JP6997589B2 - Direction estimation device, direction estimation method and program - Google Patents

Description

The present invention relates to a directional estimation device, a directional estimation method and a program.

Various methods for identifying the direction of wave sources such as radio waves and sound waves are being researched.
Patent Document 1 describes, as a related technique, a technique of calculating an eigenvalue and a eigenvector of a reception correlation matrix for a received signal and extracting signal components corresponding to an estimated arrival direction based on the calculated eigenvalue and the eigenvector. Are listed.

Japanese Unexamined Patent Publication No. 2006-345113

By the way, as a method of specifying the direction of the wave source, for example, the angle formed by a certain reference line and the direction from the sensor to the wave source (hereinafter referred to as "arrival angle") and the spectrum of the signal transmitted from the wave source are used. A method that can be calculated with high accuracy (MUSIC (Music Signal Classification), beam scanning, etc.) and a method that can easily calculate the arrival angle (rot-MUSIC, ESPRIT (Estimation of Signal Parametrics) Via Rotational In And so on). A method that can calculate the arrival angle and the spectrum of the signal transmitted from the wave source with high accuracy can calculate both the arrival angle and the spectrum of the signal transmitted from the wave source with high accuracy, but one-sided operation. The time is long. Further, the method capable of easily calculating the direction from the sensor to the wave source has a short calculation time, but on the other hand, the spectrum of the signal transmitted from the wave source cannot be obtained.
Therefore, there is a demand for a technique that can obtain both the arrival angle and the spectrum of the signal transmitted from the wave source by simple processing.

An object of the present invention is to provide a directional estimation device, a directional estimation method, and a program capable of solving the above problems.

According to the first aspect of the present invention, the orientation estimation device inputs a specified number of wave sources based on the received signals received by a plurality of sensors, assuming that the number of wave sources is equal to or greater than the true number of wave sources. The input unit, the angle calculation unit that calculates the arrival angle indicating the wave source direction of each wave source of the number of wave sources input by the wave source number input unit, the intensity spectrum for each arrival angle, and the intensity spectrum before and after each arrival angle. A spectrum calculation unit that calculates the intensity spectrum in a predetermined range of angles small enough to find the maximum value even when the change in is large, the intensity spectrum for each arrival angle, and the intensity spectrum before and after each arrival angle. It is provided with an estimation unit for estimating the wave source direction based on an intensity spectrum at an angle in a predetermined range small enough to find a maximum value even when the change is large .

According to the second aspect of the present invention, the orientation estimation device in the first aspect finds a maximum value even when the change between the intensity spectrum for each arrival angle and the intensity spectrum before and after each arrival angle is large. A threshold setting unit for storing a threshold value with an intensity spectrum in a predetermined range of angles as small as possible is provided in the storage unit, and the estimation unit includes an intensity spectrum for each arrival angle and each of the arrival angles. It estimates the wave source direction corresponding to the intensity spectrum higher than the threshold value among the intensity spectra in a predetermined range of angles small enough to find the maximum value even when the change in the intensity spectrum before and after is large. May be good .

According to the third aspect of the present invention, the directional estimation device in the second aspect is calculated for each of the intensity spectrum calculated by the spectrum calculation unit and the arrival angle for each angle that is unlikely to be the arrival angle. It may be provided with a threshold value calculation unit for calculating the threshold value based on the maximum intensity spectrum of the intensity spectrum.

According to the fourth aspect of the present invention, the directional estimation device in the second aspect may include a threshold value calculation unit for calculating the threshold value .

According to the fifth aspect of the present invention, in the directional estimation device according to the fourth aspect, the threshold value calculation unit has the maximum intensity spectrum and the minimum intensity spectrum among the intensity spectra calculated for each arrival angle. If the difference from and is smaller than a predetermined difference, the threshold value may be calculated again .

