JP2012173209A - Fmcw radar system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FMCW radar system, even when intermittently transmitting/receiving signals by one antenna, capable of preventing deterioration of target detection capacity.SOLUTION: The FMCW radar system includes a transmission part, an antenna, a reception part, and an antenna sharing part. The transmission part includes a local signal generation part, a transmission signal generation part, a transmission side mixer, and a transmission side control part for intermittently outputting a transmission/reception start command. The reception part includes a reception side mixer for generating a beat wave, a high-pass filter and a target information extraction part. The transmission signal generation part successively outputs an amplitude gradual increase signal in which amplitude is gradually increased from zero up to a predetermined amplitude after reading the transmission/reception start command, a chirp signal in which frequency is continuously changed in a predetermined range, and an amplitude gradual decrease transmission signal in which amplitude is gradually reduced down to zero.

Description

  The present invention relates to an FMCW radar system, and more particularly to an FMCW radar system in which a two-terminal single-ended mixer is applied as a receiving-side mixer and intermittent transmission / reception is performed using one antenna.

An FMCW (Frequency Modulated Continuous Wave) radar system is known as one type of radar system.
This FMCW radar system not only can measure the distance to the target, but can also detect the relative speed of the target from the frequency difference between the transmitted wave and the received wave due to the Doppler effect, so it aims at measuring the distance between vehicles. An on-vehicle FMCW radar system has already been proposed (see, for example, Patent Document 1).

In order to simplify the system configuration, the FMCW radar system according to the above proposal includes a configuration in which an antenna is used for both transmission and reception and a two-terminal single-ended mixer is used as a mixer.
And when one antenna is used for both transmission and reception, a configuration for preventing a decrease in detection capability due to a leak signal in which a transmission wave leaks to the reception unit is also proposed.

JP 2007-024890 A

  FIG. 12 is a schematic configuration diagram and a waveform graph when the radar system disclosed in Patent Document 1 is configured as an FMCW radar system, where (a) is a schematic configuration, (b) is a transmission / reception timing, ( c) shows a transmission wave waveform, (d) shows a transmission wave mixer output waveform, and (e) shows a high-pass filter output waveform.

  That is, the FMCW radar system disclosed in Patent Document 1 includes a transmission unit 2, an antenna 3, a reception unit 4, and an antenna sharing unit 5, as shown in FIG. An end-type receiving side mixer 41 and a high-pass filter (hereinafter referred to as “HPF”) 42 are included.

The transmission unit 2 generates a chirp signal whose frequency changes within a predetermined range every predetermined period T as shown by the solid line in (b) and (c), and goes from the antenna 3 to the target TG via the antenna sharing unit 5. Radiate.
A reflected wave that is a transmitted wave reflected by the target TG is received as a received wave by the antenna 3 and supplied to the receiving-side mixer 41.

Not all of the transmitted waves are supplied to the antenna 3, but a part of the transmitted waves leaks from the antenna sharing unit 5, becomes a leaky wave, is amplified by the amplifier 40, and then is supplied to the receiving-side mixer 41.
Then, the reception-side mixer 41 outputs the beat wave shown in (d) with the leak wave as a local signal and the reception wave as a reception signal.

Here, since the receiving side mixer 41 is of a single end type, a direct current component is generated at the output of the receiving side mixer 41.
Since this DC component narrows the dynamic range in the process of extracting the target information from the beat wave, the DC component is removed by the HPF 42, and the target information is detected from the beat wave whose DC component is zero as shown in (e). Is extracted.
That is, when a two-terminal single-ended mixer is applied as the receiving-side mixer 41, it is necessary to install the HPF 42 at the subsequent stage.

  However, the radar system disclosed in Patent Literature 1 performs transmission and reception continuously, and is an FMCW radar system that performs transmission and reception intermittently, for example, FMCW that alternately executes antenna directivity control and transmission and reception. The following issues arise when applied to radar systems.

