JP7501111B2 - Radar device and control method thereof - Google Patents

Description

The present invention relates to a radar device and a control method thereof.

The radar device according to the first conventional example uses a fast chirp modulation (FCM) radar device that detects the distance and relative speed of a target by transmitting chirp waves whose frequency changes continuously. In the radar device according to the first conventional example, chirp signals are transmitted at irregular intervals (randomly) to avoid mutual interference between radars (see, for example, Patent Document 1).

In addition, in order to detect chirp wave interference with high accuracy, a radar device according to the following conventional example 2 has been proposed. Here, the transmitting unit outputs a transmission wave in which multiple chirp waves are repeated by a chirp signal whose frequency changes continuously. In response to this, the receiving unit performs a first FFT process on a beat signal for each chirp wave generated from the chirp signal and a received signal corresponding to the reflected wave of the transmission wave by the target, and then determines the presence or absence of chirp wave interference by comparing the peak state of the frequency spectrum, which is the result of the first FFT process, between the multiple chirp waves.

Japanese Patent Application Laid-Open No. 10-105228 JP 2019-158828 A

However, the radar device according to the first conventional example had a problem in that the chirp signals were not received at equal intervals, leading to an erroneous estimation of the relative speed of the target.

In addition, the radar device according to Conventional Example 2 can indeed detect interference between spectra with high accuracy, but has the problem that the accuracy of estimating the position and relative velocity of a target is low due to the need to remove spectra with interference.

The object of the present invention is to solve the above problems and provide a radar device and a control method thereof that can improve the accuracy of estimating the position and relative velocity of a target, regardless of whether or not interference is detected, compared to conventional techniques.

The radar device according to the present invention comprises:
A radar device comprising: a radio transmitting unit that transmits a plurality of transmission chirp signals at irregular intervals based on a transmission interval signal; and a radio receiving unit that receives the plurality of transmission chirp signals after the plurality of transmission chirp signals are reflected by a target,
The wireless receiving unit includes:
receiving the plurality of transmitted chirp signals as a plurality of received chirp signals at a predetermined reception interval;
detecting a plurality of beat signals by mixing the plurality of received chirp signals with the plurality of transmitted chirp signals;
generating a plurality of equally-spaced beat signals by performing a signal interpolation process on the plurality of beat signals based on the transmission interval signal so that the reception intervals of the plurality of beat signals are substantially the same;
A relative velocity with respect to the target is estimated based on the plurality of equally spaced beat signals.

Therefore, the radar device according to the present invention can improve the accuracy of estimating the position and relative velocity of a target, regardless of whether interference is detected, compared to conventional techniques.

1 is a block diagram showing an example of the configuration of a radar device 100 according to an embodiment. FIG. 11 is a waveform diagram showing a first part of an operation example of a radar device according to an embodiment in which the transmission intervals of transmission chirp signals are unequal. 10A to 10C are waveform, phase and spectrum diagrams showing a second part of an operation example of a radar device according to an embodiment in which the transmission intervals of transmission chirp signals are unequal. 2 is a flowchart showing a range, speed and arrival angle estimation process executed by the radar device 100 of FIG. 1 . 10A to 10C are waveform and spectrum diagrams showing a first part of an operation example of a radar device in which the transmission chirp signals are transmitted at equal intervals in accordance with Comparative Example 1; 10A to 10C are waveform, phase and spectrum diagrams showing a second part of an example of operation of a radar device in which the transmission chirp signals are transmitted at equal intervals in accordance with Comparative Example 1; 11A and 11B are waveform and spectrum diagrams showing a first part of an operation example of a radar device in which the transmission intervals of transmission chirp signals are unequal, in accordance with Comparative Example 2; 10A to 10C are waveform, phase and spectrum diagrams showing a second part of an example of operation of a radar device in which the transmission intervals of transmission chirp signals are unequal, in accordance with Comparative Example 2;

Below, an embodiment of a radar device using the FCM method and a control method thereof according to a comparative example and an embodiment will be described with reference to the attached drawings. Note that the present invention is not limited to these embodiments.

