JP2767512B2 - Distance measuring device between vehicle and control object - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver capable of transmitting a pulse signal to a control object at regular intervals and receiving a reflected signal from the control object, and a time between the transmission and reception. And a calculation unit for calculating a distance to the object based on the distance measurement device.

[0002]

2. Description of the Related Art Conventionally, a vehicle collision prevention device which measures the distance between a host vehicle and a control object and activates a brake device in accordance with the distance between the host vehicle and the control object has been disclosed in, for example, Japanese Patent Publication No. Sho 61-61. No. -4700.

[0003]

However, in the prior art, the distance is calculated based on the time between one transmission of the pulse signal and the reception of the first reflected signal accompanying the transmission. Therefore, there are the following problems.

[0004] As shown in FIG. 6 (a), when noise due to reflection from a road surface and a floating object is detected in a state where another vehicle as a control object is running ahead of the own vehicle,
As shown in FIG. 6 (b '), the noise A and B cannot be detected separately from the preceding vehicle, so that the preceding vehicle cannot be distinguished from the noise A and B, and the behavior of the preceding vehicle can be accurately grasped. It cannot be performed, causing malfunction.

As shown in FIG. 7A, when another vehicle interrupts between the preceding vehicle and the own vehicle,
In (b '), while the distance to the preceding vehicle is measured in section C, the distance to the interrupted vehicle is measured in section D from the middle, and the distance between the leading vehicle and the preceding vehicle is measured. The behavior of each interrupted car cannot be accurately determined, causing malfunction.

[0008] As shown in FIG. 8 (a), further ahead of the motorcycle traveling in front of the host vehicle, there is a four-wheeled vehicle which is more important in view of the risk of collision and is in a running state. When the motorcycle passes through the front four-wheeled vehicle with the deceleration of the two-wheeled vehicle, as shown in FIG. There is a possibility that the presence of the vehicle cannot be grasped and the determination of the collision with the front four-wheeled vehicle is delayed.

[0007]; as shown in FIG. 9 (a), the traveling on a curved road with the roadside corner reflectors E ₁ to E _8, as shown in FIG. 9 (b '), their corner reflectors E ₁ It will be detected one after another the ~E _8, does not grasp the behavior of the preceding vehicle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a vehicle and a distance measuring device between contrast objects which can calculate the distance to a plurality of contrast objects with a simple configuration. I do.

[0009]

According to the first aspect of the present invention, a pulse signal is transmitted to a control object at regular intervals while the vehicle is running, and is reflected from the control object. A transmission / reception unit capable of receiving a signal, and a calculation unit that calculates a distance to a target based on the time between the transmission and reception, is mounted on a vehicle, and includes a plurality of targets. A distance measuring device between the vehicle and the reference object, wherein the distance between the vehicle and the reference object can be calculated in accordance with the transmission of the pulse signal at regular intervals. In order to independently measure a fixed sampling time shorter than the transmission cycle of the pulse signal from the unit, the timing of the sampling time is started at the same time as the transmission of the pulse signal at every fixed cycle, and at the end of the timing. Output reset signal First for that sampling time setting
A timer, in order to measure the time from transmission of the pulse signal of the transmission / reception unit to reception of the reflection signal within the sampling time, to start timing at the same time as the transmission of the pulse signal at regular intervals, and A second timer for measuring the reception time reset by the input of the reset signal;
A distance calculation that reads the time measured by the second timer every time a reflected signal is received by the sending / receiving unit during the time counting of the timer, and calculates the distance to each control object based on the read time measured. Means.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the arithmetic unit includes a transmitting / receiving unit that receives a reflected signal while the second timer measures time. And a label storage unit that stores the labels in correspondence with the calculated distances of the distance calculation unit, and that is reset by a reset signal from the first timer.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 9 show an embodiment of the present invention. FIG. 1 is a diagram showing an overall configuration, FIG. 2 is a diagram showing operation timings of respective components of a distance measuring device, FIGS. FIGS. 4 and 5 are flowcharts showing the determination procedure of the determination device, FIG. 6 is a characteristic diagram at the time of noise detection, FIG. 7 is a characteristic diagram at the time of vehicle interruption, FIG. 8 is a characteristic diagram at the time of passing through the motorcycle, and FIG.
Is a characteristic diagram when traveling on a curved road.

