WO1999032899A1

WO1999032899A1 - Radar apparatus for vehicles

Info

Publication number: WO1999032899A1
Application number: PCT/JP1997/004756
Authority: WO
Inventors: Masahito Sato; Yoshihiko Konishi; Shuji Urasaki; Shinichi Sato; Tetsuo Haruyama
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 1997-12-22
Filing date: 1997-12-22
Publication date: 1999-07-01
Also published as: JP3421058B2

Abstract

A radar apparatus for vehicles comprising a radar sensor for transmitting and receiving an FM signal and extracting a beat signal, and a relay for offsetting the frequency after receiving this FM signal and transmitting a relay wave. This radar apparatus does not detect a false image depending on leak-in of a DC component in the radar sensor, can avoid the interference due to a direct wave from an oncoming vehicle without using polarized wave isolation and can eliminate the beat signal corresponding to stationary objects.

Description

Description Automotive radar equipment Technical field

The present invention relates to an on-vehicle radar device for the purpose of preventing collision or monitoring forward. Background art

Fig. 1 is a document (Konno and Koshikawa, "Milliwave radar sensor with simplified communication function", IEICE Electronics Society Conference, C1-2-7, P.107, September 1997, September 1997. 2) is a circuit block diagram showing the configuration of a radar sensor in the conventional on-vehicle radar device shown in FIG. 2), and FIG. 2 is a waveform diagram showing a mode switching signal in this on-vehicle radar device.

In FIG. 1, 1 is a radar sensor, 2 is a VCO (voltage controlled oscillator), 3 is a transmitting antenna connected to the VC02, 5 is a receiving antenna, 6 is a directional coupler, 7 is the receiving antenna 5 and The mixers connected to the directional coupler 6 and 8 and 9 are the BPF (no-pass filter) and LPF (mouth-pass filter) connected to the mixer 7, respectively. A video amplifier connected to the LPF 9, 11 is a video amplifier connected to the BPF 8, and 12 and 13 are a mode selection circuit and an ASK modulator connected to VC 02.

Next, the operation will be described.

The radar sensor 1 operates in two modes, radar mode and communication mode, according to the mode switching signal shown in Fig. 2. Although not shown in the figure in the communication mode, the rear part of the vehicle ahead running ahead of the vehicle equipped with the radar sensor 1 It communicates with the communication device mounted on the device.

First, the operation in the radar mode will be described. The carrier of VC02 becomes a transmission signal FM-modulated by the triangular waveform of the radar mode output from the mode selection circuit 12, and is transmitted to the transmission antenna 3 and the mixer 17 via the directional coupler 6. The transmission signal radiated from the transmission antenna 3 reaches the preceding vehicle, and its reflected wave is received by the reception antenna 5. At this time, the reflected wave is affected by the Doppler shift according to the relative speed between the own vehicle and the preceding vehicle on the frequency axis, and the distance between the own vehicle and the preceding vehicle based on the transmission signal on the time axis. Received as a signal delayed by the corresponding delay time.

The received signal is mixed with the transmission frequency by the mixer 7, and a beat signal corresponding to the up and down of the triangular waveform is output. Although this beat signal differs depending on the system, it generally has a frequency component of 100 kHz or less. Therefore, only this beat signal can be extracted as a radar mode signal by the LPF 9.

Next, the communication mode will be described. In the communication mode, the mode switching signal has a constant voltage waveform as shown in Fig. 2. At this time, the carrier of V C02 is subjected to ASK modulation by the ASK modulator 13 in accordance with the modulation signal (data over time). The ASK-modulated carrier is transmitted to transmission antenna 3 and mixer 7 via directional coupler 6 as a transmission signal having data information. The transmission signal radiated from the transmission antenna 3 is not shown in the figure, but is received by the reception antenna of the communication device mounted on the vehicle ahead and the envelope is detected.

When transmitting data information to the radar sensor 1 from the communication device, the communication device transmits the data as a PSK modulated signal using a 45 OKHz subcarrier from the transmission antenna. In radar sensor 1, A signal obtained by adding Doppler shift to this modulated signal is received by the receiving antenna 5 and then mixed by the mixer 7 with the transmitted signal to obtain a modulated signal component of the 45 OKHz subcarrier and a Doppler frequency component. Of these, only the modulated signal component of the 45 OKHz subcarrier is extracted by the BPF 8 as a communication mode signal.

