JPH0148965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an in-vehicle navigation device in which a departure point, a destination, and the current position of the vehicle are displayed on a display such as a cathode ray tube using respective marks.

[Prior art]

Conventional in-vehicle navigation devices, such as those disclosed in Japanese Unexamined Patent Publication No. 146814/1983, detect the distance traveled and the heading direction of the vehicle, and calculate the current position of the vehicle from this information. The current position of the vehicle on the map displayed on the screen of the display device is displayed by displaying the image information of the map read from the storage device on a display device such as a cathode ray tube and displaying a mark indicating the calculated current position of the vehicle. A device has been proposed that can determine the However, map image information has a very large amount of information, and there is a limit to the amount of information that can be stored in a small and inexpensive storage device suitable for in-vehicle use. In addition, in cases where the starting point and destination are fixed, even if a map prepared in advance in the storage device is displayed on the screen of the display device and a mark of the current location is superimposed on it, the actual driving The change in position is often a very limited portion of the display screen. Furthermore, when the distance between the departure point and the destination is long, multiple maps are used, making it difficult to understand the entire travel process. Although these technical issues are not necessarily impossible with large-capacity storage devices and high-speed arithmetic units, the overall scale of the devices has become increasingly large, making it difficult to mount them in vehicles.

[Summary of the invention]

The present invention has been made in view of the above points, and the storage device stores not the map image information itself but the place names and their geographical coordinates of various places.
When the place names of the departure point and destination are specified using the input device, the control device reads out the place names and their coordinates from the storage device, displays marks indicating the departure point and destination at an appropriate scale on the display device, and displays the marks on the display device. An in-vehicle navigation device that can have a practically sufficient navigation function using a small and inexpensive storage device and arithmetic device by displaying a mark indicating the current position of the vehicle according to the location of the vehicle. The purpose is to provide

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the device of this embodiment includes a traveling distance detecting means 1 for detecting the traveling distance of the vehicle, a traveling direction detecting means 2 for detecting the traveling direction of the vehicle, and these means 1 and 2. A current position calculation means 3 that calculates the current position of the vehicle from the travel distance and traveling direction obtained respectively, a current position initialization means 4 that initializes the current position for the current position calculation means 3, and a two-dimensional orthogonal A display means 5 capable of displaying a plane using a coordinate system, a geographical information storage means 6 that stores a plurality of place names and the geographical coordinates of each place name, and a vehicle departure point and destination from among the plurality of place names. a place name specifying means 7 for specifying the name of each place; a geographical information retrieval means 8 for reading out the corresponding place name and its coordinates from the geographical information storage means 6 based on the commands from the place name specifying means 7; The scale is determined so that the mark indicating the current position of the vehicle is displayed on the outer periphery of a rectangular area that is virtually set in advance on the screen of the display means 5, and the mark indicating the current position of the vehicle is displayed on the screen together with the departure point and destination marks based on this scale. The approximate location of the vehicle in motion can be determined from the positional relationship between the departure point, destination, and marks indicating the current location of the vehicle displayed on the screen.

