JPH11118917A - FM-CW radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an FM-CW radar apparatus by which the threshold value of a target detection is set easily and by which a plurality of targets can be detected so as to restrain their mutual interference even when they are adjacent by a method wherein the gain of a transmitter-receiver and the mean value of a receiver noise are measured in advance and the threshold value of the target detection is set so as to match the gain. SOLUTION: Regarding a beat signal which is converted into a digital signal in an A/D converter 11, the magnitude of the beat signal is checked by a gain control means 27. The gain of an amplifier 10 is adjusted so as to become an optimum level. The gain control means 27 sends, to a threshold-vale computing means 29, an argument corresponding to a value which is set in the amplifier 10. The computing means 29 fetches a set value, corresponding to the gain, from a noise-mean-value storage means 28. The set value is a value in which a nose component generated from a transmitter- receiver 15 is evaluated. The threshold-value computing means 29 finds a threshold value which discriminates a noise from a target, and it gives the value to a comparison means 30. The comparison means 30 judges the threshold value as a target value when the output of a frequency analytical means 12 exceeds the threshold value. The amplitude value of the selected target is sent to a maximum-value detecting means 31 so as to detect a maximum point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to prevent a collision accident during traveling of a car, a bus, a truck, or the like, which occurs when visibility is bad in bad weather such as rain, fog, snow, or the like, and which occurs due to carelessness of a driver. The present invention relates to an FM-CW radar device which detects a preceding vehicle, a person, an obstacle, and the like, obtains a relative distance and a relative speed, notifies a driver of danger, and applies the danger to a safe driving of the vehicle.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional FM-C.
FIG. 13 schematically shows a W radar device, and FIG.
It is a lineblock diagram of a W radar device.

[0003] In Fig. 12, reference numeral 1 denotes a self-vehicle equipped with an FM-CW radar device, 2 denotes a forward vehicle running in a forward direction, and 3 denotes an oncoming vehicle running in an oncoming lane.

[0004] FM-C mounted near the front of the vehicle 1
The transmission wave transmitted from the W radar device is reflected, for example, when the vehicle 2 ahead is present, and returns to the FM-CW radar device as a reception wave (reflected wave). The FM-CW radar device calculates the frequency difference between the transmitted radio wave and the received radio wave, and calculates the relative distance and relative speed between the own vehicle 1 and the preceding vehicle 2. The same detection can be performed for oncoming vehicles 3 and obstacles (not shown) in the oncoming lane other than the preceding vehicle 2 by directing the transmission wave.

[0005] In Fig. 13, 4 is a modulating means, 5 is an oscillator, 6 is a directional coupler, 7 is a transmitting antenna, 8 is a receiving antenna,
9 is a mixer, 10 is an amplifier, and 11 is an A / D (Analog).
(gto Digital) converter, 12 is frequency analysis means, 13 is target detection means, 14 is distance speed calculation means, 1
5 is a modulating means 4, an oscillator 5, a directional coupler 6, and a mixer 9
1 shows a transceiver including an amplifier 10.

First, the modulating means 4 generates a frequency modulation (FM) signal and sends it to the oscillator 5. The oscillator 5 generates a high-frequency signal modulated by the FM signal, and sends it to the transmission antenna 7 and the mixer 9 via the directional coupler. The transmission antenna 7 emits the transmitted high-frequency signal to a target object such as a vehicle ahead as a transmission wave. If a target exists, a reception wave (reflected wave) having a time delay is received by the reception antenna 8 and sent to the mixer 9. The mixer 9 generates a signal having a frequency difference between the reflected wave and the transmission wave distributed by the directional coupler 6 (hereinafter referred to as a beat signal), and sends the signal to the amplifier 10. The amplifier 10 amplifies the beat signal and converts the A / D converter 1
Come to 1. The A / D converter 11 converts the beat signal from an analog signal format to a digital signal format and sends it to the frequency analysis means 12. The frequency analysis means 12 takes in the digitized beat signal and obtains a frequency distribution by processing such as FFT (Fast Fourier Transform). The target detecting means 13 compares the frequency distribution with the threshold value, and sets the maximum value among those exceeding the threshold value as a target. The distance speed calculating means 14 calculates the relative distance and the relative speed of the target based on the frequency picked up by the target detecting means 13.

