JP2000329844A - Pedestrian detecting device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate a detection distance of a pedestrian and to detect the position, by generating a transmission signal obtained by shifting a received radar signal frequency as much as a prescribed frequency and by transmitting the signal with a built-in power source, by a portable transmitter/receiver. SOLUTION: When a signal detecting circuit 24 of a portable transmitter/receiver 2 detects a radar signal of an on-vehicle transmitter/receiver, a CPU 25 controls a transmission signal generating circuit 23 to allow to generate a transmission signal obtained by shifting a radar signal frequency as much as a prescribed frequency, and transmits the signal with a transmission power of a built-in battery 29. The on- vehicle transmitter/receiver transmits and receives electromagnetic waves, and a filter circuit 7 executes filter processing of an intermediate frequency (IF) signal obtained by mixing transmitted and received signals. And a reflected signal S1 from an object in front of a vehicle is segregated from a transmission signal from the portable transmitter/receiver 2 (pedestrian signal) S2. A CPU 8 detects the positions of the object in front and the pedestrian carrying the portable transmitter/receiver 2 based on the reflected signal S1 and the pedestrian signal S2. In this case, a detection distance is elongated, because the potable transmitter/receiver 2 transmits the signal with the built-in power source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a device for detecting a pedestrian from a vehicle side.

[0002]

2. Description of the Related Art A pedestrian carries a radio wave reflector provided with an LC series resonance circuit of a coil (inductance L) and a capacitor (capacitance C) also serving as a loop antenna, and has a frequency f0 at which an ID signal is superimposed. 2. Description of the Related Art A pedestrian detection device for a vehicle has been known in which a transmitter that emits a radio wave and a receiver that selectively receives a radio wave having a frequency of 2f0 and performs ID matching are installed on the vehicle side (for example, see Japanese Patent Application Laid-Open No. HEI 2 (1990) -1990).
298883). In this pedestrian detection device,
When a radio wave of a frequency f0 emitted from a vehicle is received by a loop antenna of a radio wave reflector carried by a pedestrian, the LC circuit of the radio wave reflector tunes to the frequency of 2f0 and resonates, and the radio wave of 2f0 is spatially transmitted from the loop antenna. Is radiated. The receiver of the vehicle receives this radio wave, and as a result of ID collation, when it is determined that the radio wave is a reflected wave of the radio wave emitted by itself, a warning of approaching to a pedestrian is issued.

[0003]

However, in the above-mentioned conventional pedestrian detecting device for a vehicle, the radio wave reflector carried by the pedestrian has no power source, and the radio wave reflector radiated from the vehicle side is received. Since transmission is performed using electric power as transmission power, there is a problem that a pedestrian within about 30 m from a vehicle can be detected, and the detection distance is short. In addition, the conventional vehicle pedestrian detection device has a problem that the distance and the direction to the pedestrian are not detected.

[0004] It is an object of the present invention to extend the detection distance of a pedestrian and to detect the position of the pedestrian.

[0005]

Means for Solving the Problems (1) The invention of claim 1 will be described with reference to FIGS. 1 and 2 showing the configuration of the first embodiment of the invention. A vehicular pedestrian detection device including a transceiver 1 and a portable transceiver 2, wherein the on-vehicle transceiver 1 transmits a radar signal of a predetermined frequency, a reception unit 3 for receiving the signal, An intermediate frequency signal generating means 37 for mixing the signal and the received signal to generate an intermediate frequency signal; and separating the signal transmitted from the portable transceiver 2 from the signal reflected from the object based on the intermediate frequency signal. Signal separation means 7
And a distance detecting means 8 for detecting a distance to the portable transceiver 2 based on the transmission signal from the portable transceiver 2 separated by the signal separating means 7, and the portable transceiver 2 receives a radar signal. Receiving means 21, transmission signal generating means 23 for generating a transmission signal in which the frequency of the radar signal is shifted by a predetermined frequency, transmitting means 21 for transmitting the transmission signal, receiving means 21, transmission signal generating means 23 and transmission means 21 And a power supply 29 for supplying power to the power supply. (2) The invention of claim 2 will be described with reference to FIGS. 10 and 11 showing the configuration of the fourth embodiment of the invention.
The invention according to claim 2 is characterized in that the in-vehicle transceiver 1D and the portable transceiver 2
B, the vehicle-mounted transceiver 1D includes a transmitting unit 3 for transmitting a radar signal of a predetermined frequency, a receiving unit 3 for receiving the signal, and a mixture of the transmitted signal and the received signal. An intermediate frequency signal generating means 37 for generating an intermediate frequency signal, and a signal separation for detecting a signal transmitted from the portable transceiver 2B and a signal reflected from an object based on the intermediate frequency signal in different detection periods, respectively. Means 14 and the portable transceiver 2B based on the transmission signal from the portable transceiver 2B separated by the signal separation means 14.
And a distance detecting means 8 for detecting a distance to the mobile phone 2B.
A transmission signal generation unit 23B that generates a transmission signal having the same frequency as the frequency of the reception signal a predetermined time after receiving the radar signal, a transmission unit 21 that transmits the transmission signal,
It includes a receiving unit 21, a transmission signal generating unit 23B, and a power supply 29 for supplying power to the transmitting unit 21. (3) The invention of claim 3 will be described with reference to FIGS. 5 and 6 showing the configuration of the second embodiment of the invention. The vehicle pedestrian detection device of claim 3 comprises an on-vehicle transceiver 1A, 1
B, scanning means 38, 39 for scanning the radar signals of the transmitting means 3A, 3B in the horizontal direction in front of the vehicle, and azimuth detecting means for detecting the azimuth of the portable transceiver 2 based on the scanning direction of the scanning means 38, 39 8 is provided. (4) The pedestrian detection device for a vehicle according to claim 4 is configured to intermittently transmit radar signals by the transmission means of the on-vehicle transceiver. (5) In the vehicle pedestrian detection device according to claim 5, the radar signal is continuously transmitted by the transmission means of the vehicle-mounted transceiver.