According to the sixth aspect of the present invention, in the directional estimation device in any one of the first aspect to the fifth aspect, the angle calculation unit comprises the plurality of sensors with sensors in a predetermined range. The sample-phase matrix of the entire array may be calculated by dividing the sum of the sample-phase matrices for each sub-array to be performed by the number of sub-arrays .

According to the seventh aspect of the present invention, in the directional estimation device according to the sixth aspect , the angle calculation unit may calculate the arrival angle based on the eigenvector of the sample phase matrix. ..

According to the eighth aspect of the present invention, the orientation estimation method inputs a specified number of wave sources based on the received signals received by a plurality of sensors, assuming that the number of wave sources is equal to or greater than the true number of wave sources. , Calculate the arrival angle indicating the wave source direction of each wave source of the input number of wave sources, and find the maximum value even when the change in the intensity spectrum for each arrival angle and the intensity spectrum before and after each arrival angle is large. It includes calculating the intensity spectrum at an angle in a predetermined range as small as possible, and estimating the wave source direction based on the calculated intensity spectrum .

According to the ninth aspect of the present invention, the program inputs to the computer a specified number of wave sources based on the received signals received by the plurality of sensors, assuming that the number of wave sources is equal to or more than the true number of wave sources. And, the arrival angle indicating the wave source direction of each wave source of the input number of wave sources is calculated, and the calculated intensity spectrum for each arrival angle is maximized even when the change in the intensity spectrum before and after each arrival angle is large. It is made to calculate the intensity spectrum at an angle in a predetermined range small enough to find a value, and to estimate the direction of the wave source based on the calculated intensity spectrum .

According to the directional estimation device according to the embodiment of the present invention, both the angle formed by a certain reference line and the direction from the sensor to the wave source and the spectrum of the signal transmitted from the wave source can be obtained by simple processing.

It is a figure which shows the structure of the receiving system by 1st Embodiment of this invention. It is a figure which shows the structure of the direction estimation apparatus by 1st Embodiment of this invention. It is a figure which shows the processing flow of the direction estimation apparatus by 1st Embodiment of this invention. It is a figure for demonstrating the threshold value in 1st Embodiment of this invention. It is a figure which shows the sub-array in the 2nd Embodiment of this invention. It is a figure which shows the processing flow of the direction estimation apparatus by the 2nd Embodiment of this invention. It is a figure which shows the structure of the direction estimation apparatus by the 3rd Embodiment of this invention. It is a figure for demonstrating the threshold value in the 3rd Embodiment of this invention. It is a figure for demonstrating the evaluation of the direction estimation result estimated by the estimation part in 4th Embodiment of this invention. It is a figure which shows the processing flow of the direction estimation apparatus according to 4th Embodiment of this invention. It is a figure for demonstrating the spectrum calculated by the spectrum calculation part in the 6th Embodiment of this invention. It is a schematic block diagram which shows the structure of the computer which concerns on at least one Embodiment.

<First Embodiment>
Hereinafter, embodiments will be described in detail with reference to the drawings.
The receiving system 1 according to the first embodiment of the present invention uses a method (root-MUSIC, ESPRIT, etc.) that can easily calculate the direction from the sensor to the wave source by specifying the number of wave sources, and is a reference line. And the angle between the sensor and the direction to each wave source (hereinafter referred to as "arrival angle") is calculated. The receiving system 1 is a method (MUSIC,) capable of calculating a spectrum (intensity spectrum) (hereinafter referred to as “spectrum”) indicating the arrival angle and intensity of a signal transmitted from a wave source detected by a sensor with high accuracy. Apply the calculated arrival angle to (beam scanning, etc.). By doing so, the receiving system 1 calculates each arrival angle and the spectrum of the signal transmitted by each wave source, and estimates the direction of the wave source (that is, the direction indicated by the vector from the sensor to the wave source). In the receiving system 1 according to the first embodiment of the present invention, the root-MUSIC method is used as a method capable of easily calculating the arrival angle by specifying the number of wave sources, and the arrival angle and the signal transmitted from the wave source are transmitted. A case where the MUSIC method is used as a method capable of calculating the spectrum with high accuracy will be described as an example.

