JP3381520B2 - Navigation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device for detecting the position of a vehicle from the output of a self-supporting sensor such as an acceleration sensor.

[0002]

2. Description of the Related Art A conventional navigation device will be described below.

FIG. 5 is a block diagram showing the configuration of a conventional navigation device, which is mounted on a vehicle 100. FIG. 5 illustrates a state in which the vehicle 100 is viewed from above, and arrows shown in blocks of an acceleration sensor 101 and a gyro sensor 102, which will be described later, indicate detection directions of both sensors.

In FIG. 5, reference numeral 101 denotes an acceleration sensor for detecting an acceleration in the traveling direction of the vehicle 100 in order to obtain the moving distance of the vehicle 100, and reference numeral 102 denotes a yaw operation of the vehicle 100 for obtaining the moving distance of the vehicle 100. A gyro sensor for detecting the angular velocity in the direction, 201 is an arithmetic device for obtaining the position of the vehicle 100 from the acceleration output from the acceleration sensor 101 and the angular velocity output from the gyro sensor 102.

Acceleration sensor 101 and gyro sensor 1
From 02, data is output at every predetermined time period Δt. As shown in FIG. 4, first, the arithmetic device 201
The data output from the acceleration sensor 101 is integrated twice on the time axis every predetermined period Δt. In other words, the vehicle 1 can be calculated by performing the following equations (1) and (2).
The velocity V _{n of} 00 and the movement distance ΔD _n are obtained. However, the time period in which the output data of the acceleration sensor 101 is obtained is Δ
t, the acceleration of the vehicle 100 at the time n, a _n , the time n
_Let V _{n be} the velocity of the vehicle 100, ΔD _{n be} the moving distance of the vehicle 100 in the time period Δt, and V ₀ be the initial velocity of the vehicle 100.

[0006]

[Equation 1]

[0007]

[Equation 2]

The arithmetic unit 201 also integrates the data output from the gyro sensor 102 on a time axis at every predetermined time period Δt. That is, the moving azimuth θ _n of the vehicle 100 is obtained by performing the following calculation (Equation 3). However, the time period in which the output data of the gyro sensor 102 is obtained is Δt, the angular velocity of the vehicle 100 at time n is ω _n , the moving direction of the vehicle 100 at the time period Δt is θ _n , and the initial direction of the vehicle 100 is θ ₀ . .

[0009]

[Equation 3]

FIG. 6 is a conceptual diagram of the position calculation of the conventional navigation device. When the calculation device 201 obtains the moving distance ΔD _n and the moving direction θ _n of the vehicle 100, it is shown below as shown in FIG. Vehicle 100 according to (Equation 4) and (Equation 5)
The cumulative position from the initial position is calculated to calculate the position of the vehicle 100. However, the position coordinate of the vehicle at time n is (x
_n , y _n ) and the initial position are (x ₀ , y ₀ ).

[0011]

[Equation 4]

[0012]

[Equation 5]

As described above, the position of the vehicle 100 obtained by the arithmetic unit 201 is combined with the map data stored in the storage unit (not shown), and the display unit (not shown) such as LCD (liquid crystal display). The user is navigated by displaying in.

By the way, as described above, the acceleration sensor 1
In the navigation device using 01 and the gyro sensor 102, processing such as correction of bias (output voltage value when the detected physical quantity becomes zero), correction of gravity leak, correction of zero reset of speed, etc. are required. .

Bias correction means, as shown in FIG.
The acceleration sensor 101 and the gyro sensor 102 are sensors that output the detected physical quantity as an electric signal, and subtract the bias from the output voltage value that is the output data. However, since the bias changes irregularly due to factors such as temperature changes and aging changes (B → B ′), the vehicle 1
00 stops (that is, the acceleration sensor 101,
If the output value of the physical quantity detected by the gyro sensor 102 is zero) is obtained as a bias and the bias used up to that time is not corrected, the correct output value of the sensor cannot be obtained.