In the section of the means for solving the above-described problem, a diagram of one embodiment is used for easy understanding of the description, but the present invention is not limited to this embodiment. .

[0007]

According to the first aspect of the present invention, when a portable transceiver receives a radar signal from a vehicle-mounted transceiver, a transmission signal is generated by shifting the frequency of the radar signal by a predetermined frequency. It transmits with the transmission power of the power supply built in the device. On the other hand, the onboard transceiver generates an intermediate frequency signal by mixing the transmission signal and the reception signal,
Since the transmission signal from the portable transceiver and the reflected signal from the object are separated based on the intermediate frequency signal and the distance to the portable transceiver is detected based on the transmission signal from the portable transceiver, A pedestrian carrying a transceiver can be distinguished from other objects, and a distance to a pedestrian carrying a portable transceiver can be detected.
Further, the detection distance at which a pedestrian carrying a portable transceiver can be found is increased, and an operation of avoiding contact with a pedestrian can be performed with a sufficient margin, and safety can be improved. (2) According to the second aspect of the present invention, a transmission signal having the same frequency as the frequency of the received signal is generated after a predetermined time from the reception of the radar signal of the on-vehicle transceiver by the portable transceiver, and the transmission signal is built in the portable transceiver. Transmit with the transmission power from the power supply.
On the other hand, in the on-vehicle transceiver, the reflected signal from the object and the transmitted signal from the mobile transceiver are detected with different detection periods, so that the mobile transceiver transmits the received signal without shifting the frequency of the received signal. Even if a signal is generated and radiated, objects such as buildings and vehicles in front of the vehicle can be distinguished and detected from pedestrians carrying the portable transceiver. Distance can be detected. Furthermore, the detection distance at which a pedestrian carrying a portable transceiver can be found becomes longer, and an operation of avoiding contact with a pedestrian with sufficient margin can be performed.
Safety can be improved. (3) According to the invention of claim 3, since the radar signal is scanned in the horizontal direction in front of the vehicle and the direction of the portable transceiver is detected based on the scanning direction, the pedestrian carrying the portable receiver. Can be detected.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS << First Embodiment of the Invention >> FIG.
Shows the configuration of a vehicle-mounted transceiver mounted on a vehicle, and FIG. 2 shows the configuration of a portable transceiver carried by a pedestrian. This first
This embodiment comprises an on-vehicle transceiver 1 shown in FIG. 1 and a portable transceiver 2 shown in FIG. First, in FIG. 1, a radar head unit 3 of a vehicle-mounted transceiver 1 is a pulse-type radar head that transmits and receives a radar signal of an electromagnetic wave pulse, radiates a radar signal in front of a vehicle, and emits a radar signal from an object such as a pedestrian or a vehicle. The distance to the reflective object is detected by receiving the reflected wave, and the distance to the pedestrian carrying the portable transceiver 2 is detected by receiving the transmission radio wave from the portable transceiver 2.

The radar head unit 3 includes a transmitting / receiving antenna 3
1. Voltage controlled oscillator (VCO) 32, isolator 3
3, a circulator 34, an RF switch 35, a circulator 36, and a mixer (mixer) 37. The transmission / reception antenna 31 transmits and receives electromagnetic waves (radio waves), and the voltage controlled oscillator 32 generates a transmission signal having a frequency according to the input voltage. Further, the isolator 33 protects the voltage controlled oscillator 32 from the received radio wave, and the circulator 34 transmits the transmission signal totally reflected by the RF switch 35 to the mixer 37 when the RF switch 35 is in the cut-off state.
Supply as O signal. The RF switch 35 passes and blocks a transmission signal transmitted from the voltage controlled oscillator 32 according to a transmission pulse signal from the trigger circuit 4 described later. The circulator 36 supplies the transmission signal to the transmission / reception antenna 31 when the RF switch 35 is in the passing state, and converts the signal received by the transmission / reception antenna 31 to RF.
The signal is supplied to the mixer 37 as a signal. The mixer 37
The RF signal and the LO signal received by the transmitting / receiving antenna 31 are mixed to generate an intermediate frequency signal (hereinafter, referred to as an IF signal).

