JP6809674B2 - Arrival wave angle estimation method and arrival wave angle estimation device - Google Patents

Description

The present invention relates to an incoming wave angle estimation method and an incoming wave angle estimation device.

There is a radar device that detects a target. The radar device can calculate the distance to the target, the relative speed, and the direction of the target by transmitting and receiving frequency-modulated electromagnetic waves.

In order to calculate the direction of the target, it is necessary to estimate the direction of arrival of the electromagnetic wave reflected by the target. To estimate the direction of arrival of the electromagnetic wave reflected by the target, estimate the correlation matrix from the received signal, apply the spatial average to reduce the cross-correlation component between the incoming waves (received signal), and use the correlation matrix. The number of incoming waves is estimated, the spectrum is estimated using a high-resolution method, etc., and the direction of arrival is estimated. Multiple receiving antennas are required to identify incoming waves with small angular differences.

Japanese Unexamined Patent Publication No. 2005-249629

There are manufacturing errors and the like in the antenna element of the radar device for each individual. There are variations in antenna characteristics due to manufacturing errors and the like. In a radar device, errors such as gain error, phase error, and mutual coupling between elements occur due to variations in the characteristics of each antenna element. As a result, these errors may result in deterioration of the arrival wave direction estimation accuracy (error of side angle processing). Therefore, if the error model correction method using a plurality of known wave sources according to the number of antenna elements is used to correct the variation in the characteristics of each antenna element, an error such as a gain error can be reduced. A known wave source is a source of electromagnetic waves whose direction is known from the radar device.

The directions of the plurality of known wave sources used in the conventional error model correction method when viewed from the antenna element are set to + 20 °, + 10 °, 0 °, −10 °, −20 °. That is, the angular difference in the directions of adjacent known wave sources is made equal. However, when the angle difference between the directions of adjacent known wave sources is equal, the error in estimating the direction of the incoming wave may become large. Depending on the characteristics of the antenna element, it is not always optimal to make the angle difference between the directions of adjacent known wave sources equal.

An object of the present invention is to improve the accuracy of estimating the direction of the incoming wave.

The present invention employs the following means in order to solve the above problems.
That is, the first aspect is
It is a method of estimating the arrival wave angle that corrects the arrival direction of the target to the radar device that receives the electromagnetic wave from the target by using the error model matrix.
The computer
A predetermined number of signals are selected from a plurality of signals from a known wave source whose direction is known from the radar device, and the error model matrix is calculated.
Using the error model matrix, the directions of all the known sources are estimated, and the sum of the absolute values of the differences between the estimated directions of the known sources and the actual directions of the corresponding known sources is calculated. Run and
Further, by changing the combination of the predetermined number of signals and repeating the calculation of the error model matrix and the calculation of the absolute value of the difference, the sum is 0 or smaller than the other sums. Performing the calculation of the error model matrix,
The method for estimating the angle of the incoming wave is used.

Aspects of disclosure may be realized by executing the program by an information processing device. That is, the structure of the disclosure can be specified as a program for causing the information processing apparatus to execute the process executed by each means in the above-described embodiment, or as a computer-readable recording medium on which the program is recorded. Further, the structure of the disclosure may be specified by a method in which the information processing apparatus executes the processing executed by each of the above means. The configuration of the disclosure may be specified as a system including an information processing device that performs processing executed by each of the above means.

The steps of writing a program include not only processes performed in chronological order in the order described, but also processes executed in parallel or individually, although not necessarily processed in chronological order. Some steps in writing the program may be omitted.

According to the present invention, the accuracy of estimating the direction of the incoming wave can be improved.

FIG. 1 is a configuration diagram of a radar device 1 according to an embodiment. FIG. 2 is a diagram showing an example of the overall operation flow of estimating the arrival direction of the signal from the target by the radar device 1. FIG. 3 is a diagram showing an example of an operation flow of estimating the arrival direction of a signal from a target by the radar device 1. FIG. 4 is a diagram showing an example of an operation flow for calculating the optimum angle combination of known wave sources. FIG. 5 is a diagram showing an example of an operation flow for calculating the error model matrix. FIG. 6 is a diagram showing an example comparing the method of the embodiment, the conventional correction method, and the error in the arrival direction without correction.

Hereinafter, embodiments will be described with reference to the drawings. The configuration of the embodiment is an example, and the configuration of the invention is not limited to the specific configuration of the disclosed embodiment. In carrying out the invention, a specific configuration according to the embodiment may be appropriately adopted.