FIGS. 14 and 15 are diagrams for explaining a method of calculating a relative distance and a relative speed of a target.
Shows a change in frequency, and FIG. 15 shows a frequency distribution. The basic principle is S. A. Hovanesian's book "R
adar System Design & Anal
ysis "(published by Artech House).
78-P. 81. 14 indicates the transmission frequency of the FM-CW radar device, and 17 indicates the reception frequency.

First, the transmission frequency 16 is constant in section a, b
The radio wave is transmitted while being changed to ascending in the section and decreasing in the section c. The vehicle 2 ahead in FIG. 12 has a relative speed v relative distance R
, The speed of light C [m / s], the transmission wavelength λ
[M] and the slope of the frequency K [Hz / s], the beat frequency fd in the section a is given by Equation 1, and the beat frequency fr in the section b
1 is expressed by Expression 2, and the beat frequency fr2 in the c section is expressed by Expression 3.

[0009]

(Equation 1)

[0010]

(Equation 2)

[0011]

(Equation 3)

Therefore, from the frequency analysis, fd, fr1, fr
2, the target relative speed and relative distance can be obtained by solving the combination of the relative speed V and the relative distance R that satisfy Expressions 1, 2, and 3.

Fd, fr1, fr2 are a section, b section,
The beat signal in the section c can be obtained by frequency analysis of an FET (Fast Fourier Transform) or the like. FIG.
Shows a case where a beat signal when only one target object is subjected to frequency analysis. (A) is section a, (b) is section b,
(C) is the result of the FET in the section c, and the respective peak frequencies correspond to fd, fr1, and fr2. If there are two or more targets that reflect radio waves, such as vehicles ahead, frequency analysis will also synthesize a spectral waveform on the frequency axis, and there will be multiple peak frequencies. By searching for a frequency combination that satisfies Equation 3, the relative speed and relative distance of each target can be obtained.

[0014]

A conventional FM-CW radar apparatus can easily determine a threshold value after frequency analysis when a beat signal includes only a signal from a target, and can determine the frequency of the target. In practice, however, thermal noise (receiver noise) is also amplified and mixed into the output of the transceiver 14,
The frequency distribution becomes complicated as shown in FIG. If the threshold is set too high, such as the threshold 19, the first target 2
Although 0 can be detected, the second target 21 cannot be detected. If the threshold is set too low, such as the threshold 22, the receiver noise 23 is detected. FIGS. 16B and 16C are diagrams showing a detection method in which the target frequency is compared with the average value of the surroundings and a target is detected when the average value is higher than the average value of the surroundings. , 25 indicate a threshold value obtained by multiplying the average value 24 by a coefficient determined from the false alarm probability, and 26 indicates a range in which the average value is selected. The threshold value 25 in FIG.
This is a threshold value when the target 21 is focused on, and is a second target 2
Since the amplitude of 1 exceeds the threshold value 25, it is detected as a target. However, in the case where the first target 20 is adjacent to the second target 21 as shown in FIG. 16C, the average value increases, and the second target 21 cannot be detected.

An FM-CW radar apparatus according to the present invention has been made to solve the above-mentioned problem. The FM-CW radar apparatus can easily set a target detection threshold value. In order to detect each of them while suppressing interference.

[0016]

Means for Solving the Problems FM-CW of the first invention
The radar apparatus measures an average value of the gain of the transceiver and the average value of the noise of the receiver in advance, and sets a target detection threshold according to the gain.

Further, the FM-CW radar apparatus according to the second invention measures the gain of the transceiver and the spectrum of the receiver noise in advance, and sets the target detection threshold in accordance with the gain. .

The FM-CW radar apparatus according to the third aspect of the present invention measures the relationship between the gain of the transceiver and the average value of the receiver noise and the relationship between the inclination of the vehicle body and the spectrum of the receiver noise in advance. The threshold value for target detection is set according to the inclination of the vehicle body.