The correction of the gravity leak-in means, as shown in FIG. 8, when the vehicle 100 has an attitude angle α,
The acceleration a that accompanies the progress of the vehicle 100 is (Equation 6)
Represented by This indicates that the acceleration A detected by the acceleration sensor 101 detects the traveling direction component G · sinα of the gravitational acceleration in addition to the acceleration a generated as the vehicle 100 advances. Therefore, when the vehicle 100 has the posture angle α, when the vehicle 100 stops (that is, when the acceleration a is zero), the fact that the acceleration a is zero is utilized to calculate the posture angle from (Equation 6). α is obtained, and the traveling direction component G · s of the gravitational acceleration is calculated from the output value A of the acceleration sensor 101.
inα must be removed.

[0017]

[Equation 6]

Further, the correction of zero reset of the speed means that the speed of the vehicle 100 calculated from the output data of the acceleration sensor 101 must be zero when the vehicle 100 is in a stopped state, but due to various errors. Not necessarily zero. For this reason, by forcibly correcting the speed to zero, the cumulative error in calculating the position of the vehicle is reduced.

The correction processing such as the correction of the bias, the correction of the leakage of gravity, the correction of the zero reset of the speed, etc. all require the determination of the stopped state of the vehicle 100. The operation of determining the stopped state of vehicle 100 will be described below.

FIG. 9 is an operation flowchart of the stop determination in the conventional navigation device.
The process of determining the stop state of the vehicle 100 from the change in the output value of 01 is described.

As shown in FIG. 9, the arithmetic unit 201 first stores the output value of the acceleration sensor 101 (Step).
501). Upon reaching the predetermined time [Delta] T, the average value P of the plurality of output values p _n of the acceleration sensor 101 stored (STEP 502).

[0022]

[Equation 7]

Next, at a predetermined time ΔT, the difference between the stored individual output value p _{n of} the acceleration sensor 101 and the average value P obtained in (Equation 7) is calculated, the difference is squared, and further calculated individually. The sum pΔT of the values is calculated (Step 503).

[0024]

[Equation 8]

The value of pΔT obtained by this (Equation 8),
By comparing with a predetermined threshold value k (Step 50
4) If the value of pΔT is smaller than the threshold value k, the vehicle 1
00 is in a stopped state (Step 505), and if the value of pΔT is the threshold value k or more, it is determined that the vehicle 100 is in a non-stop state (Step 506).

That is, if the value indicating the change in the output value of the acceleration sensor 101 at the predetermined time ΔT is smaller than the value indicated by the threshold value k, it is determined that the vehicle 100 is in the stopped state.

In the above description, the process for determining the stopped state of the vehicle 100 from the change in the output data of the acceleration sensor 101 is shown.
The stop state of the vehicle 100 can be similarly determined from the output data of No. 2 and will be described below.

FIG. 10 is a flow chart of a stop determination operation in the conventional navigation device, and shows a process of determining the stop state of the vehicle 100 from the change in the output value of the gyro sensor 102.

As shown in FIG. 10, first, the arithmetic unit 20
1 stores the output value q _n of the gyro sensor 102 (Step 801). When the predetermined time ΔT is reached, the output value q _n of the gyro sensor 102 at the predetermined time ΔT
The average value Q of is calculated (Step 802).

[0030]

[Equation 9]

Next, the difference between the individual output data q _{n of} the gyro sensor 102 stored during the predetermined time ΔT and the average value Q obtained from (Equation 9) is calculated, and the difference is squared. Then, the sum qΔT of the values obtained in
3).

[0032]

[Equation 10]

The value of qΔT obtained by this (Equation 10) is compared with a predetermined threshold value m (Step 8).
04), if the value of qΔT is smaller than the threshold value m, the vehicle 1
00 is determined to be in a stopped state (Step 805), and q
If the value of ΔT is equal to or larger than the threshold value m, it is determined that the vehicle 100 is in the non-stop state (Step 806).

That is, if the value indicating the change in the output value of the gyro sensor 102 at the predetermined time ΔT is smaller than the value indicated by the threshold value m, it is determined that the vehicle 100 is in the stopped state.

The thresholds k and m described above are determined by the vehicle 100.
It is desirable to set it between the constant velocity motion state and the stopped state.