[Embodiment]
FIG. 1 is a configuration diagram of a radar device 1 according to the present embodiment. The radar device 1 according to the present embodiment is mounted on a vehicle and can be used to detect targets existing around the vehicle such as other vehicles, signs, and guardrails. The target detection result is output to a vehicle storage device, an ECU (Electrical Control Unit) 2, or the like, and can be used for vehicle control such as a PCS (Pre-crash Safety System). However, the radar device 1 according to the present embodiment may be used for various purposes other than the in-vehicle radar device (for example, monitoring of an aircraft in flight or a ship in flight).

The radar device 1 includes a transmitting antenna 7, an oscillator 8, and a signal generation unit 9. Further, the radar device 1 includes receiving antennas 3 (ch1-4) arranged at equal intervals, mixers 4 (ch1-4) connected to each receiving antenna 3, and AD (Analog to Digital) conversion connected to each mixer 4. A device 5 (ch1-4) and a signal processing device 15 for processing data of each AD converter 5 are provided. Here, the number of the receiving antenna 3, the mixer 4, and the AD converter 5 is set to 4 each, but the number of these is not limited to 4 each. The radar device 1 is an example of an incoming wave angle estimation device.

The radar device 1 may be provided with a dedicated receiving circuit for each receiving antenna, but may be provided with a receiving circuit for collectively receiving the reception signals from all the receiving antennas. In this case, it is necessary to control the receiving antennas corresponding to the receiving circuits to be sequentially switched by time division, but the circuit configuration of the radar device 1 can be made compact.

The radar device 1 generates a transmission wave (chirp) ST by the signal generation unit 9, modulates it by the oscillator 8, and transmits it via the transmission antenna 7. The radar device 1 receives the reflected wave from the target as the received wave SR via the receiving antenna 3. The mixer 4 (ch1-4) obtains a beat signal SB by mixing the received wave SR with a part of the transmitted wave ST and taking the absolute value of the difference between the transmitted wave ST and the received wave SR. In the case of FMCW (Frequency Modulation Continuous Wave), the frequency difference between the transmitted wave ST and the received wave SR increases or decreases in proportion to the distance between the target and the radar device, and this frequency difference becomes a variation component of the distance. In the case of FCM (First Chirp Modulation), the phase difference (phase shift) between the transmitted wave ST and the received wave SR increases or decreases in proportion to the distance between the target and the radar device, so the fluctuation component of the beat signal due to this phase difference Is the variable component of the distance. In addition, when reflected by the target, the received wave SR is affected by the speed of the target, and the frequency difference between the pulses increases or decreases in proportion to the relative speed (Doppler frequency) between the target and the radar device. The fluctuation component of the beat signal due to the frequency difference between the pulses becomes the fluctuation component of the velocity. When there are a plurality of targets having different relative velocities and distances, each receiving antenna 3 receives a plurality of reflected waves having different phase shift amounts and Doppler shift amounts, and beats obtained from each mixer 4 (ch1-4). The signal SB will contain various components corresponding to each target.

The AD converter 5 (ch1-4) obtains a beat signal SB from each mixer 4 (ch1-4), samples the beat signal SB, which is an analog signal, at a predetermined frequency, and converts it into a digital signal.

The signal processing device 15 is a computer including a processor 6 that performs signal arithmetic processing according to a computer program and a memory 16 that stores information related to the arithmetic processing. The memory 16 may be composed of a plurality of memories such as an auxiliary storage unit for storing a computer program and set values, and a main storage unit for temporarily storing information used for arithmetic processing. In the signal processing device 15, the processor 6 executes a computer program when electric power is supplied from the vehicle, and realizes functional units such as a transmission control unit 10, a Fourier transform unit 11, a peak extraction unit 12, and a calculation unit 13. For example, the transmission control unit 10 controls the signal generation unit 9 so as to generate and output a transmission signal based on preset parameters. Since the Fourier transform unit 11 receives the reflected waves from a plurality of targets as a received signal SR in a superposed state, the beat signal SB generated based on the received signal SR is converted into the reflected waves of each target. A process for separating the based frequency component (for example, an FFT (Fast Fourier Transfer) process) is performed. In FFT processing
The reception level and phase information are calculated for each frequency point (sometimes called a frequency bin) set at a predetermined frequency interval. The peak extraction unit 12 detects the peak from the result of the FFT process or the like by the Fourier transform unit 11. Further, the peak extraction unit 12 obtains the distance to the target by detecting the frequency bin in which the peak is generated according to the distance to each target. The calculation unit 13 calculates the correlation matrix based on the signal of the frequency bin in which the peak is generated. The calculation unit 13 estimates the direction in which the target exists based on the correlation matrix.