Further, the FM-CW radar apparatus according to the fourth aspect of the present invention measures the relationship between the gain of the transceiver and the average value of the receiver noise and the relationship between the rainfall and the spectrum of the receiver noise in advance to determine the gain and the rainfall. The target detection threshold is set according to the state.

The FM-CW radar apparatus according to the fifth invention measures the relationship between the gain of the transceiver and the average value of the receiver noise and the relationship between the temperature of the transceiver and the receiver noise in advance to determine the gain and the transmission / reception. The target detection threshold is set according to the temperature of the machine.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a diagram showing an embodiment 1 of the present invention.
FIG. 2 is a configuration diagram of an M-CW radar device. In the figure,
5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15 is the same as FIG. 27 is a gain control means, 28 is a noise average value storage means, 29 is a threshold value calculation means, 30 is a comparison means, and 31 is a local maximum value detection means.

The beat signal converted into a digital signal format by the A / D converter 11 is sent to the frequency analysis means 12 and the gain control means 27. The gain control means 27 checks the magnitude of the beat signal and checks whether the level of the A / D converter 11 is not saturated or the input is not too small, and adjusts the gain of the amplifier 10 so that the beat signal has an optimum level. I do. Further, the gain control means 27 sends an argument corresponding to the value set in the amplifier 10 to the threshold value calculation means 29. The threshold value calculating means 29 fetches a set value (average value of the noise component) corresponding to the gain from the noise average value storing means 28 according to the argument passed from the gain control means 27. The average value of the noise component is a value obtained by receiving a beat signal in a state where there is no target object in advance, analyzing the frequency, and calculating the average value in the frequency axis direction, and evaluating the noise component generated from the transceiver 15. It is. FIG. 6 is a diagram showing the relationship between the frequency distribution of noise components and the average value when the gain changes. 36a, 3
6b, 36c and 36d show frequency distributions of noise components. 37a, 37b, 37c and 37d indicate average values of noise components. Normally, the noise component increases in proportion to the gain or in a monotonically increasing relationship. FIG. 7 is a diagram showing the relationship between the gain and the average value of the noise components. Reference numeral 38 denotes a characteristic curve representing a change in the noise component, which is data stored in the noise average value storage means 28. The threshold value calculating means 29 fetches the noise average value corresponding to the gain from the noise average value storing means 28, finds a threshold value for distinguishing the noise from the target by Expression 4, and gives the threshold value to the comparing means 30. Equation 4 is a threshold a,
The coefficient k is a noise average value b, and the coefficient k is set so that the probability of occurrence of erroneous detection is sufficiently low.

[0023]

(Equation 4)

Next, if the output of the frequency analyzing means 12 exceeds the threshold a, the comparing means 30 determines that the object is a target.
FIG. 8 shows an example in which the receiver noise 23 is not selected by the threshold a (threshold 25), and only the first target 20 and the second target 21 are selected. The amplitude value of the target selected by the comparing means 30 is sent to the local maximum value detecting means 31. Local maximum value detecting means 31
If the amplitude value is continuous on the frequency axis, the maximum point is detected and the value of the frequency of the maximum point is sent to the distance / velocity calculation means 11. The distance speed calculation means 14 can calculate the relative speed and the relative distance of the target in the same manner as in the related art.

Embodiment 2 FIG. 2 is a configuration diagram of an FM-CW radar device according to a second embodiment of the present invention. In the figure, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1
Reference numerals 3, 14, and 15 are the same as those in FIG. 27 is gain control means, 29 is threshold value calculation means, 30 is comparison means, 3
1 is a local maximum value detecting means, and 32 is a noise pattern storing means.