Next, a more specific configuration of this embodiment will be explained with reference to FIG.
It consists of The mileage sensor 10 detects the rotation of the wheel using an electromagnetic pickup or a reed switch, and outputs a pulse number proportional to the number of rotations of the wheel. For example, as shown in FIG. 3, the direction sensor 11 uses a flux gate type geomagnetic detector fixed to the vehicle 16 to detect the geomagnetism H→ on the vehicle 1.
6, the moving direction component Ha and its vertical component Hb. As shown in FIG. 4, the keyboard 12 is used for "a", "i", "o", "la", etc.
The character key section 12a consists of keys for Katakana characters such as "RO", "WA", "N", voiced key "〓", and half-voiced key ".", "Departure", "Destination", "Set", "Start", etc. ” control key section 12b. Note that each key may also be referred to as a character key "a", a "starting point" key, etc. The semiconductor memory 14 is composed of, for example, a ROM (read only memory), and stores place names and their coordinates. For example, as shown in the memory map in Figure 5, the place name "Osaka" is stored in addresses "0000" to "0003", and the coordinates (X ₁ , Y ₁ ) are stored in addresses "0004" to "0007". . It should be noted that the memory at the lowest point is 8 bits. Also, the coordinates (X ₁ , Y ₁ ) are based on the coordinate axes x, y set for convenience as shown in Figure 6, and if the whole of Japan (approximately 1700 km square) is expressed in 2 bytes, 1 bit will be approximately 26 m. This is a practically sufficient value. As for place names, for example, there are approximately 680 cities across Japan.
Furthermore, if we assume that each prefecture has approximately 300 place names, including towns and villages, there will be 13,800 place names in all of the 46 prefectures, excluding Okinae Prefecture. The average number of letters in place names is 5.
character (one character is 1 byte), and the coordinate data is 4 bytes (x, y each 2 bytes) as described above.
bytes), 124,200 bytes are required. To store this data, four ROMs are required with the 256Kbit ROM, which has the highest capacity on the market to date.
One 1Mbit ROM, which is expected to be commercially available in the future, will be sufficient, making it possible to use such a small, lightweight, and highly reliable semiconductor memory. Braun tube 1
5 may be a conventional one, and as shown in FIG. 7, it has a rectangular screen 15a. Note that the coordinate axes u and v are orthogonal coordinate axes that indicate the coordinates (u, v) on the screen 15a, and the destination and
The departure point and current location marks (described later) are displayed. The control circuit 13 consists of a well-known microcomputer system, includes various input/output interface circuits (not shown), calculates the current position based on the signal from the mileage sensor 10 and the signal from the direction sensor 11, and calculates the current position from the keyboard. 12, the place name and coordinates are retrieved from the semiconductor memory 14, and the starting point, destination, and current position are displayed as marks on the corresponding coordinates on the screen 15a of the cathode ray tube 15. .

Next, the operation of the control circuit 13 will be explained in detail based on the flowcharts shown in FIGS. 8a to 8f. FIG. 8a shows a flowchart of the main routine, which starts with the power supply operation to the control circuit 13, clears the memories Fs and Fg (details will be described later) to zero in step 101, and then enters the key input steps in order. 102, Departure point input processing subroutine 103, Destination input means subroutine 1
04. Subroutine 1 of departure point/destination display processing
05 and the current position initial setting input processing subroutine 106 are repeatedly executed. To explain in more detail, the user first decides on the starting point and inputs it. For example, if "Osaka" is selected as the starting point, the keyboard 12 shown in FIG. 4 is used to operate each key in order as "starting point,""o,""o,""sa,""ka," and "set." As a result, in the flowchart of subroutine 103 for the departure point input process shown in FIG. Character key processing (step 208) is executed each time the character key is operated one by one, and the characters to be input are memorized. Finally, determine the end of the character data by operating the "Set" key (step 2).
04), Geographic information is searched in step 205. In other words, the input place name data "Osaka"
is searched from the semiconductor memory 14, and the coordinate data X ₁ ,
Read Y ₁ and register it as the departure point data.
Thereafter, in step 206, 2 is set in the memory Fs to indicate that the departure point has been registered.

Next, input the destination, but if you select "Nagoya" as the destination, the order of operation of each key is "destination", "na", "ko", "〃", "ya", "set", After operating the ``destination'' key instead of the ``departure'' key in the case of inputting the departure point, the place name can be input using the same procedure as inputting the departure point. FIG. 8c shows the details of the destination input processing subroutine 104, and the execution procedure is the same as the flowchart of the departure point input processing in FIG. 8b, so a detailed explanation will be omitted. still,
Memory Fg is memory Fs in departure point input processing
corresponds to and indicates the program execution status.