First, in FIG. 1, a distance between a passenger vehicle and a control object 17 located in front of the passenger vehicle is measured by a distance measuring device 1 mounted on the passenger vehicle, and a determination device 2 including a computer determines a distance. The relative speed between the passenger vehicle and the control object 17 is calculated based on the distance obtained by the distance measuring device 1, and a collision judgment is made based on the relative speed. 4 and the operation of the brake 5 are controlled.

The distance measuring device 1 includes a driver circuit 6 for outputting a high-level driving signal for a predetermined period of time at a predetermined period T _C (see FIG. 2), and responding to a fall of the driving signal input from the driver circuit 6. A transmission / reception unit 7 capable of transmitting a constant pulse signal to the reference object 17 and receiving a reflected signal from the reference object 17, and a distance to the reference object 17 based on the time between the transmission and reception. Calculation unit 8 for calculating
A delay circuit 9 that outputs a trigger signal with a delay of a predetermined time T _D from the time of reception when the transmission / reception unit 7 receives a reflected signal, and an input of a trigger signal from the delay circuit 9. And a memory 10 for fetching and storing the operation result in the operation unit 8 in response.

The transmitting / receiving section 7 has a predetermined spread angle α (FIG. 2).
The laser diode 11 transmits a single pulse signal having the reference signal to the control object 17 in response to the fall of the drive signal input from the driver circuit 6, and goes high in response to the input of the reflection signal from the control object 17. And a photodiode 12 for outputting a level reception signal.

The arithmetic unit 8 is adapted to transmit a pulse signal from the transmission / reception unit 7, that is, a sampling time set shorter than the transmission period T _{C of the} pulse signal in accordance with the fall of the drive signal output from the driver circuit 6. A first timer 13 that starts measuring the time of T _S (see FIG. 2) and outputs a reset signal when the measurement of the sampling time T _S ends.
And a second signal which is reset by the input of a reset signal from the first timer 13 and starts the time measurement in response to the transmission of the pulse signal from the transmission / reception unit 7, that is, the fall of the drive signal output from the driver circuit 6. A timer 14,
Each time a reflected signal is received by the transmission / reception section 7 during the counting of the second timer 14, the time counted by the second timer 14 is read, and the time to the control 17 is determined based on the read time and the propagation speed of the pulse signal. Distance calculating means 15 for calculating a distance,
Each time a reflected signal is received by the transmission / reception unit 7 while the second timer 14 is counting, each label is assigned a different label and stored in correspondence with the distance calculated by the distance calculation means 15. And a label storage unit 16 reset by a reset signal from the control unit 13.

Each time a trigger signal is input from the delay circuit 9, the memory 10 reciprocates the distance to the object 17 calculated by the distance calculating means 15 and the label stored in the label storing means 16. The content stored in the memory 10 is given to the determination device 2.

The operation timing of each component in the distance measuring apparatus 1 is as shown in FIG. 2, for example.

Here, the vehicle V equipped with the distance measuring device 1
A first contrast object 17 ₁ (for example, a motorcycle) is traveling in front of the first contrast object 17 ₁ , and a second contrast object is further ahead of the first contrast object 17 ₁ .
It is assumed that a contrast object 17 ₂ (for example, a four-wheeled vehicle) is traveling, and the contrast objects 17 ₁ and 17 ₂ are within the spread angle α of the pulse signal from the transmission / reception unit 7. Thus,
As shown in FIG. 2A, the constant period T
_In response to the drive signal being output at _C , a pulse signal is output from the laser diode 11 of the transmission / reception unit 7 at regular intervals T _{C as} shown in FIG.
The timekeeping operation of the second timer 14 is started as shown in FIG. Next, when the reflected signal from the first control object 17 ₁ is input to the photodiode 12 of the transmission / reception unit 7 as shown in FIG. 2E, the time count T ₁ of the second timer 14 at that time is shown in FIG. 2
As shown in (f), the label is read by the distance calculating means 15, and the label of the first control object 17 ₁ is labeled as "L1" in the label storage means 16 as shown in FIG. “L1” is stored.