The trigger circuit 4 generates a pulse signal having a predetermined width τ at a predetermined time interval (referred to as a transmission pulse signal in this specification), and generates an RF switch 35, a VCO driving circuit 5,
It is sent to the gate circuit 6 and the CPU 8. VCO drive circuit 5
Is the voltage controlled oscillator VCO3 only during the τ period of the transmission pulse signal.
2 is output. The gate circuit 6 is a circuit that controls the passage and cutoff of the IF signal sent from the mixer 37 to the filter circuit 7. In the first embodiment, at least the period τ during which the output pulse signal is sent from the trigger circuit 4 is used. Blocks the passage of IF signals.

The filter circuit 7 is connected to the I
The F signal is filtered to separate a reflected signal s1 from an object in front of the vehicle and a transmitted signal (hereinafter, referred to as a pedestrian signal) s2 from the portable transceiver 2. Based on the reflected signal s1 and the pedestrian signal s2, the CPU 8 detects the distance and the relative speed to the object in front of the vehicle, and also detects the distance and the relative speed to the pedestrian carrying the portable transceiver 2.
Note that the relative speed is calculated based on the time interval of the radar signal transmitted from the radar head unit 3 and the detection distance to the object. The CPU 8 displays information on the obstacle in front and the pedestrian on the display device 9 to give a warning.

Next, the portable transceiver 2 will be described with reference to FIG. The transmitting / receiving antenna 21 is an omnidirectional antenna that transmits and receives electromagnetic waves. The circulator 22 sends the transmission signal from the transmission signal generation circuit 23 to the antenna 21 and sends the radar signal from the onboard transceiver 1 received by the antenna 21 to the signal detection circuit 24. The transmission signal generation circuit 23 generates a transmission signal having a frequency shifted by a predetermined frequency from the frequency of the radar signal of the vehicle-mounted transceiver 1.

Note that, even if the frequency is shifted by a predetermined frequency, if the frequency is within the range of the Doppler frequency, the on-vehicle transceiver 1 cannot distinguish the reflected signal s1 from the transmission signal s2 of the portable transceiver 2, so that the center frequency is, for example, 60 GHz. When the Doppler frequency is set to 20 KHz, it is desirable to shift the transmission signal from the portable transceiver 2 by 60 GHz ± several MHz or more to facilitate separation.

A transmission signal generating circuit 23 generates a transmission signal having a frequency corresponding to the input voltage.
6, an isolator 27 that protects the voltage-controlled oscillator 26 from received radio waves, and an RF switch 28 that passes and blocks a transmission signal sent from the voltage-controlled oscillator 26 in accordance with a transmission pulse signal from the CPU 25 described below. I have.

The signal detection circuit 24 includes an FV converter and the like, and detects the form and frequency of a received signal. In this embodiment, a pulse-type electromagnetic wave radar is described as an example. Therefore, if the received signal is an electromagnetic wave pulse of a predetermined frequency, it is determined that the received signal is a radar signal transmitted from the vehicle-mounted transceiver 1. The CW radar that emits continuous electromagnetic waves will be described later.

The CPU 25 controls the transmission signal generation circuit 23 based on the detection result of the signal detection circuit 24, and when a radar signal from the on-vehicle transceiver 1 is detected, shifts the frequency of the radar signal by a predetermined frequency. A transmission signal of a frequency is radiated from the antenna 21. Note that the portable transceiver 2 has a battery 29 mounted thereon, and the CPU 2
5 and necessary circuits 22 to 24.

FIG. 3 is a time chart showing a reflected signal from an object in front of the vehicle, and FIG. 4 is a time chart showing a pedestrian signal from the portable transceiver 2. The operation of the first embodiment will be described with reference to these time charts. In order to make the description easy to understand, the distance from the vehicle to the general object is the same as the distance from the vehicle to the pedestrian carrying the portable transceiver 2, and the radar signal is radiated from the on-board transceiver 1. , The time from when the vehicle-mounted transceiver 1 receives the reflected signal from the forward object is T, and the time from when the radar signal is emitted from the vehicle-mounted transceiver 1 to when it is received by the portable transceiver 2 is T / 2. And

The trigger circuit 4 generates a transmission pulse signal having a predetermined width τ at predetermined time intervals as shown in FIG. The VCO drive circuit 5 sends a modulation signal to the voltage controlled oscillator 32 during the period τ of the transmission pulse signal, so that the voltage controlled oscillator 32 changes from the fundamental frequency f0 to the frequency f1 (= f0).
+ Δf). Also, the transmission pulse signal τ
The RF switch 35 is switched to the passing state only during the period, and a radar signal having a frequency f1 and a pulse width τ is radiated from the antenna 31 as shown in FIGS. 3 (2) and 4 (1). During the period other than the τ period of the transmission pulse signal, the signal of the frequency f0 from the voltage controlled oscillator 32 is
5, the light is totally reflected from the circulator 34 to the mixer 37.
Is supplied to the LO terminal.