FIG. 13 is a waveform graph when antenna directivity control and transmission / reception are alternately executed in a conventional FMCW radar system, where (f) indicates transmission / reception timing, (g) indicates transmission wave waveform, (h ) Shows the output waveform of the receiving side mixer, and (i) shows the output waveform of the HPF.
That is, when transmission / reception is performed intermittently, the DC component of the output of the consultation-side mixer 41 changes in a step shape at the transmission start time and end time.
Since the step-like change of the DC component includes a high-frequency component, a pulse-like waveform (ringing) is generated at the output of the HPF 42.
For this reason, the problem that a beat wave will be buried in ringing and target detection ability will fall will generate | occur | produce.

  The present invention has been made in view of the above problems, and applies a two-terminal single-ended mixer as a receiving-side mixer, and prevents deterioration of target detection capability even when intermittent transmission / reception is performed with one antenna. An object of the present invention is to provide an FMCW radar system capable of performing the above.

The FMCW radar system according to the present invention includes a transmission unit that generates a transmission wave radiated toward a target, and radiates the transmission wave in the air and receives a reflected wave that is a transmission wave reflected by the target as a reception wave. An FMCW radar comprising: an antenna that extracts information about the target based on the received wave; and an antenna sharing unit that outputs the transmitted wave to the antenna and outputs the received wave to the receiver A system,
The transmission unit generates a local signal, a local signal generation unit, a transmission signal generation unit that generates a transmission signal, a transmission-side mixer that mixes the local signal and the transmission signal into the transmission wave, and the local signal A transmission side control unit that intermittently outputs a transmission / reception start command to the signal generation unit and the transmission signal generation unit,
The receiving unit mixes the transmission wave and the reception wave to generate a beat wave, a high-pass filter that removes a low-frequency component of the beat wave, and the beat from which a low-frequency component has been removed A target information extraction unit that extracts information on the target based on waves,
An amplitude gradually increasing signal in which the transmission signal generation unit gradually increases from zero to a predetermined amplitude after reading the transmission / reception start command, a chirp signal whose frequency continuously changes in a predetermined range at the predetermined amplitude, In addition, an amplitude gradually decreasing transmission signal whose amplitude gradually decreases from the predetermined amplitude to zero is sequentially output.

  According to the above configuration, even when a two-terminal single-ended mixer is applied as the receiving-side mixer and transmission / reception is performed intermittently, ringing that occurs in the output of the HPF can be suppressed.

  In the FMCW radar system according to the present invention, the antenna is a variable directivity antenna, and includes an antenna directivity control unit that controls the directivity of the antenna. The transmission-side control unit includes the antenna directivity control unit. During the execution of the antenna directivity change control, the generation of the transmission wave is stopped, and the transmission / reception start command is output after the antenna directivity change control is completed.

  According to the above configuration, antenna directivity control and target search can be performed alternately.

The control method of the FMCW radar system according to the present invention includes a transmission unit that generates a transmission wave radiated toward a target, and radiates the transmission wave in the air and receives a reflected wave that is a transmission wave reflected by the target. An antenna that receives as a wave, a receiving unit that extracts information on the target based on the received wave, and outputs the transmitted wave generated by the transmitting unit to the antenna and outputs the received wave to the receiving unit And an antenna sharing part,
The transmission unit generates a local signal, a local signal generation unit, a transmission signal generation unit that generates a transmission signal, a transmission-side mixer that mixes the local signal and the transmission signal into the transmission wave, and the local signal A transmission side control unit that outputs a transmission / reception start command to the signal generation unit and the transmission signal generation unit, and
The receiving unit mixes the transmission wave and the reception wave to generate a beat wave, a single-ended reception-side mixer, a high-pass filter that removes a low-frequency component of the beat wave, and information about the target A method for controlling an FMCW radar system comprising: a target information extracting unit for extracting;
The transmission side control unit intermittently outputs a transmission / reception start signal to the local signal generation unit and the transmission signal generation unit, and the transmission signal generation unit sets the amplitude of the transmission signal to zero after reading the transmission / reception start command. A gradually increasing signal that gradually increases from a predetermined amplitude to a predetermined amplitude, a chirp signal whose frequency changes continuously within a predetermined range at the predetermined amplitude, and a gradually decreasing transmission signal that gradually decreases from the predetermined amplitude to zero And outputting the information, and extracting the information about the target based on the frequency of the beat wave from which the low frequency component has been removed.

