JPH10300482A - Navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the freedom of setting direction of an acceleration sensor to a moving body without being limited by the setting direction of a navigation device body by providing a switching means for detecting the setting direction of an acceleration detecting means to the moving body and switching the polarity of output of the acceleration detecting means on the basis of the detected setting direction. SOLUTION: An acceleration sensor 1 is mounted on a base 101 within a navigation device through a rotatable mounting base 102. Click stop recessed parts 103 are provided every 90 deg. on the peripheral part of the mounting base 102, and engaged with a protruding part provided on a guide 104, whereby a rotating mechanism is formed. The rotating mechanism is driven and rotated in order to fix the acceleration sensing direction of the acceleration sensor 1 to the advancing direction of a vehicle. Since the acceleration sensor 1 can be thus rotated by 90 deg., its setting direction to the vehicle can be selected from four directions. The mounting base 102 may have a knob or lever operable by a user. Two uniaxial acceleration sensors 1 may be mounted on the mounting base 102 in 90 deg.-directions (X, Y axes).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation system for displaying the current position of a vehicle such as a vehicle and a route to a destination and supporting the operation of the vehicle. The present invention belongs to the technical field of a navigation system having an acceleration detecting means for detecting an acceleration generated in a vehicle.

[0002]

2. Description of the Related Art At present, as a positioning device for various moving objects such as automobiles, airplanes, ships, and the like, the position of the moving object is displayed on a map including a point where the moving object is currently located. There is known a so-called navigation system that superimposes and displays the current position mark shown and guides a route to a destination based on the mark. Among these navigation systems, the navigation system mounted on a vehicle is roughly classified into a self-contained navigation system and a GPS (Global Positioning System) navigation system.

In the former, a current position is calculated using a traveling distance sensor or an angular velocity sensor provided on a moving body, and a position mark and a corresponding map are displayed on a display screen based on the calculated current position. is there.

[0004] The latter receives positioning radio waves from a plurality of GPS satellites launched in outer space and calculates the current position of the moving object by a three-dimensional survey method or a two-dimensional survey method based on the reception result. Then, a position mark and a corresponding map are displayed on the display screen based on the calculated current position.

[0005] Among these, the latter system using the GPS type positioning has the advantage that there is no need to set the own vehicle position on a map in advance, and the positioning error of the position is extremely small and high reliability can be obtained. However, GPS positioning has a drawback that positioning cannot be performed in the shade of buildings, tunnels, forests, and the like, and self-contained positioning is also easily affected by integration errors and accumulated errors, the effects of temperature changes, and the conditions inside and outside the vehicle body. For example, the detected data is not always accurate, and the positioning is not always perfect.

[0006] Therefore, recently, a hybrid vehicle navigation system in which the GPS type positioning and the self-contained positioning are used together so as to compensate for the respective disadvantages is becoming popular. This hybrid navigation system can perform high-accuracy positioning.However, when performing positioning using sensors installed in the vehicle in advance, such as a mileage sensor, a back sensor, and a side brake, as self-contained positioning. However, there is a problem that it is necessary to electrically connect the navigation device and the sensor, and the connection work becomes complicated.

[0007] Therefore, there has been proposed a navigation system including an acceleration sensor that does not need to be electrically connected to a sensor installed in a vehicle. The navigation system including the acceleration sensor obtains an output from the acceleration sensor, calculates an acceleration associated with the movement of the vehicle based on the output, calculates the speed by integrating the acceleration, and further calculates the speed. The positioning of the current position is performed by calculating the distance by integration.

[0008]

In a conventional navigation system having an acceleration sensor, the sensing direction of the acceleration sensor depends on the mounting direction (installation direction) of the acceleration sensor with respect to the moving object or the navigation apparatus main body incorporating the acceleration sensor. And the traveling direction of the moving body may be different, and there is a problem that the acceleration in the traveling direction of the moving body may not be detected.

That is, when trying to detect the acceleration in the traveling direction of the moving body, the installation direction of the acceleration sensor or the navigation device body is limited, and there is a problem that the degree of freedom in the installation direction is low. In particular, when the sensitivity axis of the acceleration sensor is one axis (one direction), the installation direction of the acceleration sensor or the navigation device main body is limited to one direction in order to use the acceleration sensor effectively.

Therefore, the present invention has been made in view of the above problems, and the problem is that the installation direction of the navigation device main body is not limited, and the freedom of the installation direction with respect to the moving body is high. To provide a navigation system.

In order to solve the above-mentioned problems, the invention according to claim 1 is an acceleration detecting means for detecting an acceleration generated on a moving body, and an installation direction detecting means for detecting an installation direction of the acceleration detecting means with respect to the moving body. Switching means for switching the polarity of the output of the acceleration detecting means based on the detected installation direction.

According to a second aspect of the present invention, in the navigation system according to the first aspect, the acceleration detecting means is built in the navigation apparatus main body, and the installation direction detecting means is provided in an installation direction of the navigation apparatus main body with respect to the moving body. Is detected.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the navigation system described in the above, the installation direction detection means is a switch provided in the navigation system, the switch is operated in accordance with the installation direction of the acceleration detection means or the navigation apparatus body with respect to the moving body, the state of the switch It is characterized by detecting the installation direction with respect to the moving body by detecting.

[0014] The invention described in claim 4 is the first or second invention.
Display means,
Display control means for displaying, on a display means, a plurality of candidates for an installation direction of the navigation device main body with respect to a moving body, and actual acceleration detection means or the navigation from a plurality of displayed candidates. Selecting means for selecting an installation direction of the apparatus main body with respect to the moving body, wherein the installation direction detecting means sets the selected candidate as an acceleration detecting means or an installation direction of the navigation apparatus main body with respect to the moving body. I do.

[0015] The invention described in claim 5 is the invention according to claim 1 or 2.
The navigation system according to the above, further comprising speed detection means for detecting the speed of the moving body, the installation direction detection means,
The installation direction of the acceleration detecting means or the navigation apparatus body with respect to the moving body is detected based on the outputs of the acceleration detecting means and the speed detecting means.

