JPH02176588A - Distance measuring instrument - Google Patents

Abstract

PURPOSE:To measure a long distance without reference to the material of an object and to measure distances to plural objects at the same time by detecting the difference in arrival time between a radio wave and an ultrasonic wave which are received by a receiving device. CONSTITUTION:A transmitting device 1 send an ultrasonic wave from an ultrasonic wave transmitting circuit 5 through a transmitting microphone 4 in synchronism with a radio wave transmitting circuit 3 while the circuit 3 sends a radio wave through a transmitting antenna 2. The receiving device 7 receives the radio wave by a radio wave receiving circuit 9 through a receiving antenna 8 and an ultrasonic wave receiving circuit 11 receives the ultrasonic wave through a receiving microphone 10. The received radio wave and ultrasonic wave are inputted to a time difference detecting circuit 12, which detects the difference in arrival time. The speed of the radio wave is extremely high, so the difference between the reception time of the radio wave and the reception time of the ultrasonic wave is the time required for the propagation of the ultrasonic wave from the device 1 to the device 7. Namely, the value obtained by multiplying this time by an acoustic velocity is the distance from the device 1 to the device 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a distance measuring device that measures distances between objects using ultrasonic waves.

(Prior art) Conventionally, this type of distance measuring device has an ultrasonic transmitter and an ultrasonic receiver installed close to each other, and emits ultrasonic waves from the ultrasonic transmitter to an object to receive reflected waves from the object. By receiving ultrasonic waves with an ultrasonic receiver, the distance to the object can be measured based on the time it takes for the ultrasonic waves to travel back and forth to the object. Additionally, mechanical scanning was required to measure distances to multiple objects.

(Problems to be Solved by the Invention) By the way, since such conventional distance measuring devices utilize reflected waves, it is difficult to measure ultrasonic waves for objects with low reflectance due to large attenuation.

Furthermore, the distance that can be measured is limited by attenuation caused by the propagation of ultrasonic waves over a distance twice the distance to the target object.

In addition, mechanical scanning is required to determine the distances to many objects, which makes the configuration complex, and one object cannot be measured for one scanning period, so it cannot be measured instantly. was impossible.

Therefore, the present invention provides a distance measuring device that can measure long distances regardless of the material of the object, and can instantly measure distances to multiple objects with a simple configuration. The purpose is to

(Means for Solving the Problems) In order to achieve such an object, the distance measuring device of the first invention includes a transmitting device and a receiving device, and the transmitting device includes:
A radio wave transmitting circuit that transmits radio waves and an ultrasonic wave transmitting circuit that transmits ultrasonic waves are provided, and the receiving device includes a radio wave receiving circuit that receives the radio waves transmitted from the transmitting device, and a radio wave transmitting circuit that transmits the ultrasound waves transmitted from the transmitting device. an ultrasonic receiving circuit that receives ultrasonic waves;
The gist is that a time difference detection circuit is provided to detect the difference in arrival time between received radio waves and ultrasonic waves.

Further, the distance measuring device of the second invention includes a radio wave transmitting device, a transmitting device, and a receiving device, the radio wave transmitting device is provided with a radio wave transmitting circuit for transmitting radio waves, and the transmitting device is provided with a radio wave transmitting circuit that transmits radio waves. A radio wave receiving circuit that receives the transmitted radio waves and an ultrasonic transmitting circuit that transmits the ultrasonic waves are provided, and the receiving device includes a radio wave receiving circuit that receives the radio waves that are transmitted from the radio wave transmitting device, and an ultrasonic wave transmitting circuit that transmits the ultrasonic waves. The gist of the present invention is to provide an ultrasonic receiving circuit that receives ultrasonic waves transmitted from a transmitter and a time difference detection circuit that detects the difference in arrival time between the received radio waves and the ultrasonic waves.

Furthermore, the distance measuring device of the third invention includes a transmitting device and a receiving device, the transmitting device is provided with a radio wave receiving circuit for receiving radio waves, and an ultrasonic transmitting circuit for transmitting ultrasonic waves, and the receiving device includes a radio wave transmitting circuit that transmits radio waves to the transmitting device, an ultrasound receiving circuit that receives the ultrasound transmitted from the transmitting device, a transmission start time of the transmitted radio waves, an arrival time of the received ultrasound waves, and The gist is that a time difference detection circuit is provided to detect the difference between the two.