When the reflected signal from the _second object 172 is input to the photodiode 12 as shown in FIG. 2E, the distance calculating means 15 causes the second timer 1
4 of the counting time T ₂ is read in as shown in FIG. 2 (f), the
In the label storage means 16, as shown in FIG.
The label "L2" is stored together with the counterpart 17 _second label is labeled as "L2".

In addition, when the signal is delayed by the delay time T _D from the reception of the reflected signal from the first control object 17 _{1 and} from the reception of the reflected signal from the second control object 17 _2, respectively, the delay circuit 9 shown in FIG. ), The distance and the label L1 calculated based on the clock time T ₁ and the clock time T are stored in the memory 10 in response to the output of the trigger signal.
_The distance calculated based on ₂ and the label L2 are stored correspondingly. Thus, the distance measuring device 1
Then, the distances between the vehicle V and the first and second control objects 17 ₁ and 17 ₂ are calculated based on the clock times T ₁ and T ₂ , and the calculated distances are calculated based on the control objects 17 ₁ and 17 2. _Two
Each label is stored with a label “L ₁ ” or “L ₂ ”.

Transmission of pulse signal from laser diode 11
Fixed sampling time T from the time of transmission _SHas passed
Then, as shown in FIG.
The reset signal is output.
2 timer 14 and label storage means 16 are as shown in FIG.
And as shown in FIG.
Therefore, such a series of measurement operations is performed
T_CIt is repeated every time.

Referring again to FIG. 1, the values detected by the steering angle detector 18, the brake operation detector 19, the accelerator operation amount detector 20, and the vehicle speed detector 21 are input to the determination device 2 via the vehicle information input unit 22. Is done. The operation of the horn 3 and the alarm display 4 is controlled by the alarm control circuit 23, and the operation of the brake 5 is controlled by the brake control circuit 24. The judgment device 2 is obtained by the distance measuring device 1. Based on the object data and the vehicle information input from the vehicle information input unit 22, a collision judgment with the object 17 is made in accordance with the procedure shown in FIGS. 3, 4 and 5, and a control signal based on the judgment result is warned. This is given to the control circuit 23 and the brake control circuit 24.

In FIG. 3, in a first step S1, each object data is fetched from the memory 10 of the distance measuring device 1, and in a second step S2, the vehicle information input unit 22 is read.
The vehicle information such as the steering angle, the presence / absence of a brake operation, the accelerator operation amount, and the vehicle speed is fetched.

In the third step S3, it is determined whether or not the control data predicted in the previous determination processing and the control data obtained this time coincide with each other within a predetermined range. If there is no reference data, the control data in which there is no corresponding predicted data is stored as new data in a fourth step S4, and the next fifth step S5
Then, the stored data is set as it is as the next prediction data, and the process proceeds to the eighth step S8.

If it is determined in the third step S3 that there is corresponding prediction data, in a sixth step S6 the relative speed between the control object and the host vehicle is determined from the previous value and the current value of the control object data. calculate. That is, the sixth step S6
Then, the relative speed can be obtained by dividing the distance change amount obtained by comparing the previous value and the current value by the transmission period T _C of the pulse signal.

In the next seventh step S7, the next prediction data is calculated based on the relative speed obtained in the sixth step S6, and the process proceeds to an eighth step S8. This eighth step S
At 8, it is determined whether or not the processing of the third to seventh steps S3 to S7 has been completed for all the control data acquired in the first step S1, and if there is any remaining control data, The process returns to the third step S3.

Such third to eighth steps S3 to S8
, The sampling time T _SSending and receiving unit 7
One or more counters received by the photodiode 12
The reference data calculated by attaching a label to each
Forecast data based on past control data and
If the same control exists by comparison with the control data
Or not, and the control
The relative speed can be obtained for each label from the distance change.
You.

Subsequent to the eighth step S8, the process proceeds to a ninth step S9 shown in FIG. 4. In the ninth step S9, it is determined whether or not there is other prediction data. That is, in the third step S3, it is determined in the ninth step S9 whether or not there is prediction data other than the prediction data used for comparison with the control data obtained this time.
Proceed to step S10. In this tenth step S10, the number of times predicted without corresponding control data is N
It is determined whether it is less than three times, for example. If it is less than three times, the process proceeds to an eleventh step S11, and the prediction data after the next fixed period T _C is replaced with the past reference data or prediction data. It is calculated based on: That is, in the eleventh step S11, the change amount is added to the present prediction data based on the change amount of the past (for example, the previous time and the present time) reference data or the prediction data, so that the change amount after the next predetermined period T _{C is} reached. Prediction data will be calculated.
If the number of predictions is N or more, the prediction data is deleted in the twelfth step S12.

