JP2856311B2 - Speed detection device and navigation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order. BACKGROUND OF THE INVENTION Means for Solving the Problems (FIGS. 1, 8 and 9) Operation (FIGS. 1, 8 and 9) Example (FIGS. 1 to 9) 9) Effects of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed detecting device and a navigation device, and can be applied to, for example, a car navigation device.

[0003]

2. Description of the Related Art Conventionally, GPS (Global Positioning Sys
tem) There is a GPS receiver as a device for measuring the position of a moving body such as an automobile using radio waves from a satellite. This GP
A so-called navigation device is a system in which the S receiver is mounted on a moving object and displays the current position and traveling direction of the moving object on a display in real time.

[0004] The navigation device uses an absolute speed and an absolute position (latitude and longitude) of a moving object obtained from a GPS receiver.
The current position and the traveling direction of the moving object are obtained based on the traveling direction and the traveling direction, and are displayed on a map read out from a recording medium such as a CD-ROM.

[0005] Further, speed can be obtained from a GPS receiver. Further, as another speed detecting method, a method of detecting using an electric signal from a wheel of a car or the like or a rotating portion of a transmission or the like, or an acceleration in a traveling direction (front-back direction) of a moving body such as a car by an acceleration sensor is used. There are a detection method of detecting the speed by integrating the acceleration and detecting the speed, and a detection method of obtaining the speed using the Doppler effect of a sound wave or a radio wave.

[0006]

However, in a method of detecting the speed of a moving body from a rotating portion such as a wheel or a transmission, a method of outputting a signal line used for the detection and a method of arranging a cable line of the signal line are used. Since the position and the like differ depending on the vehicle type, there is a problem that it takes time to take out signal lines and perform signal processing.

In the method of detecting the speed of the moving body by integrating the acceleration in the traveling direction, there is a problem that a large accumulated error occurs with the lapse of time because the integration operation is performed. Also, on a slope or the like, there is a problem that a larger cumulative error occurs because an error of the gravitational acceleration corresponding to the slope angle sin θ of the slope occurs.

Further, in the detection method in which the speed of the moving body is obtained by utilizing the Doppler effect of the sound wave or the radio wave, the mounting position of the detecting device must be outside the moving body, so that the mounting maintenance is difficult. is there.

In a navigation device, which is one of the detection methods for obtaining the speed of a moving object using radio waves,
The speed can be obtained by receiving the S radio wave, but there is a problem that the speed cannot be obtained because the GPS radio wave cannot be received, for example, in a shadow of a high-rise building such as a building or in a place such as in a tunnel. Further, even when a GPS radio wave is received, for example, when the moving body is at a low speed such as 10 to 20 [km / h] or when the state of the GPS satellite is poor,
There is a problem that a highly accurate and reliable speed cannot be obtained.

The present invention has been made in consideration of the above points, and is easy to attach to a moving object, and is capable of speeding the moving object without being affected by the gravitational acceleration due to the slope or the receiving condition of the GPS radio wave. A speed detecting device and a navigation device capable of detecting a vehicle speed are proposed.

[0011]

According to the present invention, there is provided an acceleration sensor (2) which is detachably attached to a moving body and detects vibration of the moving body, and an acceleration sensor (2). Speed detecting means (3, 1) for detecting the speed of the moving object based on the component of the band of 5 [Hz] or less among the vibration spectrum components of the moving object detected in the above manner.
0, 14).

In a navigation device having GPS receiving means, first speed detecting means for detecting the speed of the moving body based on a reception signal obtained from the GPS receiving means, and a vibration spectrum component of the moving body, A second speed detecting means (3, 3) for detecting the speed of the moving body based on a component in a band of 5 [Hz] or less among the vibration spectrum components;
10, 14).

Further, in the navigation device having GPS receiving means, first speed detecting means for detecting the speed of the moving object based on a reception signal obtained from the GPS receiving means, and detecting a vibration spectrum component of the moving object, Second speed detecting means (3, 10, 14) for detecting the speed of the moving body based on a component of a band of 5 [Hz] or less among the vibration spectrum components, and a speed detected by the first speed detecting means. And / or a control unit for controlling the reproduction unit, the display unit, or another device based on the speed detected by the second detection unit.