As shown in FIG. 1, the receiving system 1 includes a plurality of sensors 10 and an orientation estimation device 20.
Each of the plurality of sensors 10 receives the signal transmitted by each wave source. In the example of the plurality of sensors 10 shown in FIG. 1, the receiving system 1 is provided with M sensors 10 to form an array sensor.
As shown in FIG. 2, the directional estimation device 20 includes a wave source number input unit 201, an angle calculation unit 202, a spectrum calculation unit 203, an estimation unit 204, a threshold value setting unit 205, and a storage unit 206.

The wave source number input unit 201 inputs an assumed wave source number L'based on the received signals received by the plurality of sensors 10. The root-MUSIC method calculates the arrival angle of the same number as the set number of wave sources. When the set number of wave sources is smaller than the actual number of wave sources, the root-MUSIC method cannot calculate all the arrival angles. Therefore, the wave source number input unit 201 needs to input the assumed wave source number L'that is equal to or larger than the true wave source number L. For example, the number of past actual wave sources (that is, the true number of wave sources L) when the waveform of the past received signal closest to the waveform of the received signal is specified and the direction estimation is actually performed for the wave source of the past received signal. Enter the number of wave sources L'by adding the number of wave sources that are considered to exceed the true number of wave sources L to the number of wave sources that are considered to be the closest). The number of wave sources to be added is, for example, a wave source number indicating a fixed number such as 0.2 times the number of wave sources of the past actual results and three. Further, the assumed number of wave sources L'may be the same as the true number of wave sources L.

The angle calculation unit 202 calculates the arrival angle of the same number as the wave source number L'input by the wave source number input unit 201.
The spectrum calculation unit 203 calculates a spectrum for each arrival angle calculated by the angle calculation unit 202.

The estimation unit 204 estimates the direction of each wave source based on the spectrum for each arrival angle calculated by the spectrum calculation unit 203. Specifically, the estimation unit 204 compares the spectrum for each arrival angle calculated by the spectrum calculation unit 203 with the threshold value of the spectrum used to identify the true wave source from the wave sources. Then, the estimation unit 204 specifies a spectrum equal to or larger than the threshold value from the spectra for each arrival angle calculated by the spectrum calculation unit 203. The estimation unit 204 estimates the direction indicated by the vector in the direction away from the sensor 10 forming the arrival angle corresponding to the specified spectrum with respect to the reference line passing through the sensor 10 as the direction of the wave source. Further, the estimation unit 204 identifies a position separated from the estimated wave source direction by a distance corresponding to the value indicated by the spectrum as the wave source. Here, the distance corresponding to the value indicated by the spectrum may be the distance from the specified sensor 10 in the past performance to the wave source. Further, the distance corresponding to the value indicated by the spectrum may be the distance from the sensor 10 to the wave source calculated based on a simulation or an experiment.

The threshold value setting unit 205 stores the threshold value of the spectrum used for identifying the true wave source from the wave sources in the storage unit 206.
The storage unit 206 stores various information necessary for the processing performed by the directional estimation device 20, such as the threshold value of the spectrum used to identify the true wave source from the wave sources.

Next, the processing of the direction estimation device 20 shown in FIG. 3 will be described.
Here, as an example of the processing of the direction estimation device 20, the processing in the case of estimating the direction of the wave source by using the root-MUSIC method and the MUSIC method will be described.
In the root-MUSIC method, the arrival angle is calculated on the assumption that the sensors 10 are arranged at equal intervals. Therefore, it is assumed that M sensors 10 are arranged at equal intervals as the plurality of sensors 10 described here. Further, it is assumed that the wave source number input unit 201 inputs a wave source number L'assumed in advance based on the received signals received by the plurality of sensors 10 and stores it in the storage unit 206.