Therefore, the radar sensor 1 can obtain the radar mode signal and the communication mode signal by switching the observation time according to each mode of the mode switching signal, and the communication device mounted on the vehicle ahead has the radar sensor only in the communication mode. Communicates with the server 1. In other words, while operating as an FM-CW radar that performs the radar function only with the vehicle equipped with the radar sensor 1, it is used by both the vehicle equipped with the radar sensor 1 and the vehicle ahead equipped with the communication device by time division. It acts as a vehicle-mounted radar device with a communication function that allows two-way communication.

Since the conventional on-vehicle radar system is configured as described above, the frequency components of the reflected wave from the vehicle ahead and the reflected wave from other stationary objects (for example, guardrails and falling objects on the road) are the Doppler frequency. Except for the component, it has the same transmission frequency (carrier frequency) component. For this reason, the instantaneous radar mode signal (beat signal) finally obtained by the radar sensor does not make it possible to distinguish between the target of the vehicle ahead and other stationary objects, and the speed and distance on the time axis It is necessary to distinguish from separation and changes in angle information (beam scan angle or handle angle). Therefore, processing using evening target information (distance, speed, angle) on the time axis becomes complicated, and in some cases, execution of processing to avoid collisions (warning to the driver, automatic deceleration, automatic emergency There is a problem that delay occurs in braking).

In addition, there is actually leakage of radio waves from the transmitting antenna to the receiving antenna in the radar sensor, or leakage of radio waves to the receiving side inside the radar sensor other than the antenna. Speed There is a DC component corresponding to degree 0. For this reason, there is a problem unique to FM-CW radar that a false image of the evening that depends on this DC component can be seen.

If the oncoming vehicle traveling in the opposite lane is equipped with the same radar sensor, the polarization of the transmitting / receiving antenna of the radar sensor must be obliquely reduced to avoid direct wave interference from the oncoming vehicle to the host vehicle. The antenna must have linear or circular polarization, and depending on the antenna system (for example, a traveling wave-fed slot antenna), this improvement in polarization isolation hinders an improvement in antenna efficiency. . For this reason, there is also a problem that it is necessary to reduce (or increase) the S / N of the receiver in order to reduce the risk of the maximum detection distance or to prevent it.

The present invention has been made in order to solve the above-described problems, and to obtain an on-vehicle radar device in which a false image does not occur due to leakage of a DC component, and to prevent interference by a direct wave from an oncoming vehicle. The purpose is to obtain an in-vehicle radar device that can be avoided regardless of the wave isolation.

It is another object of the present invention to obtain a vehicle-mounted radar device capable of removing a beat signal corresponding to a stationary object by H / W without using signal processing and extracting a beat signal for a vehicle ahead. Disclosure of the invention

An on-vehicle radar device according to the present invention includes a radar sensor mounted on an own vehicle and, after receiving a transmission signal transmitted from the radar sensor, offsets a frequency of the received signal within a band receivable by the radar sensor. And a repeater having a transmitting means for transmitting the signal as a relay wave. With this configuration, it is possible to obtain a vehicle-mounted radar device that can avoid detection of a false image depending on leakage of a DC component in a radar sensor. Only However, even when the radar sensors of the own vehicle and the oncoming vehicle have the same polarization, the radar sensor of the own vehicle detects the beat signal of the relay wave whose frequency has been offset by the repeater. Therefore, it is possible to avoid the interference of a direct wave from an oncoming vehicle that is not offset, and to obtain a vehicle-mounted radar device that does not need to restrict the polarization of the transmitting and receiving antennas.