As described above, Step 505 shown in FIG.
Alternatively, in Step 805 shown in FIG.
When 01 determines that the vehicle 100 is in a stopped state, it performs correction processing such as the above-described bias correction, gravity leak correction, and zero speed reset correction.

[0037]

In such a conventional navigation device, the stop state of the vehicle 100 is determined from the change in the output value of the acceleration sensor 101 or the gyro sensor 102, and when the stop state is determined, the bias is applied. The correction processing such as the correction of, the correction of the leakage of gravity, and the correction of the zero reset of the speed are performed. However, when determining the stopped state of the vehicle 100 from the change in the output value of the sensor, the output value of the sensor varies depending on how the threshold value is determined. If the bias correction is not performed with little variation, the output value of the zero point will not be accurate. On the other hand, the correction of the zero reset of the speed can be performed regardless of the variation in the output value of the sensor as long as the vehicle 100 is stopped, and the error can be prevented from being accumulated. Therefore, if the zero reset of the speed is corrected in accordance with the determination of the stop state suitable for the bias correction,
There arises a problem that the effect of improving the accuracy by correcting the zero reset of the speed cannot be obtained so much.

According to the present invention, the stop state of the vehicle is determined from the change of the output value of the detecting means for detecting the operation state of the vehicle, and the correction processing is performed according to the output value level in the stop state.
It is an object of the present invention to provide a navigation device that can perform highly accurate position detection.

[0039]

To achieve this object, the present invention provides an acceleration detecting means for detecting the acceleration of a vehicle.
Based on the data output from the acceleration detecting means
And a distance calculating means for calculating the moving distance of the vehicle.
A vignetting device, comprising a plurality of acceleration detecting means.
Output value storage means for storing the output value of the
The stop condition of the vehicle based on the plurality of output values stored in the means.
Stop determination means for determining the state and stop by the stop determination means
When it is determined that the status is
Output value level determination means for determining the
The output value level judgment for the data obtained from the means
Corrector that performs correction according to the output value level determined by the means
And a step .

Thus, the stop state of the vehicle is determined from the change in the output value of the detecting means for detecting the operation state of the vehicle, and the correction processing is performed according to the output value level in the stop state, thereby providing a highly accurate position. A navigation device is obtained that is capable of performing detection.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is an acceleration detecting means for detecting an acceleration of a vehicle, and the acceleration detecting means.
Based on the data output from the speed detection means,
Navigation comprising a distance calculating means for calculating a moving distance
A plurality of output values of the acceleration detecting means.
Output value storage means for storing and storage in the output value storage means
Determine the vehicle's standstill based on multiple output values
Stop determining means and the stop determining means determine the stopped state
The output value level from the plurality of output values
Output value level determining means and the acceleration detecting means
The output data level judgment means for the data
With the configuration including the correction unit that performs the correction according to the output value level, it is possible to perform the appropriate correction processing according to the output value level in the stopped state of the vehicle.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a functional block diagram of a navigation device according to an embodiment of the present invention. The navigation device of this embodiment will be described as being mounted in a vehicle, as in the conventional example.

In FIG. 1, 11 is an acceleration detecting means for detecting the acceleration in the traveling direction of the vehicle in order to obtain the moving distance of the vehicle, and 12 is an angular velocity in the yaw operation direction of the vehicle in order to obtain the moving direction of the vehicle. Detecting angular velocity detecting means, 13 is distance calculating means for calculating the moving distance of the vehicle from the output data of the acceleration detecting means 11, 14 is azimuth calculating means for calculating the moving azimuth of the vehicle from the output data of the angular velocity detecting means 12, and 15 is It is a calculating means for obtaining the position of the vehicle based on the moving distance calculated by the distance calculating means 13 and the moving direction calculated by the direction calculating means 14.

Reference numeral 16 is an output value storage means for storing the output values of the acceleration detection means 11 and the angular velocity detection means 12, and 17 is a stop determination means for determining the stop state of the vehicle based on the data stored in the output value storage means 16. , 31 are stop determination means 1
When the stop state of the vehicle is determined in 7, the output value storage means 1
6 is an output value level determining means for determining the output value level based on the degree of variation in the output value.