According to a sixth aspect of the present invention, in the navigation system, an acceleration detecting means for detecting an acceleration generated in the moving body, a speed detecting means for detecting a speed of the moving body, and outputs of the acceleration detecting means and the speed detecting means. Switching means for switching the polarity of the output of the acceleration detecting means based on

According to a seventh aspect of the present invention, in the navigation system according to the sixth aspect, when the speed of the moving object detected by the speed detecting means is equal to or higher than a predetermined value, the polarity of the output from the acceleration detecting means is changed. Detecting means for detecting;
When the polarity detected by the detection means is negative, the polarity of the output of the acceleration detection means is switched.

According to an eighth aspect of the present invention, in the navigation system according to the sixth aspect, when the moving body is moving forward, and the speed of the moving body detected by the speed detecting means is equal to or higher than a predetermined value. Then, when the polarity of the output of the acceleration detecting means is negative, the polarity of the output of the acceleration detecting means is switched when the polarity detected by the detecting means is negative.

The invention according to claim 9 is the invention according to claims 6 to 8
Wherein the speed detecting means detects the speed of the moving object based on positioning data obtained by GPS positioning.

According to a tenth aspect of the present invention, in a navigation system having a navigation device main body having built-in acceleration detection means for detecting acceleration generated in a moving body, the acceleration detection means is configured to be rotatable with respect to the navigation device main body. It is characterized by the following.

According to an eleventh aspect of the present invention, in the navigation system according to the tenth aspect, the acceleration detecting means is rotated so as to detect the acceleration of the moving body in the traveling direction.

[0022]

According to the present invention, the installation direction of the navigation device incorporating the acceleration detecting means or the acceleration detecting means is not limited, and the degree of freedom of the installation direction with respect to the moving body can be increased.

[0023]

Next, a preferred embodiment of the present invention will be described with reference to the drawings. In the following embodiments, a case will be described in which the present invention is applied to a vehicle navigation system in an automobile or the like.

First Embodiment FIG. 1 is a block diagram showing the overall configuration of a navigation system according to the present invention.
As shown in FIG. 1, the navigation system according to the present invention detects acceleration when a moving body, for example, a vehicle starts or stops, and when the vehicle is accelerated or decelerated, as an independent positioning means, and outputs acceleration data. And an angular velocity when the direction of the vehicle changes, for example.
An angular velocity sensor 2 as one of displacement detecting means for outputting angular velocity data and relative azimuth data, and detects a moving distance per unit time based on, for example, the number of vehicle speed pulses per one rotation of an axle, and outputs traveling distance data. A travel distance sensor 3 is provided.

Here, since the traveling distance of the vehicle is calculated based on the output of the acceleration sensor 1, it is not always necessary to connect the traveling distance sensor 3 of the vehicle to the navigation device. By using the travel distance sensor 3 and the acceleration sensor 1 together, the detection accuracy of the travel distance is improved.

As a GPS type positioning means, a GPS
GP that receives radio waves from satellites and outputs GPS positioning data such as latitude, longitude, altitude, and speed at which the moving object is located, and outputs absolute azimuth data in the traveling direction of the vehicle.
And an S receiver 4.

Further, based on acceleration data, relative azimuth data, angular velocity data, GPS positioning data and absolute azimuth data output from the acceleration sensor 1, angular velocity sensor 2 and GPS receiver 4 via the bus line 10, The system includes a system controller 5 that calculates a position and controls the entire navigation device, and an input device 11 including a remote controller and the like for inputting various data.

[0028] DVD-ROM further storing map information
(Digital Video Disk Read Only Memory) Disk D
K1 or CD-ROM (Compact Disk Read Only Me)
mory) A DVD-ROM drive 12 for playing the disks DK2 under the control of the system controller 5, respectively.
a or a CD-ROM drive 12b, a display unit 13 for displaying various display data under the control of the system controller 5, and an audio reproducing unit 18 for reproducing and outputting various audio data under the control of the system controller 5. And VICS (Vehicle Information andCommu)
VICS that receives traffic congestion information using the Communication System
And a receiving unit 22.

The system controller 5 includes an interface section 6 for performing an interface operation of the above-described various sensors and the like, and a CPU for controlling the entire system controller 5.
7, a ROM (Read Only Memory) 8 in which a control program executed by the CPU 7 is stored, and an input device 1
RAM (Random A) for storing various readable data such as route data preset by the user via
ccess Memory) 9, an input device 11, a DV
The D-ROM drive 12a or CD-ROM drive 12b, the display unit 13, the sound reproduction unit 18, and the VICS receiving unit 22 are connected via the bus line 10. Further, the above-mentioned various sensors and the like are connected via the interface unit 6 and the bus line 10.

The display unit 13 includes a graphics controller 14 for controlling the entire display unit 13 based on control data sent from the CPU 7 via the bus line 10, and a memory such as a VRAM (Video RAM) for immediate display. A buffer memory 15 for temporarily storing various image information, and a liquid crystal display (CRT) based on image data output from the graphics controller 14.
(Cathode Ray Tube) or the like.

The sound reproducing unit 18 is a DVD-ROM
A D / A converter 19 for performing D / A conversion of an audio digital signal sent from the drive 12a or the CD-ROM drive 12b or the RAM 9 via the bus line 10
And an amplifier 20 for amplifying an audio analog signal output from the D / A converter 19, and a speaker 21 for converting the amplified audio analog signal into audio and outputting the audio.

The “navigation apparatus main body” in each of the following embodiments means at least the system controller 5 such as the CPU 7, the DVD-ROM drive 12a,
It is assumed that it indicates a housing in which the CD-ROM drive 12b is stored.

When the navigation system having the above configuration is started, the system controller 5 first operates the DVD-R
OM disk DK1 or CD-ROM disk DK
From step 2, information for accessing map information and the like and information necessary for displaying a vehicle position mark and the like are read out and stored in the RAM 9.