The angle calculation unit 202 receives signals via the M sensors 10 at time k (step S1). The angle calculation unit 202 stores the received signal in the storage unit 206 (step S2). The received signal received by the M sensors 10 can be represented as a received signal represented by the following equation (1).

The received signal x (k) represented by the equation (1) can be expressed as the following equation (2) when the true number of wave sources is L.

In the equation (2), the symbol _sl (k) is a wave source signal. Further, the symbol n (k) is the observed noise of white Gaussian. Further, the symbol a (θ) is a direction vector (a vector expressing a phase difference determined according to the array element arrangement). The direction vector a (θ) can be expressed by the following equation (3).

The root-MUSIC method (also the MUSIC method) requires an eigenvector of the spatial autocorrelation matrix of the received signal vector. The angle calculation unit 202 sets the number of correlation points as P, and calculates the sample correlation matrix R _x (k) at time k according to the following equation (4) (step S3). The interphase score P is the number of sample signals used to calculate the sample correlation matrix.

In equation (4), the symbol H represents Hermitian transpose. The angle calculation unit 202 reads out the assumed number of wave sources L'from the storage unit 206 (step S4). Let the eigenvalues of the sample correlation matrix R _x (k) be λ ₁ > λ ₂ >...> λ _M (step S4). Further, the angle calculation unit 202 sets the eigenvectors of the sample correlation matrix R _x (k) to e ₁ , e ₂ , ..., E _M (step S4). Theoretically, λ ₁ ≧ λ ₂ ≧ ・ ・ ・ ≧ λ _L ＞ λ _{L + 1} = λ _{L + 2} ＝ ・ ・ ・ ＝ λ _M , but the angle calculation unit 202 is affected by the calculation error of the phase matrix. Considering this, the eigenvalues are set as above.
Here, the MUSIC spectrum function _PM (θ) can be expressed by the following equation (5).

In the equation (5), the symbol L'is the assumed number of wave sources. In general, L ≠ L'.
The root-MUSIC method does not calculate the spectrum. Therefore, in the root-MUSIC method, the angle θ at which the denominator of the MUSIC spectrum function _PM (θ) represented by the equation (5) becomes 0 is directly calculated.
The angle calculation unit 202 defines the direction vector a (θ) as the symbol p (z) and uses p ^T (z ^-1 ) instead of ^pH (z) to form a root-MUSIC polynomial Q (z). Is the following equation (6).

The angle calculation unit 202 derives the coefficients α ₀ , α ₁ ..., α _{2 (M-1)} of the root-MUSIC polynomial Q (z) represented by the equation (6). The angle calculation unit 202 derives a polynomial equation represented by the following equation (7) using the derived coefficients α ₀ , α ₁ ..., α _{2 (M-1)} .

The angle calculation unit 202 solves the equation (7) to obtain the complex number solutions z _q , q = 1, 2, ..., 2 (M-1). Of the complex solutions z _q , q = 1, 2, ..., 2 (M-1), the double solution having a magnitude of 1 is z _l , l = 1, 2, ..., L'. Then, the angle calculation unit 202 calculates the arrival angle θ _l , which is the result of the orientation estimation by the root-MUSIC method, as shown in the following equation (8) (step S5).

In the equation (8), the symbol l is each wave source, the symbol λ is the wavelength, and the symbol d is the distance between the sensors 10.

As described above, the angle calculation unit 202 can calculate the corresponding arrival angle θ _l for each wave source l (l = 1, 2, ..., L').
If the assumed number of wave sources L'is the same as the number of true wave sources L, all true wave sources can be specified. However, the true number of wave sources L is unknown, and there is a possibility that the assumed number of wave sources L'is set to a number lower than the true number of wave sources L, and in that case, an unspecified true wave source appears. Therefore, here, as an example in which an unspecified true wave source does not appear, the assumed wave source number L'is set to the number of wave sources that are considered to be larger than the true wave source number L. Therefore, at this time, the arrival angle θ _l calculated by the angle calculation unit 202 using the root-MUSIC method includes (L'−L) erroneous arrival angles.