Reference numeral 18 is a map storage means for storing map data, 19 is a display means for displaying image data, 20 is a map data of a predetermined area from the map storage means 18 based on the position of the vehicle output from the computing means 15. Is a control unit that causes the display unit 19 to display the position of the vehicle together with the read map data.

Reference numeral 30 indicates a bias correction, a gravity leak correction on the data obtained from the acceleration detecting means 11 and the angular velocity detecting means 12 according to the output value level judged by the output value level judging means 31. It is a correction means for correcting the zero reset of the speed. The correction process by the correction unit 30 is not limited to these. Further, in the following description, the correction process performed by the correction unit 30 has been described in the conventional example, and thus the description will be simplified.

FIG. 2 is a block diagram showing the configuration of a navigation device according to an embodiment of the present invention. Reference numeral 21 is an acceleration sensor forming the acceleration detecting means 11, 22 is a gyro sensor forming a gyro sensor, and 23 is map data. A stored CD-ROM, 24 is an LCD that displays image data, 25 is a CPU that executes various programs, 2
6 is an R storing a program executed by the CPU 24
OM, 27 is a RAM for temporarily storing data, and 28 is a communication bus for communicating data.

The operation of the navigation device configured as described above will be described below.

As shown in FIGS. 1 and 2, the calculation means 15
Calculates the position of the vehicle using (Equation 1) to (Equation 5) as shown in the conventional example. This is briefly explained.

The distance calculating means 13 is the acceleration detecting means 11
The data output from the vehicle is integrated to obtain the speed of the vehicle, and further the integral is calculated to obtain the moving distance of the vehicle. Further, the azimuth calculating means 14 obtains the moving azimuth by integrating the data output from the angular velocity detecting means 12. The calculating unit 15 calculates the position of the vehicle by performing cumulative calculation from the initial position regarding the moving distance calculated by the distance calculating unit 13 and the moving direction calculated by the direction calculating unit 14.

Next, in the present embodiment, the operation of performing the correction process when the stop state of the vehicle is determined will be described. In the present embodiment, the bias correction, the gravity leak correction, and the zero speed reset are performed. The correction process will be described as an example.

FIG. 3 is an operation flow chart of the stop judging means in one embodiment of the present invention.
The operation performed by the stop determination means 17 and the output value level determination means 31 based on the output value of 1 is shown.

As shown in FIG. 3, the output value storage means 16
Stores the output value of the acceleration detecting means 11 every predetermined time ΔT (Step 31). When the predetermined time ΔT is reached, the stop determination means 17 causes the conventional example Ste in FIG.
Similar to p502, the average value P of the plurality of output values p _n stored in the output value storage means 16 is obtained (Step 32).
Further, like Step 503 in FIG. 9 of the conventional example,
The difference between the plurality of output values p _n stored in the output value storage means 16 and the average value P obtained in Step 32 is obtained and squared, and the sum pΔT (difference sum of differences) of the individually obtained values is obtained. Ask (Step 33). The sum of squared differences pΔT is
The variation of the plurality of output values p _n is shown. Up to this point, it is the same as the conventional example.

The present embodiment differs from the conventional example in that
The value of the sum of squared differences pΔT obtained in 33 is compared with a plurality of different thresholds k1, k2, and k3, respectively.

First, the stop determination means 17 determines the sum of squared differences p.
ΔT is compared with the threshold value k1 (Step 34), and if the sum of squared differences pΔT is equal to or greater than the threshold value k1, the process proceeds to YES, it is determined that the vehicle is in the non-stop state, and the correction process by the correction unit 30 is not performed. (Step 35). On the other hand, Ste
If the sum of squared differences pΔT is smaller than the threshold value k1 in p34, the process proceeds to NO, it is determined that the vehicle is in a stopped state, and the output value level determination means 31 determines the output value level (Step 36). That is, the threshold value k1 is the vehicle 10
0 is a threshold value for determining whether or not it is in a stopped state.