(Comparative Example 1)
4A and 4B are waveform diagrams, phase diagrams, and spectrum diagrams of an operation example of a radar device in which the transmission chirp signals are transmitted at equal intervals according to Comparative Example 1. Below, an overview of the operation example of a radar device in which the transmission chirp signals are transmitted at equal intervals according to Comparative Example 1 will be described with reference to Figs. 4A and 4B.

In FIG. 4A(a), the wireless transmission unit wirelessly transmits multiple transmission chirp signals St with successively higher frequencies at a predetermined transmission interval T based on a predetermined transmission interval signal toward a target. Here, the transmission interval T is expressed by the following formula and is constant regardless of the transmission chirp signal St. Note that n is an integer greater than 1.

T = _tn - _tn-1 , n > 1

Here, t _n is the transmission start time.

4A(b) and (c), the wireless receiving unit receives multiple transmitted chirp signals St reflected by targets, mixes a received chirp signal Sr, which is the received transmitted chirp signal, with the transmitted transmitted chirp signal St, and then performs low-pass filtering to detect multiple beat signals y ₁ (t) to y ₃ (t). Here, beat signal y _n (t) is expressed by the following equation:

_yn (t)=sin( _2πfBt + _θn )

Here, f _B is the beat frequency, and the phase difference θ _n is expressed by the following equation.

θ _n =4πv(t _n -t ₁ )/λ

where v is the relative velocity of the target [m/s] and λ is the wavelength of the radio signal including the transmitted chirp signal.

4A(d), the beat signal _yn (t) is converted to a distance spectrum _Rn (ω) of the beat signal _yn (t) by performing FFT (Fast Fourier Transformation). Here, the distance spectrum _Rn (ω) of the beat signal _yn (t) is expressed by the following equation.

R _n (ω) = 10 log ₁₀ | Y _n (ω) | ²
|Y _n (ω)|exp(−jω+θ _n )=FFT[y _n (t)]

Here, FFT[ ] is the Fast Fourier Transform operator.

In FIG. 4B(a), a peak value R _np of the distance spectrum R _n (ω) of the beat signal y _n (t) is detected, and then in FIG. 4B(b), its phase θ _n is extracted.

When the phase _θn of the peak value _Rnp of the distance spectrum _Rn (ω) of the extracted beat signal _yn (t) is represented on the time axis, it becomes as shown in FIG. 4B(c). By performing an FFT on this graph, it is converted into the velocity spectrum V(ω) of FIG. 4B(d). Based on the peak value, the relative velocity v of the target can be calculated using the following equation.

v = λΔθ / (4πT)
Δθ＝ _θ2 − _θ1

(Comparative Example 2)
In contrast, a comparative example 2 in which the transmission interval T is an irregular interval _Tn will be described with reference to Fig. 5A and Fig. 5B. Fig. 5A and Fig. 5B are waveform diagrams, phase diagrams, and spectrum diagrams showing an operation example of a radar device in which the transmission intervals of the transmission chirp signal St are irregular according to the comparative example 2.

5A(a), the wireless transmitter repeatedly transmits a plurality of transmission chirp signals St with successively increasing frequencies at unequal transmission intervals _Tn based on a predetermined transmission interval signal, and wirelessly transmits the signals to a target. Here, the transmission intervals _Tn are expressed by the following equation and are not constant regardless of the transmission chirp signal St. Here, n is an integer greater than 1.

T _n =t' _n -t' _n-1 , n>1

Here, _t'n is the transmission start time.

5A(b) and (c), the wireless receiving unit receives multiple transmitted chirp signals S t reflected by targets, mixes the received transmitted chirp signal Sr with the transmitted transmitted chirp signal S t , and then performs low-pass filtering to detect multiple beat signals y ₁ (t) to y ₃ (t), where beat signal y _n (t) is expressed by the following equation:

_yn (t)=sin( _2πfBt + _θn )

Here, f _B is the beat frequency, and the phase difference θ _n is expressed by the following equation.

θ _n =4πv(t' _n -t' ₁ )/λ

Here, v is the relative velocity of the target [m/s], and λ is the wavelength of the radio signal including the transmitted chirp signal S t .