Next, an acceleration is calculated based on the output of the acceleration sensor 1 as described later, and a speed and a traveling distance are obtained from the calculated acceleration. Further, the traveling direction is calculated based on the output of the angular velocity sensor 2. Then, the traveling distance data, the traveling direction data, and the GP from the GPS receiver 4 are output.
The current position of the own vehicle is calculated based on the S positioning data, and the current position of the vehicle is obtained.

The obtained map data around the current position is stored in the DVD-ROM disc DK1 or CD-R.
The data is read from the OM disk DK2 and sent to the graphics controller 14, and the map of the current position is displayed on the display 1.
7 is displayed.

Hereinafter, a specific method of calculating the acceleration, speed, and travel distance based on the output of the acceleration sensor 1 will be described. Further, the acceleration sensor 1 or the navigation apparatus main body in which the acceleration sensor 1 is built is moved in a direction in which the acceleration sensor 1 detects acceleration in the front-rear direction (traveling direction) of the vehicle, and when the vehicle is accelerating.
The description will be made assuming that the vehicle is installed in the vehicle in a direction in which the output of the vehicle becomes positive.

FIG. 2 is a block diagram showing a procedure for processing the output from the acceleration sensor 1. As shown in FIG. 2, a voltage corresponding to the acceleration generated in the vehicle detected from the acceleration sensor main body 1 a through the detection circuit 1 b is applied to the low-pass filter 1.
After the noise is removed by c, the A / D converter 1d performs A / D conversion m times during the sampling period T. Note that the processing described below is performed by the CPU 7.

The A / D converted output of the acceleration sensor main body 1a is output to the sampling period T by the averaging processing means 1e.
The period averaging process is performed, and an average value a ′ _n of the acceleration sensor output values in the sampling period T is calculated for each sampling period T. For example, the sampling period T is set to 0.1 s, during which A / D conversion is performed ten times.

Next, since the offset value _aoe is set in advance in the output of the acceleration sensor 1, this average value _a'n
Is subtracted from the offset value, and further multiplied by a predetermined gain and a gain correction coefficient to calculate the acceleration occurring in the vehicle by the equation (1). The calculated acceleration _An is stored and held in a shift register ₍ not shown) or the like.

[0040] In _{A n = C x · G k} · G · (a 'n -a oe) ··· (1) where, A _n is the vehicle at sampling time nT acceleration ^{[m / s 2], G} k Is a gain correction coefficient, and G is a gain [m / s ² ] of the acceleration sensor 1. Both G _k and G do not always take a constant value, but are set to appropriate values according to the use situation. C _x is the polar coefficient determined according to the installation direction of the acceleration sensor 1, + 1, or takes a value -1. The initial state is set to C _x = + 1. As described later, the polarity switching of the output of the acceleration sensor 1 by switching the C _x. a ' _n is the sampling period T
The average value of the acceleration sensor output values during the period, and _aoe is the offset value of the acceleration sensor 1.

Here, assuming that the running state of the vehicle during the sampling period T is a constant acceleration linear motion, the speed change amount ΔV _n [km /
h] is obtained by equation (2), where T is the sampling period. ΔV _n = (3600/1000) · A _n · T (2) where (3600/1000) is converted from seconds [s] to hours [h] and meters [m] to kilometers [km]. It is a coefficient to perform.

The speed V _n [km / h] of the vehicle at the sampling time nT is _{equal to} the previous sampling time (n−1) T
In the velocity V _n-1, determined by and a speed variation [Delta] V _n of the vehicle at the sampling time nT (3) expression. _{V n = △ V n + V} n-1 ··· (3)

The change amount ΔD _n [m] of the traveling distance of the vehicle at the sampling time nT is obtained by equation (4). ΔD _n = (1/2) ・ A _n・ T ² + (1000/3600) ・ V _n-1・ T (4)

Therefore, the cumulative traveling distance D _n [m] of the vehicle at the sampling time nT is the _sum of the cumulative traveling distance D _{n−1 at} the previous sampling time (n−1) T and the traveling distance of the vehicle at the sampling time nT. From the change amount ΔD _n, it is obtained by the equation (5). D _n = ΔD _n + D _n-1 (5)

By performing the above calculations mainly by the CPU 7, the speed and travel distance of the vehicle can be obtained based on the output of the acceleration sensor 1 and used for processing such as estimation of the current position.

It is also possible to use two uniaxial sensors in the direction of 90 ° (X-axis and Y-axis directions) as acceleration sensors, and to make the acceleration sensing directions in two directions. In this case, the acceleration sensor 1 detects the acceleration of the vehicle in the front-rear direction.
x and acceleration sensor 1y for detecting the lateral acceleration of the vehicle
, The acceleration in the left-right direction that occurs when the vehicle travels in a curve is also obtained. The output of the acceleration sensor 1y is also processed based on the above equations (1) to (5).

Although not shown, an acceleration sensor in the Z-axis direction, which is the acceleration in the vertical direction, can be combined with the vehicle. By detecting the change in the gravitational acceleration caused by the inclination of the vehicle body, the altitude of the vehicle can be changed. (The amount of movement in the vertical direction) can also be detected.

Hereinafter, a configuration for accurately detecting the acceleration according to the traveling direction of the vehicle irrespective of the installation direction of the acceleration sensor 1 or the navigation apparatus main body incorporating the acceleration sensor 1 in the vehicle will be described in detail.

In the navigation device according to the first embodiment, the acceleration sensor main body is attached to an arbitrary rotatable rotation mechanism, and the navigation device main body including the acceleration sensor 1 is installed in the vehicle in the direction of installation. The rotation sensor is driven so that the acceleration sensor body detects acceleration in the traveling direction of the vehicle.

FIG. 3 is a schematic diagram showing the structure of the rotation mechanism to which the acceleration sensor main body 1a is attached. FIG.
3A and 3B show the case where the acceleration sensing direction of the acceleration sensor 1 is one axis in the X-axis direction as shown in FIG.
FIG. 3B is a diagram when the rotation mechanism is viewed from above, and FIG. 3B is a diagram when the rotation mechanism is viewed from the side.

