JPS62261011A - Vehicle navigation apparatus - Google Patents

Abstract

PURPOSE:To obtain highly accurate position information, by combining position information from GPS (global positioning system) and a direction sensor. CONSTITUTION:A running position of a vehicle is calculated in a CPU3, basing upon vehicle running direction detected by a direction sensor 1 and vehicle running distance detected by a speed sensor 2 and the position data are displayed continuously on a screen for display of a displaying apparatus 10. At the same time, position signals sent from three artificial satellites 9 of a GPS system are received by a GPS receiver 7 and magnetization correction of the sensor 1 is performed basing upon this for preventing deviation of a road on the display screen from a running locus. This magnetization correction is performed properly at the time of the deviation, eliminating necessity of a circular detecting operation by rotating the vehicle through an angle of 360 deg..

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a vehicle navigation system, specifically a GPS system.
The present invention relates to a high-precision vehicle navigation device that corrects errors in a direction sensor using absolute position information obtained from an artificial satellite.

[Conventional technology]

Vehicle navigation devices electrically calculate the vehicle's current location based on the vehicle's travel direction and amount of travel, and display it on the display screen of a display device, allowing the driver to easily know the vehicle's travel location. , when driving long distances,
As a particularly convenient device, its development has been active in recent years. Regarding this vehicle navigation device,
Various types have been proposed in Japanese Patent Laid-Open No. 58-135911 and others.

This type of vehicle navigation device uses a direction sensor that detects the vehicle's running direction based on geomagnetism.
The current position of the vehicle is displayed on the display screen of the display device based on the direction of travel of the vehicle detected by the direction sensor.

Therefore, in order for this navigation device to operate accurately, it is a prerequisite that the vehicle traveling direction detected by this direction sensor is accurate.

[Problem that the invention seeks to solve]

However, errors may occur in this direction sensor due to causes such as magnetization, and if the error exceeds a few percent, there will be a misalignment between the road on the display screen of the display device and the vehicle's travel trajectory, causing a guide. Its function will be completely lost.

In this way, when a discrepancy occurs, it is necessary to operate the input device to make corrections to match the road on the display screen with the vehicle's travel trajectory, but at this time, find a place where the vehicle can make one full rotation. , it was necessary to conduct a so-called test to collect yen data. However, this circle test requires a large space and cannot be performed anywhere, making it impossible to perform correction operations frequently. In this way, when an error occurs in the orientation sensor due to causes such as magnetization, troublesome operations are required to correct the error, which has also been a cause of hindering the widespread use of vehicle navigation devices.

This invention corrects the error of this direction sensor using GPS.
(global positioning system
tem) It is intended to be carried out by using equipment signals composed of artificial satellites, and it does not require any complicated operations such as circle verification, and has high accuracy that can easily correct the error of the direction sensor while driving. The purpose of the present invention is to provide a navigation device for a vehicle.

Note that the GPS system is a system that detects absolute position using device signals composed of three or more artificial satellites, and the present invention combines position information obtained from this GPS system and position information obtained from a direction sensor. The aim is to compensate for the shortcomings of both systems and obtain highly accurate position information.

Although GPS systems can detect absolute positions, they have drawbacks such as not being able to recognize continuous positions at all times, not being able to obtain any position information in areas where radio waves from satellites cannot be received, and not being able to determine the direction of travel. are doing.

[Means for solving problems]

This invention includes a direction sensor that detects the vehicle's running direction based on geomagnetism, a speed sensor that detects the amount of vehicle movement, and a c that receives position signals emitted from GPS satellites.
The vehicle running position is calculated from the PS receiver, the vehicle running direction detected by the direction sensor, and the vehicle movement amount detected by the speed sensor, and the error correction of the direction sensor is performed using the absolute position information obtained from the GPS satellite. CPU
The above-mentioned conventional problems are solved by configuring a vehicle navigation device from the following: and a display device that receives input from the CPU and sequentially displays the vehicle traveling position on a display screen.

[Effect]

Based on the vehicle running direction detected by the direction sensor and the vehicle movement amount detected by the speed sensor, the CPU calculates the vehicle running position and displays it sequentially on the display screen of the display device.At the same time, the GPS receiver calculates the vehicle running position. Receives device signals from three artificial satellites, performs magnetization correction of the orientation sensor based on this position signal,
To prevent the road trajectory on the display screen from being out of sync with the driving trajectory. This magnetization correction can be performed appropriately when a discrepancy occurs between the road on the display screen and the travel trajectory, and does not require a circle verification operation in which the vehicle is rotated 360 degrees.

〔Example〕

FIG. 1 is a block diagram of an embodiment of a vehicle navigation device according to the present invention, in which 1 is a direction sensor, 2 is a speed sensor, and 3 is a CPU (centre
ral processing unit) and the azimuth sensor 1 includes an azimuth sensor amplifier 4, an A/D
The speed sensor 2 is connected to the CPU 3 via a converter 5, and the speed sensor 2 is connected to the CPU 3 via a waveform shaping circuit 6.
It is connected to the. On the other hand, 7 is a GPS receiver connected to the CPt 13, and the attached GPS antenna 8 allows three or more GPS (global position).

) It is possible to receive position signals emitted from the artificial satellite 9. Further, 10 is a display device which can receive input from the CPII and display the vehicle traveling position on a display screen.