The spectrum calculation unit 203 calculates a spectrum for each arrival angle θ _l calculated by the angle calculation unit 202 (step S6).

Here, the threshold value setting unit 205 calculates the threshold value of the spectrum used to identify the true wave source from the wave sources by the spectrum calculation unit 203 in the process of step S6 as shown in FIG. The value is determined between the maximum value and the minimum value of the spectrum, and is stored in the storage unit 206.

The estimation unit 204 compares the spectrum for each arrival angle calculated by the spectrum calculation unit 203 with the threshold value of the spectrum used to identify the true wave source from the wave sources (step S7). Then, the estimation unit 204 specifies a spectrum equal to or larger than the threshold value from the spectra for each arrival angle calculated by the spectrum calculation unit 203. The estimation unit 204 estimates the direction indicated by the vector in the direction away from the sensor 10 forming the arrival angle corresponding to the specified spectrum with respect to the reference line passing through the sensor 10 as the direction of the wave source (step S8). Further, the estimation unit 204 identifies a position separated from the estimated direction by a distance corresponding to the value indicated by the spectrum as the wave source. The estimation unit 204 updates the time (step S9) and returns to step S1.
The spectrum calculated by the spectrum calculation unit 203 for each arrival angle calculated by the angle calculation unit 202 may be normalized so that the maximum spectrum is 0 dB.

The receiving system 1 according to the first embodiment of the present invention has been described above.
In the direction estimation device 20 of the receiving system 1, the angle calculation unit 202 calculates the arrival angle of the same number as the wave source number L'input by the wave source number input unit 201. The spectrum calculation unit 203 calculates a spectrum for each arrival angle calculated by the angle calculation unit 202. It is highly possible that the wave source having the wave source number L'includes a wave source other than the true wave source number L. The estimation unit 204 compares the spectrum for each arrival angle calculated by the spectrum calculation unit 203 with the threshold value of the spectrum used to specify the true wave source, and estimates the direction of the true wave source.
In this way, the azimuth estimation device 20 can easily obtain both the angle formed by the reference line and the direction from the sensor to the wave source (that is, the arrival angle) and the spectrum of the signal transmitted from the wave source. Can be done.

<Second embodiment>
Hereinafter, the receiving system 1 according to the second embodiment of the present invention will be described.
In the receiving system 1 according to the second embodiment of the present invention, the plurality of sensors 10 are composed of the sensors 10 of a certain part of all the sensors 10, for example, as shown in FIG. 5, and are shifted by one sensor. A sub-array (in the example shown in FIG. 5, a sub-array consisting of two sensors 10) is defined, and a sample correlation matrix is calculated for each sub-array. Then, the receiving system 1 calculates the entire sample correlation matrix using the calculated sample correlation matrix for each subarray.

Next, the processing of the direction estimation device 20 shown in FIG. 6 will be described.
The angle calculation unit 202 receives signals via the M sensors 10 at time k (step S1). At this time, the angle calculation unit 202 calculates the sample function matrix for each subarray (step S10). Assuming that the number of all sensors 10 is M and the number of sub-arrays is M _s smaller than M, the number of sub-arrays N _s is (MM _s +1). At this time, the angle calculation unit 202 calculates the sample correlation matrix of the qth subarray as in the following equation (9).

In the equation (9), the portion represented by the following equation (10) is the received signal vector of the sub-array obtained by extracting the qth to (q + M _s -1) components of the array received signal vector x (k). ..

The angle calculation unit 202 calculates the average of the sample correlation matrix of the sub-array and the sample correlation matrix of the entire array as in the following equation (11) (step S11). The method of calculating the sample correlation matrix of the entire array as in this equation (11) is one of the spatial averaging methods and is an example of the averaging method.