The acceleration sensor 1 is a rotatable mounting table 1
Attached to the internal chassis or the board 101 of the navigation device via the reference numeral 02. In this example, a concave portion 103 for click stop is provided at every 90 ° in the peripheral portion of the mounting base 102, and is configured to engage with a convex portion provided on the click stop guide 104. A rotation mechanism is constituted by the mounting table 102, the internal chassis or substrate 101, and the click stop guide 104.

By providing the mounting base 102 with a recess every 90 °, each time the mounting base 102 rotates 90 °, it engages with the protrusion provided on the click stop guide 104, so that the mounting base 102 rotates 90 °. Each time it is performed, it is fixed to the internal chassis or the substrate 101 or the like. By being fixed, the mounting base 102 to which the acceleration sensor 1 is mounted does not move freely due to the vibration of the vehicle or the like, and the acceleration in the fixed direction can always be detected.

Therefore, regardless of the installation direction of the navigation apparatus main body incorporating the acceleration sensor 1 in the vehicle, the above-described rotation mechanism is driven and rotated to fix the acceleration sensing direction of the acceleration sensor in the traveling direction of the vehicle. If you do,
The acceleration in the traveling direction of the vehicle can always be detected.
In the case of the above example, since the fixing can be performed every 90 ° rotation, the installation direction of the navigation device main body including the acceleration sensor 1 in the vehicle can be selected from four directions.

The method of rotating the mounting table 102 is not particularly limited. For example, a knob or lever formed integrally with the mounting table 102 and operable by a user is provided, and the user rotates the knob or lever. Thus, the mounting base 102 may be rotated, or the amount of rotation or the direction of fixing may be instructed from an input device such as a remote controller, and driven by a motor or the like. When the above-mentioned knob or lever is provided, the acceleration sensor 1 can accurately provide the user with acceleration in the traveling direction of the vehicle by forming the knob or lever into a shape having directionality or adding a mark. The fixing direction to be detected can be instructed from a manual or the like.

The selection of the fixed direction of the acceleration sensor is as follows.
Since the selection only needs to be made at the time of attachment to the vehicle, a selection hole may be provided in the housing of the navigation device and driven by a driver or the like.

Further, a uniaxial sensor is used as an acceleration sensor on the mounting base 102 in a direction of 90 ° to each other (X-axis, Y-axis directions).
, Two sensors may be attached to the sensor and the acceleration sensing directions may be two directions. In this case, an acceleration sensor 1x for detecting the acceleration in the front-rear direction of the vehicle and an acceleration sensor 1y for detecting the acceleration in the left-right direction of the vehicle are arranged on the mount 102 as shown in FIG. Needless to say, an acceleration sensor 1z for detecting acceleration in the Z-axis direction may be further attached to make the sensing directions three directions.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. Note that the schematic configuration of the navigation system of the present embodiment is the same as that of the first embodiment. In the second embodiment, the polarity of the acceleration sensor 1 is switched by the user operating the polarity switch according to the installation direction of the acceleration sensor 1 or the navigation device body incorporating the acceleration sensor 1 in the vehicle. It was made.

FIG. 4 is a diagram showing the relationship between the installation direction of the navigation device main body in the vehicle and the polarity changeover switch when the navigation device main body incorporates an acceleration sensor whose sensing direction is one direction (one axis). Sensing direction is 1
In the case of using an acceleration sensor in one direction (one axis), in order to detect the acceleration in the traveling direction of the vehicle, two installation directions of FIGS. 4A and 4B are considered as installation directions of the navigation device body. .

FIG. 4A shows a case where the navigation device main body is installed in the vehicle such that a disk insertion slot for inserting a DVD-ROM disk or a CD-ROM disk into the navigation device main body faces the front of the vehicle. . When the navigation device main body is installed as shown in FIG. 4 (a), an acceleration sensor is attached to the navigation device main body so that the acceleration in the traveling direction of the vehicle is accurately (so that the output becomes positive when the vehicle advances). Have been.

When the navigation apparatus main body is installed as shown in FIG. 4A, a positive output is obtained from the acceleration sensor when the vehicle moves forward, so that the switch SW is turned off, that is, an acceleration sensor output (not shown). given "L" as the information from the switch SW to the polarity inversion circuit, it is set to +1 polarity coefficient C _x for the acceleration sensor 1.

FIG. 4B shows a case where the navigation apparatus main body is installed in the vehicle such that the disk insertion opening faces the rear of the vehicle. When the navigation device body is installed as shown in FIG. 4B, a negative output is obtained from the acceleration sensor 1 when the vehicle moves forward. Therefore, the switch SW is turned on, that is, the polarity of the acceleration sensor output (not shown). given "H" as the information from the switch SW to the inverting circuit, and sets the C _x -1.

[0062] By C _x is set to -1, although the acceleration sensor has a negative output is obtained when the vehicle moves forward, the acceleration is calculated by the above formula (1) is traveling in a vehicle Thus, the acceleration in the direction of travel of the vehicle can be accurately detected.

For the user, a manual or the like may be used, for example, "Please turn on the changeover switch when the main body is installed so that the disc insertion port is behind the vehicle. When the navigation system is installed in the vehicle, the switch operation may be performed.

Next, for example, the uniaxial acceleration sensors 1x, 1x
y are arranged at 90 ° to each other (X-axis, Y-axis directions)
A case of a navigation device body incorporating an acceleration sensor having sensing directions in two directions of the X-axis and the Y-axis will be described.

FIG. 5 shows the installation direction of the navigation device main body in the vehicle and the polarity changeover switch of the acceleration sensor in the case of a navigation device main body having a built-in acceleration sensor having sensing directions in two directions of the X axis and the Y axis. FIG. Since the sensing directions of the acceleration sensor are two directions, two polarity changeover switches composed of SWx for the acceleration sensor 1x and SWy for the acceleration sensor 1y are used to independently switch the polarity.

When an acceleration sensor having two sensing directions (two axes) is used, the four installation directions of FIGS. 5A, 5B, 5C, and 5D are used as the installation directions of the navigation device body. Conceivable.