A control program for an FMCW radar system according to the present invention includes a transmission unit that generates a transmission wave radiated toward a target, and a reflected wave that is a transmission wave that radiates the transmission wave in the air and is reflected by the target. An antenna that receives as a received wave, a receiving unit that extracts information on the target based on the received wave, the transmission wave generated by the transmitting unit is output to the antenna, and the received wave is sent to the receiving unit An antenna sharing unit that outputs, and a control unit that controls the transmission unit and the reception unit, wherein the transmission unit mixes the local signal and the transmission signal, and a local signal generation unit that generates a local signal. A single-ended reception unit that generates a beat wave by mixing the transmission wave and the reception wave. And mixer, a control program of the FMCW radar system comprising a high-pass filter, a removing low-frequency components of the beat wave,
The control unit includes a transmission side control unit that intermittently outputs a transmission / reception start signal to the local signal generation unit and the transmission signal generation unit, and after reading the transmission / reception start command, the amplitude of the transmission signal is changed from zero to a predetermined amplitude A transmission signal that sequentially outputs an amplitude gradually increasing signal that gradually increases until a predetermined amplitude, a chirp signal whose frequency continuously changes within a predetermined range at the predetermined amplitude, and an amplitude gradually decreasing transmission signal that gradually decreases from the predetermined amplitude to zero The generation unit functions as a target information extraction unit that extracts information on the target based on the frequency of the beat wave from which low-frequency components have been removed.

  According to the present invention, an FMCW radar system is provided in which a two-terminal single-ended mixer is used as a receiving-side mixer, and deterioration in target detection capability can be prevented even when intermittent transmission / reception is performed with one antenna. The

It is a functional block diagram of the FMCW radar system concerning the present invention. It is a hardware block diagram of the FMCW radar system which concerns on this invention. It is a flowchart of a main control routine. It is a flowchart of a transmission signal generation routine. It is a graph which shows the time change of a transmission signal. It is a graph which shows the effect of a taper process. It is a flowchart of a reception routine. It is a flowchart of a correction routine. It is a flowchart of the reception routine in the case of applying a correction process. It is a graph which shows the effect of amendment processing. It is a graph which shows the effect at the time of performing a taper process and a correction process simultaneously. It is a schematic block diagram and a waveform diagram of a conventional FMCW radar system. It is a waveform graph at the time of performing the directivity control and transmission / reception of an antenna alternately with the conventional FMCW radar system.

  Embodiments of an FMCW radar system according to the present invention will be described below with reference to the drawings.

  In the embodiment, a FMCW radar system will be described in which a variable directivity antenna is applied as an antenna and antenna directivity control and target search are alternately repeated to extract two-dimensional or three-dimensional target information.

FIG. 1 is a functional block diagram of an FMCW radar system according to the present invention.
That is, the FMCW radar system 1 according to the present invention receives a transmission unit 2 that generates a transmission wave radiated toward the target TG, and a reflected wave that is a transmission wave that is radiated in the air and reflected by the target TG. An antenna 3 that receives a wave, a receiving unit 4 that extracts information about the target based on the received wave, and an antenna sharing unit 5 that outputs the transmitted wave to the antenna 3 and outputs the received wave to the receiving unit 4.

  The transmission unit 2 includes a local signal generation unit 21 that generates a local signal, a transmission signal generation unit 22 that generates a transmission signal, a transmission-side mixer 23 that mixes the local signal and the transmission signal to form a transmission wave, A transmission-side control unit 24 that intermittently outputs a transmission / reception start command to the local signal generation unit 21 and the transmission signal generation unit 22.

  The receiving unit 4 also includes a two-terminal single-ended reception-side mixer 41 that generates a beat wave by mixing a transmission wave and a reception wave, an HPF 42 that removes a low-frequency component of the beat wave, and a low-frequency component. A target information extraction unit 43 that extracts information on the target TG based on the removed beat wave.

FIG. 2 is a hardware configuration diagram of the FMCW radar system according to the present invention.
That is, the radar system 1 according to the present invention includes a local signal generation unit 21, a transmission-side mixer 23, an antenna 3, a reception-side mixer 41, an HPF 42, an antenna sharing unit 5, and a microcomputer 6.
The transmission signal generation unit 22, the transmission side control unit 24, and the target information extraction unit 43 are configured by software by a program incorporated in the microcomputer 6.