When the departure point input process (subroutine 103) and the destination input process (subroutine 104) are both executed, memories Fs and Fg are both set to 2 (steps 206 and 306), and the departure point/destination display process (subroutine 104) is executed. 105) is executed. The flowchart of this subroutine 105 is shown in FIG.
Shown below. It is determined in step 401 that both the departure point and destination have been set, and the memories Fs and Fg are cleared to zero (step 402).

Next, the departure point and _destination marks are marked on the screen _15a of the cathode ray tube 15 in FIG.
A scale is determined so as to be displayed on c, and marks for the departure point and destination are displayed based on this scale. That is, the coordinates of the departure point and destination in FIG. 6 are generally (Xs, Ys) and (Yg, Yg), respectively, and in step 403, the east-west distance between the departure point and the destination |Xs−Xg | and the horizontal length of the rectangular area 15b
The ratio between l _{x and} the north _- south _direction |Ys _{- Yg} | Find |, step 40
In step 4, compare r _x and r _y . As a result, r _x ≦ r _y
If so, r _x is determined, and if r _x > _ry , then _ry is determined as the scale r (steps 405 and 406).

Next, the coordinates of the midpoint between the departure point and the destination (Xo,
Yo) is calculated in step 407, and the coordinates are converted and reduced by the scale r so that the midpoint corresponds to the center of the rectangular area 15b, that is, the point (origin) of u=0, v=0, and in step 408 Us=r (Xs-Xo) Vs=r(Xs-Yo) Ug=r(Xg-Xo) Vg=r(Yg-Yo) Coordinates (Ug, Vg) are obtained. These coordinates (Us, Vs), (Ug, Vg)
It is obvious that this is on the outer periphery 15c of the rectangular area 15b. Therefore, in step 409, a departure point mark 17a and a destination mark 17b are displayed at the coordinates (Us, Vs) (Ug, Vg) as shown in FIG. 9a.

Now, if there is a vehicle at the starting point when inputting, immediately press "Start" on the keyboard 12.
Operate the keys. If you are at a point a little far from the starting point coordinates, just press the "Start" key when you reach the starting point coordinates (Xs, Ys). When the "Start" key is operated, the current position initial setting input process (subroutine 106) shown in FIG. 8a is performed.
is executed. Figure 8e shows this subroutine 10.
6, it is determined whether or not the "start" key is operated (step 50).
1) In step 502, the coordinates of the starting point (Xs, Ys)
are set in the memories x _p and y _p representing the coordinates of the current position used for the cumulative calculation of the current position.

As described above, once the initial values of the departure point, destination, and current position have been set and the vehicle is driven,
Based on the pulse signal obtained by the traveling distance sensor 10, an interrupt command is input to a microcomputer (not shown) every unit traveling distance dl (for example, 1 m), and this causes the interrupt shown in FIG. A processing routine is executed. In Fig. 8 f, first the direction signal
Ha and Hb are input (step 601), and the angle θ between the earth's magnetic field H→ shown in FIG. 3 and the traveling direction 16a of the vehicle 16 is calculated (step 602). next,
The directional components of the unit traveling distance dl with respect to each coordinate axis x and y are calculated in step 603 and added to the cumulative values x _p and y _p of the current position (step 604).
Furthermore, in step 605, the coordinates ( _up , _vp ) on the screen 15a are calculated based on the scale r, and in step 606, they are displayed. Figure 9b
is an example of the display, and 17c indicates the current position mark. Note that the dotted line 18 indicates the travel trajectory up to that point.

As described above, in this device, simply by inputting the place names of the departure point and the destination, the two points are automatically displayed on the screen 15a at an appropriate scale according to the distance between the two points, and the current position and the two points are automatically displayed. It is very practical as it allows you to know the driving situation of the vehicle from the approximate positional relationship between the two. Furthermore, by storing coded place names and their coordinates rather than complex map image information, storage capacity can be reduced.

The current position initial setting means 4 shown in FIG.
In particular, it corresponds to the operation part shown in the flowchart of FIG.
3, in particular corresponds to the operational part shown in the flowchart of FIGS. 8b and 8c, and the geographical information retrieval means 8 is operated by the control circuit 13, particularly the steps 205 and 8b of FIGS. 8b and 8c.
305, the current position calculation means 3
The display control means 9 corresponds to the control circuit 13, particularly the operating portion shown in FIG.
This corresponds to the operating part shown in 06.