FIG. 5 (a) shows a case where the navigation device main body is installed in the vehicle such that a disk insertion slot for inserting a DVD-ROM disk or a CD-ROM disk into the navigation device main body faces the front of the vehicle. . In addition, when the navigation device main body is installed as shown in FIG. 5A, the acceleration sensors 1x and 1y accurately calculate the acceleration in the traveling direction of the vehicle and the acceleration in the left-right direction of the vehicle without switching the polarity. The acceleration sensor detects the acceleration sensor 1x so that the acceleration generated when the vehicle moves forward becomes positive, and the acceleration sensor 1y detects the acceleration generated to the right of the vehicle becomes positive). Shall be attached to

When the main body of the navigation device is installed with the disc insertion port facing forward of the vehicle as shown in FIG. 5A, a positive output from the acceleration sensor 1x is detected when the acceleration in the forward direction of the vehicle is detected. In addition, since a positive output is output from the acceleration sensor 1y when detecting an acceleration generated to the right of the vehicle, both the switches SWx and SWy are turned off, that is, the switch SWx to the polarity inversion circuit of the outputs of the acceleration sensors 1x and 1y. , giving the "L" as the information from SWy, and sets both the +1 polarity coefficient C _y to polar coefficients C _x and the acceleration sensor 1y for the acceleration sensor 1x.

The CPU 7 includes switches SWx, SW
If both “L” are output as information from y,
The acceleration sensor 1x recognizes that the acceleration generated in the front-rear direction of the vehicle is detected, and the acceleration sensor 1y detects the acceleration generated in the left-right direction of the vehicle.

FIG. 5 (b) shows a case where the navigation apparatus main body is installed in the vehicle such that the disc insertion opening faces the right of the vehicle. When the navigation device main body is installed as shown in FIG. 5B, the acceleration sensor 1x detects the acceleration generated in the left-right direction of the vehicle, and the acceleration sensor 1x
y will detect the acceleration in the front-rear direction of the vehicle.

As is clear from FIG. 5B, since the direction of the acceleration sensor 1y is opposite to the direction of travel of the vehicle, the acceleration generated by the acceleration sensor 1y when the vehicle moves forward is expressed as a negative output. The acceleration generated in the right direction of the vehicle by the acceleration sensor 1x is detected as a positive output. In this case off the switch SWx manipulates so as to turn on the SWy, set to +1 C _x for the acceleration sensor 1x give "L" as the information from the switch SWx to the polarity inversion circuit of the output of the acceleration sensor 1x And a switch SWy to a polarity inversion circuit of the output of the acceleration sensor 1y.
Set to -1 C _y for the acceleration sensor 1y give "H" as the information from.

The CPU 7 outputs “L” as information from the switch SWx and “L” as information from the switch SWy.
When H ″ is output, it is recognized that the acceleration generated in the left-right direction of the vehicle is detected by the acceleration sensor 1x, and the acceleration generated in the front-rear direction of the vehicle is detected by the acceleration sensor 1y.

FIG. 5C shows a case where the navigation apparatus main body is installed in the vehicle such that the disc insertion opening faces the rear of the vehicle. When the navigation device main body is installed as shown in FIG. 5C, the acceleration sensor 1x detects the acceleration generated in the front-rear direction of the vehicle, and the acceleration sensor 1x
y is to detect the acceleration in the left-right direction of the vehicle.

As is clear from FIG. 5 (c), the acceleration generated when the vehicle moves forward is detected as a negative output by the acceleration sensor 1x, and the acceleration generated rightward of the vehicle is detected as the negative output by the acceleration sensor 1y. Will be done. In this case, the switches SWx and SWy are operated to be turned on, and the switches SWx and SWy are both turned on.
That is, the information from the switches SWx and SWy to the polarity inversion circuits of the outputs of the acceleration sensors 1x and 1y are both "
Give H ", and sets both to -1 C _y for C _x and the acceleration sensor 1y for the acceleration sensor 1x.

The CPU 7 includes switches SWx, SW
If both "H" are output as information from y,
The acceleration sensor 1x recognizes that the acceleration generated in the front-rear direction of the vehicle is detected, and the acceleration sensor 1y detects the acceleration generated in the left-right direction of the vehicle.

FIG. 5 (d) shows a case where the navigation device main body is installed in the vehicle such that the disc insertion opening faces the left side of the vehicle. When the navigation device main body is installed as shown in FIG. 5D, the acceleration sensor 1x detects acceleration generated in the left-right direction of the vehicle, and the acceleration sensor 1x
y will detect the acceleration in the front-rear direction of the vehicle.

As is clear from FIG. 5D, the acceleration generated by the acceleration sensor 1y when the vehicle moves forward is detected as a positive output, and the acceleration generated rightward by the acceleration sensor 1x is detected as a negative output. Will be done. The case switch SWx is turned on and operated to turn off the SWy, to -1 C _x for the acceleration sensor 1x give "H" as the information from the switch SWx to the polarity inversion circuit of the output of the acceleration sensor 1x Set, acceleration sensor 1
The C _y for the acceleration sensor 1y given "L" as the information from the switch SWy to the polarity inversion circuit of the output of the y +
Set to 1.

The CPU 7 sets “H” as information from the switch SWx and “H” as information from the switch SWy.
When L ″ is output, it is recognized that the acceleration generated in the left-right direction of the vehicle is detected by the acceleration sensor 1x and the acceleration generated in the front-rear direction of the vehicle is detected by the acceleration sensor 1y.

Thus, the acceleration generated in the vehicle can be accurately detected by the user operating the polarity switch according to the set direction of the acceleration sensor or the navigation apparatus body having the built-in acceleration sensor. Further, when the acceleration sensor is built in the navigation device, the mounting direction (fixing direction) of the acceleration sensor is not limited to the above-described example. In short, the polarity may be switched in accordance with the direction in which the acceleration sensor is fixed to the navigation device body and the direction in which the navigation device body is installed in the vehicle.

Third Embodiment Next, a third embodiment of the present invention will be described. Second
In the embodiment, the user operates the polarity switch SW in order to cause the CPU 7 to recognize the installation direction of the acceleration sensor or the navigation device body having the built-in acceleration sensor in the vehicle.