The signal processing device 15 is configured as, for example, an MCU (Micro Controller Unit).
The configuration is not limited to this, and any configuration may be adopted as long as the functions of the transmission control unit 10, the Fourier transform unit 11, the peak extraction unit 12, and the calculation unit 13 can be realized. Further, the transmission control unit 10, the Fourier transform unit 11, the peak extraction unit 12, and the calculation unit 13 are functional units realized by the processor 6 executing a computer program in cooperation with the memory 16. For convenience, FIG. 1 illustrates each functional unit in the processor 6. Note that these functional units are not limited to the configuration realized by the general-purpose processor 6 based on the computer program (software), and are, for example, by a dedicated arithmetic circuit (hardware) arranged inside or outside the processor 6. It may be a configuration in which all or a part thereof is realized. The memory 16 stores calculation formulas, values, calculation results, and the like used in the calculation. The signal processing device 15 may be a computer independent of the radar device 1. At this time, the signal processing device 15 receives data such as a received signal from the radar device 1. The signal processing device 15 is an example of an incoming wave angle estimation device.

(Operation example)
<Overall>
FIG. 2 is a diagram showing an example of the overall operation flow of estimating the arrival direction of the signal from the target by the radar device 1. The direction of arrival of the signal from the target corresponds to the direction of the target. The operation flow of FIG. 2 is an operation flow executed by the processor 6 when power is supplied to the radar device 1 from a vehicle equipped with the radar device 1. When the drive source of the vehicle is in an operating state, for example, when the drive source is an internal combustion engine and the ignition switch is turned on, the processor 6 is turned on when the hybrid system or EV (Electric Vehicle) system is used. In this case, the operation flow of FIG. 2 is started.

In S101, transmission control is performed so that the processor 6 of the radar device 1 outputs a transmission signal ST according to predetermined parameters according to the target detection speed range, speed resolution, detection distance range, etc. according to the required specifications of the radar device 1. The unit 10 causes the signal generation unit 9 to instruct the generation and output of the transmission signal ST. The transmission control unit 10 instructs the signal generation unit 9 to generate and output the transmission signal ST. The signal control unit 9 generates a transmission signal ST based on the instruction.

When the transmission signal ST generated based on the instruction is transmitted from the transmission antenna 7 via the transmitter 8 and the reflected wave reflected by the target is received by the reception antenna 3 as the reception signal SR, the mixer 4 A beat signal SB is generated from the transmission signal ST and the reception signal SR, and the AD converter 5 (ch1-4) A / D-converts the beat signal SB.

In S102, the Fourier transform unit 11 of the processor 6 acquires the A / D-converted signal by the AD converter 5 (ch1-4) and performs FFT (Fast Fourier Transform) processing.

In S103, the peak extraction unit 12 of the processor 6 detects the peak (frequency bin) from the processing result of S102. The distance to the target is calculated based on this peak.

The process of acquiring the beat signal SB generated from the received signal SR and detecting the peak is executed for each of the beat signals generated from the received signal SR received by the receiving antenna 3.

In S104, the arithmetic unit 13 of the processor 6 receives the reflected wave reflected by the target with the receiving antenna 3, and the direction of the target (direction of arrival of the reflected wave) based on the received signal SR or the signal based on the received signal SR. ) Is estimated. A specific method for estimating the direction of the target will be described in detail later. The calculation unit 13 outputs the detection result of the target to the storage device (memory 2 or the like), the ECU 2, or the like. The target detection result includes the distance to the target and the direction of the target.

<Estimation of arrival direction>
FIG. 3 is a diagram showing an example of an operation flow of estimating the arrival direction of a signal from a target by the radar device 1. The operation flow of FIG. 3 is an example of details of the process of S104 of FIG. Here, consider a case where the transmitted wave transmitted from the transmitting antenna 7 is reflected at the target and the reflected wave (received wave) arrives at the plurality of receiving antennas 3.

In S201, the arithmetic unit 13 of the processor 6 corrects the phase error and the amplitude error for the peak of the signal in which the beat signal SB based on the received signal SR by each receiving antenna 3 is Fourier transformed.

The ideal received signal X (vector) is expressed as follows.

Here, n is the noise vector, a (θ _k ) is the kth mode vector, N is the number of antenna elements, d is the antenna element spacing, K is the number of incoming waves, _sk is the kth complex amplitude, and λ is a known wave source. The wavelength of the electromagnetic wave from.