When the electromagnetic wave radiated from the antenna 31 of the vehicle-mounted transceiver 1 is reflected by an object in front of the vehicle, and the reflected wave is received by the antenna 31 of the vehicle-mounted transceiver 1, the received signal is transmitted from the circulator 36 to the RF terminal of the mixer 37. (See FIG. 3 (3)). In the mixer 37, the frequency f
The reflected signal (RF signal) of 1 (= f0 + Δf) has a frequency f
0 is mixed with the transmission signal (LO signal) of FIG.
As shown in (4), an IF signal having the difference frequency Δf is output. This IF signal is sent to the filter circuit 7 via the gate circuit 6 and subjected to a filtering process. Since the reflected signal radiated from the laser head unit 3 and reflected by the forward object has the same frequency f1 (= f0 + Δf) as the transmission signal, the frequency of the IF signal generated from the reflected signal is Δf. Therefore, as a result of the filter processing by the filter circuit 7, if the frequency of the IF signal is Δf, it can be determined that the received signal is the reflected signal s1 from the forward object.

The CPU 8 has a delay time T from the emission of the transmission signal to the reception of the reflection signal s1 from the forward object.
Based on (see FIG. 3), the distance D to the reflecting object is calculated by the following equation.

D [m] = 0.5 × C × T (where C = 3 ×
10 ⁸ [m / sec]) The CPU 8 displays the distance D to the object in front of the vehicle on the display device 9, and further sounds a buzzer (not shown) when the distance D to the object in front becomes less than a predetermined value. I do.

When an electromagnetic wave is received by the portable transceiver 2 carried by a pedestrian, the signal detection circuit 24 detects the form and frequency of the received signal. When it is determined that the received signal is an electromagnetic pulse signal having a frequency f1 (= f0 + Δf) as shown in FIG. 4B, the CPU 25 determines that the received signal is a radar signal radiated from the on-vehicle transceiver 1. , The frequency f of the radar signal from the transmission signal generation circuit 23
A transmission signal having a pulse width τ of a frequency f2 (= f1 + β) obtained by shifting 1 by β is generated and radiated from the antenna 21.

The transmission signal radiated from the portable transceiver 2 is generated by the voltage controlled oscillator 26. The voltage controlled oscillator 26 is supplied with necessary and sufficient power from the battery 29 built in the portable transceiver 2. Compared to the above-described conventional radio wave reflector that uses the power of a received signal for transmission without incorporating a battery, in this embodiment, a frequency-shifted transmission signal can be radiated from the portable transceiver 2 with a larger power. . That is, the portable transceiver 2 of the present embodiment shifts the frequency of the radar signal transmitted from the on-vehicle transceiver 1 and amplifies and returns the power.

When the electromagnetic wave radiated from the portable transmitter / receiver 2 is received by the antenna 31 of the vehicle-mounted transmitter / receiver 1, the same processing as the above-mentioned reflected signal from the front object is performed. That is,
The received signal is transmitted from the circulator 36 to the R
It is sent to the F terminal (FIG. 4 (4)). In the mixer 37,
The reflected signal (RF signal) at the frequency f2 (= f1 + β) is mixed with the transmission signal (LO signal) at the frequency f0, and the difference frequency (f2−f0 = Δf +) as shown in FIG.
β) is output. This IF signal is sent to the filter circuit 7 via the gate circuit 6 and subjected to a filtering process. The radar signal radiated from the laser head unit 3 is received by the portable transceiver 2, and the pedestrian signal returned from the portable receiver 2 by shifting the frequency is shifted in frequency by β from the radar signal of the frequency f1. Therefore, the frequency of the IF signal generated from the pedestrian signal is (Δf + β). Therefore, as a result of the filter processing by the filter circuit 7, the frequency of the IF signal becomes (Δf
+ Β), it can be determined that the received signal is the pedestrian signal s2 from the portable transceiver 2 carried by the pedestrian.

The CPU 8 calculates a time T / 2 until a radar signal from the on-vehicle transceiver 1 is received by the portable transceiver 2.
And a processing time Δt from the reception of this signal to emission of an electromagnetic wave from the portable transceiver 2 and a time T from the reception of the radiated electromagnetic wave from the portable transceiver 2 to the vehicle-mounted transceiver 1.
/ 2, the distance D1 to the pedestrian carrying the portable transceiver 2 is calculated by the following equation.

D1 [m] = 0.5 × C × (T−Δt) Then, the CPU 8 displays the distance D1 to the pedestrian in front of the vehicle on the display device 9, and furthermore, the distance D1 to the pedestrian is predetermined. When the value becomes lower than the value, a buzzer (not shown) sounds and an alarm is issued.

Here, the detectable distance of a forward object other than a pedestrian carrying the portable transceiver 2 and the detectable distance of a pedestrian carrying the portable transceiver 2 will be compared. First, when detecting a forward object other than a pedestrian carrying the portable transceiver 2, the transmission power of the transceiver 1 is Pt, the antenna gain of the transceiver 1 is Gt, and the radar signal of the transceiver 1 is detected. When the wavelength is λ, the reflected power Pref from an object having a scattering cross section σ at a point at a distance R [m] from the vehicle-mounted transceiver 1 is represented by the following equation.