In the third embodiment, a display means such as a CRT or a liquid crystal display device displays an acceleration sensor or a plurality of candidates for the installation direction of the navigation apparatus body having the built-in acceleration sensor in a vehicle. By selecting the direction of the actual installation from among the candidates, that is, instead of operating the polarity switch SW, the installation direction to the vehicle is input on the display screen, and the polarity switching of the acceleration sensor and the acceleration sensor are performed. Is made to be recognized by the CPU 7.

FIG. 6 shows an example of a display screen for selecting the installation direction of the acceleration sensor or the navigation apparatus body having the built-in acceleration sensor in the vehicle. FIG. 6A shows a case where the sensing direction of the acceleration sensor is one direction (one axis).
FIG. 6B shows two directions (two axes) of the acceleration sensor.
Is the case.

When the user operates a cursor key provided on the input device 11 such as a remote controller to select an item for switching the mounting direction of the acceleration sensor (in the figure, the acceleration sensor is a G sensor), the setting can be performed. Direction candidates are displayed as shown in FIGS. 6 (a) and 6 (b).

From the displayed installation direction candidates, the direction that the user has actually mounted on the vehicle is selected. In this case, for example, if the direction of installation of the navigation device main body with the built-in acceleration sensor in the vehicle is to be selected, an insertion hole for inserting a disk is provided in the vehicle as shown in FIG. 5 of the second embodiment. On the other hand, it is sufficient to make the user select which of the front, the rear, the left, and the right.

Next, referring to the flowchart of FIG.
A procedure for switching the polarity of the acceleration sensor according to the embodiment will be described. The flowchart of FIG. 7 corresponds to the case where the sensing directions of the acceleration sensor are two directions (two axes).

When the user selects a direction in which the vehicle is actually mounted on the vehicle from the displayed installation direction candidates, first, in step S30, if it is determined that "forward" has been selected, the navigation device body since when installed as shown in FIG. 5 (a), both set to +1 C _y for C _x and the acceleration sensor 1y for the acceleration sensor 1x proceeds to step S31, the process proceeds to step S34.

If it is determined in step S30 that "forward" has not been selected, it is determined whether or not "backward" has been selected in step S32. If "backward" has been selected, navigation is performed. because when the apparatus body is installed as shown in FIG. 5 (c), the set together to -1 C _y for C _x and the acceleration sensor 1y for the acceleration sensor 1x proceeds to step S33, the process proceeds to step S34.

In step S34, the acceleration sensor 1x detects the acceleration occurring in the front-rear direction of the vehicle, and recognizes that the acceleration sensor 1y detects the acceleration occurring in the left-right direction of the vehicle. The switching process ends.

If it is determined in step S32 that "backward" has not been selected, then in step 35 "rightward"
It is determined whether or not has been selected. Because if the "right direction" is selected is when the car navigation device is installed as shown in FIG. 5 (b), +1 and acceleration sensor C _x for the acceleration sensor 1x proceeds to step S36 1y
The C _y is set to -1 for, the process proceeds to step S39.

If it is determined in step S35 that "right direction" has not been selected, the flow advances to step S37 to determine whether "left direction" has been selected. Because if "left direction" is selected is when the car navigation device is installed as shown in FIG. 5 (d), C _y against -1 and the acceleration sensor 1y a C _x for the acceleration sensor 1x proceeds to step S38 Is set to +1 and step S39 is set.
Proceed to.

If it is determined in step S37 that "left direction" has not been selected, no direction has been selected, and the process returns to step S30.

In step S39, the acceleration generated in the left-right direction of the vehicle is detected by the acceleration sensor 1x, and it is recognized that the acceleration generated in the front-rear direction of the vehicle is detected by the acceleration sensor 1y. The switching process ends.

With the above-described procedure, the processing for switching the polarity of the acceleration sensor according to the third embodiment is completed, and the acceleration, the moving speed, and the traveling distance generated in the vehicle are calculated based on the output of the acceleration sensor.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIGS. Note that the schematic configuration of the navigation system of the present embodiment is the same as that shown in the first embodiment.

In the fourth embodiment, the travel distance per unit time is detected based on sensors other than the acceleration sensor, for example, GPS positioning data or the number of vehicle speed pulses per axle revolution, and the travel distance data is output. Using the speed obtained based on the data from the sensor 3 and the speed obtained from the acceleration sensor, the installation direction of the acceleration sensor or the navigation device body having the built-in acceleration sensor in the vehicle is detected, and the acceleration sensor output is output. Is switched.

FIG. 8 shows the installation direction of the acceleration sensor or the navigation apparatus body incorporating the acceleration sensor in the case where an acceleration sensor having one sensing direction (one axis) is used, and the polarity of the output of the acceleration sensor. 6 is a flowchart showing a switching procedure.

First, the current vehicle acceleration A _n [m / s ² ] is calculated by using the above-mentioned equation (1) (step S5).
1).

In step S52, it is determined whether the GPS is in a positioning state. Ye if GPS is in positioning state
In s, the process moves to the next step S53. If the GPS is not in the positioning state, the process ends with No.

In step S53, it is determined whether or not the speed data Vgps obtained by the GPS positioning is higher than a predetermined speed Vth. Here, Vth is 30 [km / h]
Is used. In general, the back traveling is not performed at 30 [km / h] in a daily traveling state, so that it can be determined that the vehicle is moving forward if the traveling is 30 [km / h] or more.

Velocity data Vgp obtained by GPS positioning
s is greater than the speed Vth, ie, 30 [km / h]
If it is above, it is assumed that the vehicle is moving forward and Ye
Move to the next step in s. If the speed data Vgps is smaller than the speed Vth or less than 30 [km / h], the vehicle is not necessarily moving forward and may be stopped or moving backward. To stop and end.

In step S54, it is determined whether or not the speed Vac obtained from the output of the acceleration sensor is negative. If negative, the vehicle is traveling backward as far as the speed obtained from the output of the acceleration sensor is concerned.
In 3, the current speed of the vehicle is a speed that cannot be normal back traveling, so that the installation direction of the acceleration sensor or the navigation device body including the acceleration sensor is installed in the opposite direction to the traveling direction of the vehicle. You can see that.