The receiving system 1 according to the second embodiment of the present invention has been described above.
In the direction estimation device 20 of the receiving system 1, the angle calculation unit 202 calculates the sample correlation matrix for each sub-array and averages the sample correlation matrix for each sub-array to calculate the sample correlation matrix for the entire array.
In this way, the directional estimation device 20 can calculate the correlation between the signals transmitted from each wave source with a correlation score smaller than the correlation score P in the first embodiment of the present invention. The directional estimation of the wave source can be performed in the same manner as the directional estimation device 20 in the first embodiment of the invention.
The angle calculation unit 202 calculates the average of the sample correlation matrix of the subarray by using the Forward-Backward spatial averaging method (a known technique for reducing the correlation between wave sources and an example of the averaging method). It may be a thing.
When the root-MUSIC method is used, since the arrangement of each sub-array is the same, the conditions for applying the spatial averaging method are satisfied, so that the root-MUSIC method and the spatial averaging method are compatible with each other.

<Third embodiment>
Hereinafter, the receiving system 1 according to the third embodiment of the present invention will be described.
Similar to the receiving system 1 according to the first embodiment of the present invention, the receiving system 1 according to the third embodiment of the present invention is a method capable of easily calculating the arrival angle by designating the number of wave sources. -It is a system that uses the MUSIC method as a method that can calculate the arrival angle and the spectrum of the signal transmitted from the wave source with high accuracy by using the MUSIC method.
In the receiving system 1 according to the third embodiment of the present invention, as shown in FIG. 7, the direction estimation device 20 has a wave source number input unit 201, an angle calculation unit 202, a spectrum calculation unit 203, an estimation unit 204, and a threshold value setting. In addition to the unit 205 and the storage unit 206, a threshold value calculation unit 207 is provided. Then, the threshold value setting unit 205 stores the threshold value calculated by the threshold value calculation unit 207 in the storage unit 206, and the estimation unit 204 uses the threshold value calculated by the threshold value calculation unit 207. It differs from the receiving system 1 according to the first embodiment of the present invention in that the direction of the true wave source is estimated.

The threshold value calculation unit 207 calculates the spectrum for an angle (for example, −90 degrees, 90 degrees, etc. of the arrival angle) that is unlikely to be the direction of the wave source by the spectrum calculation unit 203. Since this spectrum calculated by the threshold value calculation unit 207 is a spectrum of a signal from a direction other than the wave source, it is considered to be a value close to the minimum value of the spectrum.
The threshold value calculation unit 207 is based on the spectrum calculated by the spectrum calculation unit 203 for an angle that is unlikely to be the direction of the wave source and the largest spectrum among the spectra calculated for each arrival angle calculated by the spectrum calculation unit 203. To calculate the threshold of the spectrum used to identify the true wave source. For example, as shown in FIG. 8, the threshold value calculation unit 207 may have the largest spectrum among the spectra calculated for each arrival angle calculated by the spectrum calculation unit 203, and the spectrum calculation unit 203 may be the direction of the wave source. The difference ΔP from the spectrum calculated for the low angle is calculated. The threshold value calculation unit 207 identifies the true wave source by adding the value obtained by multiplying the difference ΔP by a predetermined value β to the spectrum calculated by the spectrum calculation unit 203 for an angle that is unlikely to be the direction of the wave source. Calculate the threshold of the spectrum used to do this.
The threshold value setting unit 205 stores the threshold value calculated by the threshold value calculation unit 207 in the storage unit 206.
The estimation unit 204 reads the threshold value calculated by the threshold value calculation unit 207 from the storage unit 206. The estimation unit 204 compares the threshold value calculated by the threshold value calculation unit 207 with the spectrum for each arrival angle calculated by the spectrum calculation unit 203.

