JPS5960271A - Optical radar apparatus - Google Patents

Abstract

PURPOSE:To achieve an accurate measurement of distance to an object to be measured by obtaining the true propagation delay time of a transmission modulated light from a time lag between transmission and reception pulses as determined when a part of a transmission pulse modulated light and a reception pulse modulated light are received with a common element. CONSTITUTION:A drive circuit 21 supplies a pulse signal A to a light emitting element 1 and a trigger signal J synchronizing the signal A to a time lag arithmetic circuit 22. In the arithmetic circuit 22, a gate 13 is opened while the Q output of an FF23 is at H, and the output H of a high frequency oscillator 12 is fed to a high speed counter 14, the output of which gives a distance data N. The data N corresponds to the time difference between the transmission pulse signal Mt and a reception pulse signal Mr composing a pulse train M outputted from an amplifier 9. Then, a transmission pulse modulated light Lt and the reception pulse modulated light Lr are received with a light receiving element 5 and amplified with the amplifier 9. Thus, the delayed times equal to each other when the signals Mt and Mr are outputted and the time difference between the signals coincides with the true propagation delay time of the modulated light Lt.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention uses light to move W1! to a target object! Kaida goes to Hikari 1 Nork device FY, which seeks separation.

For example, 1J shown in Fig. 1,
There are 6 eels.

In the same figure, the optical fiber 1 is composed of, for example, a laser tie auto tongue, and is pulse-modulated with a laser beam (hereinafter referred to as ")" which is pulse-modulated by a drive pulse signal A supplied from a drive circuit 2. It is called pulse modulated light! II) 1-t
is generated, and this transmitted pulse modulated light 1 is turned into a beam with a spread angle θt by the condenser lens 3.

It is illuminated by q.1.

Above) 'A Buddha pulse modulated light 1-t, find the distance 1 and J
The reflected light (hereinafter referred to as received pulse modulated light) is reflected by the target object (hereinafter referred to as the object to be measured).
r is condensed by a condensing lens 4 and is incident on a light receiving probe 5).

On the other hand, the transmitted pulse modulated light 1 generated from the light emitting cord 1
A part of -[ is introduced via the optical fiber 6 into the light receiving cable 7 in a detour manner.

This is because the generation timing of the transmission pulse modulated light LL generated from the light emitting element 1 is delayed by a minute time with respect to the generation timing of the drive pulse signal Δ outputted from the drive circuit 2. It is used to obtain the exact timing of the occurrence of

The light receiving signal 13 output from the light receiving element 7 and the light receiving signal C output from the light receiving element 5 are respectively amplified by amplifiers ε3 and 9, and then sent to the time difference calculation circuit 10.
supplied to

This 1171 differential output 1') circuit 10 is connected to the received pulse modulated light that is emitted from the sent 13 pulse modulated light l-1 toward the object to be measured, is reflected by the object to be measured, and is returned back. 1-1
There is a device C that calculates the propagation delay time until the light is received and outputs it as distance data to the object to be measured. output (hereinafter referred to as TJ))
, and the output of the amplifier 9 (hereinafter referred to as the received pulse signal) [which time difference is determined and is defined as the transmission 11Ii delay time.

The above-mentioned time difference calculation circuit 10 is set by, for example, JJ shown in FIG. <S flip-flop 11 and high frequency pulse 911
It is composed of a frequency oscillator 12 which outputs a frequency oscillator 12, AND gates 1 to 13, and a high speed counter 14 which counts the number of pulses of the high frequency pulse train supplied through the AND gates 1 to 13.

Then, by the output 10 of the S flip-flop 11, it is determined that the time difference τ between the transmitted pulse 1 and the received pulse F is determined by the output 10 of the S flip-flop 11.
Open-C1 high frequency pulse train 11 is high speed counter 14
supplied to

Therefore, the C1 high-speed counter 14 outputs 1-81 numerical data corresponding to the time difference τ, which becomes the external cutting data.

The distance data [is supplied to a disturbance circuit such as a microphone [ ] computer, and the distance βII to the object to be measured is
R(R=(high speed)×(time difference τ>/2) will be calculated.