When the stop state of the vehicle is determined in Step 36, the output value level determination means 31 compares the sum of squared differences pΔT with the threshold value k2 (Step 37) and sums the squared differences pΔ.
When it is determined that T is equal to or greater than the threshold value k2, the process proceeds to YES, and the correction unit 30 performs only the correction process of zero reset of the speed (Step 38).

On the other hand, in Step 37, the variance value pΔ
When it is determined that T is smaller than the threshold value k2, the process proceeds to NO, and the output value level determination means 31 compares the sum of squared differences pΔT with the threshold value k3 (Step 39). Step39
When it is determined that the variance value pΔT is greater than or equal to the threshold value k3,
The process proceeds to YES, and the correction unit 30 performs the process of correcting the gravity leak and the process of resetting the speed to zero (Step 40).

On the other hand, when it is determined in Step 39 that the sum of squared differences pΔT is smaller than the threshold value k3, the process proceeds to NO and the correcting means 30 performs the process of correcting the bias.
The process of correcting the leakage of gravity and the correction of zero reset of the speed are performed (Step 41).

In this way, first, the difference sum of squares pΔT and the threshold value k1 are compared to determine the stop state of the vehicle. Further, even when the same vehicle is in the stop state, the acceleration is accelerated by a plurality of different threshold values k2 and k3. By dividing the level according to the variation of the output value of the detection means 11 and performing the correction processing according to the level, the positional accuracy of the vehicle obtained by the calculation means 15 is improved.

In the above description, the output value of the acceleration detecting means 11 is used for the description, but it will be shown below that the output value of the angular velocity detecting means 12 can be similarly used. The description of the overlapping portions is simplified.

FIG. 4 is an operation flowchart of the navigation device according to the embodiment of the present invention, and shows the operations performed by the stop determination means 17 and the output value level determination means 31 based on the output value of the angular velocity detection means 11.

As shown in FIG. 4, the output value storage means 16
Stores the output value of the angular velocity detecting means 12 every predetermined time ΔT (Step 51). When the predetermined time ΔT is reached, the stop determination means 17 causes St in FIG.
Similar to ep802, the average value Q of the plurality of output values q _n stored in the output value storage means 16 is obtained (Step 52).
Further, as in Step 803 in FIG. 10 of the conventional example, a plurality of output values q stored in the output value storage means 16 are stored.
The difference between _n and the average value Q obtained in Step 52 is obtained and squared, and the sum qΔT (sum of differences squared) of the individually obtained values is obtained (Step 53). Up to this point, it is the same as the conventional example.

The present embodiment differs from the conventional example in that Step
The value of the variance pΔT obtained in 53 is set to a plurality of different threshold values m1,
The point is to compare with m2 and m3, respectively.

First, the stop determination means 17 determines the variance value qΔT.
And the threshold m1 are compared (Step 54), and the sum of squared differences q
If ΔT is equal to or greater than the threshold value m1, the process proceeds to YES, it is determined that the vehicle is in the non-stop state, and the correction process by the correction unit 30 is not performed (Step 55). On the other hand, Step54
In, if the variance value qΔT is smaller than the threshold value m1,
If NO, the vehicle is determined to be in a stopped state, and the output value level determination means 31 determines the output value level (Step).
p56).

When the stop state of the vehicle is determined in Step 56, the output value level determination means 31 compares the sum of squared differences qΔT with the threshold m2 (Step 57), and the sum of squared differences qΔ.
When it is determined that T is equal to or greater than the threshold value m2, the process proceeds to YES, and the correction unit 30 performs the correction process of zero reset of the speed (Step 58).

On the other hand, in Step 37, when it is determined that the sum of squared differences qΔT is smaller than the threshold value m2, the process proceeds to NO, and the output value level determination means 31 determines the sum of squared differences qΔT.
And the threshold value m3 are compared (Step 59). Step5
When it is determined in 9 that the sum of squared differences qΔT is equal to or larger than the threshold value m3, the process proceeds to YES, and the correction unit 30 performs a process of correcting the gravity leak and a process of correcting the zero reset of the speed (Step 60). On the other hand, when it is determined in Step 59 that the sum of squared differences qΔT is smaller than the threshold value m3,
When the process proceeds to NO, the correction unit 30 performs the bias correction process, the gravity leak correction process, and the zero speed reset correction process (Step 41).