ここで、Ｗは誤差モデル行列、Ｃは素子間相互結合に関する行列、Γは素子間利得・位相誤差である。ここでのＣは、４素子のリニアアレーの受信アンテナの例である。ｄｉａｇ｛・・・｝は、対角行列を表す。 On the other hand, the received signal X when there is an error is expressed as follows.

Here, W is an error model matrix, C is a matrix related to inter-element interconnection, and Γ is an inter-element gain / phase error. Here, C is an example of a receiving antenna of a 4-element linear array. diag {...} represents a diagonal matrix.

The calculation unit 13 corrects the received signal X by using the error model matrix W. The corrected received signal X ~ is expressed as follows.

The characteristics of the antenna of the radar device 1 are corrected by W. By appropriately obtaining W, the arrival direction estimation error can be reduced. Other methods may be used as specific methods for correcting the phase error and the amplitude error.

In S202, the calculation unit 13 calculates the reception correlation matrix R. Each component of the received signal X is the peak value of the signal processed in S201 for each receiving antenna 3.

ここで、［・］^Ｈは、複素共役転置を表す。 The reception correlation matrix R is expressed as follows using the corrected reception signals X ~.

Here, [・] ^H represents a complex conjugate transpose.

In S203, the calculation unit 13 performs the direction calculation using the reception correlation matrix R calculated in S202. The size of the correlation matrix R corresponds to the number of elements in the antenna array.

As the directional calculation, for example, DBF, Capon, high resolution method MUSIC (MUltiple SIgnal Classification), MODE, and the like are used. The method of directional calculation is not limited to these.

In S204, the calculation unit 13 extracts the angle of the target (the angle in the direction of arrival of the signal from the target). The calculation unit 13 obtains the direction of arrival of the signal from the target based on the direction calculation in S203. The arrival direction obtained here is the estimated arrival direction of the signal from the target.

<Calculation of the optimum angle combination of known wave sources>
FIG. 4 is a diagram showing an example of an operation flow for calculating the optimum angle combination of known wave sources. The operation flow of FIG. 4 is an operation flow of calculating the error model matrix W by combining the optimum angles of known wave sources used in the phase / amplitude correction of S201 of FIG. The error model matrix W based on the combination of the optimum angles of the known wave sources is calculated for each radar device 1. Here, it is assumed that the number of elements of the receiving antenna 3 of the antenna array included in the radar device 1 is 4.

In S301, the arithmetic unit 13 of the radar device 1 receives an electromagnetic wave from a known wave source as a reception signal. A predetermined direction from the radar device 1 on a predetermined plane is 0 ° (for example, a front direction on a horizontal plane), and -20 ° to + 20 ° on the predetermined plane is a known wave source direction (angle). .. The range from −20 ° to + 20 ° is the angle estimation range in the radar device 1. The angle estimation range is a range in which the radar device 1 estimates the arrival direction of the target. Here, known wave sources are installed from −20 ° to + 20 ° in 1 ° increments, and the radar device 1 individually receives reception signals from each known wave source. That is, the radar device 1 receives reception signals from 41 types of directions (−20 °, ..., 0 °, ..., + 20 °). The radar device 1 stores the received signal in the memory 16 or the like after performing a predetermined process.

ここで、Θ_ｎ，ｍは、第ｎ回目の選択における、ｍ番目の角度の組み合わせを示す。また、θ_ｎ，ｍ ^（ｐ）は、第ｎ回目の選択における、ｍ番目の角度の組み合わせのＰ番目の要素（角度）を示す。θ_ｎ，ｍ ^（ｐ）のうち、最も角度の小さいものがｐ＝１、最も角度の大きいものがｐ＝Ｐとなる。 In S302, the calculation unit 13 selects the angle of the known wave source used in the calculation of the error model matrix. The calculation unit 13 selects P types of angles. The number of types P of known wave source angles used in the calculation of the error model matrix is the number of elements of the receiving antenna 3 + 1. In the first selection, the calculation unit 13 selects the maximum angle, the minimum angle, and the angle between the minimum angle and the maximum angle at equal intervals of P-1 among the angles of the known wave sources. To do. For example, when selecting 5 types of angles from the above 41 types of angles (-20 °, ..., 0 °, ..., + 20 °), + 20 °, -20 °, + 10 °, 0 ° and -10 ° are selected. When arranged from the smallest, they are -20 °, -10 °, 0 °, + 10 °, and + 20 °. In the first selection, only this one combination is selected. Here, this combination Θ ₁ , ₁ is expressed as follows.