Equation 3] ^{Pref = (Pt × Gt 2 ×} λ 2 × σ) / ((4π) 3 × R 4) The minimum reception sensitivity of the in-vehicle transceiver 1, S and thermal noise
Assuming that the / N ratio is 10 dB, it is expressed by (k × B × Ta × 10) (k is a Boltzmann constant, B is a pass band width, and Ta is a temperature).

Specifically, the transmission power Pt is 10 mW, the transmission antenna gain Gt is 30 dB, the wavelength λ of the radar signal is 4 mm, the pass bandwidth B is 400 MHz, and the temperature Ta is 300.
Assuming the degree K and the receiver conversion loss to be 9.5 dB, the maximum distance at which a reflected signal from an object having a scattering cross section of 1 m ² can be detected is about 30 m. This detectable distance corresponds to the pedestrian detection distance by the conventional radio wave reflector described above.

On the other hand, when detecting a pedestrian carrying the portable transmitter / receiver 2, the portable transmitter / receiver 2 has a built-in battery 29 as described above, and can transmit at the maximum transmission power stipulated by law. In addition to this, the receiving sensitivity of the on-vehicle transceiver 1 is sufficiently larger than the receiving sensitivity of the mobile transceiver 2, and therefore, the maximum detection distance of a pedestrian carrying the mobile transceiver 2 is determined by the transmission signal of the mobile transceiver 2. Is determined by whether the portable transceiver 2 can receive the radar signal of the vehicle-mounted transceiver 1 rather than whether the radar can be received by the vehicle-mounted transceiver 1.

The radar signal of the on-vehicle transceiver 1 is transmitted to the distance R
The reception power Pr when received by the portable transceiver 2 at the point [m] is Pt, the transmission antenna gain is Gt, the wavelength of the radar signal is λ, and the transmission power of the onboard transceiver 1 is λ. If the receiving antenna gain is Gr, it is expressed by the following equation.

## EQU4 ## Pr = (Pt × Gt) / 4πR ² × (λ ² × Gr) / 4π

Specifically, the transmission power Pt is 10 mW, the transmission antenna gain Gt is 30 dB, the radar signal wavelength λ is 4 mm, the pass bandwidth B is 400 MHz, and the temperature Ta is 300.
Assuming that the degree K is the same as that of the above-mentioned reflected signal and that the antenna gain Gr of the portable transceiver 2 is 0 dB, the distance at which the portable transceiver 2 can receive the radar signal of the vehicle-mounted transceiver 1 is about 80 m. As described above, the distance at which the portable transceiver 2 can receive the radar signal of the on-vehicle transceiver 1 can be regarded as the detectable distance of the pedestrian who carries the portable transceiver 2, so that the portable transceiver 2 can be carried. For example, it can be detected by the on-vehicle transceiver 1 even at a distance of about 80 m.

As described above, according to the first embodiment,
When the portable transceiver 2 receives the radar signal of the vehicle-mounted transceiver 1, it generates a transmission signal in which the frequency of the radar signal is shifted by a predetermined frequency, and transmits the transmission signal with the transmission power of the battery 29 built in the portable transceiver 2. On the other hand, the in-vehicle transceiver 2 generates an intermediate frequency signal by mixing the transmission signal and the reception signal, and separates the transmission signal from the portable transceiver 2 from the reflection signal from the object based on the intermediate frequency signal. Since the distance to the portable transceiver 2 is detected based on the transmission signal from the portable transceiver 2, the pedestrian carrying the portable transceiver 2 can be distinguished from other objects. The distance to the pedestrian carrying the portable transceiver 2 can be detected. Further, the detection distance at which a pedestrian carrying the portable transmitter / receiver 2 can be found is increased, and an operation of avoiding contact with the pedestrian can be performed with a sufficient margin, and safety can be improved.

<< Second Embodiment of the Invention >>
In the embodiment, an example using a radar head having a fixed detection direction is shown. However, if a beam steer type or multi-beam type radar head is used, a pedestrian carrying the portable transceiver 2 or other forward In addition to the distance to the object, their orientation can be detected.

FIG. 5 shows the configuration of an on-vehicle transceiver 1A having a beam steer type radar head 3A. Circuits and devices similar to those of the on-vehicle transceiver 1 according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and differences will be mainly described. The on-vehicle transceiver 1A other than the radar head 3A and the portable transceiver 2 carried by a pedestrian are the same as the circuits and devices of the first embodiment shown in FIGS. Description is omitted. The radar head 3A of the on-vehicle transceiver 1A is provided with an antenna driving circuit 38 for causing the transmitting / receiving antenna 31 to "swing" in a horizontal direction in front of the vehicle. Scans forward in the horizontal direction. The CPU 8 determines the direction based on the reflected signal s1, the pedestrian signal s2, and the direction of the transmitting / receiving antenna 31.
It is possible to detect the distance and direction to a pedestrian carrying the portable transceiver 2 and other objects in front.