(Function) The distance measuring device of the first invention transmits radio waves and ultrasonic waves from the radio wave transmitting circuit and the ultrasonic transmitting circuit of the transmitting device,
These radio waves and ultrasonic waves are received by a radio wave receiving circuit and an ultrasonic receiving circuit of the receiving device. Since the time from when a radio wave is transmitted to when it is received can be ignored, the distance between the transmitter and the receiver can be determined by detecting the difference in arrival time between the radio wave and the ultrasonic wave received by the receiver using a time difference detection circuit. can be measured.

Moreover, the distance measuring device of the second invention transmits a radio wave from the radio wave transmitting circuit of the radio wave transmitting device, receives the radio wave by the radio wave receiving circuit of the transmitting device, and transmits an ultrasonic wave from the ultrasonic wave transmitting circuit. The receiving device receives the radio wave transmitted from the radio wave transmitting device and the ultrasound transmitted from the transmitting device using a radio wave receiving circuit and an ultrasound receiving circuit, respectively. The distance between the ultrasonic transmitter and the receiver can be measured by detecting the difference in arrival time between the radio waves and the ultrasonic waves received by the receiver using the time difference detection circuit.

Furthermore, the distance measuring device of the third invention transmits radio waves from the radio wave transmitting circuit at the receiving position g. The transmitting device receives this radio wave with its radio wave receiving circuit and transmits the ultrasonic wave from its ultrasonic transmitting circuit. The receiving device receives this ultrasonic wave with an ultrasonic receiving circuit. Since the time between transmitting radio waves from the receiving device and transmitting ultrasound from the transmitting device can be ignored, a time difference detection circuit detects the difference between the start time of transmitting the radio waves and the arrival time of the ultrasound, so that the difference between the transmitting device and the ultrasonic wave can be ignored. The distance to the receiving device can be measured.

(Embodiment) FIG. 1 shows a block diagram of an embodiment of the distance measuring device of the first invention.

The transmitting device 1 includes a radio wave transmitting circuit 3 equipped with a transmitting antenna 2.
and an ultrasonic transmitting circuit 5 provided with a transmitting microphone 4. The radio wave transmitting circuit 3 and the ultrasonic transmitting circuit 5 are connected by a signal line 6 for synchronization.

The receiving device 7 includes a radio wave receiving circuit 9 provided with a receiving antenna 8.
, an ultrasonic receiving circuit 11 provided with a receiving microphone 10, and a time difference detection circuit 12. Radio wave receiving circuit 9
and the ultrasonic receiving circuit 11 each output the received signal to the time difference detection circuit 12.

Next, the operation will be explained.

In the transmitting device 1, a radio wave is transmitted from a radio wave transmitting circuit 3 via a transmitting antenna 2, and at the same time, an ultrasonic wave is transmitted from an ultrasound transmitting circuit 5 via a transmitting microphone 4 in synchronization with the radio wave transmitting circuit 3. Ru.

In the receiving device 7, the transmitted radio waves are received by the radio wave receiving circuit 9 via the receiving antenna 8, and the transmitted ultrasound waves are received by the ultrasound receiving circuit 11 via the receiving microphone 10. The received radio wave and ultrasonic wave signals are each input to a time difference detection circuit 12, and the difference in arrival time is detected. Since the speed of radio waves is extremely high, the time it takes to reach the receiving device 7 from the transmitting device 1 can be ignored. Therefore, the difference between the time when the receiving device 7 receives the radio wave and the time when the receiving device 7 receives the ultrasonic wave is the time required for the ultrasonic wave to propagate from the transmitting device 1 to the receiving device 7.

That is, the value obtained by multiplying this time by the speed of sound becomes the distance from the transmitting device 1 to the receiving device 7.

FIG. 2 is a time chart of the transmitted signal and received signal of the embodiment shown in FIG. The following will explain based on FIG. 1 and FIG. 2.

When a radio wave transmission signal is transmitted from the transmitter 1 at time L0, an ultrasonic transmission signal is transmitted at time L0 in synchronization with this. At the receiving device 7, the radio wave reception signal arrives at the same time as time L0. However, the ultrasonic reception signal is delayed by the time T2 required to propagate from the transmitting device 1 to the receiving device 7. Arrive late. Here, for example, time T
If 2 is 01 seconds and the speed of sound is 340 meters/second, the distance between the transmitting device 1 and the receiving device 7 will be 34 meters.

Furthermore, radio waves and ultrasonic waves are intermittently transmitted from the transmitting device 1 at fixed time intervals TI, and the distance between the transmitting device 1 and the receiving device 7 at each time Tl can be measured.