The beat signal converted into a digital signal format by the A / D converter 11 is sent to the frequency analysis means 12 and the gain control means 27. The gain control means 27 checks the magnitude of the beat signal and checks whether the level of the A / D converter 11 is not saturated or the input is not too small, and adjusts the gain of the amplifier 10 so that the beat signal has an optimum level. I do. Further, the gain control means 27 sends an argument corresponding to the value set in the amplifier 10 to the threshold value calculation means 29. The threshold value calculating means 29 fetches a noise pattern corresponding to the gain from the noise pattern storing means 32 according to the argument passed from the gain control means 27. The noise pattern is a pattern in which a beat signal is received in a state where there is no target in advance, and a frequency-analyzed spectrum, that is, a noise spectrum is averaged a plurality of times. FIG. 9A is a diagram showing the relationship between the noise spectrum when the gain changes and the noise pattern subjected to the averaging process. 39a, 39b and 39c show noise spectra. Reference numerals 40a, 40b, and 40c denote noise patterns. Usually, the amplitude of the noise component increases almost in proportion to the gain. Further, due to the low-pass characteristics until the beat signal is output from the transceiver 15, the amplitude value tends to decrease as the frequency increases as shown in FIG. 9A. The threshold value calculating means 29 fetches a noise pattern corresponding to the gain from the noise pattern storing means 32, obtains a threshold value for distinguishing the noise from the target by Expression 5, and gives the threshold value to the comparing means 30. Number 5
Is the threshold a, the coefficient k, the gain G of the transceiver, and n on the frequency axis.
The coefficient k is set so that the probability of occurrence of erroneous detection is sufficiently low.

[0027]

(Equation 5)

If the output of the frequency analyzing means 12 exceeds the threshold a, the comparing means 30 determines that the object is a target. FIG.
Shows an example in which the receiver noise 32 is not selected by the threshold a (threshold 34), and only the first target 29 and the second target 30 are selected. The amplitude value of the target selected by the comparing means 30 is sent to the local maximum value detecting means 31. If the amplitude value is continuous on the frequency axis, the local maximum value detecting means 31 detects the local maximum point and sends the frequency value of the local maximum point to the distance / velocity calculating means 11. The distance speed calculation means 14 can calculate the relative speed and the relative distance of the target in the same manner as in the related art.

Embodiment 3 FIG. 3 is a configuration diagram of an FM-CW radar apparatus according to Embodiment 3 of the present invention. In the figure, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1
Reference numerals 3, 14, and 15 are the same as those in FIG. 27 is a gain control means, 28 is a noise average value storage means, 29 is a threshold value calculation means, 30 is a comparison means, 31 is a local maximum value detection means, 3
3 is a vehicle body inclination detecting means.

The beat signal converted into a digital signal format by the A / D converter 11 is sent to the frequency analysis means 12 and the gain control means 27. The gain control means 27 checks the magnitude of the beat signal and checks whether the level of the A / D converter 11 is not saturated or the input is not too small, and adjusts the gain of the amplifier 10 so that the beat signal has an optimum level. I do. Further, the gain control means 27 sends an argument corresponding to the value set in the amplifier 10 to the threshold value calculation means 29. The threshold value calculating means 29 takes in the noise average value according to the gain from the noise average value storage means 28 according to the argument passed from the gain control means 27. The threshold value calculating means 29 also takes in the angle from the vehicle body tilt detecting means 33 indicating how much the vehicle body is tilted up and down from the horizontal direction. The vehicle body inclination detecting means 33 calculates from the change in the positional relationship of the vehicle body with respect to the ground by detecting expansion and contraction of the suspension supporting the wheels. The threshold calculating means 29 obtains a threshold for distinguishing a target from the noise average value and the inclination angle of the vehicle body.

FIG. 10 is a diagram showing the relationship between the vehicle and the transmission radio waves. Reference numeral 41 denotes a vehicle 41 on which the apparatus is mounted, and reference numeral 42 denotes a transmission / reception beam indicating the directivity of the antenna. (A) is a case where the vehicle 41 is horizontal to the ground, and (b) is a case where the vehicle 4 is
(C) is the vehicle 41 when 1 faces upward from the horizontal.
Is below the horizontal. Since radio waves are generally reflected from the ground, the more the vehicle 41 faces the ground, the greater the reflection from the ground. FIG. 11 is a diagram showing the relationship between the noise component frequency distribution and the noise pattern obtained by averaging the noise distribution when the pitch angle of the vehicle 41 is changed in a situation where there is no target and the gain of the transceiver 15 is constant. .
43a, 43b and 43c indicate frequency distributions of noise components. 44a, 44b and 44c indicate noise patterns.
When the transmission / reception beam 42a is directed upward as shown in FIG. 10A, the noise component is a noise pattern 44a, and FIG.
When the transmission / reception beam 42b is horizontal, the noise component differs from the noise pattern 44b, and when the transmission / reception beam 42c is horizontal as shown in FIG. 10C, the noise component differs from the noise pattern 44c. The threshold value for discriminating the target object is obtained by an approximate expression such as Expression 6, and is provided to the comparison means 30. Equation 6 is a threshold a, a coefficient k, a noise average value b, a frequency f, and an nth noise level N (n) on the gradient Δθ axis, and the coefficient k is set so that the probability of erroneous detection is sufficiently low. .