  The microcomputer 6 has a configuration in which, for example, a CPU 61, a memory 63, an operation unit 64, a target information display unit 65, and a radar interface (I / F) 66 are coupled to each other around a bus 61.

  Here, the CPU 62 executes a radar control program for controlling the operation of the radar system 1, and the memory 63 stores the radar control program and the processing result of the CPU 62. The display unit 65 functions as a man-machine I / F, and the radar I / F 66 is connected to the local signal generation unit 21, the transmission side mixer 23, the antenna 3, the reception side mixer 41, the HPF 42, and the antenna sharing unit 5. This is for outputting operation commands and taking in feedback signals from these to the microcomputer 6.

Hereinafter, the operation of the radar system according to the present invention will be described with reference to the flowchart of the radar control program.
The microcomputer 6 includes a timer that generates a beam direction control start command and a transmission / reception start command at predetermined time intervals.

FIG. 3 is a flowchart of a main control routine executed by the CPU 62. The CPU 62 prepares to read a beam direction control start command (step S31).
The CPU 62 determines whether or not a beam direction control start command has been read (step S32), and if not, returns to step S31.
When reading the beam direction control start command, the CPU 62 executes beam direction control (step S33).

  The beam direction control is a well-known technique and will not be described in detail. However, the antenna 3 is an array antenna, and the antenna is controlled by controlling a phase shifter (not shown) provided between the antenna 3 and the antenna sharing unit 4. A phased array antenna that changes directivity can be applied.

Next, the CPU 62 prepares to read a transmission / reception start command (step S34).
The CPU 62 determines whether or not a transmission / reception start command has been read (step S35), and if not, returns to step S34.
When reading the transmission / reception start command, the CPU 62 executes transmission / reception (step S36), returns to step S31, and repeats the above processing.

FIG. 4 is a flowchart of a transmission signal generation routine executed by the CPU 62 when transmission / reception is performed. The CPU 62 first generates an amplitude increase signal in which the amplitude gradually increases from zero to a predetermined value at a predetermined initial frequency F _I (eg, 150 MHz). (Step S41).

Next, the CPU 62 generates a chirp signal whose frequency changes with time from the initial frequency to the final frequency F _F (for example, 650 MHz) (step S42), and then the frequency is the final frequency and the amplitude gradually increases from a predetermined value to zero. A decreasing amplitude decreasing signal is generated (step S43), and this routine is finished.

FIG. 5 is a graph showing temporal changes in the transmission signal generated by the transmission signal generation routine, where (A) shows the waveform, (B) shows the frequency, and (C) shows the temporal change in amplitude.
That is, when the amplitude increases signal generator, the frequency of the transmission signal is a F _I, its amplitude increases gradually from zero to the predetermined amplitude A.
When the chirp signal generator, the amplitude of the transmission signal is maintained at a predetermined amplitude A, the frequency varies with time from an initial frequency F _I to a final frequency F _F.
Then, when the amplitude decreasing signal generation, the frequency of the transmission signal is a F _F, the amplitude gradually decreases to zero from a predetermined amplitude A.
In addition, it is desirable that the temporal change of the amplitude is smooth and can be continuously differentiated.

Here, the description of the processing by the microcomputer 6 is temporarily interrupted, and the operations of the receiving side mixer 41 and the HPF 42 which are configured by hardware elements in the receiving unit 4 will be described.
In other words, the receiving-side mixer 41 of the receiving unit 4 of the FMCW radar system 1 according to the present invention is a two-terminal single-ended mixer, and is composed of a half-wave rectifying element such as a diode. It is well known to those skilled in the art that a bipolar transistor or a unipolar transistor (FET) can be used as the half-wave rectifying element.
Two terminals mean an input terminal and an output terminal, and a local signal and a received signal are input from one input terminal.