In this embodiment, the radio waves and ultrasonic waves transmitted by the transmitting device 1 are synchronized so that they start transmitting at the same time, but they may be synchronized so that they start transmitting at different times. . In this case, the time difference detection circuit 12 of the receiving device 7
Now, the distance between the transmitting device 1 and the receiving device 7 can be measured by taking into account the time difference between the start of transmission.

Therefore, by attaching the transmitter to the object, the distance to the object can be measured. in this case,
Since the incident wave sent out from the transmitting microphone is used instead of the reflected wave, the distance to the object can be measured regardless of the reflectance of the object. Furthermore, since the propagation distance of the ultrasonic waves is only one way rather than the round trip distance to the target object, there is little attenuation and it is possible to measure even longer distances.

FIG. 3 shows a block diagram of an embodiment of the distance measuring device of the second invention.

The radio wave transmitting device 20 includes a radio wave transmitting circuit 22 provided with a transmitting antenna 21 .

The transmitting device 23 includes a radio wave receiving circuit 25 provided with a receiving antenna 24 and an ultrasonic transmitting circuit 27 provided with a transmitting microphone 26. Further, the radio wave receiving circuit 25 and the ultrasound transmitting circuit 27 are connected by a signal line 28 for outputting a trigger signal from the radio wave receiving circuit 25 to the ultrasound transmitting circuit 27.

The receiving device 29 includes a radio wave receiving circuit 31 provided with a receiving antenna 30, an ultrasonic receiving circuit 33 provided with a receiving microphone 32, and a time difference detection circuit 34. The radio wave receiving circuit 31 and the ultrasonic receiving circuit 33 each output received signals to the time difference detection circuit 34.

Next, the operation will be explained.

In the radio wave transmitting device 20 , radio waves are transmitted from a radio wave transmitting circuit 22 via a transmitting antenna 21 . This radio wave is transmitted to the radio wave receiving circuit 25 via the receiving antenna 24 of the transmitting device 23.
The signals are received by the radio wave receiving circuit 31 via the receiving antenna 30 of the receiving device 29.

When the transmitting device 23 receives this radio wave, a trigger signal is output from the radio wave receiving circuit 25 to the ultrasound transmitting circuit 27 via the signal line 28. This trigger signal causes
The ultrasonic transmitting circuit 27 transmits ultrasonic waves from the transmitting microphone 26. In the receiving device 29, the transmitted radio waves are received by the radio wave receiving circuit 31 via the receiving antenna 3°, and the transmitted ultrasound waves are received by the ultrasound receiving circuit 33 via the receiving microphone 32. The received radio wave and ultrasonic wave signals are each input to a time difference detection circuit 34, and the difference in arrival time is detected. The time from receiving the radio waves transmitted from the radio wave transmitting device 20 to transmitting the ultrasonic waves from the transmitting microphone 26 can usually be ignored. therefore,
The value obtained by multiplying the time difference detected by the time difference detection circuit 34 by the speed of sound is the distance from the transmitting device 23 to the receiving device 29.

FIG. 4 is a time chart of the transmitted signal and received signal of the embodiment shown in FIG. The following will explain based on FIGS. 3 and 4.

When a radio wave transmission signal is transmitted from the radio wave transmitter 20 at time t0, it is received by the transmitter 23, and in synchronization with this, an ultrasonic transmission signal is transmitted at time L0. In the receiving device 29, the received radio signal is time-stamped. arrive at the same time. However, the received ultrasonic signal is only transmitted at time t0 by the time T2 required to propagate from the transmitting device 23 to the receiving device 29.
Arrive late. Therefore, the distance between the transmitting device 23 and the receiving device 29 is the value obtained by multiplying the time T2 by the speed of sound.

Furthermore, the radio wave transmitting device 20 intermittently transmits radio waves at each fixed time TI, and the transmitting device 20
3 and the receiving device 29 can be measured.

In this embodiment, the radio waves transmitted from the radio wave transmitting device 20 and the ultrasound transmitted by the transmitting device 23 are synchronized so that they start transmitting at the same time, but they start transmitting at different times. You can also synchronize it like this. In this case, the time difference detection circuit 34 of the receiving device 29 detects the difference between the transmitting device 23 and the receiving device 29 by taking into account the time difference in starting transmission.
distance can be measured.

FIG. 5 shows a block diagram of an embodiment of the distance measuring device according to the third invention. Components that are the same as those in FIG. 3 are given the same numbers and their explanations will be omitted.

The transmitting device 40 has exactly the same configuration as the transmitting device 23 in FIG. 3.

The receiving device 41 has a configuration in which the radio wave receiving circuit 31 of the receiving device 29 in FIG. 3 is replaced with the radio wave transmitting device 20.