The on-vehicle radar device according to the present invention further comprises a beat sensor extracting means for obtaining only a beat signal for the relay wave in the radar sensor, a two-beat signal for obtaining two types of beat signals for the reflected wave from the preceding vehicle and the relay wave. It is characterized by signal extraction means. This makes it possible to extract the beat signal for the reflected wave even when the forward car is out of order and the repeater is not operating, and in addition to vehicles without a repeater other than the preceding car, autopigs, bicycles, In addition, it is possible to obtain an on-vehicle radar device capable of detecting a beat signal for various stationary objects (guard rails and falling objects) ο

Also, the on-vehicle radar device of the present invention uses a subcarrier for a transmission signal obtained by FM-modulating the transmission frequency with a triangular waveform or a transmission signal composed of a modulation signal with the above triangular waveform and an unmodulated signal with a constant voltage waveform. A waveform adding means for adding a modulation waveform obtained by modulating with a modulation signal (data information such as an ID code), and a signal at a preceding stage for modulating a reception signal with a modulation signal using the above subcarrier. A radar sensor having beat signal extraction means for obtaining a beat signal for a relay wave after mixing is provided. With this configuration, it is possible to identify whether the extracted beat signal is for a transmission signal transmitted from a radar sensor of another vehicle (for example, a vehicle traveling in an adjacent lane) or for the transmission signal of the own vehicle. A vehicle-mounted radar device can be obtained.

Further, the on-vehicle radar device according to the present invention provides a radar output device having a Having two types of beat signal extraction means to obtain two types of beat signals for reflected waves and relay waves from vehicles ahead after mixing with the signal at the previous stage where the power is modulated with a modulation signal using a subcarrier It is characterized by the following. With this configuration, even when multiple vehicles equipped with the same radar sensor travel, even if the repeater breaks down, the vehicle does not operate, the vehicle does not have the repeater, and various stationary objects (guard rails). The present invention provides an on-vehicle radar device capable of extracting a beat signal for a transmission signal transmitted from a radar sensor of the own vehicle from among beat signals for reflected waves of the vehicle and a falling object. A relay mounted on the rear part of the vehicle in front of the vehicle, demodulating means for demodulating the first data information from the received signal, and forming a portion of the received signal modulated by the first data information into an unmodulated signal. And a modulating means for modulating a part of the non-modulated signal by second decoding information using a subcarrier. With this configuration, a two-way communication can be performed between the own vehicle and the preceding vehicle. In other words, an on-vehicle radar device having both a vehicle-to-vehicle communication function and a collision prevention function for the front and rear of the own vehicle can be obtained. it can. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a circuit block diagram showing a configuration of a radar sensor showing an example of a conventional radar device, FIG. 2 is a waveform diagram of a mode switching signal in the radar device, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a circuit block diagram showing a configuration of an on-vehicle radar device according to Embodiment 1, FIG. 4 is a waveform diagram of a transmission signal according to Embodiment 1 of the present invention, and FIG. 5 is an on-vehicle vehicle showing Embodiment 2 of the present invention. FIG. 6 is a circuit block diagram of a radar sensor constituting a radar apparatus for use in a vehicle, FIG. 6 is a waveform diagram of a transmission signal in a vehicle-mounted radar apparatus according to Embodiment 3 of the present invention, and FIG. FIG. 8 is a circuit block diagram of a radar sensor constituting the on-vehicle radar device according to the third embodiment of the present invention. FIG. 8 is a diagram showing a radar sensor constituting the on-vehicle radar device according to the fourth embodiment of the present invention. FIG. 9 is a circuit block diagram, FIG. 9 is a waveform diagram of a transmission signal in the on-vehicle radar device according to the fifth embodiment of the present invention, and FIG. 10 is a block diagram of the on-vehicle radar device according to the fifth embodiment of the present invention. FIG. 2 is a circuit block diagram of a relay device that performs the operation. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiment 1.