In the FMCW radar system 1 according to the present invention, the antenna 3 is used for both transmission and reception, and the transmission wave output from the transmission unit 2 is supplied to the antenna 3 via the antenna sharing unit 5.
However, since leakage is actually present in the antenna sharing unit 5, not all transmission waves are supplied to the antenna 3, and part of the transmission waves are supplied to the reception-side mixer 41 as a leak signal and used as local signals. Function. In order to use the leak signal as a local signal, a certain amount of amplification is required. Therefore, the amplifier 40 is actually arranged in front of the two-terminal single-ended mixer. Here, it is desirable that the amplifier 40 be a low noise type amplifier.

A reflected wave, which is a transmitted wave reflected by the target TG, is received as a received wave by the antenna 3 and supplied to the receiving-side mixer 41 via the antenna sharing unit 5.
As a result, the local signal and the reception signal are supplied to the reception side mixer 41 from one input terminal.

Then, the receiving side mixer 41 outputs the received signal and the beat signal of the local signal to the output terminal.
As described above, the reception-side mixer 41 is basically a half-wave rectifier, and the beat signal contains a direct current component because the local signal has a higher strength than the received wave.
Since this direct current component narrows the dynamic range of an A / D converter (not shown) included in the radar I / F 66 of the microcomputer 6, in the FMCW radar system to which the two-terminal single-end mixer is applied, the receiving side mixer is used. An HPF 42 is arranged at the subsequent stage of 41 to remove this DC component.

However, when transmission / reception is executed intermittently as in the FMCW radar system according to the present invention, the DC component included in the output of the receiving-side mixer 41 is zero when transmission / reception is interrupted, and is stepped at the start of transmission / reception. Occurs at the end of transmission and reception, and becomes zero in a stepped manner.
Due to the step-like variation of the DC component, high peak ringing occurs in the output of the HPF 42, and the beat signal containing the target information is buried.

  Therefore, in the FMCW radar system according to the present invention, the peak of ringing is suppressed by a taper process that adds an amplitude gradually increasing signal at the start of transmission and adds an amplitude gradually decreasing signal at the end of transmission as described above. The dynamic range is ensured.

FIG. 6 is a graph showing the effect of the taper processing. The vertical axis represents the amplitude of the output signal of the HPF 42, and the horizontal axis represents time.
When (D) does not perform taper processing, (E) adds 10% (= 0.25 microsecond) amplitude gradually increasing signal and amplitude gradually decreasing signal to 2.5 microsecond transmission time. (F) shows a case where an amplitude gradually increasing signal and an amplitude gradually decreasing signal of 20% (= 0.5 microsecond) are added to the transmission time of 2.5 microseconds, respectively.
From FIG. 6, it can be seen that the taper processing increases the dynamic range of the beat signal as the taper section becomes longer.
However, if the taper section is lengthened, the transmission time also becomes long, so that the reception time for receiving the reflected wave is inevitably long, which is harmful to the high-speed search for the target TG.
On the other hand, when the transmission / reception time is constant, if the taper section is lengthened, the chirp signal section becomes relatively short, and the target information extraction accuracy deteriorates.
Therefore, it is desirable that the taper section is appropriately determined according to the application of the FMCW radar system according to the present invention.

In the FMCW radar system according to the present invention, the output of the HPF 42 is taken into the microcomputer 6 and the information extraction process of the target TG is performed, so the operation of the reception routine will be described again with reference to the flowchart.
FIG. 7 is a flowchart of a reception routine executed when the CPU 62 executes transmission / reception. First, the output signal of the HPF 42 is read via the radar I / F 66 (step S71).

Next, the CPU 62 performs a Fourier transform on the output signal of the HPF 42 to calculate a frequency spectrum (step S72), and extracts target information from the frequency spectrum (step S73). Note that a dedicated DSP may be provided in the microcomputer 6 in order to execute the Fourier transform at high speed.
Then, the CPU 62 displays the target information on the target information display unit 65 which is a display panel, for example, and ends this routine.

In addition, although what kind of information is extracted as target information is not specified in particular, a method for extracting a distance to the target TG will be described below.
That is, the frequency spectrum obtained by Fourier transform of the output signal of the HPF 42, obtaining the frequency f _b exceeds a certain threshold intensity. Here, the threshold value refers to an intensity (level) that serves as a reference value for determining the target TG, and is a parameter that can be arbitrarily set by the user.