FIG. 6 shows a multi-beam type radar head unit 3.
2 shows a configuration of an on-vehicle transceiver 1B provided with a wireless communication device B. FIG.
The same circuits and devices as those of the on-vehicle transceiver 1 of the first embodiment shown in FIG. The on-vehicle transceiver 1B other than the radar head 3B and the portable transceiver 2 carried by a pedestrian are the same as the circuits and devices of the first embodiment shown in FIGS. Description is omitted. A plurality of transmitting / receiving antennas 31a, 31b, 31c,... And an antenna switching unit 39 for switching the antennas are provided in the radar head unit 3B of the on-vehicle transceiver 1B. A plurality of transmitting / receiving antennas 31a, 31b, 31c,.
Are directed so that their respective radar beams are radiated to different ranges in the horizontal direction in front of the vehicle, and the antennas are sequentially switched by the antenna switching device 39, whereby each of the antennas 31a, 31b, 31
The radar beam emitted from c,... scans in the horizontal direction in front of the vehicle. Based on the reflected signal s1, the pedestrian signal s2, and the direction of the antenna switched when the signals s1 and s2 are received, the CPU 8 determines the distance to the pedestrian carrying the portable transceiver 2 and other forward objects. And the direction can be detected.

<< Third Embodiment of the Invention >> The first embodiment described above
In the second embodiment, the pulse type radar head which emits an electromagnetic wave pulse has been described as an example. However, a CW type radar head which continuously emits an electromagnetic wave may be used.

FIG. 7 shows the configuration of a vehicle-mounted transceiver 1C having a CW radar head. Circuits and devices similar to those of the on-vehicle transceiver 1 according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and differences will be mainly described.
The triangular wave generator 11 repeatedly generates a triangular wave signal,
It is sent to the O drive circuit 5. The VCO drive circuit 5 outputs a signal for modulating the voltage controlled oscillator 32 according to the triangular wave signal, and the voltage controlled oscillator 32 generates a transmission signal whose frequency increases and decreases along the triangular wave as shown by the solid line in FIG.
The antenna coupler 12 transmits the transmission signal from the voltage controlled oscillator 32 to the antenna 31 via the circulator 36.
And to the LO terminal of the mixer 37. The signal received by the antenna 31 is supplied to the RF terminal of the mixer 37 via the circulator 36, and the IF of the difference frequency between the RF signal and the LO signal is supplied to the mixer 37.
A signal is generated. This IF signal is amplified by the amplifier 13 and sent to the filter circuit 7.

FIG. 8 shows a configuration of the portable transceiver 2A corresponding to the CW type radar head. In addition, the first shown in FIG.
Circuits and devices similar to those of the portable transmitter / receiver 2 according to the embodiment are denoted by the same reference numerals, and differences will be mainly described. The signal detection circuit 24A includes an FV converter and the like, and detects the form and frequency of a received signal. In the third embodiment, since the CW type radar head is used for the on-vehicle transceiver 1C, a continuous electromagnetic wave whose frequency increases and decreases in a triangular waveform is determined to be a radar signal transmitted from the on-vehicle transceiver 1C. I do.

The transmission signal generation circuit 23A generates a transmission signal having a frequency obtained by shifting the frequency of the radar signal by a predetermined frequency. The CPU 25A controls the transmission signal generation circuit 23A based on the detection result of the signal detection circuit 24A. When a radar signal from the on-vehicle transceiver 1C is detected, transmission of a frequency shifted by a predetermined frequency from the frequency of the radar signal is performed. The signal is radiated from the antenna 21 with sufficient transmission power supplied from the built-in battery 29.

The frequency of the reflected signal from a forward object other than a pedestrian carrying the portable transceiver 2A is the same as the frequency of the radar signal transmitted from the onboard transceiver 1C, as shown by the broken line in FIG. Signal s1. That is, the signal has the same frequency as the frequency of the radar signal of the on-vehicle transceiver 1, and is delayed by a delay time corresponding to the distance to the reflecting object.

On the other hand, the frequency of the pedestrian signal transmitted from the portable transceiver 2A is shifted by a predetermined frequency from the frequency of the radar signal of the vehicle-mounted transceiver 1C. s2. That is, the signal is a signal having a frequency higher than the frequency of the radar signal of the on-vehicle transceiver 1 and delayed by a delay time corresponding to the distance from the mobile transceiver 2A.

The filter circuit 7 of the on-vehicle transceiver 1C is
Based on the frequency curve of the received signal as shown in FIG. 9, a reflected signal s1 from a forward object other than a pedestrian carrying the portable transceiver 2A and a pedestrian signal s2 from a pedestrian carrying the portable transceiver 2A. And outputs the result to the CPU 8.

As described above, the pedestrian can be distinguished from other objects even by using the CW type radar head.
In the same manner as in the embodiment, even if the distance is about 80 m, it can be detected. If the CW radar head is driven by the beam steering method or the multi-beam method described above, and the radar beam is scanned in the horizontal direction in front of the vehicle, the heading can be detected in addition to the distance to the object ahead including the pedestrian. Can be.

<< Fourth Embodiment of the Invention >> The first embodiment described above
In the second embodiment, the reply signal is transmitted immediately when the mobile transceiver receives the radar signal from the on-board transceiver. However, the mobile transceiver receives the radar signal from the on-board transceiver. A fourth embodiment in which a reply signal is transmitted after a predetermined time ΔT has elapsed will be described.