FIG. 3 is a configuration diagram of an on-vehicle radar device according to Embodiment 1 of the present invention, and FIG. 4 is a waveform diagram showing a transmission signal in Embodiment 1 of the present invention. In FIG. 3, 21 a is a radar sensor mounted on the own vehicle, 22 is an FM modulator in the radar sensor 21 a, 23 a is a VCO whose voltage is controlled by the FM modulator 22, 24a is a transmitting antenna, 25a is a receiving antenna, 26 is a directional coupler connected between the VC023a and the transmitting antenna 24a, 27a and 27b are mixers, Reference numeral 28a denotes a BPF connected to the output side of the mixer 27a, and 29a denotes a local oscillator connected to the mixer 27b.These components constitute a radar sensor 2la. You. Here, the transmission means is provided by the FM modulator 22, VC 0 2 3 a, and the directional coupler 26, and is received by the directional coupler 26, the mixer 27 a, and the BPF 28 a Means are also constituted by a mixer 27 b and a local oscillator 29 a, respectively.

30a is a repeater mounted on the rear of the vehicle ahead of the vehicle. It has a receiving antenna 25b, a local oscillator 29b, a mixer 27c, and a transmitting antenna 24b. 3 1 is a reflected wave transmitted from the transmitting antenna 24 a and reflected by the vehicle ahead, 32 is transmitted from the transmitting antenna 24 a and passes through the repeater 30 a to the receiving antenna 25 a It is an incoming relay wave. In FIG. 4, 33a and 34a are the modulated signal and the unmodulated signal output from the VC023a, respectively, and 35a is the modulated signal 33a and the unmodulated signal 34a respectively. Is a transmission signal.

Next, the operation of the on-vehicle radar device will be described.

The modulation waveform formed by the FM modulator 22 includes a triangular waveform, a triangular waveform, and a constant voltage waveform. In this case, the VC023a controls the voltage by the latter triangle waveform and the constant voltage waveform. The case in which it is performed will be described. In this case, the output from VCO 23a is a transmission signal 35a composed of a modulated signal 33a and an unmodulated signal 34a. Here, the modulation signal 33a is an FM modulation signal whose center frequency is f0 and whose frequency changes (up and down) within the band of the radar sensor 2la.

In order to simplify the expression in the following description, the frequency of the transmission signal 35a is typically represented using f0. This transmission signal 35a is supplied to the transmission antenna 24a and the mixer 27a via the directional coupler 26. The transmitted signal 35a radiated from the transmitting antenna 24a is received by the reflected wave 31 reflected by the vehicle traveling ahead and by the receiving antenna 25b of the repeater 30a. The output (frequency foff) of the local oscillator 29 b is mixed by the mixer 27 c and split into two relay waves 32 transmitted from the transmission antenna 24 b, which are both reception antennas of the own vehicle. Received at 25a.

At this time, if the relative speed between the own vehicle equipped with the radar sensor 21a and the preceding vehicle equipped with the repeater 30a is not 0, the driver according to the relative speed is used. The frequency of the reflected wave 31 is f 0 + fd, and the frequency of the relay wave 32 is f 0 + fd + foff because of the influence of the shifter shift. Here, fd is the Doppler frequency due to the Doppler shift, and in the case of an on-vehicle radar device, the frequency component is approximately 100 kHz or less. The reflected wave 31 and the relay wave 32 received by the receiving antenna 25a are mixed by the transmission signal 35a (frequency component f0) and the mixer 27a, and the frequency component fd for the reflected wave 31 and relayed. Two groups of beat signals of frequency component fd + foff for wave 32 are obtained.

Now, if the frequency foff of the local oscillator 29 b in the relay wave 32 is set to a frequency sufficiently higher than the Doppler frequency component fd, the relay wave 32 2 whose frequency is offset among the two groups of beat signals Only the beat signal of frequency component fd + foff can be extracted from BPF 28a. Further, the beat signal is mixed with the signal of the local oscillator 29a having the same frequency foff as that of the local oscillator 29b of the repeater 30a by the mixer 27b, thereby forming the relay wave 32. The corresponding Doppler frequency component fd can be extracted.

To be precise, in the mixer 27a, the frequency component of the two beat signals (up and down) corresponding to the difference between the modulated signal portions of the triangular waveform and the Doppler frequency component corresponding to the difference between the unmodulated signal portion of the constant voltage waveform are Since it is extracted, the output of the mixer 27 b becomes the frequency components of the above two types of beat signals and the Doppler frequency component (however, the Doppler frequency component can be calculated from the above two types of bit signals).

