JP2000098023A - Radar wave detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar wave detecting device which can detect radar waves in three or more different frequency bands with a simple constitution. SOLUTION: The signals received by means of a horn antenna 1 are alternately mixed with frequency signals generated from first local oscillators 3 and 4 by means of a first mixer 2 and first intermediate-frequency signals having the frequency corresponding to the difference between the received signals and frequency signals are generated. A second local oscillator 7 sweeps the frequency of oscillating signals generated from the oscillator 7 and a second mixer 6 mixes the oscillating signals with the first intermediate-frequency signals and generates second intermediate-frequency signals having the frequency corresponding to the difference between the oscillating signals and first intermediate- frequency signals. A band-pass filter 8 extracts a prescribed frequency from the second intermediate-frequency signals and a detector 10 detects the prescribed frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar wave detecting device for detecting radar waves in three or more frequency bands.

[0002]

2. Description of the Related Art Conventionally, various measuring devices using radar waves have been widely used for various purposes such as position measurement and velocity measurement. For example, a speed measuring device using a radar wave is used for automatic speed measurement of an automobile.

On the other hand, a radar wave detecting device for detecting a radar wave transmitted from various measuring devices for the purpose of maintenance of various measuring devices using such radar waves is known. For example, a radar wave detecting device that detects a radar wave transmitted by the speed measuring device is realized for the speed measuring device.

[0004] Here, radar waves transmitted by various measuring devices are respectively transmitted using frequency bands in order to avoid interference and the like. For example, in the above-mentioned speed measuring apparatus, radar waves in two frequency bands, a 10.525 GHz radar wave called X band and a 24.150 GHz radar wave called K band, have been used. A radar wave detecting device that detects a radar wave transmitted by the speed measuring device corresponding to the speed measuring device using the two frequency bands is configured to detect a radar wave of the two frequency bands. I was

In such a radar wave detecting apparatus, a local oscillator having an oscillation frequency of 11.558 GHz is provided, and the intensity of the intermediate wave signal generated by mixing the oscillation signal of the local oscillator and the received radar wave is around 1.033 GHz. Was configured to detect. The difference between the oscillation frequency of the local oscillator and the frequency in the X band and the difference between the second harmonic of the oscillation frequency of the local oscillator and the K band are both about 1.033 GHz and the intermediate wave signal is 1.03 GHz.
Since the intensity of the X-band and K-band radar waves appears in the intensity near 3GHZ, by detecting this, the X-band and K-band radar waves can be detected.

[0006]

In recent years, it has been proposed in a speed measuring device or the like to perform measurement using three or more different frequency bands in order to enable more appropriate speed measurement. .

On the other hand, a conventional radar wave detecting device that detects a radar wave transmitted by a speed measuring device can only detect radar waves in two frequency bands. Further, if the configuration of the conventional radar wave detection device is applied to detection of radar waves in three or more frequency bands, the following problem occurs.

That is, according to the configuration of the conventional radar wave detecting device, only the radar wave of the frequency band having the above-mentioned fixed relation with the oscillation frequency of the local oscillator and its harmonics can be detected. When considering three or more frequency bands, it is generally physically difficult to make such a relationship between these three or more frequency bands and the oscillation frequency of the local oscillator. is there.

Therefore, with the configuration of the conventional radar wave detecting device, it was substantially impossible to detect three or more radar waves.

Therefore, the present invention provides a simple configuration.
It is an object to provide a radar wave detection device capable of detecting radar waves of three or more different frequency bands.

[0011]

In order to achieve the above object,
The present invention provides a radar antenna that receives a radar wave of three or more frequency bands and converts it into a received signal, and a frequency difference between a frequency band corresponding to each of the three or more frequency bands and a corresponding frequency band is within a predetermined frequency band. A local oscillator that generates a local signal including three or more frequency components, a mixer that generates an intermediate frequency signal obtained by mixing the local signal and a received signal received by the radar antenna, and the predetermined signal of the intermediate frequency signal. A detector that detects a frequency band component, and an alarm that outputs an alarm when the detector detects the predetermined frequency band component, wherein the local oscillator includes a plurality of oscillators having different oscillation frequencies, A radar wave detecting device is provided which generates, as the local signal, a signal alternately including signals output from a plurality of oscillators.