As described above, in the present embodiment, the stop state of the vehicle is determined from the change in the output value of the acceleration detecting means 11 or the angular velocity detecting means 12, and when various correction processes are performed, the output value in the stop state is determined. By setting the output value level according to the variation and performing the correction processing according to the output value level, the appropriate correction processing can be performed in a timely manner, and the accuracy of vehicle position detection is improved.

[0069]

As described above, according to the present invention, the detection means for detecting the operating state of the vehicle, the output value storage means for storing a plurality of output values output from the detection means, and the output value storage means are provided. Stop determination means for determining a stop state of the vehicle based on a plurality of stored output values, and output value level determination means for determining an output value level from the plurality of output values when the stop determination means determines a stop state And a correction means for correcting the data obtained from the detection means according to the output value level determined by the output value level determination means. Since the appropriate correction process can be performed, the accuracy of detecting the position of the vehicle is improved.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a navigation device according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a navigation device according to an embodiment of the present invention.

FIG. 3 is an operation flowchart of the navigation device according to the embodiment of the present invention.

FIG. 4 is an operation flowchart of the navigation device according to the embodiment of the present invention.

FIG. 5 is a configuration block diagram of a conventional navigation device.

FIG. 6 is a conceptual diagram of position calculation of a conventional navigation device.

FIG. 7 is a diagram showing output characteristics of an acceleration sensor and a gyro sensor.

FIG. 8 is a diagram showing a vehicle traveling on a slope.

FIG. 9 is an operation flowchart of stop determination in a conventional navigation device.

FIG. 10 is an operation flowchart of stop determination in a conventional navigation device.

[Explanation of symbols]

11 Acceleration detection means 12 Angular velocity detecting means 13 Distance calculation means 14 Direction calculation means 15 Calculation means 16 Output value storage means 17 Stop determination means 30 Correction means 31 Output value level determination means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-157572 (JP, A) JP-A-3-287009 (JP, A) JP-A-3-285110 (JP, A) JP-A-8- 43113 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01C 21/00-21/36 G01C 19/00 G01P 15/00 G01C 22/00-22/02 G01C 23/00 -25/00

Claims (3)

(57) [Claims] 1. A navigation device comprising: an acceleration detecting means for detecting an acceleration of a vehicle; and a distance calculating means for calculating a moving distance of the vehicle based on data output from the acceleration detecting means. Output value storage means for storing a plurality of output values of the means, stop determination means for determining a stop state of the vehicle based on the plurality of output values stored in the output value storage means, and a stop state by the stop determination means When it is determined that the output value level is determined from the plurality of output values, the output value level determining means determines the output value level, and the data obtained from the acceleration detecting means is determined according to the output value level determined by the output value level determining means. A navigation device comprising: a correction unit that performs correction. 2. An acceleration detecting means for detecting an acceleration of the vehicle, a distance calculating means for calculating a moving distance of the vehicle based on data output from the acceleration detecting means, and an angular velocity detecting means for detecting an angular velocity of the vehicle. A azimuth calculating means for calculating the moving azimuth of the vehicle based on the data output from the angular velocity detecting means, and a vehicle based on the moving distance calculated by the distance calculating means and the moving azimuth calculated by the azimuth calculating means. Of the output value storage means for storing a plurality of output values of the acceleration detection means or the angular velocity detection means, and a plurality of outputs stored in the output value storage means. Stop determination means for determining the stop state of the vehicle based on the value, and when the stop determination means determines that the vehicle is in the stop state, the output value level is determined from the plurality of output values. Output value level determining means and correction means for correcting the data obtained from the both detecting means in accordance with the output value level determined by the output value level determining means. Navigation device. 3. The output value level determination means, when the stop determination means determines the stop state of the vehicle, obtains a value indicating a degree of variation among a plurality of output values stored in the output value storage means, The output value level is determined by comparing a value indicating the variation of the plurality of output values with a plurality of different threshold values .
Among navigation apparatus according to any one.