Therefore, the distance and relative speed between the front vehicle equipped with the repeater 30a and the own vehicle can be known from these frequency components, and the vehicle mounted to prevent or avoid collision between the own vehicle and the front vehicle. Act as a radar device for

In the case of a conventional on-vehicle radar system as shown in Fig. 1, The beat signal is only the beat signal for the reflected wave 31 of the vehicle ahead, and due to the leakage of the DC component in the radar sensor 2 la, it always becomes an object with a speed of 0 or a combination of this DC component and the beat signal. More false images are detected.

In addition, if the DC component is cut by signal processing to avoid this problem, if the own vehicle and the preceding vehicle are moving at the same speed, the preceding vehicle cannot be detected. Therefore, it is necessary to correlate time-series data such as distance, relative speed, and angle, and considerable processing time is required to remove false images by signal processing, and a collision prevention radar competing for tens of milliseconds In such cases, it is fatal.

On the other hand, according to the on-vehicle radar device of the first embodiment, since the DC component due to the leakage is removed by the BPF 28a, the problem of the false image caused by the leakage of the DC component is solved. it can. In addition, since the finally obtained beat signal is for the relay wave 32 that has passed through the repeater 30a mounted on the vehicle ahead, the bee signal from a stationary object other than the vehicle ahead (for example, a guard rail or a signboard) is obtained. Signal can be removed, and the effect of being able to reliably detect the preceding vehicle even when traveling on a curve is obtained.

Furthermore, since the repeater 30a offsets the frequency of the received signal and returns it to the radar sensor 2 la, even if the polarizations of the radar sensors of the own vehicle and the oncoming vehicle are the same, it is finally obtained. The transmitted beat signal is for the preceding vehicle, avoids interference from the direct waves of oncoming vehicles, and does not require the polarization to be limited to diagonal 45-degree polarization or circular polarization. 4b ゃ The effect of improving the degree of freedom in designing the receiving antennas 25a and 25b is also obtained.o Embodiment 2. FIG. 5 is a configuration diagram of a radar sensor 21b constituting an on-vehicle radar device according to Embodiment 2 of the present invention. In the second embodiment, the output of the mixer 27a in the radar sensor 21a of the on-vehicle radar device in the first embodiment shown in FIG. 3 is divided into two, one of which is a BPF 28a, and the other is a BPF 28a. Is supplied to the LPF 36a. Here, the output of the BPF 28a is the same as that of the radar sensor 21a of the first embodiment.

In this configuration, the output of 29 a is supplied to the mixer 27 b. The repeater (not shown) in the second embodiment is the same as repeater 3Oa shown in FIG. 3, and the transmission signal is the same as transmission signal 35a shown in FIG. As described above, according to the on-vehicle radar device of the second embodiment, the two groups for the reflected wave 31 and the relay wave 32, which are the outputs of the mixer 27a, as two types of beat signal extracting means. Beat signal of BPF 28a and LPF

Since the filter is applied at 36a, the bit signal (frequency component fd) for the reflected wave 31 is higher than that of the LPF 36a, and the bit signal for the relay wave 32 (frequency component fd + foff ) Can be extracted from the BPF 28a.Moreover, similarly to the first embodiment, the beat signal extracted by the BPF 28a is mixed with the output of the local oscillator 29a (frequency component foff) by the mixer 27b. By mixing, a beat signal (frequency component fd) for the relay wave 32 can be obtained. For this reason, a beat signal for the reflected wave 31 can be obtained in addition to the beat signal for the relay wave 32, and even if the forward vehicle fails and the repeater 30a is not operating, the own vehicle and the preceding vehicle can be obtained. The vehicle can calculate the relative speed and distance from the vehicle, and can also use vehicles other than the vehicle in front without a repeater 30a, as well as motorcycles, white wheels, and various stationary objects (gardrails and falling objects). An effect that can be detected is obtained. Embodiment 3.