5A(d), the beat signal _yn (t) is converted to a distance spectrum _Rn (ω) of the beat signal _yn (t) by performing FFT (Fast Fourier Transformation). Here, the distance spectrum _Rn (ω) of the beat signal _yn (t) is expressed by the following equation.

R _n (ω) = 10 log ₁₀ | Y _n (ω) | ²
|Y _n (ω)|exp(−jω+θ _n )=FFT[y _n (t)]

In FIG. 5B(a), a peak value R _np of the distance spectrum R _n (ω) of the beat signal y _n (t) is detected, and then in FIG. 5B(b), its phase θ _n is extracted.

When the phase _θn of the peak value _Rnp of the distance spectrum _Rn (ω) of the extracted beat signal _yn (t) is represented on the time axis, it becomes as shown in Fig. 5B(c), and when this is compared with the true value, it becomes as shown in Fig. 5B(d), and it is clear that the estimated value deviates from the true value. By performing an FFT on this graph, it can be converted into the velocity spectrum V(ω) of Fig. 5B(e) and the relative velocity v of the target can be calculated based on the peak value, but it is clear that an error will occur in the relative velocity v of the target.

That is, the relative speed v is expressed by the following equation, but because the transmission interval T in the denominator is not constant, an error occurs in the relative speed v.

v = λΔθ / (4πT)
Δθ＝ _{θ2 −θ1}

(Embodiment)
In the embodiment according to the present invention, in order to reduce the above-mentioned error, in the comparative example 2, the reception intervals are corrected so that a plurality of beat signals are spaced at equal intervals.

Figure 1 is a block diagram showing an example of the configuration of a radar device 100 according to an embodiment. The example of the configuration of the radar device 100 is described below.

In Fig. 1, the radar device 100 estimates the distance and relative speed of a target by using, for example, an FCM (Fast Chirp Modulation) method. In the FCM method, a transmission chirp signal, which is a repetition of multiple chirp signals whose frequencies change continuously, is wirelessly transmitted to the target to detect the distance and relative speed of each target present within a detection range. Specifically, the FCM method estimates the distance and relative speed of the target by performing two-dimensional fast Fourier transform processing (hereinafter referred to as two-dimensional FFT processing) on multiple beat signals y _n (t) for each chirp signal generated from a modulated signal that generates multiple chirp signals St and a received signal obtained by receiving a reflected wave of the transmission signal by the target. Note that the two-dimensional FFT processing includes two FFT processes, a distance FFT process and a speed FFT process.

In FIG. 1, the radar device 100 includes a wireless transmitter 1, a wireless receiver 2, and a signal processor 3. Here, the wireless transmitter 1 includes a transmission controller 10, a modulated signal generator 11, an oscillator 12, a power amplifier 13, and a transmission antenna 14. The wireless receiver 2 includes one or more N receiving antennas 21-1 to 21-N (hereinafter collectively referred to as 21), a plurality of N low noise amplifiers 22-1 to 22-N (hereinafter collectively referred to as 22), a plurality of N mixers 23-1 to 23-N (hereinafter collectively referred to as 23), a plurality of N low pass filters (LPFs) 24-1 to 24-N (hereinafter collectively referred to as 24), and a plurality of N analog-to-digital converters (ADCs) 25-1 to 25-N (hereinafter collectively referred to as 25). Furthermore, the signal processing unit 3 includes a plurality of N reception interval correction units 31-1 to 31-N (hereinafter collectively referred to as 31), a plurality of N distance and speed estimation units 32-1 to 32-N (hereinafter collectively referred to as 32), and an arrival angle estimation unit 33.

A transmission control unit 10 of the wireless transmission unit 1 generates a transmission interval signal Si having unequal transmission intervals _Tn and outputs the signal to a modulation signal generation unit 11 and a reception interval correction unit 31. The modulation signal generation unit 11 generates a modulation signal whose frequency changes in a triangular wave shape, such as a sawtooth wave shape, and outputs the modulation signal to an oscillator 12. The oscillator 12 generates a transmission chirp signal St having unequal transmission intervals _Tn in accordance with the modulation signal, which is output to a transmission antenna 14 via a power amplifier 13, and a wireless signal including the transmission chirp signal St is radiated from the transmission antenna 14 toward a target.