From the radio wave transmitting circuit 42 of the receiving device 41 to the transmitting antenna 43
When radio waves are transmitted via the transmitter 4o, ultrasonic waves are transmitted from the transmitter 4o and received by the ultrasonic receiver circuit 33 of the receiver 4I. Since the time from when a radio wave is transmitted to when an ultrasound is transmitted can usually be ignored, by detecting the time difference between the transmission start time of the radio wave and the arrival time of the ultrasound with the time difference detection circuit 34, the transmission device 40 and The distance to the receiving device 41 can be measured.

Note that the radio waves transmitted from the receiving device 41 and the transmitting device 40
The ultrasonic waves transmitted from the transmitter may be synchronized so that they start transmitting at the same time, or may be synchronized so that they start transmitting at different times.

In the above-described embodiments, the transmitting device and the receiving device are one-to-one, but the present invention is not limited to this. You can also. In this case, the large number of radio waves and the large number of ultrasonic waves that are transmitted may each have a unique signal.

In such a configuration, by providing a transmitting device or a receiving device for a large number of objects, distances to a large number of objects can be measured instantaneously with a simple structure without the need for mechanical scanning. .

(Effect of the invention) As explained above, according to the distance measuring device of the present invention,
Since reflected waves are not used to measure the distance to the object, it is possible to measure even objects with low reflectance.

Further, since ultrasonic waves do not need to be propagated over a round trip distance to and from the object and can be measured only over a one-way distance to the object, there is less attenuation and the distance over which measurement can be made can be extended. Further, by providing transmitting devices or receiving devices to a large number of objects, distances to a large number of objects can be measured instantaneously with a simple configuration without requiring mechanical scanning or the like.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the distance measuring device of the first invention, Fig. 2 is a time chart of the transmitting signal and receiving signal of the distance measuring device of the first invention, and Fig. 3 is the distance measuring device of the second invention. A block diagram of an embodiment of the measuring device, FIG. 4 is a time chart of the transmitted signal and a received signal of the distance measuring device of the second invention, and FIG. 5 is a block diagram of an embodiment of the distance measuring device of the third invention. . ■, 23.40... Transmitting device, 7.29.41... Receiving device, 20... Radio wave transmitting device, 3.22.42... Radio wave transmitting circuit, 8.25.31... Radio wave receiving circuit, 5.27...Ultrasonic transmission 1i21 path, 11.33...
・Ultrasonic receiving circuit, 12.34... Time difference detection circuit. , 7 arrogance A iris art 40 oi famous burial place

Claims (3)

[Claims] (1) A transmitting device and a receiving device are provided, the transmitting device is provided with a radio wave transmitting circuit that transmits radio waves, and an ultrasonic transmitting circuit that transmits ultrasonic waves, and the receiving device is provided with a radio wave transmitting circuit that transmits radio waves, and an ultrasonic wave transmitting circuit that transmits ultrasound waves, and the receiving device includes a radio wave receiving circuit that receives the received radio waves, an ultrasound receiving circuit that receives the ultrasound transmitted from the transmitting device, and a time difference detection circuit that detects a difference in arrival time between the received radio waves and the ultrasound. Distance measuring device. (2) A radio wave transmitting device, a transmitting device, and a receiving device are provided, the radio wave transmitting device is provided with a radio wave transmitting circuit that transmits radio waves, and the transmitting device is provided with a radio wave receiving circuit that receives the radio waves transmitted from the radio wave transmitting device. a circuit, and an ultrasonic transmitting circuit for transmitting ultrasonic waves, and the receiving device includes a radio wave receiving circuit for receiving radio waves transmitted from the radio wave transmitting device, and a radio wave receiving circuit for receiving the ultrasonic waves transmitted from the transmitting device. A distance measuring device equipped with an ultrasonic reception circuit and a time difference detection circuit that detects the difference in arrival time between received radio waves and ultrasonic waves. (3) A transmitting device and a receiving device are provided, the transmitting device is provided with a radio wave receiving circuit that receives radio waves, and an ultrasound transmitting circuit that transmits ultrasonic waves, and the receiving device is provided with a radio wave receiving circuit that receives radio waves and an ultrasound transmitting circuit that transmits ultrasound waves, and the receiving device transmits radio waves to the transmitting device. A radio wave transmitting circuit for transmitting, an ultrasound receiving circuit for receiving the ultrasound transmitted from the transmitting device, and a time difference detection circuit for detecting the difference between the transmission start time of the transmitted radio waves and the arrival time of the received ultrasound waves. A distance measuring device equipped with a