FIG. 6 is a waveform diagram of a transmission signal in the on-vehicle radar device according to Embodiment 3 of the present invention, and FIG. 7 is a configuration of a radar sensor 2lc in the on-vehicle radar device according to Embodiment 3 of the present invention. FIG. In the third embodiment, in addition to the modulated signal 33a and the non-modulated signal 34b, the transmission signal 35a of the vehicle-mounted radar device according to the first embodiment shown in FIG. A modulation signal 33b obtained by modulating with data information (for example, an ID code) is provided. The transmission signal 35b is transmitted from the transmission antenna 24a of the radar sensor 21c. The reflected wave 31 and the relay wave 32 are received by the receiving antenna 25a.

Also, in the radar sensor 21c, the transmitting system is provided with a modulator 37a between the output of the directional coupler 26 and the input of the transmitting antenna 24a, and the modulator 37a is connected to the FM modulator 22c. Is controlled by the timing signal 39 from the transmitter, and the data information 38 using the subcarrier (frequency component fsc) is used to control the transmission signal 35a formed by the VC02 3a (see FIG. 4). In this configuration, a part of the modulation signal 34a is modulated (for example, PSK modulation) to generate a transmission signal 35b provided with the modulation signal 33b.

The receiving system supplies the output of the mixer 27a to the BPF 28a, mixes the output of the BPF 28a and the output of the local oscillator 29a with the mixer 27b, and mixes the output of the mixer 27b. The output is supplied to LPF 36b and BPF 28b. Note that the repeater (not shown) in the third embodiment is the same as repeater 30a shown in FIG. 3, and the output of VC023a is the same as transmission signal 35a shown in FIG.

As described above, according to the on-vehicle radar device of the third embodiment, in addition to the modulated signal 33a and the unmodulated signal 34b used for radar, data information of the own vehicle (for example, ID code) is used. Modulated signal with 3 3 b and Is transmitted from the transmitting antenna 24a of the radar sensor 21c, and the reflected wave 31 and the relay wave 32 are received by the receiving antenna 25a and then transmitted to the mixer 27a. In order to mix with the signal of the transmission signal 35 a (frequency component f 0) composed of the modulated signal 33 a and the unmodulated signal 34 a supplied from the directional coupler 26, the mixer 27 is used. The output of a is a beat signal (frequency component fsc + fd) for the reflected wave 31 containing data (frequency component fsc) using the subcarrier and a beat signal (frequency component fsc + fd + foff).

By passing the two groups of beat signals through the BPF 28a, only the beat signal for the relay 32 can be extracted, and the output of the local oscillator 29a is output by the mixer 27b. After mixing with the frequency component foff), the beat signal (frequency component fd) and the de-night information (frequency component fsc) for the intermediate wave 32 are applied to the filter with the LPF 36b and BPF 28b. Can be separated and extracted.

Therefore, it is determined whether the beat signal detected by the radar sensor 21c corresponds to the relay wave 32 of the transmit signal 35b transmitted from the own vehicle's transmit antenna 24a or not. Code, etc.) and the transmitted data (eg, the ID code of the own vehicle). In other words, whether the extracted beat signal is a relay wave 32 for the transmission signal 35 b transmitted from the radar sensor 21 c of another vehicle (for example, a vehicle traveling in the next lane) or the transmission of the own vehicle The effect of being able to identify whether the signal is a signal of the relay wave 32 for the signal 35b is obtained. Embodiment 4.

FIG. 8 is a configuration diagram of a radar sensor 21 d in a vehicle-mounted radar device according to Embodiment 4 of the present invention. This Embodiment 4 corresponds to FIG. The output of the mixer 27a in the radar sensor 21c of the on-vehicle radar device in the third embodiment shown in Fig. 3 is divided into two, and one is supplied to the BPF 28a and the other is supplied to the LPF 36a. Further, the output of the LPF 36a is supplied to the LPF 36c and the BPF 28c.