The transmission chirp signal St from the oscillator 12 is also distributed to the mixer 23 of the wireless receiver 2. The transmission interval signal Si is also distributed to the reception interval correction unit 31 of the wireless receiver 2.

In the radio receiving unit 2, a plurality of N receiving antennas 21 constituting an array antenna receive radio signals including a transmission chirp signal St, which is a reflected wave from a target, as a reception radio signal including a reception chirp signal Sr, and output the reception radio signal to a mixer 23 via a low-noise amplifier 22. Each mixer 23 mixes the reception chirp signal Sr included in the reception radio signal from each low-noise amplifier 22 with the transmission chirp signal St from the oscillator 12, and outputs the result to each low-pass filter 24. Each low-pass filter 24 performs low-pass filtering to remove unnecessary signal components from the input mixed signal, thereby detecting a beat signal _yn (t) having a beat frequency _fB and outputting the result to each AD converter 25. Each AD converter 25 AD-converts the input beat signal _yn (t) into a digital beat signal, and outputs the digital beat signal to each reception interval correction unit 31 of the signal processing unit 3.

The number N of the receiving antennas 21, etc. shown in FIG. 1 is, for example, 1 or more. In this embodiment, distance estimation or speed estimation is possible with one receiving antenna 21, but two or more receiving antennas 21 are required to estimate the angle of arrival.

The signal processing unit 13 is configured by a microcomputer including, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), input/output ports, etc., and controls the entire radar device 100.

Each reception interval correction unit 31 performs signal interpolation processing on the input beat signal _yn (t) at intervals shorter than the transmission interval _Tn that satisfies the desired maximum detectable speed, based on the transmission interval signal Si from the transmission control unit 10, to generate beat signals _yn (t) with a predetermined equal interval T. Here, the beat signals _yn (t) with equal intervals T are expressed by the following equation.

y _en (t)
= _yn (t) + ( _yn (t) - _yn-1 (t)) / (tn _{- t'n-1} )
× (t' _n - t' _{n - 1} )

Here, signal interpolation (interpolation) is performed, but the present invention is not limited to this, and signal extrapolation processing (extrapolation) may be performed to generate beat signals y _en (t) having predetermined equal intervals T. Note that the signal interpolation processing can use known signal interpolation methods such as linear interpolation, multi-order spline function method, Lagrange interpolation method, exponential spline interpolation method, and least squares method-based interpolation method.

Each distance and velocity estimation unit 32 performs known two-dimensional FFT processing (distance FFT processing and velocity FFT processing) on the beat signal y _en (t) output from each reception interval correction unit 31, calculates the distance and relative velocity of the target based on the result of the two-dimensional FFT processing, and outputs the calculated distance and relative velocity to the arrival angle estimation unit 33. Each distance and velocity estimation unit 32 may further determine the presence or absence of interference using the result of the distance FFT processing.

That is, each distance and speed estimation unit 32 detects interference by focusing on the difference in the peak state in the beat signal y _en (t). Specifically, the presence or absence of interference between the multiple received chirp signals Sr is determined by comparing the peak states (peak value, number of peaks, and position of peaks) of the results of the distance FFT processing between the multiple received chirp signals Sr. For example, if there is a chirp signal among the multiple received chirp signals that has a different peak state, such as the number of peaks or the position of peaks, from the other received chirp signals, it is determined that the chirp signal is being interfered with. In this way, the radar device 100 can detect interference of the received chirp signal with high accuracy by comparing the peak states of the results of the distance FFT processing. In particular, interference with a radar device other than the radar device 100, for example, mounted on another vehicle, can also be detected with high accuracy.