Furthermore, 11 is a watchdog circuit, and 12 is l? A storage circuit consisting of AM and ROM, 13 a recent circuit, and 14 a power supply.

Next, the operation of this vehicle navigation device will be explained with reference to FIGS. 2 to 6.

FIG. 2 is an explanatory diagram schematically depicting road running conditions, and FIGS. 3 and 4 are flowcharts explaining the calculation procedure in CPt13. When the ignition switch is turned on, in step 101, the CPU initial cent is In step 102, circle data is collected. In addition, this circle data collection is done by dividing the entire 360' circumference into 1
This was done in 28 parts to collect R12+ RZ2, which will be described later.

Next, in step 103, the direction signal is analog/
Digital conversion is performed to determine N, X, and Y (see Figure 5).

In step 104, the magnetic direction, that is, the direction θ of the direction sensor 1 is calculated.

-X In step 105, a straight line correction is performed and the true orientation θ is determined.

In step 106, speed pulses SP emitted from the speed sensor 2 are counted.

In step 107, the direction (X, Y), the amount of movement (
DIS) position calculation is performed.

X'= -SP X DTS U cos θH(
m) Y= 5PXDIS U sin θH(m
) DIS = 5PXDIS U (m) Each of these steps is exactly the same as in a conventional vehicle navigation device.

Next, in step 108, the position coordinates (X c I, Y GI) of the first point (see FIG. 2) are measured using the position signal obtained from the GPS satellite.

In step 109, position coordinates X, Y, are calculated by the direction sensor 1 and speed sensor 2.

In step 110, it is checked whether the vehicle has traveled a certain distance, for example, Nm or more, and has reached a second point (see FIG. 2).

In step 111, the GPS position coordinates Xazr Yaz of the second point are measured.

In step 112, the orientation sensor 1. The speed sensor 2 calculates the position coordinates X 2 +Y2 of the second point.

In step 113, it is checked whether the vehicle has traveled for more than Nm again and reached the third point.

In step 114, the position coordinates X G 3 + Y G 3 of the third point are measured by GPS.

In step 115, the orientation sensor 1. The position coordinates X3°Y of the third point by the speed sensor 2 are calculated. Note that even during the above operation, CPIJ 3 continues to collect circle data in order to obtain Rz, R+□.

Next, in step 116, the angular direction θ0, 2 of the second point as seen from the first point according to the GPS measurement results, the angular direction θ, 23 of the second point as seen from the first point, and the azimuth sensor 1. The angular direction θ2ff of the second point when viewed from the first point based on the measurement results of the speed sensor 2 and the angular direction θ2ff of the third point when viewed from the second point are calculated.

In step 117, it is checked that -30°≦θi<120'.

In step 118, R, □ from the circle data.

RZ+ is required. The relationship between the center A before magnetization, the center D after magnetization, and R12 and R23 is as shown in the diagram shown in FIG. However, in this case, when θ is within the conditions in step 119, the magnetization C correction iAE, Dε is calculated by the following formula, and the magnetization correction of the orientation sensor 1 is performed.

The principle by which an accurate heading can be calculated by determining the above-mentioned AE and DH is also clear from the chart shown in FIG.

In the same figure, the orientation θ when there is no magnetization is I N-X 1 The orientation θ after magnetization is based on the true orientation calculated from the AE and DE and the travel amount information obtained from the speed sensor 2. The position inside is determined and displayed on the display screen of the display device 10.

(Effect of the invention) In the vehicle navigation device according to the present invention, the G
Since the position signal from the PS satellite is received and the error correction of the direction sensor is performed using this position signal, it can be easily corrected even while driving, and the accuracy can be improved without the need for troublesome circle verification operations. You can obtain high-level location information. In addition, since the direction sensor and GPS system are used together,
Position information can be continuously displayed on the display screen even when driving in areas where radio waves from GPS satellites do not reach, and it has extremely high practical value, making it easier for drivers to It has an excellent effect of reducing the burden on people and contributing to improving operational efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a vehicle navigation device according to the present invention, FIG. 2 is an explanatory diagram schematically depicting road running conditions, FIG. 3 is a flowchart showing the calculation procedure in the CPU, and FIG. Figure 4 is also a flowchart showing the calculation procedure in CPII, Figure 5 is an explanatory diagram geometrically showing the relationship between the center A before magnetization, the center after magnetization, and R1□, R2, and Figure 6. is an explanatory diagram geometrically illustrating the principle of calculating accurate orientation by determining AE and DE. 1... Orientation sensor, 2... Speed sensor, 3
...CPt1, 4... Orientation sensor amplifier, 5.
... A/D converter, 6... Waveform shaping circuit, 7...
・GPS receiver, 8...GPS antenna, 9...G
PS satellite, 10... Display device, 11... Watchdog circuit, 12... Memory circuit, 13... Reset circuit, 14... Power supply. Patent applicant: Niles Parts Co., Ltd. Figure 6

Claims (1)

[Claims] A direction sensor that detects the vehicle running direction based on geomagnetism, a speed sensor that detects the amount of vehicle movement, a GPS receiver that receives a position signal emitted from a GPS satellite, and a vehicle running direction detected by the direction sensor. a CPU that calculates a vehicle running position from the amount of vehicle movement detected by the speed sensor and corrects an error in the direction sensor based on absolute position information obtained from the GPS satellite;
1. A vehicle navigation device comprising: a display device that receives input from a vehicle and sequentially displays a vehicle traveling position on a display screen.