According to such a radar wave detecting apparatus, three or more radar waves can be detected by a simple structure in which each of the subsequent components in the signal processing after the mixer is shared for three or more frequency bands. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a radar wave detecting apparatus according to the present invention will be described with reference to an X band called 10.525 GHz.
The following describes an example of detecting three different bands of a radar wave, a 13.410 GHz radar wave called a Ku band, and a 24.150 GHz radar wave called a K band.

FIG. 1 shows a circuit configuration of the radar wave detecting device, and FIG. 2 shows an appearance of the radar wave detecting device.

In FIG. 1, reference numeral 1 denotes a horn antenna for receiving a radar wave, and 3 denotes an X / K for generating a frequency signal of 11.560 GHz.
The first local oscillator for band 4 is the first local oscillator for Ku band which generates a frequency signal of 12.377 GHz. here,
The X / K band first local oscillator 3 and the Ku band first local oscillator 4 are configured to oscillate alternately.

Reference numeral 2 denotes a received signal received by the horn antenna 1, a first local oscillator 3 for the X / K band, and a first local oscillator 3 for the Ku band.
This is a first mixer that mixes frequency signals generated alternately by the local oscillator 4 and generates a first intermediate frequency signal. Further, 5 is 1.1 of the first intermediate frequency signal generated by the first mixer.
This is a first intermediate frequency amplifier that amplifies only the frequency components near 030 GHz.

Next, 7 is, for example, 1.033 GHz ± 0.1 GHz.
Is a second local oscillator that repeatedly sweeps the oscillation frequency in the range of and is constituted by a voltage controlled oscillator (VCO) or the like. 6 is the first intermediate frequency signal generated by the first mixer and the second intermediate frequency signal
A second mixer that mixes the frequency signal generated by the local oscillator 7 and generates a second intermediate frequency signal.

8 is the second intermediate frequency signal, for example, 10.7 MHz
A band-pass filter that passes only nearby components, 9
Is a second intermediate frequency amplifier that amplifies the second intermediate frequency signal that has passed through the band pass filter 8, and 10 is a pass frequency of the band pass filter 8 of the second intermediate frequency amplifier amplified by the second intermediate frequency amplifier, for example, , A detector that detects the 10.7 MHz component and generates an alarm signal when the intensity is equal to or higher than a predetermined intensity.
The alarm device outputs an alarm in a form such as blinking a display such as D or outputting a buzzer sound.

Here, the circuit of the radar detector except for the horn antenna 1 is constructed on an electronic printed board, and the electronic printed board is mounted in a box 21 of a housing as shown in FIG. To be housed. The opening 22 of the housing as shown in FIG. 2 forms the horn antenna 1.

The operation of such a radar wave detecting device will be described below.

A radar wave continuously or pulsed from the radar wave generator is received by the horn antenna 1 and input to the first mixer 2 as a received signal.

On the other hand, the first local oscillator 3 for X / K band and Ku
The frequency generated by the band first local oscillator 4 is input to the first mixer 2 while being switched at a cycle shorter than the pulse width at which the radar wave is projected. However, this switching is controlled by a control circuit which is not shown and is constituted by a microcomputer or the like.