たとえば、ｆ_ｂ＝３ＭＨｚ、Ｔ＝２．５マイクロ秒、Δｆ＝４５０ＭＨｚ、Ｃ＝３×１０^８ｍ／秒とすると、Ｒ＝２．５メートルとなる。 Then, the distance R to the target TG is calculated based on [Equation 1].

For example, if f _b = 3 MHz, T = 2.5 microseconds, Δf = 450 MHz, and C = 3 × 10 ⁸ m / second, then R = 2.5 meters.

Next, correction processing for further reducing the influence of ringing will be described.
In this correction process, transmission / reception is performed in the absence of the target TG, the output of the HPF 42 is stored as a correction signal, and the target information is extracted after the correction signal is subtracted from the output of the HPF 42 in the presence of the target TG. Is.

FIG. 8 is a flowchart of a correction routine executed by the CPU 62 before execution of the main control routine (FIG. 3). The CPU 62 executes a transmission signal generation routine (FIG. 4) to generate a transmission signal, and there is no target TG. Radiate into the state space (step S81).
Next, the CPU 62 reads the output signal of the HPF 42 via the radar I / F 66 (step S82) and stores it in the memory 63 as a correction signal (step S83).

FIG. 9 is a flowchart of the reception routine when the correction process is applied. The correction signal is subtracted from the HPF output signal read via the radar I / F 66 between step S71 and step S72 of the reception routine of FIG. Correction processing (step S91) is added.
The processing of other steps is the same as the reception routine of FIG.

FIG. 10 is a graph showing the effect of the correction process. The vertical axis represents the intensity of the frequency spectrum, and the horizontal axis represents the distance to the target TG converted by [Equation 1].
(G) shows the spectrum without correction processing, and (H) shows the spectrum with correction processing.
FIG. 10 shows that the influence of ringing can be reduced by about 10 dB by performing the correction process.

  FIG. 11 is a graph showing the effect when the taper process and the correction process are performed simultaneously. The vertical axis represents the frequency spectrum intensity, and the horizontal axis represents the distance to the target TG converted by [Equation 1].

(I) adds 10% (= 0.3 microsecond) amplitude gradually increasing signal and amplitude gradually decreasing signal to the transmission time of 3 microseconds, and (J) is 3 microseconds when correction processing is performed. A case is shown where a 20% (= 0.6 microsecond) amplitude gradual increase signal and an amplitude gradual decrease signal are added to each transmission time and correction processing is performed.
FIG. 11 shows that the maximum value of the spectrum is further clarified by performing the taper process and the correction process at the same time, and the target can be reliably captured.

  The FMCW radar system according to the present invention is industrially useful because deterioration in target detection capability is prevented even when intermittent transmission / reception is performed with one antenna.

DESCRIPTION OF SYMBOLS 1 ... FMCW radar system 2 ... Transmitter 3 ... Antenna 4 ... Receiver 5 ... Antenna shared unit 6 ... Microcomputer 21 ... Local signal generator 22 ... Transmit signal generator 23 ... Transmitter mixer 24 ... Transmitter side Control unit 40 ... Amplifier 41 ... Receiving side mixer 42 ... HPF
43 ... Target information extraction unit 61 ... Bus 62 ... CPU
63 ... Memory 64 ... Operation unit 65 ... Target information display unit 66 ... Radar interface

Claims (5)