Here, Θ _{n and m} indicate the combination of the m-th angles in the nth selection. Further, θ _{n and m} ^(p) indicate the P-th element (angle) of the m-th angle combination in the nth selection. Of θ _{n and m} ^(p), the one with the smallest angle is p = 1, and the one with the largest angle is p = P.

In the nth selection (n is an integer of 2 or more), the calculation unit 13 selects one of the angles included in the combination Θ _{n, m0} of the angles having the smallest average error in the _n-1th selection. All combinations of one angle plus + 1 ° or -1 ° are used as the angle combination in the nth selection. Therefore, when P = 5, the combination in the nth selection is as follows.

However, combinations including those in which θ _{n and m} ^(p) are outside the angle estimation range are excluded. Therefore, the number of angle combinations in the nth selection is from 2 × P-2 to 2 × P. For example, when P = 5, the number of angle combinations is 8 to 10. Here, the set G _n of the combination of the angles of the nth selection is expressed as follows.

Here, Mn in the nth selection is the number of combinations of angles. Further, the arithmetic unit 13, among the elements of _{G n,} excluding those contained in the elements from _{G 1} to _{G n-1.} This is because what is included in the elements from G ₁ to G _n-1 has already been evaluated. It represents a set G _{n 'combinations} of angle after the process in the following manner.

Here, Mn'(≦ Mn) is the number of combinations of angles after the above treatment.

In S303, calculation unit 13 uses the received signal from a known wave source of angles included in the combination of the set G _{n 'selected} in S302, the error model matrix W for the combination of the m-th angle of the n-th Calculate _{n and m} . The calculation of the error model matrix W _{n, m} will be described later.

In S304, the calculation unit 13 uses the error model matrices Wn _{and m} for each combination calculated in S303 to operate the operation of FIG. 3 for all received signals (received signals at all angles) from known wave sources. The arrival direction is estimated from the flow.

In S305, the calculation unit 13 calculates the absolute value of the difference between the arrival direction estimated for the received signal at each angle and the direction of the actual known wave source corresponding to the received signal for each combination calculated in S303. .. Let ε _{n, m} be the average value of the absolute values of the differences with respect to the nth m-th angle combination. Further, among the nth combination of angles, the one having the smallest average value of the absolute values of the differences is defined as ε _{n and m0} .

In S306, the calculation unit 13 determines whether or not to end the search for the combination of angles. The calculation unit 13 determines whether or not ε _{n and m} 0 are 0. When ε _{n and m0} are 0 (S306; YES), the process proceeds to S307. When ε _{n, m0} is not 0, the calculation unit 13 compares ε _{n-1, m0} and ε _{n, m0} , which have the smallest average value of the absolute values of the differences in the _{n-1th time} . If ε _{n-1, m0} is smaller (S306; YES), the process proceeds to S307. When ε _{n-1, m0} is larger (S306; NO), the process returns to S302.

In S307, the calculation unit 13 outputs the optimum combination of known wave source angles. When ε _{n and m} 0 are 0, the calculation unit 13 outputs Θ _{n and m} 0 as the optimum combination of known wave source angles. When ε _{n and m0} are not 0, the calculation unit 13 outputs Θ _{n-1, m0} as the optimum combination of known wave source angles.

In S308, the calculation unit 13 calculates the error model matrix W by using the received signal of the angle combination of the optimum known wave source angles output in S307. The error model matrix W calculated here is the optimum error model matrix for the radar device 1.

<Calculation of error model matrix>
FIG. 5 is a diagram showing an example of an operation flow for calculating the error model matrix. The operation flow of FIG. 5 is an operation flow of calculating the error model matrices Wn _{and m} used in the error model estimation process of S303 of FIG. Here, the calculation unit 13 calculates the error model matrix W _{n, m} by using the received signal from the known wave source of the angle included in the combination Θ _{n, m} . In S303 of FIG. 4, the calculation unit 13 calculates an error model matrix for all the combinations included in the _nth set G _n '.

In S401, the calculation unit 13 extracts the received signal at the angle included in the combination Θ _{n, m} from the memory 16. The calculation unit 13 calculates the correlation matrix R from the extracted received signal X. The correlation matrix R is obtained as follows.

In S402, the calculation unit 13 performs eigenvalue analysis based on the correlation matrix calculated in S401. The correlation matrix R is expressed as follows using the eigenvector ej and the eigenvalue λj.