[0032]

(Equation 6)

If the output of the frequency analyzing means 12 exceeds the threshold a, the comparing means 30 determines that the object is a target. FIG.
1 (b) indicates that the amplitude of the first target 20 is a threshold a (threshold 25)
The amplitude value is sent to the local maximum value detecting means 31. If the amplitude value is continuous on the frequency axis, the maximum value detecting means 31 detects the maximum point and sends the value of the frequency of the maximum point to the distance / velocity calculating means 14. The distance speed calculation means 14 can calculate the relative speed and the relative distance of the target in the same manner as in the related art.

Embodiment 4 FIG. 4 is a configuration diagram of an FM-CW radar device according to a fourth embodiment of the present invention. In the figure, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1
Reference numerals 3, 14, and 15 are the same as those in FIG. 27 is a gain control means, 28 is a noise average value storage means, 29 is a threshold value calculation means, 30 is a comparison means, 31 is a local maximum value detection means, 3
Reference numeral 4 denotes rainfall detection means.

The beat signal converted into a digital signal format by the A / D converter 11 is sent to the frequency analysis means 12 and the gain control means 27. The gain control means 27 checks the magnitude of the beat signal and checks whether the level of the A / D converter 11 is not saturated or the input is not too small, and adjusts the gain of the amplifier 10 so that the beat signal has an optimum level. I do. Further, the gain control means 27 sends an argument corresponding to the value set in the amplifier 10 to the threshold value calculation means 29. The threshold value calculating means 29 takes in the noise average value according to the gain from the noise average value storage means 28 according to the argument passed from the gain control means 27. The threshold calculator 29 also takes in rainfall information from the rainfall detector 34. The rainfall detecting means 34 obtains information by, for example, attaching a sensor for detecting moisture to a hood or a rainwater groove of a vehicle. The threshold value calculating means 29 calculates a threshold value for distinguishing the target from the noise average value and the rainfall information, and sends the threshold value to the comparing means 30. Normally, when rainfall occurs, the reflection of radio waves from the ground becomes strong, so that the amplitude of the noise component is reduced. It shows the same tendency as the state where it rose. Therefore, the noise average value at the time of rainfall and the noise average value at the time of restriction are measured in advance,
By having the difference as the correction value, the threshold value can be calculated more accurately. The comparison means 30 is a frequency analysis means 12
If the output exceeds the threshold value, it is determined that the object is the target, and the amplitude value is sent to the maximum value detecting means 31. Local maximum value detecting means 31
If the amplitude value is continuous on the frequency axis, the maximum point is detected and the value of the frequency of the maximum point is sent to the distance / velocity calculating means 14. The distance speed calculation means 14 can calculate the relative speed and the relative distance of the target in the same manner as in the related art.

Embodiment 5 FIG. 5 is a configuration diagram of an FM-CW radar device according to a fifth embodiment of the present invention. In the figure, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1
Reference numerals 3, 14, and 15 are the same as those in FIG. 27 is a gain control means, 28 is a noise average value storage means, 29 is a threshold value calculation means, 30 is a comparison means, 31 is a local maximum value detection means, 3
5 is a temperature detecting means.