The ninth to twelfth steps S9 to S
By the processing of 12, new prediction data is calculated for all the prediction data that does not correspond to the control data,
Or the process of whether it will be deleted will be performed,
When processing of all remaining prediction data is performed,
From step S9, the process proceeds to a thirteenth step S13 shown in FIG.

In a thirteenth step S13, a collision determination is made based on each object data and the vehicle information. That is, based on the distance and relative speed between each control object, the steering angle of the own vehicle, the presence or absence of the brake operation, the accelerator operation amount, and the vehicle speed, the determination as to the possibility of the own vehicle colliding with the control object is performed. You.

In the next fourteenth step S14, the result of the collision judgment in the thirteenth step S13 is classified into four levels from level 0 to level 3. That is, when the possibility of collision is low, the vehicle is classified as level 0. When there is a possibility of collision and the driver should be alerted, the vehicle is classified as level 1. When the possibility of collision is high and an avoidance operation is necessary, the vehicle is leveled. The vehicle is classified as level 2 when the possibility of collision is extremely high and braking should be performed.

After such a classification process, it is determined in a fifteenth step S15 whether or not the level is 0.
If it is not, it is determined whether or not it is level 1 in a 16th step S16. If it is not level 1, it is determined whether or not it is level 2 in a 17th step S17. If it is not level 2, it is level 3. In step S18, a brake control signal is output. When the level is level 1, a primary alarm signal is output in step S19, and when the level is level 2, a secondary alarm signal is output in step S20.

The output of the brake control signal causes the brake control circuit 24 to activate the brake 5, the output of the primary alarm signal causes the alarm control circuit 23 to activate the alarm display 4, and the output of the secondary alarm signal. Alarm control circuit 2
3 activates the alarm 3 and the alarm indicator 4 simultaneously.

Next, the operation of this embodiment will be described. In the arithmetic unit 8 of the distance measuring device 1, the first timer 13 sets the fixed sampling time T _S in response to the transmission of the pulse signal from the transmission / reception unit 7. At the same time as the time measurement is started, the second timer 14 starts the time measurement. When the transmission / reception unit 7 receives a reflected signal during the counting of the second timer 14, the distance calculating means 15 reads the counted time of the second timer 14 and reads the counted time every time the reflected signal is received. The label storage means 16 assigns a different label each time the reflected signal is received, and stores each label in correspondence with the time measured by the distance calculation means 15 based on the distance. Moreover, the second timer 14 and the label storage means 16
Is the first timer 13 associated with the elapse of the sampling time T _S.
Reset by the reset signal from Therefore, every time a reflected signal is received by the transmission / reception unit 7 within a certain sampling time T _S , the distance to the object is calculated based on the elapsed time from the time of transmission of the pulse signal, and an individual label is attached. Thus, the calculation can be performed while individually identifying the distances to the plurality of objects.

In addition, the control data predicted based on the past control data and the newly obtained control data are compared to determine whether or not the same control exists for each label. The distance change amount is obtained for each label by comparing the previous data and the current data with respect to the control object data determined to be the same, and the distance change amount is determined by the transmission period T of the pulse signal.
_Since the relative speed is obtained by dividing by _C , there are the following advantages as compared with the conventional one in which only a single reference data can be obtained by one pulse signal transmission.

As shown in FIG. 6 (a), when another vehicle, which is a control object, is traveling in front of the own vehicle and noise due to reflection from a road surface and a floating object is detected,
As shown in FIG. 6B, noise A and B can be detected together with the preceding vehicle, and by distinguishing the preceding vehicle in distinction from noise A and B, as shown in FIG. The relative speed with respect to the preceding vehicle can be continuously detected separately from the noise B, and the cause of the malfunction can be eliminated. Since the noise A is detected only once in FIG. 6B, the relative speed in FIG. 6C is not calculated.