[0014]

The vibration of the moving body is detected by an acceleration sensor (2) detachably attached to the moving body, and the movement detected by the acceleration sensor (2) in the speed detecting means (3, 10, 14). Of the vibration spectrum components of the body, 5 [H
z] The speed of the moving object is detected based on the following band components. Further, in the navigation device having the GPS receiving means, the speed of the moving body is detected by the first speed detecting means based on the reception signal obtained from the GPS receiving means, the vibration spectrum component of the moving body is detected, and the second speed is detected. The detecting means (3, 10, 14) detects the speed of the moving body based on the frequency band component of 5 [Hz] or less among the vibration spectrum components. From these facts, it is easy to attach to the moving body, and the speed of the moving body can be detected without being affected by the gravitational acceleration due to the slope or the receiving state of the GPS radio wave.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows the overall configuration of the speed detecting device. The speed detecting device 1 comprises an acceleration sensor 2 for detecting the acceleration of a vehicle, and an arithmetic device 3 for detecting a speed based on the vibration detected by the vibration sensor 2. The arithmetic unit 3 includes an amplifier 4 for amplifying a signal from the acceleration sensor 2, a filter 5 for extracting a specific low-frequency band, a detection circuit 6 for detecting a signal input from the filter 5, and a signal after the detection. It comprises a smoothing circuit 7 for cumulative addition and a signal level detector 8.

The acceleration sensor 2 may be fixed to the vehicle to extract the acceleration applied to the vehicle. The acceleration sensor 2 detects the vibration generated when the vehicle travels by detecting the acceleration of the vehicle, and outputs a sensor output signal S1 as a detection result to the amplifier 4. Further, since the vibration detected by the acceleration sensor 2 is small, the amplifier 4 outputs the sensor output signal S1 transmitted from the acceleration sensor 2.
After that, the sensor output signal S1 is amplified with an amplification degree corresponding to the output sensitivity of the acceleration sensor 2.

Here, the acceleration sensor 2 is fixed to the trunk of the automobile, and the FFT (fast Fourier transform) analysis of the vibration detected by the acceleration sensor 2 during running is shown in FIG.
7 to FIG. FIG. 2 shows the idling of a gasoline-powered vehicle (that is, a state in which the engine is stopped while the engine is running;
h]), the vibration spectrum in the front-rear direction at the time of traveling at 5 [km / h] and at the time of traveling at 10 [km / h] is shown. 3 and 4 show when the gasoline vehicle is idling.
The vertical and horizontal vibration spectra when traveling at 5 [km / h] and 10 [km / h] are shown. Similarly, FIG. 5, FIG. 6 and FIG. 7 show the spectrum of vibration in the front-rear direction, the vertical direction, and the horizontal direction when the diesel vehicle is idling, when traveling 5 km / h, and when traveling 10 km / h, respectively. Show.

As can be seen from FIGS. 2 to 7, the difference between the idling state and the traveling state (ie, at 5 km / h, 10 km / h) in any of the front, rear, up, down, left, and right directions. And this difference is 10 to 20 d in the band of 5 Hz or less.
B]. 3 and 6 that the vibration at the time of idling increases in a band of 10 [Hz] or more. However, this is due to the vibration of the engine rotation,
The vibration at this time is higher for diesel cars than for gasoline cars. The vibration caused by the engine varies depending on the type of the vehicle, but is 8 Hz or more in view of the engine speed. Therefore, the difference between the idling state and the running state appears at 5 [Hz] or less. This difference is caused by the movement of the automobile, and occurs in any direction of vibration, so that the speed can be detected. For this reason, the filter 5 is a bandpass filter that extracts only the low frequency band of 0.5 to 5 [Hz].

In the above configuration, the acceleration sensor 2 is fixed to the trunk of the vehicle, and detects the vibration generated by running the vehicle by detecting the acceleration of the vehicle.
Since the sensor output signal S1 as the detection result has a small vibration, it is input to the amplifier 4 and amplified. The analog signal S2 amplified by the amplifier 4 is input to the filter 5.
Since the filter characteristic of the filter 5 is set so as to extract the band of 0.5 to 5 [Hz], only the band of 0.5 to 5 [Hz] of the analog signal S2 output from the amplifier 4 is extracted. The analog signal S3 extracted by the filter 5 is input to an electric circuit including a detection circuit 6 and a smoothing circuit 7 for accumulative addition. Thereafter, the analog signal S
4 is input to a signal level detector 8 comprising a level comparator or an A / D converter, etc., to detect the speed of the vehicle.

According to the above arrangement, the vibration of the automobile is detected by the acceleration sensor 2, and only the low frequency band of the detected vibration is extracted by the filter 5 and the arithmetic processing is carried out. It is possible to detect the speed of the vehicle without being affected by the above. Further, since the acceleration sensor 2 is detachable, the speed of the automobile can be detected by easy installation.