[0102] Therefore, if the speed Vac is negative by reversing the polarity of the acceleration sensor output C _x as -1 in step S55, the process ends switching the polarity of the acceleration sensor output. Here, C _x is assumed to be set to +1 in the initial state.

[0103] If the speed Vac is not negative, C _x installation direction coincides with the traveling direction of the vehicle navigation apparatus body with a built-in acceleration sensor or the acceleration sensor can remain +1. No is determined in the step S54, and the polarity sensor output switching processing is ended.

After the polarity of the output of the acceleration sensor is switched, the acceleration, the moving speed, and the traveling distance generated in the vehicle are obtained from the output of the acceleration sensor.

FIG. 9 shows a case where uniaxial acceleration sensors 1x and 1y are used as acceleration sensors in directions 90 ° from each other (X-axis and Y-axis directions).
2 shows a procedure for detecting an installation direction of an acceleration sensor or a navigation apparatus body incorporating the acceleration sensor, which has sensing directions in two directions of X-axis and Y-axis directions, and switching the polarity of the output of the acceleration sensor. It is a flowchart.

First, in step S70, it is determined which of the acceleration sensors 1x and 1y has detected the acceleration when the vehicle started. If the acceleration at the time of starting is detected by the acceleration sensor 1x, the acceleration sensor 1x is determined in step S71.
It can be seen that x is the longitudinal direction of the vehicle and the acceleration sensor 1y is the lateral direction of the vehicle. When the acceleration at the time of starting is detected by the acceleration sensor 1y, it is understood that the acceleration sensor 1x is in the left-right direction of the vehicle and the acceleration sensor 1y is in the front-rear direction of the vehicle in step S72.

Next, from the acceleration sensor (either 1x or 1y) that detects the longitudinal acceleration of the vehicle, the current vehicle acceleration A _n [m / s ² ]
Is calculated (step S73).

In step S74, it is determined whether the GPS is in a positioning state. Ye if GPS is in positioning state
In s, the process moves to the next step S75. If the GPS is not in the positioning state, the process ends with No.

In step S75, it is determined whether or not the speed data Vgps obtained by the GPS positioning is higher than a predetermined speed Vth.

Speed data Vgp obtained by GPS positioning
s is greater than the speed Vth, ie, 30 [km / h]
If it is above, it is assumed that the vehicle is moving forward and Ye
The process moves to step S76 in s. If the speed data Vgps is smaller than the speed Vth or less than 30 [km / h], the vehicle is not necessarily moving forward and may be stopped or moving backward. To stop and end.

At step S76, it is determined whether or not the speed Vac obtained from the output of the acceleration sensor is negative. If the speed Vac is negative, in step S77, the acceleration sensor 1x detects the longitudinal acceleration of the vehicle.
Is determined.

If the acceleration sensor 1x detects the longitudinal acceleration of the vehicle, the process proceeds to step S78. At this time, the installation directions of the acceleration sensors 1x and 1y are shown in FIG.
C _y together -1 for C _x and the acceleration sensor 1y for the acceleration sensor 1x since become manner of (c)
Set to.

If it is the acceleration sensor 1y that detects the longitudinal acceleration of the vehicle, the flow advances to step S79. At this time, the installation directions of the acceleration sensors 1x and 1y are shown in FIG.
(B) Since looks like a C _x for the acceleration sensor 1x +1 and C _y -1 for the acceleration sensor 1y
Set to.

If the speed Vac is positive, step S8
At 0, it is determined whether or not the acceleration sensor 1x detects the longitudinal acceleration of the vehicle.

If the acceleration sensor 1x detects the longitudinal acceleration of the vehicle, the process proceeds to step S81. At this time, the installation directions of the acceleration sensors 1x and 1y are shown in FIG.
C _y together +1 for C _x and the acceleration sensor 1y for the acceleration sensor 1x because looks like (a)
Set to.

If it is the acceleration sensor 1y that detects the longitudinal acceleration of the vehicle, the process proceeds to step S82. At this time, the installation directions of the acceleration sensors 1x and 1y are shown in FIG.
Since so the (d) a C _y for -1 and the acceleration sensor 1y a C _x for the acceleration sensor 1x +1
Set to.

Through the above steps, the installation direction of the acceleration sensor having the sensing directions in the two directions of the X-axis and the Y-axis or the navigation apparatus body incorporating the acceleration sensor in the vehicle is detected, and the polarity of the output of the acceleration sensor is detected. Is completed, the acceleration generated in the vehicle from the output of the acceleration sensor,
Obtain the moving speed and running distance.

When an acceleration sensor having sensing directions in three directions of the X-axis, the Y-axis, and the Z-axis is used, the navigation device body is not only placed horizontally (as shown in FIG. 5) but also vertically. (Installation state in which the disc insertion port faces upward) is also possible. At this time, if the acceleration sensor that detects the acceleration in the traveling direction of the vehicle is selected from the three, the polarity switching of each acceleration sensor can be performed by the method described above.

In the flowcharts of FIGS. 8 and 9, in order to recognize that the vehicle is in the forward direction, the speed data Vgps obtained by the GPS positioning in step S53 of FIG. 8 and step S75 of FIG. The condition that the speed is higher than the speed Vth is used. This is based on the fact that in general, the vehicle does not perform the reverse traveling at 30 [km / h] in the daily traveling state.

However, it is possible that the reverse traveling is performed at 30 [km / h] or more while the polarity of the output of the acceleration sensor shown in FIGS. 8 and 9 is being switched. If the flowcharts of FIGS. 8 and 9 are executed while the vehicle is performing the reverse traveling at 30 [km / h] or more, it is determined that the vehicle is moving forward despite the reverse. As a result, the polarity of the acceleration sensor is set in reverse.