FIG. 10 shows the configuration of a vehicle-mounted transceiver 1D according to the fourth embodiment, and FIG. 11 shows the configuration of a portable transceiver 2B of the fourth embodiment. Circuits and devices similar to those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and differences will be mainly described. First, FIG.
1 will be described. When the portable transceiver 2B carried by the pedestrian receives electromagnetic waves,
The signal detection circuit 24 detects the form and frequency of the received signal. Then, the received signal has a frequency f1 (= f0 + Δf).
CPU 25B
Determines that the received signal is an electromagnetic wave radar signal emitted from the onboard transceiver 1D, and controls the transmission signal generation circuit 23B to generate a transmission signal having the same frequency as the radar signal and a pulse width τ after a delay time ΔT. , From the antenna 21.

In FIG. 10, the on-vehicle transceiver 1D is provided with a delay signal detection circuit 14,
Among the signals received at D, a reflected signal from a forward object and a pedestrian signal from the portable transceiver 2B are detected with different detection periods. In other words, the period from the emission of the transmission signal until the time T1 elapses is a period for detecting the reflected signal s1 from the front object, and the period between the time T1 after the detection period of the reflected signal and the time T2 elapses is defined as the portable transceiver 2B. Is a period for detecting the pedestrian signal s2 from the vehicle. This T1 is, for example, a reflected signal s1 from an object 100 to 150 m away.
Is set, and T2 is set to, for example, 100 to 15
The time for receiving the pedestrian signal s2 from the portable transceiver 2B 0 m away is set.

FIG. 12 is a time chart showing a reflected signal from a forward object and a pedestrian signal from the portable transceiver 2B. The operation of the fourth embodiment will be described with reference to FIG. Note that, as in the above-described embodiment, the distance from the vehicle to a general object other than the pedestrian is the same as the distance from the vehicle to the pedestrian carrying the portable transceiver 2B, and the radar signal is transmitted from the on-board transceiver 1D. Is the time from the emission of the radar signal to the reception of the reflected signal from the forward object by the on-board transceiver 1D, and the time from the emission of the radar signal from the on-board transceiver 1D to the reception by the portable transceiver 2B. Is T / 2.

The on-vehicle transceiver 1D modulates the frequency from the fundamental frequency f0 to Δf during the τ period of the transmission pulse signal,
(1) As shown in the figure, an electromagnetic wave radar signal having a frequency f1 (= f0 + Δf) is emitted. T / 2 hours after the emission of the radar signal, the portable transceiver 2B receives the radar signal of the in-vehicle transceiver 1D as shown in FIG.
The portable transceiver 2B emits a transmission signal having a frequency f1 and a pulse width τ after a delay time ΔT after receiving the radar signal of the vehicle-mounted transceiver 1D as shown in FIG. The in-vehicle transceiver 1D receives a reflected signal from a forward object other than a pedestrian T times after emitting a radar signal as shown in FIG.
After (T + ΔT) time, a transmission signal from the portable transceiver 2B is received.

The on-vehicle transceiver 1D detects a reflected signal s1 from a general object in front of the vehicle during the period T1 after emitting the radar signal, and the portable transceiver 2B carried by the pedestrian during the period T2 after the period T1. From the pedestrian signal s2.

As described above, the transmission signal is not emitted immediately after the portable transceiver 2B receives the radar signal of the vehicle-mounted transceiver 1D, and after a predetermined delay time ΔT, the transmission signal having the same frequency as the frequency of the reception signal is transmitted. Generate and use portable transceiver 2B
Is transmitted with the transmission power of the battery 29 built in the. On the other hand, in the on-vehicle transceiver 1D, the transmission signal and the reception signal are mixed to generate an intermediate frequency signal, and the reflected signal s1 from the object and the portable transceiver 2B are generated based on the intermediate frequency signal.
And the pedestrian signal s2 from the pedestrian are detected and provided with different detection periods, so that an object such as a building or a vehicle in front of the vehicle and a pedestrian carrying the portable transceiver 2B can be detected separately. Above, the distance to the pedestrian carrying the portable transceiver 2B can be detected. If the radar head is driven by the beam steering method or the multi-beam method described above, and the radar beam is scanned in the horizontal direction in front of the vehicle, the azimuth can be detected in addition to the distance to the object ahead including the pedestrian. .

The distance D2 to the pedestrian carrying the portable transceiver 2B is obtained by the following equation.

D2 [m] = 0.5 × C × (T′−ΔT) Note that the portable transceiver 2B has a built-in battery 29 to radiate a transmission signal with sufficient transmission power. The detection distance of the pedestrian carrying the machine 2B becomes longer as in the above-described embodiment.

In each of the above-described embodiments, an example is shown in which a radar that emits an electromagnetic wave is used. However, a laser radar that emits an infrared light wave may be used. Further, in each of the embodiments described above, an example in which the pedestrian carries the portable transceiver is shown, but the portable transceiver may be mounted on the vehicle. In this case, another vehicle equipped with the portable transceiver is detected by using the on-board transceiver of the own vehicle.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a vehicle-mounted transceiver according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration of a portable transceiver according to the first embodiment.