It should be noted that the repeater (not shown) in the fourth embodiment is a repeater 30a shown in FIG. 3, an output of VC023a is a transmission signal 35a shown in FIG. The output of the transmitter 37a is the same as the transmission signal 35b shown in Fig. 6.o

As described above, according to the on-vehicle radar device of the fourth embodiment, two groups of beat signals for the reflected wave 31 and the relay wave 32 output from the mixer 27a are represented by the BPF 28a. Since the LPF 36a is used to fill the filter, the beat signal (frequency component fsc + fd) for the reflected wave 31 is lower than that of the LPF 36a, and the beat signal for the relay wave 32 (frequency component: fsc + fd + foff) can be extracted from BPF 28a. The beat signal for the relay wave 32 extracted by the BPF 28a is mixed with the output of the local oscillator 29a (frequency component foff) by the mixer 27b and the LPF 36b as in the third embodiment. And the BPF 28b to fill the signal, so that the beat signal (frequency component fd) and data information

(Frequency component f s c) can be separated and extracted.

In addition, the beat signal for the reflected wave 31 extracted by the above-mentioned LPF 36a

(Frequency component: fsc + fd) is filtered by LPF 36c and BPF 28c to separate the beat signal (frequency component fd) and de-night information (frequency component fsc) for reflected wave 31. Can be extracted.

For this reason, even if a vehicle equipped with the same radar sensor 2Id as the own vehicle is running in the adjacent lane, for example, the beat signal for the reflected wave 31 and the relay wave 32 from the preceding vehicle is Transmitted from radar sensor 2 Id An effect can be obtained in which it is possible to identify whether the signal is for the signal 35b or from another vehicle equipped with a radar sensor 21d other than the own vehicle by comparing it with the extracted data information of the own vehicle. . Therefore, even when a plurality of vehicles equipped with the same radar sensor 2Id are traveling, the transmission signal 35b transmitted from the radar sensor 21a of the own vehicle is reflected by both the reflected wave 31 and the relay wave 32. The effect of reliably detecting the beat signal is obtained. Embodiment 5

FIG. 9 is a waveform diagram of a transmission signal in the on-vehicle radar device according to Embodiment 5 of the present invention. FIG. 10 shows the configuration of a repeater in the on-vehicle radar device according to Embodiment 5 of the present invention. It is a block diagram. The fifth embodiment is different from the third embodiment shown in FIG. 6 in that the transmission signal 35 b of the on-vehicle radar device according to the third embodiment includes a modulation signal 3 having information on the own vehicle (such as an ID code). 3b is a transmission signal 35 which is a modulated signal 33c having data information of the own vehicle (for example, an ID code) and data information of another vehicle (for example, an ID code).

Further, in addition to the repeater 30b, a transmitting antenna 24b, a receiving antenna 25b, a mixer 27c and a local oscillator 29b, a demodulator 40 as a demodulating means, a synchronizing circuit 41, and a modulating means. And a signal processing unit 43 as a waveform shaping means. The radar sensor according to the fifth embodiment is the same as the radar sensors 21c and 21d shown in FIGS. 7 and 8.

As described above, according to the on-vehicle radar device of this embodiment, the modulated signal 33 having data information of another vehicle (dummy data) in addition to data information of the own vehicle (for example, ID code). The transmission signal 35c with c is transmitted to the radar sensor 21c (Fig. 7) or 2Id (Fig. 8) of the vehicle. After transmitting from the antenna 24a and receiving by the receiving antenna 25b of the repeater 3Ob of the vehicle ahead, the signal notifying the start and end of the detection of the data information storage part by the synchronization circuit 41 is sent to the demodulator 40. In order to transmit the data information of the received signal to the signal processing unit 43 as a demodulated data 42 in synchronization with this signal, the radar sensor 21 stored in the data information part of the vehicle is used. The ID code of the vehicle equipped with c or 2 Id (own vehicle) and various communication data can be received by the vehicle ahead.

For the preceding vehicle, the signal processing unit 43 stores the ID code and various communication data in the data overnight information part 33c of the other vehicle, and adds it to the received data of the own vehicle. After the modulation data 44 using the subcarriers is formed by the modulation and modulation (for example, PSK modulation) by the modulator 37b, the output of the local oscillator 29b (frequency component foff) is output by the mixer 27c. To transmit signals from the transmitting antenna 24b with the frequency offset, so that the ID code of the vehicle ahead and various communication data are communicated to the vehicle equipped with the radar sensor 21c or 2Id. be able to.