The arrival angle estimator 33 estimates the arrival angle of the target by a predetermined known arrival angle calculation process based on the multiple received chirp signals Sr or the beat signal _yn (t) generated based on the multiple received chirp signals Sr. For example, the arrival angle estimator 33 estimates the arrival angle of the target based on the difference in phase of the peaks of the same distance bin of each of the frequency spectra of the multiple beat signals _yn (t) based on the multiple received signals received by the receiving antenna 21. Note that, when it is detected that multiple targets exist in the same distance bin based on the difference in the phase of the peaks of the same distance bin, the arrival angle estimator 33 performs angle estimation for each of the multiple targets. Note that the angle estimation in the arrival angle estimator 33 is performed using a known estimation method such as ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques), DBF (Digital Beam Forming), or MUSIC (Multiple Signal Classification).

The arrival angle estimation unit 33 outputs information related to the distance and relative speed to the target estimated by each distance and speed estimation unit 32, in addition to the calculated arrival angle of the radio signal reflected by the target, to the other control device 200. Note that in FIG. 1, the other control device 200 is another radar device, or a control device that comprehensively controls the radar device 100 and the other radar devices.

2A and 2B are waveform and spectrum diagrams showing an example of the operation of a radar device according to an embodiment in which the transmission chirp signals are transmitted at irregular intervals.

2A(a), the wireless transmitter 1 wirelessly transmits a plurality of transmission chirp signals St, the frequencies of which successively increase, at unequal transmission intervals _Tn , to a target, based on a transmission interval signal Si. Here, the transmission interval _Tn is expressed by the following equation and is not constant regardless of the transmission chirp signal St, where n is an integer of 1 or more.

T _n =t' _n -t' _n-1 , n>1

Here, _t'n is the transmission start time.

2A(b) and (c), the wireless receiving unit 2 receives multiple transmitted chirp signals St reflected by targets, mixes the received transmitted chirp signal Sr with the transmitted transmitted chirp signal S t , and then performs low-pass filtering to detect multiple beat signals y ₁ (t) to y ₃ (t). Here, the beat signal y _n (t) is expressed by the following equation:

_yn (t)=sin( _2πfBt + _θn )

Here, f _B is the beat frequency, and the phase difference θ _n is expressed by the following equation.

θ _n =4πv(t' _n -t' ₁ )/λ

Here, v is the relative velocity of the target [m/s], and λ is the wavelength of the radio signal including the transmitted chirp signal S t .

2A(d), each reception interval correction unit 31 performs signal interpolation processing on the input beat signal _yn (t) at intervals shorter than the transmission interval Tn that satisfies the desired maximum detectable speed, based on the transmission interval signal Si from the transmission control _{unit 10} , to generate beat signals _yn (t) with a predetermined equal interval T. Here, the beat signals _yn (t) with equal intervals T are expressed by the following equation.

y _en (t)
= _yn (t) + ( _yn (t) - _yn-1 (t)) / (tn _{- t'n-1} )
× (t' _n - t' _n-1 )

2B(a), an FFT (Fast Fourier Transformation) is performed on the signal-interpolated equally-spaced beat signal y _en (t) to convert it into a distance spectrum R _n (ω) of the equally-spaced beat signal y en (t). Here, the distance spectrum _{R n (} ω) of the equally-spaced beat signal y _en (t) is expressed by the following equation.

R _n (ω) = 10 log ₁₀ | Y _en (ω) | ²
|Y _en (ω)|exp(-jω+θ _n )=FFT[y _en (t)]

In FIG. 2B(b), a peak value R _np of the distance spectrum R _n (ω) of the equally spaced beat signal y _en (t) is detected, and then in FIG. 2B(c), its phase θ _n is extracted.

When the phase _θn of the peak value _Rnp of the distance spectrum _Rn (ω) of the generated equally-spaced beat signal _yen (t) is represented on the time axis, it becomes as shown in Fig. 2B(c) as in Comparative Example 1, and the distance and relative velocity to the target can be estimated with higher accuracy than in the prior art. By performing an FFT on this graph, it is possible to convert it into the velocity spectrum V(ω) in Fig. 2B(d) and calculate the relative velocity v of the target based on the peak value, and no error occurs in the relative velocity v of the target.