FIG. 3 is a time chart showing a reflection signal from a general object ahead of the vehicle according to the first embodiment;

FIG. 4 is a time chart showing a pedestrian signal from the portable transceiver according to the first embodiment.

FIG. 5 is a diagram illustrating a configuration of an on-vehicle transceiver including a beam steerable radar head according to a second embodiment.

FIG. 6 is a diagram illustrating a configuration of an on-vehicle transceiver including a multi-beam radar head according to a second embodiment.

FIG. 7 is a diagram illustrating a configuration of a vehicle-mounted transceiver including a CW-type radar head according to a third embodiment.

FIG. 8 is a diagram illustrating a configuration of a portable transceiver according to a third embodiment.

FIG. 9 is a time chart illustrating a reception signal of the on-vehicle transceiver according to the third embodiment.

FIG. 10 is a diagram illustrating a configuration of a vehicle-mounted transceiver according to a fourth embodiment.

FIG. 11 is a diagram illustrating a configuration of a portable transceiver according to a fourth embodiment.

FIG. 12 is a time chart showing a reflected signal from a general object ahead of a vehicle and a pedestrian signal from a portable transceiver according to a fourth embodiment.

[Explanation of symbols]

 1, 1A, 1B, 1C, 1D Vehicle transceiver 2, 2A, 2B Portable transceiver 3, 3A, 3B Radar head unit 4 Trigger circuit 5 VCO drive circuit 6 Gate circuit 7 Filter circuit 8 CPU 9 Display device 11 Triangular wave generator DESCRIPTION OF SYMBOLS 12 Antenna coupler 13 Amplifier 14 Delay signal detection circuit 21 Transmission / reception antenna 22 Circulator 23, 23A, 23B Transmission signal generation circuit 24, 24A Signal detection circuit 25, 25A, 25B CPU 26 Voltage controlled oscillator (VCO) 27 Isolator 28 RF switch 29 Battery 31, 31a, 31b, 31c Transmission / reception antenna 32 Voltage controlled oscillator (VCO) 33 Isolator 34 Circulator 35 RF switch 36 Circulator 37 Mixer 38 Antenna drive circuit 39 Antenna off Switch s1 reflected signal s2 pedestrian signal

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B60R 21/00 626E 628Z F-term (Reference) 5J070 AB01 AB15 AB17 AB19 AC01 AC02 AC06 AC13 AD01 AD05 AE09 AF03 AG03 AH26 AH39 AK01 AK21 BA01

Claims (5)

[Claims] 1. A vehicular pedestrian detection device comprising an on-vehicle transceiver and a portable transceiver, wherein the on-vehicle transceiver includes a transmitter for transmitting a radar signal of a predetermined frequency, and a receiver for receiving the signal. An intermediate frequency signal generating means for mixing a transmission signal and a reception signal to generate an intermediate frequency signal, and separating a signal transmitted from the portable transceiver and a signal reflected from an object based on the intermediate frequency signal Signal separating means, and distance detecting means for detecting the distance to the portable transceiver based on the transmission signal from the portable transceiver separated by the signal sorting means, the portable transceiver is a radar signal Receiving means for receiving, a transmission signal generating means for generating a transmission signal by shifting the frequency of the radar signal by a predetermined frequency, a transmission means for transmitting a transmission signal, Shin means, pedestrian detection device characterized by comprising a power supply for supplying power to the transmitting signal generating unit and the transmitting unit. 2. A vehicular pedestrian detection device comprising a vehicle-mounted transceiver and a portable transceiver, wherein the vehicle-mounted transceiver is configured to transmit a radar signal having a predetermined frequency, and to receive a signal. An intermediate frequency signal generating means for mixing a transmission signal and a reception signal to generate an intermediate frequency signal, and a signal transmitted from the portable transceiver based on the intermediate frequency signal and a signal reflected from an object, respectively. Signal separation means for detecting in different detection periods, and distance detection means for detecting the distance to the portable transceiver based on the transmission signal from the portable transceiver separated by the signal separation means, The receiver is configured to receive a radar signal, and a transmission signal that generates a transmission signal having the same frequency as the frequency of the reception signal after a predetermined time after receiving the radar signal. And forming means, and transmitting means for transmitting a transmission signal, the receiving means, pedestrian detection device characterized by comprising a power supply for supplying power to the transmitting signal generating unit and the transmitting unit. 3. The pedestrian detection device for a vehicle according to claim 1, wherein the on-vehicle transceiver is configured to scan a radar signal of the transmission unit in a horizontal direction in front of the vehicle, and the scanning unit. Azimuth detecting means for detecting the azimuth of the portable transceiver based on the scanning direction of the means. 4. The vehicle pedestrian detection device according to claim 1, wherein the transmitting means of the on-vehicle transceiver transmits radar signals intermittently. Person detection device. 5. The vehicle pedestrian detection device according to claim 1, wherein the transmitting means of the on-vehicle transceiver continuously transmits a radar signal. Person detection device.