Therefore, when the received radar wave is an X-band radar wave, the frequency of this radar wave is 10.5.
Oscillation frequency of 11.5 for local oscillator 3 for 25GHz and X / K band
The 1.035GHz component corresponding to the difference from 60GHz is the first component.
It is included in the first intermediate frequency signal output from the mixer. Also,
When the received radar wave is a K-band radar wave, the frequency of the radar wave is 24.150 GHz and the frequency of the second harmonic of the oscillation frequency of the first local oscillator 3 for the X / K band is 23.1.
The 1.030 GHz component corresponding to the difference from 20 GHz is the first component.
It is included in the first intermediate frequency signal output from the mixer. Also,
If the received radar wave is a Ku-band radar wave, the frequency of the radar wave is 13.410 GHz and the first K-band radar wave is used.
A component having a frequency of 1.033 GHz corresponding to the difference from the oscillation frequency of 12.377 GHz of the local oscillator 4 is included in the first intermediate frequency signal output from the first mixer.

The first intermediate frequency amplifier 5 amplifies a frequency component near 1.033 GHz of the first intermediate frequency signal output from the first mixer 2 with a predetermined gain, and outputs the amplified signal to the second mixer 6. On the other hand, the second local oscillator 7 outputs to the second mixer 6 a frequency signal whose frequency is repeatedly swept in a range of, for example, 1.033 GHz ± 0.1 GHz. However, this sweep is performed by the control circuit controlling the second local oscillator 7 described above. For example, when the second local oscillator 7 is configured by a VCO,
The sweep is controlled by controlling the change of the frequency control voltage (VT in FIG. 1) by the control circuit.

The second mixer 6 has a second component including a frequency component corresponding to the difference between the frequency of the frequency signal input from the second local oscillator 7 and the frequency of the first intermediate frequency input from the first intermediate frequency amplifier 5. Outputs an intermediate wave signal. The band-pass filter 8 selects only the frequency component of, for example, 10.7 MHz of the second intermediate-wave signal and sends it to the second intermediate-frequency amplifier 9.

Here, as described above, the first intermediate wave signal input to the second mixer 6 has a component having a frequency of 1.035 GHz in the case of an X-band radar wave and a component in the case of a K-band radar wave. Includes a component having a frequency of 1.030 GHz, and in the case of a Ku-band radar wave, a component having a frequency of 1.033 GHz is included in the first intermediate frequency signal output from the first mixer. On the other hand, the frequency of the frequency signal input to the second mixer 6 is repeatedly swept in a range of 1.033 GHz ± 0.1 GHz. Therefore, horn antenna 1
When a radar wave of any one of the X band, the K band, and the Ku band is received, the second intermediate signal output from the second mixer 6 includes an intensity corresponding to the reception intensity of the radar wave. Of 10.7 MHz.

The second intermediate frequency amplifier 9 amplifies the second intermediate frequency signal having passed through the band-pass filter 8 with a predetermined gain. The detector 10 outputs the second intermediate frequency signal amplified by the second intermediate frequency amplifier. Amplifier band-pass filter 8
, For example, a component of 10.7 MHz is detected, and when the intensity is equal to or higher than a predetermined intensity, an alarm signal is generated.
Then, the alarm 11 outputs an alarm by blinking or buzzer of a display such as an LED according to the alarm signal.

The embodiment of the radar wave detecting apparatus according to the present invention has been described above.

In the above embodiment, the sweep range of the second local oscillator 7 has been described as 1.033 GHz ± 0.1 GHz, and the frequency component passed through the band-pass filter 8 has been described as 10.7 MHz. However, the sweep range of the second local oscillator 7 is 1.035 GHz obtained for the X-band radar wave and 1.030 GHz obtained for the K-band radar wave included in the first intermediate frequency signal. It is sufficient that the intensity corresponding to the intensity of the three frequency components of 1.033 GHz obtained for the Ku-band radar wave is within the range obtained as the intensity of the same frequency component of the second intermediate frequency signal. The frequency component that passes through the filter 8 may be a frequency component that provides an intensity corresponding to the intensity of the three frequency components. The actual sweep range of the second local oscillator 7 and the pass frequency of the band-pass filter 8 are determined in consideration of ease of control and hardware requirements. However, in general, the center of the sweep range of the second local oscillator 7 is at a frequency of 1.035 GHz obtained for the X-band radar wave and the K-band radar wave included in the first intermediate frequency signal. Frequency of 1.030GHz obtained from the radar and 1.033GHz obtained for the Ku band radar wave
It is preferable that the center frequency is 1.033 GHz.