In S403, the calculation unit 13 sets the eigenvector ej ^H and the mode vector a (θ).
It is stored in the memory 16. The mode vector a (θ) is obtained based on the wavelength λ of the electromagnetic wave from the known wave source, the interval d of the receiving antennas 3, and the direction θ of the known wave source.

In S404, the arithmetic unit 13 uses the eigenvector ej in the equation for obtaining the error model matrix W.
^H , the mode vector a (θ) is substituted. The equation for obtaining the error model matrix W is expressed as follows.

In S405, the calculation unit 13 calculates the error model matrix W. Since the error model matrix W is W = CΓ, it can be obtained by solving the above equation.

<Comparison example>
FIG. 6 is a diagram showing an example comparing the method of the present embodiment, the conventional correction method, and the error in the arrival direction without correction. The horizontal axis of the graph of FIG. 6 is the direction of the known wave source, which is an angle error. With no correction or with the conventional correction method, an error in the arrival direction occurs, but with the method of the present embodiment (this method), the error in the arrival direction is almost zero.

(Action and effect of this embodiment)
The radar device 1 selects signals from some known wave sources from signals from a plurality of known wave sources and calculates an error model matrix. Radar device 1 estimates the directions of all known sources using the error model matrix. The radar device 1 calculates the difference between the estimated direction of the known wave source and the actual direction of the known wave source. If the difference is not 0, the radar device 1 changes the combination of known wave sources (combination of angles) to be selected and calculates the error model matrix. The radar device 1 changes the combination of known wave sources, repeats the calculation of the error model matrix and the calculation of the direction difference, and calculates the error model matrix in which the difference becomes 0 or the difference becomes smaller.

According to the radar device 1, the accuracy of the arrival wave angle estimation is improved by optimizing the combination of the directions (angles) of the known wave sources used for calculating the error model matrix.

<Computer readable recording medium>
A program that enables a computer or other machine or device (hereinafter, computer or the like) to realize any of the above functions can be recorded on a recording medium that can be read by the computer or the like. Then, by causing a computer or the like to read and execute the program of this recording medium, the function can be provided.

Here, a recording medium that can be read by a computer or the like is a recording medium that can store information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read from the computer or the like. To say. In such a recording medium, elements constituting a computer such as a CPU and a memory may be provided, and the CPU may execute a program.

Further, among such recording media, those that can be removed from a computer or the like include, for example, a flexible disk, a magneto-optical disk, a CD-ROM, a CD-R / W, a DVD, a DAT, an 8 mm tape, a memory card, and the like.

In addition, there are hard disks, ROMs, and the like as recording media fixed to computers and the like.

1 Radar device
2 ECU
3 Receiving antenna
4 mixer
5 A / D converter
6 processor
7 Transmitting antenna
8 transmitter
9 Signal generator
10 Transmission control unit
11 Fourier transform part
12 Peak extraction section
13 Calculation unit
15 Signal processing device
16 memory

Claims (2)

It is an incoming wave direction estimation method that estimates the arrival direction of the electromagnetic wave reflected by the target to a radar device that receives the electromagnetic wave reflected by the target using an error model matrix.
The computer
A predetermined number of signals are selected from a plurality of signals from a known wave source whose direction is known from the radar device, and the error model matrix is calculated.
Using the error model matrix, the directions of all the known sources are estimated, and the sum of the absolute values of the differences between the estimated directions of the known sources and the actual directions of the corresponding known sources is calculated. Run and
Further, by changing the combination of the predetermined number of signals and repeating the calculation of the error model matrix and the calculation of the absolute value of the difference, the sum is 0 or smaller than the other sums. Performing the calculation of the error model matrix,
Arrival wave direction estimation method. It is an arrival wave direction estimation device that estimates the arrival direction of the electromagnetic wave reflected by the target to a radar device that receives the electromagnetic wave reflected by the target using an error model matrix.
A predetermined number of signals are selected from a plurality of signals from a known wave source whose direction is known from the radar device, and the error model matrix is calculated.
A calculation unit that estimates the directions of all the known source sources using the error model matrix, and calculates the sum of the absolute values of the differences between the estimated directions of the known source and the actual direction of the corresponding known source. With
The calculation unit changes the combination of the predetermined number of signals and repeats the calculation of the error model matrix and the calculation of the absolute value of the difference, so that the sum is 0 or the other said. Calculate the error model matrix smaller than the sum,
Arrival wave direction estimation device.

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