However, in the optical laser device as described in 1., the transmission pulse modulated light 1 introduced via the optical fiber 6 is
Since the light receiving and amplifying system of -1 and the light receiving and amplifying system of the repulsive pulse modulated light 1-r are provided separately, the light receiving element 5
．． 7 and the delay time of the amplifier 8.9.This is a matter of fact.The distance data 1 shown above is modeled as 1;

'J%;! As shown in FIG. 3, the light receiving element 5,
If the lengths of 7 and 11 are equal, then the reception of the transmitted pulse modulated light +1 output from the light receiving element 7 (i, i number B,
Light reception: l' = Received pulse modulated light 1 outputted from T-5 - Receipt of r light 1 -', CWhich time difference τ0 is the true propagation delay time tJF There are 4 tJF, but the delay time of amplifier 8 Since the IY extension time τ2 (of the amplifier 9) and τ1 are different, the time difference calculation circuit 10/＼supplied transmission pulse signal and reception pulse transmission F', [which time difference τ is 1. [Propagation of the arrangement 1 [Does not match the time, the above time difference calculation circuit 10]
An error will occur in the distance data 1: output from the distance data 1:.

40 units) Eh, the delay time of -1 light receiving elements 5 and 7 is ``
If you follow the blue line, the reliability of the above distance data ``4!l'' will be questioned.

This was done in view of the circumstances described in this enlightenment.''
A common light-receiving element receives both a part of the transmitted pulse-modulated light that is detoured through an optical transmission means such as a closed optical fiber, and the received pulse-modulated light that is inversely 13=1 at the object to be measured. By determining the time difference between the transmitted pulse and the received pulse in the pulse train output from the amplifier that amplifies the output of the common light receiving element, the true propagation delay 11.1 of the transmitted pulse modulated light is determined, An object of the present invention is to provide an optical radar device that can obtain accurate distance data.

Embodiments of the present invention will now be described in detail with reference to FIG. 4 and the following drawings.

FIG. 4 is a tJ-schematic configuration diagram showing an embodiment of the optical radar device according to the present invention. Incidentally, the same components and the same outputs as those of the conventional example shown in FIGS. 1 and 2 are denoted by the same reference numerals, and their explanations will be omitted.

The optical radar device shown in the same figure has the configuration of the conventional optical radar device shown in FIG. The transmitting pulse modulated light 1t, which is introduced in a detour from the light receiver 201) to the light receiver 201), is configured to be incident on the light receiving element 55.

Therefore, the light-receiving element 5 has the transmission pulse variation described in 17.
J light 1-t and receiver (1; pulse modulated light 1-1) both are received.

The drive circuit 21 also sends a drive pulse signal 8△ to the light-emitting cable 1.
In addition to supplying 11 (η), a trigger (Δ″r?
We supply iJ.

The X rhythmic circuit 22 between +t'1 and t'1 has, for example, the tJJ and +11 configurations shown in FIG. 7U Tsubu 11
Instead of fi, a pulse signal is supplied to the amplifier 9.
When the Q output is inverted to j, 1. Trigger message J
1. : J, the Q output is retouched using the T flip-flop [l knob 23'(tM).

Δ only during the period when the Q output of the knob 23 is ゛]do'
N+) gate 13 is opened, the output 11 of the high frequency oscillator 12 is supplied to the high speed counter 14, and accordingly,
The high-speed counter 14 increments the number of pulses of the supplied high-frequency pulse output 1-1 from 1 to 1, and inverts the output with the outer end data N.

In the optical rake device configured as described above, the iJ3
As shown in the figure, the repetition period T +1 from the drive circuit 21
As the drive pulse signal Δ is supplied to the light emitting element T-1, the trigger signal J output from the drive circuit 21 in synchronization with the drive pulse signal Δ is 1
-Flip 1" knob 23 is reset to 1.

The X pulse modulated light is emitted from the light emitting element 1 to the object to be measured, and along with this,
A part of the transmitted pulse modulated light LL is introduced in a detour to the light receiving cable 5 via the optical fiber 6.

Then, the received light of 1 mg Kt of the above-mentioned transmitted pulse modulated light is outputted from the light receiving cable 5, and the A signal pulse signal Mt is amplified by the amplifier.
The Q output of flip-flop 23 changes to LL I II.

Accordingly, AND gates 1-13 are opened, output 1 of the high-frequency shaker 12 is supplied to the high-speed counter 14, and the high-speed counter 14 starts counting.

Note that the F light receiving element 5 has an operation delay time τ3 of the amplifier 5.
) is l) J 17 it-? Reverse the extension time τ2 to the right.

Next, 1-i'A signal pulse modulated light t-tlfi?
! ! ! During distance measurement, the received pulse modulated light 1 is
The received light signal 1 (r is amplified by the amplifier 9 and is -(, the received light pulse signal M
r is supplied to the T-flip-]]1-1 tube 2, and along with this, 1゛Noritsuno゛/II y i 23 (1
) Q output is inverted and changed to -U “0”, and ΔN I
) The counter 1-13 closes and the counter of the high-speed J counter 14 stops operating.