In the above embodiment, the filter 5
As described above, a band-pass filter that extracts only a low-frequency band of 0.5 to 5 Hz has been described. However, the present invention is not limited to this, and a low-pass filter that extracts a band of 5 to 8 Hz is used. Is also good. Here, in the band of 5 [Hz] or more, since the influence of the engine appears, a steep low-pass filter is used.

In the above embodiment, the acceleration sensor 2 for detecting the acceleration of the vehicle, the amplifier 4 for amplifying the signal from the acceleration sensor 2, and only a specific low-frequency band out of the band amplified by the amplifier 4 are extracted. Although the filter 5, the detection circuit 6, the smoothing circuit 7 for accumulative addition, and the signal level detector 8 have been described, the present invention is not limited to this, and an amplifier is provided between the filter 5 and the detection circuit 6. The same effect can be obtained by adding one.

FIG. 8 showing the same reference numerals as in FIG. 1 shows another speed detecting device. The speed detection device 9 includes the acceleration sensor 2 and a calculation device 10. Arithmetic unit 10
The output signal S4 from the smoothing circuit 7 in the A / D converter 11
It is digitized by inputting to. Thereafter, the digital signal S5 is input to the digital signal processing unit 12, and the speed of the vehicle may be detected by comparing the input digital value with the digital value of the digital signal processing unit 12.

FIG. 9 showing the same reference numerals as in FIG. 8 shows another speed detecting device. This speed detection circuit 13
Is composed of the acceleration sensor 2 and the arithmetic unit 14.
The sensor output signal S1 output from the acceleration sensor 2 is transmitted to the amplifier 4, the filter 5, and the A / D converter 11 in this order.
The signal S6 digitized by the / D converter 11 is input to the digital signal processing unit 15. This digital signal processing unit 1
In step 5, first, the AC component of the input digital signal S6 is converted into an absolute value, and is cumulatively added. The speed of the vehicle may be detected by comparing the operation result obtained at this time with the digital value of the digital signal processing unit 15.
As a method of converting the AC component into an absolute value at this time, a method of calculating a difference between a reference voltage of an analog amplifier and an output signal, or a low-pass (for example, 0.1 [Hz] or less) high-pass filter is performed on the output signal. Thus, there is a method of producing an AC component.

In the above embodiment, the vibration sensor 2 of the speed detecting device 1 is fixed to the trunk of the vehicle. However, the present invention is not limited to this, and the vibration sensor 2 may be fixed to any part inside and outside the vehicle. Even so, the same effect can be obtained. At this time, the vibration sensor may be lightly fixed to the automobile with an adhesive tape or the like.

Further, in the above-described embodiment, the speed detection device 1 is attached to an automobile to detect the speed. However, the present invention is not limited to this, and the present invention is not limited to this. The same effect can be obtained even if the speed detecting device 1 is attached to the vehicle.

Further, in the above-described embodiment, the case where only the speed detecting device 1 is fixed to the moving body has been described.
The present invention is not limited to this, and the speed detecting device 1, 9 or 13 may be used in combination with another speed detecting device. For example, by using the speed detection device 1, 9, or 13 together with the GPS, the speed can be detected even in a place where GPS radio waves cannot be received, such as in a shadow of a high-rise building such as a building or in a tunnel. Further, it is possible to detect a low speed of about 10 to 20 [km / h], which has conventionally been difficult to detect accurately.

In the navigation device using the speed detecting device 9 or 13 and the GPS together, when it is determined that the vehicle is idling from the detected speed, the TV monitor is turned on by utilizing the fact that the vehicle is stopped. Or to
Character information such as FM multiplexing can be displayed on the display. In addition, when the vehicle is stopped, the power generated by the alternator decreases, so that the power consumption of the electric system can be adjusted, and the volume and the like can be adjusted according to the traveling speed. This adjustment of the volume and the like not only lowers the level of the volume and the like when stopped, but also suppresses the level reduction in the low and high ranges. For example, a sound such as voice guidance of a navigation device that emits a sound such as information by voice changes the level between when the vehicle is stopped and when the vehicle is traveling.

In addition, for example, the display of illumination or the like on a speaker or the like can be switched between when stopped and when running, or when a complicated key operation is performed during running, and other sensors are stabilized when stopped. Since a DC component is output, calibration such as an offset voltage is performed. Further, it can be used for various things such as automatically stopping a fan heater or the like when detecting external vibration such as an earthquake.

[0031]

As described above, according to the present invention, the vibration of the moving body is detected, and the speed of the moving body is detected from the component of the detection output in the band of 5 [Hz] or less. The speed of the moving body can be detected without being affected by an error caused by gravitational acceleration due to a slope. G
When used in combination with a speed detecting device such as a PS, a speed detecting device can be connected without processing a moving body, and a highly accurate speed can be detected. Further, the stop and operation of the moving object can be automatically detected, and permission / prohibition of the operation of the entertainment device or the like can be detected, so that the safety can be easily confirmed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a speed detecting device according to an embodiment of the present invention.

