FIG. 1 and the atlas MP attached thereto. FIG. 3 is a plan view showing a portion of a page inside the atlas MP. 4a, 4b, 4c, 4d, 4e, and 4f are plan views showing map areas before and after correction between adjacent maps. Figure 5a is a plan view showing the positional relationship between the whole country of Japan and the divisions divided into a network, Figure 5b is a plan view showing the positional relationship between each division and prefecture, and Figure 5C is a plan view showing the positional relationship between each division and prefecture. Figure 5d is a memory map showing the contents of table 3 in which the priority order of each prefecture included in the division is registered, and Figure 5e is a memory map showing the contents of table 4 in which data for searching within the prefecture is registered.
The figure is a plan showing the layout of map sections within Aichi Prefecture.
FIG. 5f is a memory map showing the contents of table 5 in which the correspondence between map sections and individual map data numbers is registered. 6a and 6b are memory maps showing the contents of individual map data existing as table 6. FIG. FIG. 7 is a block diagram showing the configuration of the electric circuit of the system shown in FIG. 1. Figure 8a, Figure 8b, Figure 8c, Figure 8d, Figure 8e,
and FIG. 8f is a flowchart showing the contents of processing by the electronic control unit ECU. FIG. 9 is a flowchart showing an outline of the processing of the microcomputer in the display device DSP. FIG. 10 is a flowchart showing the details of the process of correcting actual map data to create individual map data. FIGS. 11a and 11b are plan views showing area distribution within a page and shape codes in a variant map. FIG. 12 is a memory map showing a specific example of the contents of table 3. FIG. 13a is a correlation diagram showing the correspondence between the presence or absence of various maps, selection modes, and display states, and FIG. 13b is a front view showing a part of the front panel of the display device DSP. 1: Frame 1°: Corner 2; Thin plate 3, 3H, 3V: Display 51.
52, 53, 54.55: Display AG near truss gauge ECU: Electronic control unit ROM: (memory means) DS
P: Display ANT: Antenna RMT: Remote control unit MP: Atlas BL: Line Xofl. Yoff: Offset

Claims (1)

[Claims] Position detecting means for detecting the latitude and longitude of the current position, means for inputting at least one target position, and control for calculating the straight-line distance between the current position and the target position and outputting distance information. In a position information processing device comprising: a correction table means for holding correction coefficients at various latitudes, the control means corrects the correction coefficients for a latitude of an intermediate point between a latitude of a target position and a latitude of a current position. Calculates the distance between the current position and the target position in the longitude direction using the correction coefficient obtained from the table means, further calculates the distance between the current position and the target position in the latitude direction, and calculates the distance between the current position and the target position in the latitude direction. 1. A position information processing device for a moving body, characterized in that a straight-line distance between a current position and a target position is calculated based on a distance in a longitudinal direction.