The beat signal converted into a digital signal format by the A / D converter 11 is sent to the frequency analysis means 12 and the gain control means 27. The gain control means 27 checks the magnitude of the beat signal and checks whether the level of the A / D converter 11 is not saturated or the input is not too small, and adjusts the gain of the amplifier 10 so that the beat signal has an optimum level. I do. Further, the gain control means 27 sends an argument corresponding to the value set in the amplifier 10 to the threshold value calculation means 29. The threshold value calculating means 29 takes in the noise average value according to the gain from the noise average value storage means 28 according to the argument passed from the gain control means 27. The threshold calculating unit 29 also takes in the temperature information of the transceiver 15 from the temperature measuring unit 21. The temperature measuring means 21 obtains information by attaching a temperature sensor such as a thermistor to the transceiver 15, for example. The threshold value calculating means 29 calculates a threshold value for distinguishing the target from the noise average value and the temperature information, and sends the threshold value to the comparing means 30. Normally, the transmitter / receiver 15 changes its transmission output and gain depending on the temperature and the amplitude of the noise component fluctuates. . Therefore, it is possible to calculate the threshold value more accurately by measuring the noise average value at each temperature in advance with the output of the gain control means 27 fixed, and having the noise component difference between the temperatures as a correction value. it can. If the output of the frequency analysis means 12 exceeds the threshold value, the comparison means 30 determines that the object is a target, and sends the amplitude value to the local maximum value detection means 31.
If the amplitude value is continuous on the frequency axis, the maximum value detecting means 31 detects the maximum point and sends the value of the frequency of the maximum point to the distance / velocity calculating means 14. The distance speed calculation means 14 can calculate the relative speed and the relative distance of the target in the same manner as in the related art.

[0038]

According to the first aspect of the present invention, the relationship between the gain of the transceiver and the amplitude value of the noise component is measured in advance, and the threshold for target detection is set in conjunction with the gain, so that the threshold can be easily set. In addition, there is an effect that target detection can be performed while suppressing interference between a plurality of target signals.

According to the second aspect, the frequency distribution of the noise component with respect to the gain is measured in advance as a pattern, and the threshold for target detection is set in conjunction with the gain, whereby the threshold is set accurately. In addition, there is an effect that target detection can be performed while suppressing interference between a plurality of target signals.

According to the third aspect of the present invention, the relationship between the direction of the antenna and the reflection level of the radio wave from the ground is measured in advance, and the target detection threshold is linked to the direction of the vehicle and the gain of the transceiver. By setting the threshold value, there is an effect that the threshold value can be set accurately and the target can be detected while suppressing interference between a plurality of target signals.

Further, according to the fourth aspect, the relationship between rainfall and the reflection level of radio waves from the ground is measured in advance, and the threshold is set accurately by setting the relationship in association with the rainfall information and the gain of the transceiver. In addition, there is an effect that target detection can be performed while suppressing interference between a plurality of target signals.

According to the fifth aspect of the present invention, the relationship between the temperature of the transceiver and the noise amplitude value is measured in advance, and the threshold is set accurately by setting the relationship with the temperature and the gain of the transceiver. In addition, there is an effect that target detection can be performed while suppressing interference between a plurality of target signals.

[Brief description of the drawings]

FIG. 1 is a diagram for describing Embodiment 1 of the present invention.

FIG. 2 is a diagram for explaining Embodiment 2 of the present invention.

FIG. 3 is a diagram for explaining Embodiment 3 of the present invention.

FIG. 4 is a diagram for explaining Embodiment 4 of the present invention.

FIG. 5 is a diagram for describing Embodiment 5 of the present invention.

FIG. 6 is a diagram for describing Embodiment 1 of the present invention.

FIG. 7 is a diagram for describing Embodiment 1 of the present invention.

FIG. 8 is a diagram for describing Embodiment 1 of the present invention.

FIG. 9 is a diagram for describing Embodiment 2 of the present invention.

FIG. 10 is a diagram for describing Embodiment 3 of the present invention.

FIG. 11 is a diagram for describing Embodiment 3 of the present invention.

FIG. 12 is a diagram illustrating an outline of an FM-CW radar device.

FIG. 13 is a diagram illustrating a configuration of a conventional FM-CW radar device.

FIG. 14 is a diagram for explaining the principle of a conventional FM-CW radar device.