FIG. 2 is a graph showing a spectrum of a sensor output signal obtained from a front-back vibration of a gasoline-powered vehicle.

FIG. 3 is a graph showing a spectrum of a sensor output signal obtained from vertical vibration of a gasoline-powered vehicle.

FIG. 4 is a graph showing a spectrum of a sensor output signal obtained from a left-right vibration of a gasoline-powered vehicle.

FIG. 5 is a graph showing a spectrum of a sensor output signal obtained from the longitudinal vibration of the diesel vehicle.

FIG. 6 is a graph showing a spectrum of a sensor output signal obtained from a vertical vibration of a diesel vehicle.

FIG. 7 is a graph showing a spectrum of a sensor output signal obtained from left-right vibration of a diesel vehicle.

FIG. 8 is a block diagram showing another speed detecting device.

FIG. 9 is a block diagram showing another speed detecting device.

[Explanation of symbols]

1, 9, 13 ... speed detection device, 2 ... acceleration sensor,
3, 10, 14 ... arithmetic unit, 4 ... amplifier, 5 ... filter, 6 ... detection circuit, 7 ... smoothing circuit, 8 ... signal level detector, 11 ... A / D converter, 12 , 15 ...
Digital signal processing unit.

──────────────────────────────────────────────────続 き Continuation of front page (58) Fields investigated (Int.Cl. ⁶ , DB name) G01P 3/00 G01C 21/00 G01S 5/14

Claims (8)

(57) [Claims] 1. An acceleration sensor detachably attached to a moving body and detecting vibration of the moving body, and 5 Hz or less of a vibration spectrum component of the moving body detected by the acceleration sensor. Speed detecting means for detecting the speed of the moving object based on the components of the band . 2. Receiving a GPS radio wave and obtaining position information of a moving object.
GPS receiving means for detecting, and recording medium for storing map information
Body and the position of the moving body obtained from the GPS receiving means
A reproducing means for reproducing map information according to the location from the recording medium.
Navigation having steps and display means for displaying the map information
In the gaming device, an update is performed based on a reception signal obtained from the GPS reception means.
First speed detecting means for detecting the speed of the moving body, and detecting a vibration spectrum component of the moving body;
Of the spectrum component, the component of the band below 5 [Hz]
A second speed detecting means for detecting the speed of the moving object based on the second speed detecting means
A navigation device comprising a step . 3. When the reception state of the GPS radio wave is good, the mobile station moves based on a detection output of the first speed detection means.
If the speed of the body is detected and the reception condition of the GPS radio wave is not good, the moving speed is determined based on the detection output of the second speed detecting means.
3. The method according to claim 2, wherein the speed of the body is detected .
Navigation device. 4. When the reception condition of the GPS radio wave is not good.
In this case, the first speed detecting means is based on the reception of the GPS radio wave.
Then, the speed of the moving body is detected, and the speed that is not detected by the first speed detecting means is detected by the first speed detecting means.
And wherein the supplement at the detected speed second speed detecting means
The navigation device according to claim 2 or 3, wherein
Place. 5. Receiving a GPS radio wave to obtain position information of a moving object
GPS receiving means for detecting, and recording medium for storing map information
Body and the position of the moving body obtained from the GPS receiving means
A reproducing means for reproducing map information according to the location from the recording medium.
Navigation having steps and display means for displaying the map information
In the gaming device, an update is performed based on a reception signal obtained from the GPS reception means.
First speed detecting means for detecting the speed of the moving body, and detecting a vibration spectrum component of the moving body;
Of the spectrum component, the component of the band below 5 [Hz]
A second speed detecting means for detecting the speed of the moving object based on the second speed detecting means
And the speed detected by the first speed detecting means and / or
Based on the speed detected by the second detecting means,
Control means for controlling the production means, the display means or other equipment
And a navigation device comprising: 6. The control means is a device operable by the device.
The navigator according to claim 5, wherein the function is controlled.
Solution device. 7. The control means displays information on the display means.
Control whether or not the moving object is moving.
When doing so, make sure that no information is displayed on the display
7. The navigation device according to claim 6, wherein 8. A vibration spectrum of a moving object detected by an acceleration sensor.
Extract components in the band below 5 [Hz] of the vector components
That filter and a level detector for detecting the output level of the filter, which is previously stored level detected by the level detector value
Comprising a processing unit for detecting the speed of the vehicle by matching bets
A speed detecting device characterized by the above-mentioned.