JP2913677B2 - Current location display for mobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a present position display device for a mobile object suitable for a navigation system or the like.

<< Prior Art >> Conventionally, as this kind of present position display device for a moving body, there is a device which displays a connection with a road map which has been displayed so far when updating a map to an adjacent area. (Hereinafter, such a function is referred to as an automatic map turning function, as disclosed in Japanese Patent Application Laid-Open No. 58-20520).

In some cases, the position of the vehicle is always at the center of the display screen (such a function is hereinafter referred to as a full scroll function, as disclosed in Japanese Patent Laid-Open No. 29977/1985). Japanese Patent Application Laid-Open No. Sho 59-125014 discloses a combination of dead reckoning navigation based on GPS and GPS navigation based on GPS satellite positioning (hereinafter, such a method is referred to as a compound processing method).

<< Problems to be Solved by the Invention >> However, in the above-described conventional apparatus, for example, when a GPS satellite is used for radio navigation, the following errors included in the positioning position of the GPS receiver, ie, (1) ) Automatic map turning function is applied to the complex processing method because errors due to satellite position data, (2) errors due to ionospheric propagation, (3) errors due to tropospheric radio wave propagation delay, etc. are not taken into account. In such a case, when the vehicle travels near the switching point of the display map, the display map is frequently switched, and the position of the own vehicle cannot be displayed at the center of the screen.

Also, when the full scroll function is applied to the complex processing method, if there is a variation in the positioning position, it is necessary to frequently rewrite the display map to display the own vehicle position in the center of the screen, which is also difficult to see There was a problem of becoming.

The present invention has been made in view of the above problems, and provides a current position display device for a mobile object that has a display screen that is easy to see for a driver by changing the current position of the mobile object according to the estimated current position and the magnitude of the estimation error. Aim.

<< Means for Solving the Problems >> In order to achieve the above object, a present position display device for a moving body according to the present invention is configured as shown in FIG. 1, and a display map on a display screen is sequentially rewritten as the present position moves. And a present position display device for a mobile body, on which the present position is synthesized and displayed, further comprising: a guess position calculating means a for calculating a current guess position based on output values of the direction sensor 12 and the distance sensor 13; Satellite positioning position calculating means b for calculating the current positioning position based on the distance information, and the estimated current position and its estimation by filtering the position information obtained by the estimated position calculating means a and the satellite positioning position calculating means b. Filtering means c for obtaining an error; estimated current position obtained by the filtering means c; A movable range setting means d for setting a movable range of the current location to a certain range centered on the estimated current location based on the magnitude, and an entire movable range of the current location set by the movable range setting means d is the current range. A movable range determining means e for determining whether or not the display area is within the display screen; and a current display when the movable area determining means e determines that the entire movable range of the current location is within the current display screen. A first display unit f for displaying the estimated current position on the map as it is, and a case where the movable range determination unit e determines that a part or the whole of the movable range of the current position is outside the current display screen. And a second display means g for rewriting a display map so that the estimated current position can be displayed at the center of the screen and displaying the estimated current position on the display map.

<< Description of Example >> Next, an example of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing an electrical hardware configuration of a vehicle route guidance device to which the present position display device for a moving body according to the present invention is applied.

As shown in FIG. 1, this apparatus is generally controlled by a microcomputer mainly composed of a CPU 1, and its system bus 2 has an I / O controller 3 and 4, a SCSI controller 5, a graphic controller 6, a V-RAM 7, a ROM, and the like.
8, D / RAM 19, Kanji ROM 10 and backup RAM 11 are connected.

The azimuth sensor 12 is connected to the I / O controller 3 by the AMP 14.
And via the A / D converter 15,
The distance sensor 13 is connected. The I / O controller 4 is connected with keys 16 for various input operations to the device, and a speaker 12 is connected via a sound generator 18.

On the other hand, a CD-ROM 19 and a CRT 20 are connected to the SCSI controller 5 and the graphic controller 6, respectively.

CR functioning as VDT (Visull Display Tarminal)
The T20 mainly provides a vehicle occupant with guidance on a traveling route to a destination. Image information to be displayed on the CRT 20 is written in the V-RAM 7, and map information to be displayed on the CRT 20 is a CD-ROM. It is stored in ROM19.

In this embodiment, the current position of the vehicle is detected using the signal output of the GPSR _X 22 input via the I / O controller 21 together with the signal output of the direction sensor 12 and the distance sensor 13.

Further, control of the entire apparatus is performed by executing a system program stored in the ROM 8 by the CPU 1.

In this embodiment, the radio navigation means is used as described above.
Although GPS navigation is used, other radio navigation, for example, Loran C, can also be used.

Next, FIG. 3 shows a control program stored in the ROM 8, and the processing procedure of this embodiment will be described below with reference to this flowchart.