Here, it is assumed that the modulator 37 b converts the modulated signal 33 c portion of the received signal into a non-modulated signal once, and then modulates the non-modulated signal portion by the modulation decoder 44. Therefore, it is possible to obtain an on-vehicle radar device capable of two-way communication between the own vehicle and the preceding vehicle. In other words, the effect of obtaining an on-vehicle radar device having both the inter-vehicle communication function for the front and rear of the own vehicle and the collision prevention function is obtained.

Here, the radar sensors 21a to 2Id of the on-vehicle radar devices according to Embodiments 1 to 5 described above are of the homodyne type, but the homodyne type or the heterodyne type having other configurations are described. May be used.

In addition, the radar sensors 21a to 2Id and the repeaters 30a and 30b of the on-vehicle radar device according to the first to fifth embodiments have been described for simplicity. Although the amplifier and the like are removed, these may be provided. Industrial applicability

As described above, the on-vehicle radar device according to the present invention includes a radar sensor that transmits and receives an FM modulation signal and extracts a beat signal, and a relay that offsets the frequency after receiving the FM modulation signal and relays the signal. Because it consists of a relay that transmits as waves, it does not detect false images that depend on the leakage of DC components in the radar sensor, and avoids direct wave interference from oncoming vehicles regardless of polarization isolation. And a beat signal for a stationary object can be removed.

Claims

The scope of the claims

1. Transmission means for transmitting a transmission signal consisting of an FM modulation signal whose transmission frequency changes in a triangular wave form, or a transmission signal consisting of the FM modulation signal and a non-modulation signal having a constant frequency, from a transmission antenna, and reception received by a reception antenna. A radar sensor comprising a receiving means for mixing a signal and the transmission signal to obtain a plurality of beat signals;

A transmission in which the frequency of the received signal obtained by receiving the transmitted wave from the vehicle equipped with the radar sensor with the receiving antenna is offset within the band that can be received by the radar sensor, and then transmitted as a relay wave from the transmitting antenna A repeater mounted on a forward vehicle equipped with a means, and a beat signal extracting means for extracting a beat signal for the repeater wave from a plurality of beat signals obtained from the laser sensor. In-vehicle radar device.

2. Equipped with a beat signal extracting means for obtaining only the beat signal for the relay wave, or two types of beat signal extracting means for obtaining two types of beat signals corresponding to the reflected wave from the preceding vehicle and the relay wave. 2. The on-vehicle radar device according to claim 1, wherein:

3. The subcarrier is used for the transmission signal of the radar sensor as the transmission signal composed of the FM modulation signal whose transmission frequency changes in a triangular wave form, or the transmission signal composed of the FM modulation signal and the unmodulated signal of a constant frequency. A transmission signal having a modulated waveform obtained by modulating the modulated signal with the received signal, and the reception output of the radar sensor is mixed with the signal at the previous stage where it is modulated with the modulation signal using the above subcarrier, and then a relay signal is supported. Claim 1 or Claim 2 further comprising a beat signal extracting means for obtaining a beat signal to be transmitted. 2. The on-vehicle radar device according to item 2.

4. A subcarrier is used for the transmission signal of the radar sensor as a transmission signal composed of an FM modulation signal whose transmission frequency changes in a triangular waveform, or a transmission signal composed of the FM modulation signal and a non-modulation signal of a constant frequency. A transmission signal having a modulated waveform obtained by modulation by the modulated signal, and the reception output of the radar sensor is mixed with a signal at the previous stage where the output is modulated by the modulation signal using the subcarrier, and then the signal is output from a vehicle ahead. 4. The on-vehicle radar according to claim 1, further comprising two kinds of beat signal extracting means for obtaining two kinds of beat signals for reflected waves and medium-waves. apparatus.

5. A demodulator that demodulates the first data information by a demodulator from a received signal obtained by receiving a repeater mounted on a preceding vehicle with a receiving antenna, and a first demodulator information in the received signal. A repeater comprising a waveform shaping means for shaping a modulated portion into a non-modulated signal and a modulating means for modulating a part of the non-modulated signal by a modulation signal using a subcarrier. The on-vehicle radar device according to claim 3 or 4, wherein: