JP2003255045A - On-vehicle radar device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein own vehicle receives a radar transmitted wave from an opposing vehicle, interferes with the radar of another vehicle or affects another station, using a frequency close to that of the own vehicle. <P>SOLUTION: The on-vehicle radar device is composed of a distributor, pseudo- noise digital code generators for a wide band and a narrow band, a first selector which selects one of the pseudo-noise digital code generators, a modulator which PSK modulates a high-frequency wave, based on the output obtained by the selection of the first selector, a mixer which mixes the received reflection signal and the other high-frequency wave distributed by the distributor and obtains a base band therefrom, a level detector which compares the base-band input from the mixer with a prescribed level, wide-band and narrow-band filters, a second selector which selects the wide-band filter or the narrow-band filter based on the level detector, a video amplifier, an A/D converter, and a chaos signal processor which adds up the periods from an arbitrary reference time to a time, when a wide-band or narrow-band pseudo-noise code changes by positive or negative amount, while in turn shifting the periods, generates an S-shaped waveform representing the positive and negative change, and measures a period from the reference time to the S-shaped waveform. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle radar device, and in particular, when receiving an interfering wave of a radar of another vehicle, it is possible to prevent the performance of the radar of the own vehicle from being deteriorated, and further, the transmitted wave of the radar of the other vehicle is The present invention relates to a vehicle-mounted radar capable of suppressing the possibility of becoming an interfering radio wave for the wireless equipment of.

[0002]

2. Description of the Related Art An example of a conventional radar for measuring a distance to a target will be described. Conventionally, based on a pseudo noise digital code, transmission radio waves are phase-shift keyed (PSK) and transmitted to space, and the radio waves reflected by the transmission radio waves hitting a target are received and frequency-converted to a baseband signal. This baseband signal
From the arbitrary reference time, the pseudo noise digital code becomes H
By sequentially moving and integrating the time for the time until it changes from high to low (low to high is also possible), a positive and negative voltage waveform is rapidly inverted (so-called S-shaped) to create a waveform, There is a radar that measures the distance to the target by measuring the time interval from the reference time set above to the S-shaped waveform.

Hereinafter, this type of radar is called a chaotic radar. Moreover, such a signal processing method is called chaotic signal processing.

FIG. 3 is a diagram showing an operational image of a conventional chaotic radar, and FIG. 4 is a diagram showing a configuration of the conventional chaotic radar. In FIG. 3, 1 is a road, 2
Is a vehicle traveling on the road 1, 3 is another vehicle traveling on the road 1, 4 is a chaotic radar mounted on the vehicle 2, 5 is a vehicle mounted on the vehicle 2, and the distance to the other vehicle 3 is displayed. An inter-vehicle distance indicator, 7 is a transmission radio wave which is a radio wave transmitted from the own vehicle 2.

In FIG. 4, 8 is an oscillator, 9 is a distributor, 10 is a pseudo noise signal generator (wide band) for generating a wide band noise signal, 11 is a modulator, 12 is a power amplifier,
13 is a transmitting antenna, 14 is a receiving antenna, 15 is a low noise amplifier, 16 is a mixer, 17 is a filter (wide band) which is a wide band filter, 18 is a video amplifier, 19 is A.
A / D converter, 20 is a chaotic signal processor, 21 is a system diagram of a conventional chaotic radar, 22 is an inter-vehicle distance indicator, 23 is an accelerator / brake controller, and 24 is a battery.

In the operation image diagram of FIG. 3, the chaos radar main body is installed near the front bumper, and the inter-vehicle distance display is installed in the driver's seat. The power is supplied from the battery inside the bonnet.

The conventional chaotic radar has only one type of pseudo-noise digital code and filter of the receiving system, and has no band switching function. Since the chaotic radar PSK-modulates the transmission signal with a pseudo-noise digital code, it is characterized in that the frequency band of the transmission signal is widened in principle. In particular, in order to improve the range resolution of the radar, since the pseudo noise digital code having a wide frequency band is used, the above characteristics become more remarkable.

[0008]

When this type of vehicle-mounted radar device becomes widespread in general vehicles in the future, due to the characteristics of the chaotic radar described above, the radar device mounted in an oncoming vehicle or a vehicle traveling in the vicinity thereof. There is a possibility that the radio wave signal transmitted by will be received by the receiving section of the vehicle. In this case, the radio wave signal transmitted from the other vehicle becomes an interfering wave when the signal required by the own vehicle, that is, the reflected radio wave signal from the target is received, and the level of this interfering wave is usually large, so the radar of the own vehicle The receiving system of is saturated, and as a result, the maximum detection distance of the target is reduced, incorrect distance measurement is performed,
There was a strong fear that the radar performance of my vehicle would deteriorate.

Therefore, it is expected that the transmission frequency of each on-vehicle radar device will be randomly assigned to manufacture / sell, but the radio frequency band that can be used by the on-vehicle radar is limited due to the radio administration of Japan. The transmission frequency of the in-vehicle radar that is manufactured / sold is limited within the limited frequency range, and as a result, the transmission frequency bands of the radar are likely to have overlapping portions. There was a problem that the deterioration of the radar performance of the car could not be completely prevented.

Further, broadening the viewpoint, the above-mentioned characteristic of the chaotic radar not only interferes with the radar mounted on another vehicle, but also other radio stations (for example, radio astronomy) that use a frequency near the frequency used by the chaotic radar. There was a problem that it could also affect business etc.).

The present invention has been made to solve the above problems, and can prevent deterioration of the radar performance of the own vehicle when receiving a jamming radio wave of another vehicle radar,
An object of the present invention is to provide a vehicle-mounted radar device capable of suppressing the possibility that the radio wave transmitted by the radar of the vehicle becomes an interfering radio wave for other wireless equipment.

[0012]

A vehicle-mounted radar device according to a first aspect of the present invention generates a high-frequency oscillator, a distributor for distributing a high-frequency signal output from the oscillator, and a broadband pseudo-noise digital code signal. A first pseudo noise signal generator, a second pseudo noise signal generator for generating a narrow band pseudo noise digital code signal, and the first pseudo noise signal generator and the second pseudo noise signal generator , A modulator for PSK modulating the high frequency output signal of one of the distributors by the output of the first selector, an antenna for transmitting this modulated signal, and a reflected signal , A mixer that mixes the received reflected signal with the other high-frequency output signal of the distributor to output as a baseband signal, and the baseband signal level and the output from this mixer. Based on the comparison result of the level detector that compares the preset threshold level to be set, the wide band filter with a wide pass band, the narrow band filter with a narrow pass band, and the level detector, the base band that passed the level detector. A second selector for selecting either a wide band filter or a narrow band filter for passing the signal, a video amplifier for amplifying a video signal by receiving the output of the second selector, and an output of the video amplifier. A / D converter that performs A / D conversion by using a wideband pseudo noise digital code signal from an arbitrary reference time,
Alternatively, an S-shaped waveform in which the positive / negative of the voltage waveform is rapidly inverted is created by sequentially delaying and integrating the narrow band pseudo noise digital code signal by the time until it changes from positive to negative or from negative to positive. And a signal processor for measuring the time interval from the reference time to the S-shaped waveform.

A vehicle-mounted radar device according to a second aspect of the present invention is the vehicle-mounted radar device according to the first aspect of the present invention, in which instead of the signal of the level comparison result of the level detector, a switch installed outside the vehicle-mounted radar device provides a first pseudo noise. It is configured to switch between operating a radar with a combination of a signal generator and a wide band filter or operating a radar with a combination of a second pseudo noise signal generator and a narrow band filter.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 is a diagram showing a chaotic radar according to a first embodiment of the present invention.
In the figure, 8 is an oscillator, 9 is a distributor, 11 is a modulator,
12 is a power amplifier, 13 is a transmitting antenna, 14 is a receiving antenna, 15 is a low noise amplifier, 16 is a mixer, 17 is a filter (wide band) which is a wide band filter, 18 is a video amplifier, 19 is an A / D converter, Reference numeral 22 is an inter-vehicle distance indicator, 23 is an accelerator / brake controller, and 24 is a battery.

Further, 25 is a pseudo noise signal generator (narrow band) for generating a narrow band noise signal, and 26 is a pseudo noise signal generator (broad band for generating a wide band noise signal based on a saturation warning signal described later. ) 10 and a pseudo-noise signal generator (narrowband) 25 that generates a narrowband noise signal, a selector 27, which detects the level whether or not it is equal to or greater than a predetermined preset value, and A level detector that sends a saturation warning signal to the selector, 28 is a saturation warning signal that warns the saturation condition of the receiving system, and 29 is a filter that has two signals that have passed through the level detector 27 based on the saturation warning signal 28. , 30 is a narrow band filter (narrow band), 31 is a wide band filter based on the saturation warning signal 28 (wide band) 17
And a selector for selecting any one of the filters (narrow band) 30 which are narrow band filters, 32 is a chaotic signal processor, 3
3 is a system diagram of the chaotic radar according to the first embodiment.

The purpose of the first embodiment is to have a plurality of pseudo noise digital codes having different frequency bands, and also in the receiving section a low pass filter (hereinafter referred to as LPF).
There are a plurality of the above, and this LPF is switched and operated according to the pseudo noise digital code to be used.

Further, as compared with the conventional example, a receiving signal level detecting circuit is newly provided in the receiving section. If this circuit does not detect signals above a certain specified value, a pseudo noise digital code with a wide frequency band and a filter with a wide pass band are selected and operated as a radar with high range resolution performance. If the level detection circuit detects a signal above a certain level, it is determined that an interference wave has been received, and a pseudo noise digital code with a narrow frequency band and a filter with a narrow signal pass band are selected, Operate with less adverse effect.

The outline of the chaotic radar will be described below with reference to FIG. The chaotic radar is a system diagram 33 (portion within a dotted line) of the chaotic radar according to the first embodiment, and the transmitting antenna 13 and the receiving antenna 14 face each other in a desired direction (usually the front), for example, in FIG. It is installed in the front bumper of car 2. In the chaotic signal processing by the chaotic radar, the inter-vehicle distance between the other vehicle 3 in FIG. 3 traveling ahead and the own vehicle 2 in FIG. 3 is calculated and output, and the result is displayed in the driver's seat of the own vehicle 2 in FIG. The information is displayed on the installed inter-vehicle distance indicator 22, and the driver can know the inter-vehicle distance between the other vehicle 3 and the own vehicle 2 by looking at this.

Further, when the inter-vehicle distance falls below a certain value, it is of course possible to sound an alarm sound in the driver's seat to give the driver an "inter-vehicle distance non-holding alarm" or a "back-end collision alarm". Is. In addition, the inter-vehicle distance measured by the chaotic radar is the accelerator / brake controller 23 of the own vehicle 2.
(So-called auto-cruise device) to control the accelerator and brake so that the vehicle-to-vehicle distance is always constant, so that the vehicle-to-vehicle distance can be kept constant without operating the accelerator pedal or brake pedal to perform cruise traveling. It is also possible to do it.

Next, the operation of the first embodiment will be described in detail with reference to FIG. The high frequency signal generated by the oscillator 8 is divided into two by the distributor 9, and one of them is input to the modulator 11. The modulator 11 PSK-modulates the high frequency signal input from the oscillator 8 with a wide band pseudo noise digital code signal. The PSK-modulated high-frequency signal is amplified to a required high-frequency power by the power amplifier 12, and then the transmitting antenna 1
It is radiated from 3 to the front space.

The radiated signal is applied to a target (mostly the rear part of the other vehicle 3 which is a vehicle traveling in front), reflected and reaches the receiving antenna 14. The reflected signal received by the receiving antenna 14 is amplified by the low noise amplifier 15 and then input to the mixer 16. On the other hand, the other output signal of the oscillator distributed by the distributor 9 is also input to the mixer 16. The mixer 16 mixes these two input signals and outputs them as a baseband signal. The baseband signal is
After passing through the level detector 27 and further passing through the wide band filter 17 to remove unnecessary signals, the video amplifier 18 amplifies the signal to a required level to enable signal processing, and the A / D converter 19 After being A / D converted by, the signal is input to the chaotic signal processor 32. The signal processing method inside the chaos signal processor is as described above. The distance information to the target (mostly the other vehicle 3 traveling ahead) obtained in this way is
It is input to the inter-vehicle distance indicator 22 and the accelerator / brake controller 23 (so-called auto cruise device) in the driver's seat.

Here, the threshold level of the level detector 27 is set to a level at which one of the reception systems of this radar from the low noise amplifier 15 to the A / D converter 19 begins to saturate. If the input level to the level detector 27 is less than or equal to this threshold level, it means that none of the receiving systems are saturated, and even if the interfering radio wave is received, the level is still low. Since the receiving system is low and not saturated, the chaotic radar measures the distance to the target without any trouble.

On the other hand, when an interfering radio wave such as a transmission radio wave of an on-vehicle radar of another vehicle traveling near the own vehicle is received,
The input level of the level detector 27 becomes higher than the threshold level. This is because the reception level of the jamming radio waves from other vehicles is generally higher than the signal level from the reflected signal from the target,
It takes advantage of the fact that it is much larger. In this case, it means that one of the receiving systems is saturated, and the signal input to the chaotic signal processor 32 is distorted so that normal chaotic signal processing becomes impossible, and the distance cannot be measured, Distance measurement performance as a radar deteriorates due to erroneous measurement or deterioration in maximum detection distance performance.

At this time, the level detector 27 generates the saturation warning signal 28 of the receiving system, and the saturation warning signal 28 selects a narrow band signal in the pseudo noise digital code, and also narrows the reception system filter. The bandpass filter 30 is selected. Since the filter of the receiving system has a narrow band, the level of the interfering wave passing through the filter 30 and entering the latter stage of the receiving system is reduced, and as a result, the saturation of the receiving system can be avoided. As a result, it is possible to prevent deterioration of the distance measurement performance of the radar.

During radar operation under the above conditions,
When the input level to the level detection circuit 27 becomes lower than the threshold level, it is interpreted that the saturation of the reception system due to the interfering wave has disappeared, and both the pseudo noise digital code signal and the reception system filter have a wide band, that is, the pseudo noise signal. The generator (wide band) 10 and the filter (wide band) 17 are switched. As a result, the radar operation is continued under the condition that the radar range resolution is excellent.

According to this embodiment, a pseudo noise digital code having a wide frequency band is normally used for transmission, and a filter having a wide frequency band is used for operation to operate as an on-vehicle radar having excellent range resolution. However, the level detection circuit newly installed in the chaotic radar detects the level of the received signal, and if a level above a certain level is detected, it is determined that "interfering radio waves are being received" and a pseudo noise digital code with a narrow frequency band is detected. As well as transmitting by using a filter with a narrow frequency band, it is possible to reduce the possibility that the received interfering radio waves will reach the latter stage of the receiving section of the radar of the own vehicle or the chaotic signal processing section, resulting in interfering radio waves. The adverse effect due to can be reduced.

Furthermore, since the pseudo noise digital code having a narrow frequency band is used for transmission, the radar transmission wave of the own vehicle interferes with the radar of the other vehicle (which is a source of interfering radio waves for the own vehicle). Can reduce the possibility of giving
It is possible to contribute to maintaining the order of the radio wave environment in which the radio wave is not interfered with by a third party.

According to this embodiment, there is an advantage that the performance of the radar of the own vehicle can be prevented from being remarkably deteriorated when the interfering radio wave such as the transmission wave of the radar of the other vehicle is received. Further, when there is a possibility that the radio waves transmitted by the own vehicle radar may interfere with other vehicle radars, there is an advantage that this possibility can be reduced.

Embodiment 2. 2 is a diagram showing a chaotic radar according to a second embodiment of the present invention. In the figure, the same or corresponding parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. 34 is the second embodiment
The system diagram of the chaotic radar in Figure 35 is a band changeover switch for designating switching between wide band and narrow band.

In the second embodiment, as compared with the first embodiment, the level detector 27 is deleted and a band changeover switch 35 is newly installed in the driver's seat. The band selector switch 35 operates the radar by switching the pseudo noise digital code and the filter of the receiving system between the wide band and the narrow band.

That is, a band changeover switch 35 is provided in place of the level detection circuit 27, and the band changeover switch 35 operates a radar by combining a pseudo noise digital code having a wide frequency band and a filter having a wide pass band. This is a method of switching whether to operate radar by combining a pseudo noise digital code with a narrow frequency band and a filter with a narrow pass band.

In urban areas with heavy traffic or near radio astronomy equipment, the latter combination is selected to prevent the radar transmission signal of itself from interfering with other people. When traveling in the suburbs, the former combination is selected and operated as a radar with high range resolution performance.

According to this embodiment, a band changeover switch is newly installed in the vehicle, and the switch is changed at the discretion of the driver to transmit using a pseudo noise digital code having a wide frequency band and to use a filter having a wide frequency band. It is possible to select whether to operate with a pseudo-noise digital code having a narrow frequency band and to operate with a filter having a narrow frequency band.