In the same figure, when the program starts, key 16
The initial setting process is performed by the input operation by the
100) In this process, the initial position of the vehicle is input, and the current position of the vehicle is displayed in the center of the screen together with the surrounding map on the screen of the CRT 20 (step 11).
0). Here, the input of the initial position can be omitted by inputting the GPS positioning position.

When the initial setting process and the current position display process are completed in this way, the apparatus is in an operating state, and the estimated position of the current position of the vehicle is calculated by sequentially taking in the outputs of the direction sensor 12 and the distance sensor 13 as the vehicle moves (step 12).
0).

Then, by receiving the radio waves emitted from a GPS satellite GPSR _X 22, calculates the distance between the GPS satellites and the vehicle current position, thereby positioning the position of the vehicle is calculated (step
130).

By the way, since each position information obtained in step 120 and step 130 is obtained by different means of the same information, by filtering this,
A more accurate and accurate estimated current position (Fx, Fy) and its estimated error (σ) are obtained (step 140). As a well-known filtering processing method, a Kalman filter method, a MINI-MAX algorithm method, or the like can be used, but these processing methods will not be described in detail here.

Thus, the estimated current location (F
Once x, Fy) and its estimation error (σ) are obtained, the rewriting control of the display map is performed using these values.

That is, the movable range of the current position on the display map is set within a circle having a constant radius (α × σ) centered on the estimated current position (Fx, Fy) (step 150). Here, α is a constant.

If the entire movable range is within the display screen (YES in step 160), the current location (Fx, Fy) is displayed as it is on the current display map without rewriting the map (step 110). On the other hand, if a part or the whole of the movable range is set outside the range of the display screen (NO in step 160), the display map is rewritten so that the current position is displayed at the center of the display screen (step 170), The current location is displayed on the display map (step 110).

In this way, the own vehicle position is synthesized and displayed while the display map on the screen of the CRT 20 is rewritten as needed (steps 110 to 170). Although the possible range is circular, the same effect can be achieved by setting a square or a rectangle similar to the display screen, such as rewriting the map as much as possible when the estimation error is large, The effect that the display screen is fixed substantially at the center is obtained.

In the process of step 170, the display position of the current position after map rewriting is set to be the center of the screen, but it is not always necessary to set the display position of the current position to the center of the screen in order to display many maps in the traveling direction of the vehicle. .

As another embodiment, the scale of the display map is changed depending on the magnitude of the estimation error σ. That is, when the estimation error σ is large, the area of the display map is wide (a large-scale map is displayed), and when the σ is small, the area is large. By making the map narrow (displaying a small-scale map), it is possible to automatically display a map as detailed as possible while suppressing the number of times the map is rewritten.

<< Effects of the Invention >> As described above, the moving object present value display device according to the present invention is arranged such that the estimated present position and the estimated present position determined by the filtering means in the movable range setting means are centered on the estimated present position. Then, the movable range of the current location is set to a predetermined range, and it is determined whether or not the entire movable range of the current location set by the movable range determining means is within the current display screen. If it is determined that the entire movable range of the current position is within the current display screen, the first display means displays the estimated current position on the current display map as it is, and displays the movable range of the current position. If it is determined that a part or the whole is outside the current display screen, the display map is rewritten so that the estimated current position can be displayed at the center of the screen by the second display means, and the estimated current position is displayed on the display map. Displayed.

Therefore, the present invention has an effect that a current position display device for a moving object having a display screen that is easy to see for a vehicle occupant can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a block diagram showing the electrical hardware configuration of the embodiment of the present invention, and FIG. 3 is a flowchart showing the processing procedure of the embodiment of the present invention. It is. 1 CPU 8 ROM 12 Azimuth sensor 13 Distance sensor 16 Key 19 CD-ROM 20 CRT 22 GPSR _X

Claims (1)

(57) [Claims] 1. A current position display device for a mobile unit, wherein a display map on a display screen is sequentially rewritten as the current position moves and a current position is synthesized and displayed on the map, and the current position is determined based on output values of a direction sensor and a distance sensor. Estimated position calculating means for calculating an estimated position, satellite positioning position calculating means for calculating a current positioning position based on distance information from a GPS satellite, and estimated position calculating means and satellite positioning position calculating means. Filtering means for obtaining the estimated current position and its estimation error by filtering the position information; and moving the current position to a certain range around the estimated current position based on the estimated current position and the magnitude of the estimation error obtained by the filtering means. Movable range setting means for setting a movable range, and the movable range setting means Movable range determining means for determining whether or not the entire movable range of the set current location is within the current display screen; and the entire movable range of the current location is within the current display screen by the movable range determining means. A first display means for displaying the estimated current position on the current display map as it is, and a part or the whole of the movable range of the current position is outside the current display screen by the movable range determination means. And a second display means for rewriting the display map so that the estimated current position can be displayed at the center of the screen when the current position is determined to be displayed on the display map, and displaying the estimated current position on the display map. Current location display device for mobile objects.