On the other hand, in the conventional device, FIG.
As shown in (b ') and FIG. 6 (c'), the relative speed fluctuates even though there is no change in the relative speed with the preceding vehicle, and the behavior of the preceding vehicle can be accurately determined. Can not be grasped and may cause malfunction.

As shown in FIG. 7A, when another vehicle interrupts between the preceding vehicle and the vehicle,
As shown in FIG. 7B, the preceding vehicle and the interrupted vehicle can be detected separately, and as shown in FIG. 7C, the relative speed between the preceding vehicle and the interrupted vehicle can be individually detected. Therefore, it is possible to accurately grasp the behavior of each of the leading vehicle and the interrupting vehicle and eliminate the cause of the malfunction.

On the other hand, in the conventional one, FIG.
Since the relative speed is disturbed as shown in (b ') and FIG. 7 (c'), the behavior of each of the leading vehicle and the interrupting vehicle cannot be determined accurately, which causes a malfunction.

As shown in FIG. 8 (a), further ahead of the motorcycle running in front of the own vehicle, there is a four-wheeled vehicle that is more important in view of the danger of collision and is running. When the motorcycle passes through the front four-wheeled vehicle due to the deceleration of the two-wheeled vehicle, both the front four-wheeled vehicle and the two-wheeled vehicle are detected as shown in FIG. 8 (b). The front four-wheeled vehicle can always be checked as a control object.

On the other hand, in the prior art, FIG.
As shown in (b ′), the existence of the front four-wheeled vehicle cannot be grasped until the motorcycle is no longer present between the own vehicle and the front four-wheeled vehicle, and the collision determination with the front four-wheeled vehicle may be delayed. is there.

As shown in FIG. 9 (a), while traveling on a curved road having corner reflectors E _{1 to} E ₈ on the road side, as shown in FIG. 9 (b), each corner reflector E ₁
Can be detected by distinguishing between to E ₈ and a leading vehicle, thus as shown in FIG. 9 (c), the distinction to grasp is continuously behavior of a leading vehicle and the corner reflector E ₁ to E ₈ be able to.

On the other hand, in the prior art, FIG.
And as shown in FIG. 9 (c '), would be detected each corner reflectors E ₁ to E ₈ one after another, not only does grasp the behavior of a leading vehicle, a possibility of malfunction by the relative velocity varies There is.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various small design changes can be made without departing from the present invention described in the appended claims. Can be performed.

As described above, according to the first aspect of the present invention, transmission / reception capable of transmitting a pulse signal to the object at regular intervals and receiving a reflected signal from the object while the vehicle is running. And a calculation unit for calculating the distance to the object based on the time between the transmission and reception, mounted on the vehicle, in a distance measuring device between the vehicle and the object, the operation unit, In order to independently measure a fixed sampling time shorter than the transmission cycle of the pulse signal from the transmission / reception unit, the timing of the sampling time is started simultaneously with the transmission of the pulse signal at the predetermined cycle. A first timer for setting a sampling time that outputs a reset signal upon completion of the time measurement, and a time from the transmission of the pulse signal by the transmission / reception unit to the reception of the reflection signal within the sampling time should be measured. , For each of the constant period of the pulse signal
A second timer for measuring the reception time, which starts timing at the same time as the transmission and is reset by the input of the reset signal, and receives a second signal every time a reflected signal is received by the transmission / reception unit during the counting of the second timer. Read the timer time,
Distance calculating means for calculating the distance to each of the control objects based on the read time-measuring time. Since both calculations can be performed in response to transmission at a fixed period, the two timers (that is , the time measurement is started at the same time as the pulse signal transmission at a fixed period from the transmission / reception unit),
A first timer for setting a predetermined sampling time shorter than the period, and a second timer for measuring the reception time of a plurality of reflected signals within the sampling time).
The maximum detectable distance corresponding to the sampling time can be obtained by an extremely simple configuration including distance calculating means for reading the time measured by the second timer every time a reflected signal is received.
All of the reflected signals from objects within a shorter range
To process multiple contrasts within a certain distance from the vehicle.
All distances to the object can be accurately calculated, and the behavior of each of the plurality of contrast objects can be calculated based on the pulse signal from the transmitter / receiver.
It can be grasped accurately at a predetermined cycle corresponding to the transmission cycle ,
Therefore, it is effective to use a control object (obstacle) close to the vehicle while driving.
To take prompt measures such as alarms, braking, etc.
Possible and that Do not. Also, in particular, the two timers are clearly divided into functions for setting the sampling time (first timer) and for measuring the reception time of the reflected signal (second timer). Reasonable design can be easily performed. That is, the timing accuracy of the time count required for the first timer for setting the sampling time is not so high as compared with the second timer for measuring the reception time.
The timer can be designed to simply count a certain time, and the second timer can be designed to count the time precisely so that the reception time can be read accurately each time a reflected signal is received. It can contribute to cost reduction.