Therefore, normally, a pseudo noise digital code having a wide frequency band is used for transmission, and a filter having a wide frequency band is used for operation to operate as an on-vehicle radar having excellent range resolution. If it is considered that the radio waves transmitted by the vehicle's radar are adversely affected, it is recommended to use a pseudo-noise digital code with a narrow frequency band at the driver's discretion and to operate with a filter with a narrow frequency band. it can

In order to help the driver's judgment, it may be possible to display a warning such as "Be sure to transmit the in-vehicle radar in a narrow band" on the road sign or the like near the radio observatory.

[0036]

According to the present invention, when a high level interference wave is received, it is possible to reduce the possibility that the received interference wave reaches the latter stage of the receiving section of the radar of the own vehicle or the chaotic signal processing section. As a result, it is possible to reduce the adverse effects of the jamming radio waves.

According to the present invention, when a high-level jamming radio wave is received or when it seems to interfere with another radio station, the pseudo-noise digital code having a narrow frequency band is used for transmission. It is also possible to reduce the possibility that the radar transmission wave of the own vehicle may interfere with the radar, which contributes to maintaining the order of the radio environment.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a chaotic radar according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a chaotic radar according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an operational image of a conventional chaotic radar.

FIG. 4 is a diagram showing a configuration of a conventional chaotic radar.

[Explanation of symbols]

1 road, 2 own vehicle, 3 other vehicle, 4 chaotic radar,
5 Distance indicator, 7 Transmitted radio wave, 8 Oscillator, 9
Distributor, 10 Pseudo noise signal generator (wide band), 11
Modulator, 12 power amplifier, 13 transmitting antenna, 14
Receive antenna, 15 low noise amplifier, 16 mixer,
17 filter (wide band), 18 video amplifier, 19
A / D converter, 20 chaotic signal processor, 21 Conventional chaos radar system diagram, 22 Inter-vehicle distance indicator, 2
3 accelerator / brake controller, 24 battery, 25
Pseudo noise signal generator (narrow band), 26 selector, 27
Level detector, 28 saturation warning signal, 29 selector, 3
0 filter (narrow band), 31 selector, 32 chaotic signal processor, 33 System diagram of chaotic radar in the first embodiment, 34 System diagram of chaotic radar in the second embodiment, 35 band changeover switch.

Claims (2)

[Claims] 1. In a vehicle-mounted radar device, a high-frequency oscillator, a distributor for distributing a high-frequency signal output from the oscillator, and a first pseudo-noise signal generator for generating a wide-band pseudo-noise digital code signal, A second pseudo noise signal generator for generating a narrow band pseudo noise digital code signal, and a first selector for selecting an output from the first pseudo noise signal generator and the second pseudo noise signal generator And a modulator for PSK-modulating one of the high-frequency output signals of the distributor by the output of the first selector, an antenna for transmitting the modulated signal, an antenna for receiving a reflected signal, and a received reflection signal. A mixer that mixes the signal and the other high-frequency output signal of the distributor and outputs as a baseband signal, and the baseband signal level output from this mixer is preset. A level detector that compares a predetermined threshold level, a wideband filter with a wide passband, a narrowband filter with a narrow passband, and the baseband that passed the level detector based on the comparison result of the level detector. A second selector for selecting and passing either the wide band filter or the narrow band filter, a video amplifier for amplifying a video signal by receiving the output of the second selector, and an output of the video amplifier. A / D to receive and A / D convert
The converter and the output of this A / D converter are changed from an arbitrary reference time to the wide band pseudo noise digital code signal or the narrow band pseudo noise digital code signal from positive to negative or from negative to positive. A signal processor that creates an S-shaped waveform in which the positive and negative signs of the voltage waveform are rapidly inverted by sequentially moving by the time period up to and then integrating, and measuring the time interval from the reference time to the S-shaped waveform, An in-vehicle radar device comprising: 2. The radar is operated with a combination of the first pseudo noise signal generator and a wide band filter by a switch installed outside the on-vehicle radar device instead of the signal of the level comparison result of the level detector. The vehicle-mounted radar device according to claim 1, wherein it is switched between operating the radar with a combination of the second pseudo noise signal generator and a narrow band filter.