1- As described above, the distance data N output from the high-speed counter 14 is based on the I of the transmission pulse signal ML and the reception pulse signal Mr, which constitute the pulse train M output from the amplifier 9.
■It corresponds to the difference τ between 1.

Then C1 transmitting pulse modulated light Lt and receiving pulse modulated light 1-
r is received by the light-receiving cable 5 through the bar, and this light-receiving signal Kl, K
Since r is amplified by the same amplifier 9, the delay time when the transmission pulse (g signal M[ and the reception pulse signal Mr.
As a result, the 11\ difference τ matches the true propagation delay time T of the transmitted pulse modulated light LL.

In addition, when there is no object to be measured in the direction in which the transmitted pulse modulated light L[ is irradiated, the received pulse modulated light 1-r
If the Q output of the T flip-flop 23 is not received, the Q output of the T flip-flop 23 will continue to be 1'', but it is necessary to
No. J is supplied and −U, (, l output is relen(~ and AJ
With this configuration, the Q output of the flip-flop 23 is always changed to "1" when the transmission pulse signal Mt arrives, and a correct distance measuring operation can be performed.

In the first embodiment, the optical fiber 6 is used as a means for detouring a part of the Iζ transmission pulse modulated light 1-t generated from the Jfi optical element 1 to the light receiving cable 5.
In addition, for example, if a laser diode or other device with a large spread angle of the generated radar light is used as the light receiving element 5, as shown in FIG. A gap 20C is formed at the boundary with the side, and the structure is configured such that one beam (1, a part of the pulse modulated light 1-L enters the receiver 201+) J- times η is input through this gap 20C. Furthermore, it is possible to achieve a lower weight 1-stroke.

In the time difference arithmetic circuit 10 of the first embodiment, the high-speed counter 14 calculates 61 numbers corresponding to the time difference τ between the transmitted pulse signal M1 and the received pulse signal Mr. However, the structure is not limited to this, and for example, as shown in FIG.
”Q output of the knob 23) J@integrate by the integrating circuit 24,
The peak value of the output R of the integrating circuit 24 is detected by the peak value detecting circuit 25. As shown in the diagram (1), the electric current Lt and the voltage V at the level corresponding to the time difference τ are obtained 17. Things and 1. ru.

Therefore, the above-mentioned optical radar device can be applied to automatically measure the external pJl of the vehicle in front by mounting it on the front of the car body, for example.
Wear.

Below 1. As explained in detail, in the optical radar device of the present invention, it is necessary to determine the true propagation [delay time] of the transmitted pulse modulated light, and to obtain the accurate distance at the target object J: -1. It is possible to measure C1 and I.

In addition, since the number of parts can be reduced compared to conventional ones, it promotes reduction of manufacturing costs and miniaturization of equipment, and also makes it possible to easily convert the equipment into automated systems, etc. Understand the benefits.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a conventional optical radar device, Fig. 2 is a block diagram showing a specific 4T configuration of the time difference calculation circuit C3 in Fig. 1, and Fig. 33 is a block diagram of the main parts of the device. Figure 4 shows a schematic 114 diagram of an embodiment of the optical diode device according to the present invention, and Figure 5 shows an example of a specific configuration of a time difference calculation circuit in the same device. 6 is a block diagram showing the main outputs of the device, FIG. 7 is a 4-sectional view showing the main parts of another embodiment of the present invention, and FIG. Figure 9 shows other specific configuration examples of the time difference calculation circuit, and Figure 9 shows its main outputs. 1... Light emitting element 5... Light receiving element O. ...) to Tsuno Iba? ]...Amplifier 22-111'J'X-:>fr n times '82
0 c...Gap 11...Transmission pulse modulated light 1-1'...Reception pulse modulation light Ml...Transmission pulse signal Mr...Reception pulse signal τ...Difference between 1.11'Iji;i'rapplicant's production automatic reporting stock company ne 1 Figure 6 Noshi/Sor Figure 7 Figure 9

Claims (1)

[Claims] (1) Light transmission): Transmission pulse variable KIM sent from t!
Propagation of the light and the received pulse modulated light that is reflected by the distance to be measured. A common light-receiving element r that receives both a part of the pulse-modulated light introduced in a detour from the target object and a part of the received pulse-modulated light reflected by the object to be measured. an amplifier for amplifying the output of the amplifier; and a time difference calculation circuit for determining the time difference between the transmitted pulse and the received pulse that constitute the output pulse train of the amplifier;
An optical radar device that is characterized by the fact that it can be used daily.