A transmitter for generating a transmission wave radiated toward the target;
An antenna that radiates the transmitted wave into the air and receives a reflected wave that is a transmitted wave reflected by the target as a received wave;
A receiving unit that extracts information on the target based on the received wave;
An FMCW radar system comprising: an antenna sharing unit that outputs the transmission wave to the antenna and outputs the reception wave to the reception unit;
The transmission unit generates a local signal, a local signal generation unit, a transmission signal generation unit that generates a transmission signal, a transmission-side mixer that mixes the local signal and the transmission signal into the transmission wave, and the local signal A transmission side control unit that intermittently outputs a transmission / reception start command to the signal generation unit and the transmission signal generation unit,
The receiving unit mixes the transmission wave and the reception wave to generate a beat wave, a high-pass filter that removes a low-frequency component of the beat wave, and the beat from which a low-frequency component has been removed A target information extraction unit that extracts information on the target based on waves,
An amplitude gradually increasing signal in which the transmission signal generation unit gradually increases from zero to a predetermined amplitude after reading the transmission / reception start command, a chirp signal whose frequency continuously changes in a predetermined range at the predetermined amplitude, And an FMCW radar system that sequentially outputs amplitude gradually decreasing transmission signals whose amplitude gradually decreases from the predetermined amplitude to zero. The receiver is
The beat wave in the state where the target does not exist is stored as a correction signal, and includes a correction unit that subtracts the correction signal from the beat wave in the state where the target exists,
The FMCW radar system according to claim 1, wherein the target information extraction unit extracts information on the target based on the beat wave corrected by the correction unit. The antenna is a variable directional antenna;
An antenna directivity control unit for controlling the directivity of the antenna;
The transmission-side control unit stops generation of the transmission wave while the antenna directivity control unit is executing the antenna directivity change control, and the transmission / reception start command is completed after the change control of the antenna directivity is completed. The FMCW radar system according to claim 1 or 2, wherein the FMCW radar system is output. A transmitter for generating a transmission wave radiated toward the target;
An antenna that radiates the transmitted wave into the air and receives a reflected wave that is a transmitted wave reflected by the target as a received wave;
A receiving unit that extracts information on the target based on the received wave;
An antenna sharing unit that outputs the transmission wave generated by the transmission unit to the antenna and outputs the reception wave to the reception unit;
The transmission unit generates a local signal, a local signal generation unit, a transmission signal generation unit that generates a transmission signal, a transmission-side mixer that mixes the local signal and the transmission signal into the transmission wave, and the local signal A transmission side control unit that outputs a transmission / reception start command to the signal generation unit and the transmission signal generation unit, and
The receiving unit mixes the transmission wave and the reception wave to generate a beat wave, a single-ended reception-side mixer, a high-pass filter that removes a low-frequency component of the beat wave, and information about the target A method for controlling an FMCW radar system comprising: a target information extracting unit for extracting;
The transmission side control unit intermittently outputs a transmission / reception start signal to the local signal generation unit and the transmission signal generation unit;
An amplitude increasing signal in which the transmission signal generation unit gradually increases the amplitude of the transmission signal from zero to a predetermined amplitude after reading the transmission / reception start command, and a chirp in which the frequency continuously changes in a predetermined range at the predetermined amplitude Sequentially outputting a signal and an amplitude gradually decreasing transmission signal that gradually decreases from the predetermined amplitude to zero;
A method for controlling the FMCW radar system, comprising: a step of extracting information on the target based on the frequency of the beat wave from which the low frequency component is removed. A transmitter for generating a transmission wave radiated toward the target;
An antenna that radiates the transmitted wave into the air and receives a reflected wave that is a transmitted wave reflected by the target as a received wave;
A receiving unit that extracts information on the target based on the received wave;
An antenna sharing unit that outputs the transmission wave generated by the transmission unit to the antenna and outputs the reception wave to the reception unit;
A control unit for controlling the transmission unit and the reception unit,
The transmission unit includes a local signal generation unit that generates a local signal, and a transmission-side mixer that mixes the local signal and the transmission signal to form the transmission wave.
The FMCW radar system, wherein the reception unit includes a single-ended reception-side mixer that generates a beat wave by mixing the transmission wave and the reception wave, and a high-pass filter that removes a low-frequency component of the beat wave. Control program
The control unit
A transmission-side controller that intermittently outputs a transmission / reception start signal to the local signal generator and the transmission signal generator;
An amplitude gradually increasing signal that gradually increases the amplitude of the transmission signal from zero to a predetermined amplitude after reading the transmission / reception start command, a chirp signal whose frequency continuously changes within a predetermined range at the predetermined amplitude, and the predetermined signal A transmission signal generator that sequentially outputs amplitude gradually decreasing transmission signals that gradually decrease from zero to zero,
A control program for an FMCW radar system for functioning as a target information extraction unit that extracts information on the target based on the frequency of the beat wave from which low-frequency components have been removed.

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