Figure 3 is a flowchart showing the distance, speed and arrival angle estimation process performed by the radar device 100 of Figure 1.

In step S1 of FIG. 3, the wireless transmission unit 1 transmits a chirp signal at a predetermined irregular interval and outputs a transmission interval signal Si including the irregular interval to the reception interval correction unit 31.

Next, in step S2, the wireless receiving unit 2 receives the chirp signal, mixes the received chirp signal with the transmitted chirp signal, and performs low-pass filtering to detect multiple beat signals, and outputs the detected multiple beat signals to the signal processing unit 3 after AD conversion. In step S3, the receiving interval correction unit 31 of the signal processing unit 3 generates an evenly spaced beat signal sequence by performing signal interpolation processing based on the transmitting interval signal Si so that the receiving intervals of the multiple beat signals are the same.

Furthermore, in step S4, the distance and velocity estimation unit 32 of the signal processing unit 3 performs distance and velocity estimation processing on the equally spaced beat signal sequence to calculate the distance and velocity corresponding to each beat signal. Note that here, the presence or absence of interference between each distance spectrum may be determined, and if there is interference, the distance spectrum with interference may be removed, or otherwise converted into a predetermined distance spectrum from which the effects of interference have been removed, and then distance and relative velocity estimation and arrival angle estimation may be performed with higher accuracy.

Next, in step S5, the arrival angle estimation unit 33 of the signal processing unit 3 executes an arrival angle estimation process based on the phase difference of the received chirp signals received by each receiving antenna 21, and calculates the arrival angle corresponding to each beat signal. Furthermore, in step S6, an estimation result signal including the estimated distance, speed, and arrival angle is output to the other control device 200, and the estimation process is terminated.

(Effects of the embodiment)
As described above, according to the radar device 100 of this embodiment, by providing each reception interval correction unit 31 corresponding to each reception antenna 21, it is possible to generate equally spaced beat signals y _en (t) in the wireless reception unit 2. By estimating the distance to the target, the relative speed, and the arrival angle based on this, it is possible to perform estimation with higher accuracy than with the conventional technology.

Furthermore, each distance and speed estimation unit 32 detects the interference state of the beat signal y _en (t) to determine the presence or absence of interference, removes the beat signal y _en (t) with interference, and estimates the distance, relative speed, and arrival angle from the target, thereby enabling more accurate estimation than in the prior art. That is, before estimating the distance and relative speed, the beat signal is corrected to one obtained at equal reception intervals using the relationship between the transmission interval and the beat signal, making it possible to achieve both interference avoidance and speed estimation. In other words, when interference occurs, the effect of the interference can be removed and the distance, relative speed, and arrival angle can be accurately estimated.

In other words, this embodiment can be applied regardless of whether or not interference detection is performed.

(Modification)
In the above embodiment, the transmission chirp signal St has a continuously increasing frequency (i.e., an up-chirp), but it may be a chirp signal whose frequency decreases continuously (i.e., a down-chirp), or a combination thereof.

In the above embodiment, a radar device using the FCM method has been described, but the present invention is not limited to this and can be applied to radar devices using the FMCW modulation method or the pulse compression modulation method.

In the above embodiment, the position and relative velocity of the target are estimated, but the present invention is not limited to this, and may be configured to estimate only the relative velocity of the target.

Further advantages and modifications to the above embodiments may be readily derived by those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof.

As described above in detail, the radar device and the control method thereof according to the present invention improve the estimation accuracy of the target position and relative speed compared to the conventional technology, regardless of the presence or absence of interference determination. For example, it can be used as a technical means for achieving interference avoidance and speed estimation accuracy in a millimeter wave radar for road monitoring. As a specific application, the radar device can be attached to traffic lights and traffic signs to detect the position and speed of vehicles and perform traffic counting to ease congestion.

In other words, it is possible to perform more accurate speed estimation while avoiding interference between radars. This allows users to obtain accurate position information (distance, relative speed, and azimuth, which is the angle of arrival) of targets that are reflective objects, which will assist autonomous driving and reduce the occurrence of traffic accidents.