According to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, the arithmetic unit may be configured to perform the operation each time a reflected signal is received by the sending / receiving unit while the second timer is counting. And a label storage unit that is reset by a reset signal from the first timer and stores the labels in correspondence with the calculated distance of the distance calculation unit. Things can be identified.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration.

FIG. 2 is a diagram showing the operation timing of each component of the distance measuring device.

FIG. 3 is a flowchart illustrating a part of a determination procedure of a determination device.

FIG. 4 is a flowchart illustrating a part of a determination procedure of a determination device.

FIG. 5 is a flowchart illustrating the remaining part of the determination procedure of the determination device.

FIG. 6 is a characteristic diagram when noise is detected.

FIG. 7 is a characteristic diagram at the time of vehicle interruption.

FIG. 8 is a characteristic diagram when the motorcycle slips through.

FIG. 9 is a characteristic diagram when traveling on a curved road.

[Explanation of symbols]

1 distance measuring device 7 sending / receiving unit 8 calculating unit 13 first timer 14 second timer 15 ···· Distance calculation means 16 ···· Label storage means 17, 17 ₁ , 17 ₂

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryoichi Tsuchiya 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Mami Sato 1-4-1 Chuo, Wako-shi, Saitama Pref. (56) References JP-A-4-76480 (JP, A) JP-A-53-117467 (JP, A) JP-B-61-13188 (JP, B2) (58) Fields investigated Int.Cl. ⁶ , DB name) G01S 7/00-7/40 G01S 13/00-13/95 B60R 21/00

Claims (2)

(57) [Claims] An object (17, 17 ₁ , 1) during running of a vehicle.
A transmission / reception unit (7) capable of transmitting a pulse signal at a fixed period toward 7 ₂ ) and receiving a reflected signal from a reference object (17, 17 ₁ , 17 ₂ ); mounted on a vehicle and an arithmetic unit (8) for calculating the distance to the control object (17, 17 _1, 17 ₂₎ on the basis of time, counterparts (17, 17 _1, 17 ₂₎ is more The distance between the vehicle and the reference object, in which any distance to the respective reference object (17, 17 ₁ , 17 ₂ ) can be calculated in accordance with the transmission of the pulse signal at regular intervals. A measurement device, wherein the calculation unit (8) is configured to measure a single sampling time shorter than a transmission period of the pulse signal from the transmission / reception unit (7) by itself for each of the predetermined period of the pulse signal. transmitting at the same time the counting starts the counting of the sampling time With the completion the first sampling time setting for outputting a reset signal
A timer (13) for measuring the time from the transmission of the pulse signal to the reception of the reflected signal by the transmission / reception unit (7) within the sampling time, simultaneously with the transmission of the pulse signal at the predetermined period; > A second timer (14) for measuring the reception time, which is reset by the input of the reset signal at the start of the time, and a reflected signal from the sending / receiving unit (7) during the counting of the second timer (14). Distance calculating means for reading the time counted by the second timer (14) each time the signal is received, and calculating the distances to the individual objects (17, 17 ₁ , 17 ₂ ) based on the read time counted. (15) A distance measuring device between a vehicle and a control object, characterized by comprising: 2. The operation unit (8) includes a second timer (1)
Each time the reflected signal is received by the sending / receiving unit (7) during the time counting of (4), a different label is assigned to the distance calculating means (1).
The vehicle according to claim 1, further comprising: a label storage unit (16) that stores the labels in correspondence with the calculated distance of (5) and that is reset by a reset signal from a first timer (13). And a distance measuring device between the objects.