FIG. 15 is a diagram for explaining the principle of a conventional FM-CW radar device.

FIG. 16 is a diagram for explaining a problem of a conventional FM-CW radar device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 own vehicle, 2 front vehicles, 3 oncoming vehicles, 4 modulation means, 5 oscillators, 6 directional couplers, 7 transmitting antennas, 8 receiving antennas, 9 mixers, 10 amplifiers, 1
DESCRIPTION OF SYMBOLS 1 A / D converter, 12 Frequency analysis means, 13 Target detection means, 14 Distance speed calculation means, 15 Transceiver, 1
6 transmission frequency, 17 reception frequency, 18a, 18b,
18c Frequency spectrum of target, 19 threshold, 20
1st target object, 21 2nd target object, 22 threshold value, 23
Receiver noise, 24 noise average, 25 threshold, 26
Average value calculation target range, 27 gain control means, 28 noise average value storage means, 29 threshold value calculation means, 30 comparison means, 31 local maximum value detection means, 32 noise pattern storage means, 33 vehicle body inclination detection means, 34 rainfall detection means 35 temperature detecting means, 36 noise component frequency distribution, 37 noise component average value, 38 noise average value for gain, 39 noise component frequency distribution, 40 noise pattern, 41 vehicle, 42 transmit / receive beam, 43
Frequency distribution of noise components, 44 noise patterns.

Claims (5)

[Claims] 1. A vehicle mounted on a vehicle, transmits an FM-CW wave forward, receives a reflected wave from a vehicle ahead or an obstacle, and analyzes a beat signal of the transmitted wave and the received wave to analyze a beat signal of the forward vehicle. Or F to find the distance and speed to the obstacle
In the M-CW radar device, gain control means for controlling the gain of an amplifier for amplifying a beat signal, and noise average value storage means for storing an average value of noise components generated by a transceiver of the FM-CW radar device A threshold value calculating means for determining a threshold value for beat signal determination; a comparing means for comparing the frequency analysis result of the beat signal with the threshold value; and a maximum value detecting means for obtaining a maximum value of the frequency analysis result. FM-CW radar device. 2. A gain control means for controlling a gain of an amplifier for amplifying a beat signal; a noise pattern storage means for storing frequency characteristics of a noise component generated by a transceiver of the FM-CW radar apparatus; 2. The apparatus according to claim 1, further comprising: a threshold value calculating unit that determines a threshold value; a comparing unit that compares the frequency analysis result of the beat signal with the threshold value; and a local maximum value detecting unit that obtains a local maximum value of the frequency analysis result. The FM-CW radar device as described in the above. 3. A gain control means for controlling a gain of an amplifier for amplifying a beat signal; a noise average value storage means for storing an average value of noise components generated by a transceiver of the FM-CW radar apparatus; Body inclination detecting means for detecting the inclination of the vehicle, threshold calculating means for determining a threshold value for beat signal determination, comparing means for comparing the frequency analysis result of the beat signal with the threshold value, and a local maximum for obtaining a maximum value of the frequency analysis result 2. The FM-CW radar device according to claim 1, further comprising a value detection unit. 4. A gain control means for controlling a gain of an amplifier for amplifying a beat signal; a noise average value storage means for storing an average value of noise components generated by a transceiver of the FM-CW radar apparatus; Detecting means, threshold calculating means for determining a threshold value for beat signal determination, comparing means for comparing the frequency analysis result of the beat signal with the threshold value, and local maximum value detecting means for obtaining a local maximum value of the frequency analysis result The FM-CW radar device according to claim 1, wherein: 5. A gain control means for controlling a gain of an amplifier for amplifying a beat signal; a noise average value storage means for storing an average value of noise components generated by a transceiver of the FM-CW radar apparatus; Temperature detecting means for detecting the temperature of the apparatus, threshold calculating means for determining a threshold value for beat signal determination, comparing means for comparing the frequency analysis result of the beat signal with the threshold value, and a local maximum for obtaining a maximum value of the frequency analysis result 2. The FM-CW radar device according to claim 1, further comprising a value detection unit.