1 Radio transmitter 2 Radio receiver 10 Transmission control unit 11 Modulation signal generator 12 Oscillator 13 Power amplifier 14 Transmitting antennas 21, 21-1 to 21-N Receiving antennas 22, 22-1 to 22-N Low noise amplifiers 23, 23-1 to 23-N Mixers 24, 24-1 to 24-N Low pass filter (LPF)
25, 25-1 to 25-N Analog-to-digital converter (ADC)
31, 31-1 to 31-N reception interval correction units 32, 32-1 to 32-N distance and speed estimation unit 33 arrival angle estimation unit 100 radar device 200 other control devices

Claims (10)

A radar device comprising: a radio transmitting unit that transmits a plurality of transmission chirp signals at irregular intervals based on a transmission interval signal; and a radio receiving unit that receives the plurality of transmission chirp signals after the plurality of transmission chirp signals are reflected by a target,
The wireless receiving unit is
receiving the plurality of transmit chirp signals as a plurality of receive chirp signals;
detecting a plurality of beat signals by mixing the plurality of received chirp signals with the plurality of transmitted chirp signals;
generating a plurality of equally-spaced beat signals by performing a signal interpolation process on the plurality of beat signals based on the transmission interval signal so that the reception intervals of the plurality of beat signals when received as the plurality of received chirp signals are substantially the same;
estimating a relative velocity between the target and the target based on the plurality of equally spaced beat signals ;
The wireless receiving unit further comprises:
converting the plurality of equally spaced beat signals into a plurality of distance spectra of beat signals;
extracting peak states of a plurality of distance spectra of the beat signal;
determining whether or not there is interference between the plurality of received chirp signals based on peak states of the plurality of distance spectra;
Radar equipment. The wireless receiving unit further estimates a distance to the target based on the plurality of equally spaced beat signals.
The radar device according to claim 1 . The transmit chirp signals each have a continuously varying frequency.
3. A radar device according to claim 1 or 2. The wireless receiving unit estimates an arrival angle of the target based on the received chirp signals or beat signals.
The radar device according to any one of claims 1 to 3. the wireless receiving unit converts a range spectrum of the received chirp signal determined to have interference into a predetermined range spectrum from which the influence of the interference has been removed, and then estimates a range and a relative speed to the target based on the converted range spectrum;
The radar device according to claim 1 . A method for controlling a radar device including a wireless transmitter that transmits a plurality of transmission chirp signals, each having a continuously changing frequency, at irregular intervals based on a transmission interval signal, and a wireless receiver that receives the plurality of transmission chirp signals after the plurality of transmission chirp signals are reflected by a target, the method comprising:
The control method includes:
receiving the plurality of transmit chirp signals as a plurality of receive chirp signals at a receive interval;
detecting a plurality of beat signals by mixing the plurality of received chirp signals with the plurality of transmitted chirp signals;
generating a plurality of equally spaced beat signals by performing signal interpolation processing on the plurality of beat signals based on the transmission interval signal so that the reception intervals of the plurality of beat signals when received as the plurality of received chirp signals are substantially the same;
estimating a relative velocity between the target and the target based on the plurality of equally spaced beat signals;
converting the plurality of equally spaced beat signals into a plurality of distance spectra of beat signals;
extracting a plurality of peak states of the distance spectrum of the beat signal;
determining whether interference exists between the plurality of received chirp signals based on peak states of the plurality of distance spectra;
A method for controlling a radar device comprising the steps of: The control method includes:
estimating a distance to the target based on the plurality of equally spaced beat signals;
The method for controlling a radar device according to claim 6 , further comprising: The transmit chirp signals each have a continuously varying frequency.
A method for controlling a radar device according to claim 6 or 7 . 9. The method for controlling a radar device according to claim 6 , further comprising the step of estimating an arrival angle of the target based on the received chirp signals or beat signals. a step of converting a range spectrum of the received chirp signal determined to have interference into a predetermined range spectrum from which the influence of the interference has been removed, and then estimating a range and a relative velocity to the target based on the converted range spectrum;
The method for controlling a radar device according to claim 6 , further comprising:

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