Therefore, if the switching of the polarity of the output of the acceleration sensor shown in FIGS. 8 and 9 is always executed when the vehicle is moving forward, the switching of the polarity is surely performed.
In a general navigation system, the vehicle always moves forward when the sensor is initialized, so that the polarity of the acceleration sensor may be switched at the same time when the sensor is initialized.

In order to ensure that the vehicle is moving forward, step S53 in FIG. 8 and step S7 in FIG.
5 is a state where the speed data Vgps obtained by the GPS positioning exceeds a predetermined speed Vth for a predetermined time (for example, 5
Seconds) or the condition as follows. This is because, for example, it is unlikely that the reverse traveling continues for 30 seconds at 30 [km / h] or more in a normal traveling state.

In determining that the vehicle is moving forward, the travel distance of the vehicle is obtained from the GPS positioning data, and when the vehicle travels for a predetermined travel distance (for example, 200 m which is considered to be impossible in normal back travel), If the speed or distance obtained from the output of the acceleration sensor during that period indicates a negative value, the acceleration sensor may be determined to be the opposite.

[0124]

As described above in detail, according to the present embodiment, the mounting direction of the acceleration sensor when the acceleration sensor is used in the navigation device can be easily changed after the vehicle is mounted on the vehicle. Can have a degree of freedom in the mounting direction.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a navigation device according to each embodiment of the present invention.

FIG. 2 is a block diagram showing a means for processing an output from an acceleration sensor in each embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a structure of an internal chassis or a substrate on which the acceleration sensor according to the first embodiment of the present invention is mounted.

FIG. 4 is a diagram illustrating states of a polarity switch of a one-axis acceleration sensor and a polarity of acceleration according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating states of a polarity changeover switch and a polarity of acceleration of a two-axis acceleration sensor according to a second embodiment of the present invention.

FIG. 6 is an example of a display screen for selecting an installation direction according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing a processing procedure for switching the polarity of a biaxial acceleration sensor output according to a third embodiment of the present invention.

FIG. 8 is a flowchart showing a processing procedure for switching the polarity of a uniaxial acceleration sensor output according to a fourth embodiment of the present invention.

FIG. 9 is a flowchart illustrating a processing procedure for switching the polarity of a biaxial acceleration sensor output according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1 ··· Acceleration sensor 1a ··· Acceleration sensor body 1b ··· Detection circuit 1c ··· Low-pass filter 1d ··· A / D converter 1e ··· Averaging processing means 2 ··· ··· Angular velocity sensor 3 ···· Distance sensor 4 ··· GPS receiver 5 ··· System controller 6 ··· Interface unit 7 ··· CPU 8 ··· ROM 9 ··· · RAM 10 ··· Bus line 11 ··· Input device 12a ··· DVD-ROM drive 12b ··· CD-ROM drive 13 ··· Display unit 14 ··· Graphics controller 15 buffer memory 16 display control unit 17 display 18 sound reproduction unit 19 D / A converter 20 amplifier 2 ... speaker 22 ... VICS receiver 101 ... internal Shasshi or substrate 102 ... mount 103 ... recess 104 ... click stop guide

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tatsuya Okamoto 25-1, Nishimachi, Yamada-shi, Kawagoe-shi, Saitama Prefecture Pioneer Corporation Kawagoe Factory

Claims (11)

[Claims] 1. An acceleration detecting means for detecting an acceleration generated in a moving body, an installation direction detecting means for detecting an installation direction of the acceleration detecting means with respect to the moving body, and the acceleration detecting means based on the detected installation direction. Switching means for switching the polarity of the output of the navigation system. 2. The navigation system according to claim 1, wherein said acceleration detecting means is built in a navigation apparatus main body, and said installation direction detecting means detects an installation direction of said navigation apparatus main body with respect to a moving body. 3. The installation direction detecting means is a switch provided in a navigation system, and the switch is operated in accordance with an installation direction of the acceleration detecting means or the navigation apparatus main body with respect to a moving body, and a state of the switch is provided. The navigation system according to claim 1, wherein an installation direction with respect to the moving body is detected by detecting the installation direction. 4. Display means; display control means for displaying, on the display means, a plurality of candidates for installation directions of the acceleration detecting means or the navigation apparatus main body with respect to a moving body; Selecting means for selecting an actual installation direction of the acceleration detection means or the navigation apparatus main body with respect to the moving body, wherein the installation direction detection means determines the selected candidate as the acceleration detection means or the navigation apparatus main body. The navigation system according to claim 1, wherein the direction of the navigation system is an installation direction with respect to the moving body. 5. An apparatus according to claim 1, further comprising a speed detecting unit configured to detect a speed of the moving body, wherein the installation direction detecting unit detects the acceleration detecting unit or the navigation device main body based on outputs of the acceleration detecting unit and the speed detecting unit. 3. The navigation system according to claim 1, wherein an installation direction with respect to the moving body is detected. 6. An acceleration detecting means for detecting an acceleration generated in the moving body, a speed detecting means for detecting a speed of the moving body, and an output of the acceleration detecting means based on outputs of the acceleration detecting means and the speed detecting means. Switching means for switching the polarity of the navigation system. 7. A detecting means for detecting a polarity of an output from the acceleration detecting means when a speed of the moving body detected by the speed detecting means is equal to or higher than a predetermined value; 7. The navigation system according to claim 6, wherein when the polarity is negative, the polarity of the output of the acceleration detecting means is switched. 8. A detection method for detecting the polarity of the output of the acceleration detecting means when the moving body is moving forward and when the speed of the moving body detected by the speed detecting means is equal to or higher than a predetermined value. 7. The navigation system according to claim 6, wherein the polarity of the output of the acceleration detecting means is switched when the polarity detected by the detecting means is negative. 9. The navigation system according to claim 6, wherein said speed detecting means detects a speed of the moving object based on positioning data obtained by GPS positioning. 10. A navigation system having a navigation device main body incorporating acceleration detection means for detecting acceleration generated in a moving body, wherein the acceleration detection means is configured to be rotatable with respect to the navigation device main body. Navigation system. 11. The navigation system according to claim 10, wherein said acceleration detecting means is rotated so as to detect acceleration in a traveling direction of said moving body.