〔Effect of the invention〕

As described above, the present invention includes a geographical information storage means that stores a plurality of place names and the geographical coordinates of each place name, and a means for specifying the departure place and destination name of a vehicle from among the plurality of place names. a place name indicating means; a geographical information retrieval means for reading out the corresponding location name and its coordinates from the geographical information storage means based on a command from the place name indicating means; and a virtual mark indicating the departure point and destination, respectively, on the screen of the display means in advance. The present invention is equipped with a display control means that determines a scale so as to be displayed on the outer periphery of a set rectangular area, and displays a mark indicating the current position of the vehicle on the screen together with the departure point and destination marks based on this scale. In this way, the storage device stores place names and their geographical coordinates, and the screen of the display device displays only the necessary parts as much as possible, even if a storage device with a small capacity is used. Practically sufficient navigation functions can be obtained over a wide range of areas.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the device of the present invention, FIG. 2 is a specific configuration diagram of the device of the present invention, FIG. 3 is an explanatory diagram of direction detection according to the present invention, and FIG. 4 is a diagram of the keyboard according to the present invention. 5 is a memory map of the semiconductor memory according to the present invention, FIG. 6 is an explanatory diagram showing the relationship between place names and coordinates according to the present invention, FIG. 7 is an external view of the cathode ray tube according to the present invention, and FIG. 8 9 is a flowchart of a control circuit according to the present invention, and FIG. 9 is a diagram showing an example of display on a cathode ray tube according to the present invention. DESCRIPTION OF SYMBOLS 1... Travel distance detection means, 2... Travel direction detection means, 3... Current position calculation means, 4... Current position initial setting means, 5... Display means, 6... Geographical information detection means, 7... Place name indicating means, 8...Geographical information retrieval means, 9...Display control means. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. Traveling distance detecting means for detecting the traveling distance of the vehicle, traveling direction detecting means for detecting the traveling direction of the vehicle, traveling distance detected by the traveling distance detecting means, and traveling direction detected by the traveling direction detecting means. A plurality of current position calculation means for calculating the current position of the vehicle from the traveling direction, current position initialization means for initializing the current position for the current position calculation means, and display means capable of displaying a plane using a two-dimensional orthogonal coordinate system. geographical information storage means storing place names and geographical coordinates of the respective names; place name indicating means for indicating place names of the departure place and destination of the vehicle from among the plurality of place names; and based on a command from the place name indicating means. Geographical information retrieval means reads out the names of corresponding locations and their coordinates from the geographic information storage means, and marks indicating the departure point and destination, respectively, are placed on the screen of the display means based on the outputs of the geographical information retrieval means and the current position calculation means. A display control means is provided which determines a scale so as to be displayed on the outer periphery of a rectangular area that is virtually set in advance, and displays a mark indicating the current position of the vehicle on the screen together with marks of a departure point and a destination based on this scale. In-vehicle navigation device. 2. The display control means displays the coordinates (Xs,
Ys) and the coordinates of the destination (Xg, Yg), calculate the east-west distance |Xs−Xg| and the north-south distance |Ys−Yg| between the departure point and the destination, and calculate the east-west distance |
The ratio of Xs−Xg｜ to the horizontal length l _x of the rectangular area
_{The ratio} of l _x /|Xs−Xg| to the distance in the north-south direction |Ys−Yg|
The smaller ratio is determined as the scale r, and the coordinates (Xo, Yo) of the midpoint between the starting point and the destination are made to correspond to the center of the rectangular area, and the starting point on the screen is calculated based on the scale r. Claim 1, characterized by having a function of determining coordinates (Us, Vs) and destination coordinates (Ug, Vg) and displaying marks indicating the departure point and destination, respectively, on these coordinates. The vehicle navigation device described.