Further, in the above embodiment, the case where the radar waves in the three frequency bands of X band, K band and Ku band are detected has been described as an example, but the radar wave detecting the oscillation frequency of the first local oscillator is described. By appropriately setting them in accordance with the above band, radar waves in three frequency bands other than these combinations may be detected.

The radar wave detection device according to the present embodiment may be modified so as to detect radar waves in four or more frequency bands. In this case, a first local oscillator having an oscillation frequency corresponding to each band of the radar wave to be detected is provided, and a frequency signal generated by each first local oscillator is input to the first mixer 2. At this time, if the frequencies of two or more bands to be detected have an appropriate relationship, the same first embodiment as the first local oscillator for the X / K band for the X band and the K band is used in the above embodiment. The detection may be performed using a fundamental oscillation wave and a harmonic generated by the local oscillator.

As described above, the radar wave detection device according to the present embodiment can detect radar waves in three or more different frequency bands.

[0033]

As described above, according to the present invention, it is possible to provide a radar wave detecting device having a simple structure for detecting radar waves in three or more different frequency bands.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of a radar wave detection device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an appearance of a radar wave detection device according to an embodiment of the present invention.

[Explanation of symbols]

1 Horn Antenna, 2 First Mixer, 1st Local Oscillator for X / K Band, 4th Local Oscillator for Ku Band, 5
1st intermediate frequency amplifier, 6 2nd mixer, 7 2nd local oscillator, 8 band pass filter, 9 2nd intermediate frequency amplifier, 10 detector, 11 alarm.

Claims (2)

[Claims] 1. A radar antenna for receiving radar waves in three or more frequency bands and converting the same into a received signal, and a frequency difference between the frequency bands corresponding to the three or more frequency bands and the corresponding frequency bands is within a predetermined frequency band. A local oscillator that generates a local signal including three or more frequency components, a mixer that generates an intermediate frequency signal obtained by mixing the local signal and a received signal received by the radar antenna, and the mixer of the intermediate frequency signal. A detector that detects a predetermined frequency band component, and an alarm that outputs an alarm when the detector detects the predetermined frequency band component, wherein the local oscillator includes a plurality of oscillators having different oscillation frequencies. A signal that alternately includes signals output from a plurality of oscillators as the local signal. 2. A radar antenna for receiving a radar wave of three or more frequency bands and converting it into a received signal, and a frequency difference between a frequency band corresponding to each of the three or more frequency bands and a corresponding one of the frequency bands is a first predetermined value. A first local oscillator for generating a first local signal including three or more frequency components within a frequency band, and a first intermediate frequency signal obtained by mixing the first local signal and a received signal received by the radar antenna A first mixer that selectively amplifies and outputs the first predetermined frequency band component of the first intermediate frequency signal; and three or more of the three or more frequency bands and the first local signal. A second local oscillator that generates a second local signal including a frequency component whose difference from the frequency component is within a second predetermined frequency band; and a first intermediate frequency output by the first amplifier. Signal and the second local signal A second mixer that generates a second intermediate frequency signal by a bandpass filter for selectively passing the second predetermined frequency band of the second intermediate frequency signal,
A second amplifier that amplifies and outputs the second intermediate frequency signal that has passed through the band-pass filter; a detector that detects a second intermediate frequency signal output from the second amplifier; and a detector that detects the second intermediate frequency signal. An alarm that outputs an alarm when a signal is detected, wherein the first local oscillator includes a plurality of oscillators having different oscillation frequencies, and alternately outputs signals output by the plurality of oscillators as the first local signal. A radar wave detecting device for generating a signal included in the radar wave.