The receiving system 1 according to the third embodiment of the present invention has been described above.
In the directional estimation device 20 of the receiving system 1, the threshold value calculation unit 207 calculates the spectrum for an angle at which the spectrum calculation unit 203 is unlikely to be the direction of the wave source. The threshold value calculation unit 207 is based on the spectrum calculated by the spectrum calculation unit 203 for an angle that is unlikely to be the direction of the wave source and the largest spectrum among the spectra calculated for each arrival angle calculated by the spectrum calculation unit 203. To calculate the threshold of the spectrum used to identify the true wave source. The threshold value setting unit 205 stores the threshold value calculated by the threshold value calculation unit 207 in the storage unit 206. The estimation unit 204 reads the threshold value calculated by the threshold value calculation unit 207 from the storage unit 206. The estimation unit 204 compares the threshold value calculated by the threshold value calculation unit 207 with the spectrum for each arrival angle calculated by the spectrum calculation unit 203.
In this way, the directional estimation device 20 can appropriately calculate the threshold value of the spectrum used to identify the true wave source, and the directional estimation device 20 correctly estimates the direction of the wave source. Can be done.
In the third embodiment of the present invention, an example of applying the threshold value calculated by the threshold value calculation unit 207 to the reception system 1 according to the first embodiment of the present invention is shown. However, in another embodiment of the present invention, the threshold value calculated by the threshold value calculation unit 207 may be applied to the reception system 1 according to the second embodiment of the present invention.

<Fourth Embodiment>
Hereinafter, the receiving system 1 according to the fourth embodiment of the present invention will be described.
In the fourth embodiment of the present invention, a method of evaluating the directional estimation result estimated by the estimation unit 204 in the receiving system 1 according to the first to third embodiments of the present invention will be described.
As shown in FIG. 9B, for example, the directional estimation result estimated by the estimation unit 204 is calculated by the spectrum calculation unit 203 and the maximum spectrum among the spectra calculated for each arrival angle calculated by the spectrum calculation unit 203. The difference _ΔPM from the smallest spectrum among the spectra calculated for each arrival angle (in the case of the third embodiment of the present invention, the spectrum calculated by the spectrum calculation unit 203 for an angle that is unlikely to be the direction of the wave source). If the difference is smaller than the difference _ΔPM when correctly estimated as shown in FIG. 9A, it is considered that the orientation estimation result estimated by the estimation unit 204 is not appropriate.
Therefore, as shown in FIG. 10, the estimation unit 204 calculates the difference _ΔPM between the maximum spectrum and the minimum spectrum (step S12).
The estimation unit 204 determines whether or not the difference _ΔPM is larger than a predetermined difference (step S13).
When the estimation unit 204 determines that the difference _ΔPM is equal to or less than a predetermined difference (NO in step S13), the estimation unit 204 returns to the process of step S9.
Further, when the estimation unit 204 determines that the difference _ΔPM is larger than the predetermined difference (YES in step S13), the threshold value calculation unit 207 is the threshold value of the spectrum used to identify the true wave source. Is calculated (step S14). Then, the threshold value calculation unit 207 proceeds to the process of step S7.

The receiving system 1 according to the fourth embodiment of the present invention has been described above.
In the directional estimation device 20 of the receiving system 1, the estimation unit 204 calculates the difference _ΔPM between the maximum spectrum and the minimum spectrum. The estimation unit 204 determines whether or not the difference _ΔPM is larger than a predetermined difference. The estimation unit 204 reacquires data when it is determined that the difference _ΔPM is equal to or less than a predetermined difference. If the estimation unit 204 determines that the difference _ΔPM is greater than a predetermined difference, the threshold value calculation unit 207 calculates the threshold value of the spectrum used to identify the true wave source. Then, the threshold value calculation unit 207 compares the threshold value calculated by the threshold value calculation unit 207 with the spectrum for each arrival angle calculated by the spectrum calculation unit 203.
In this way, the directional estimation device 20 can correctly estimate the directional estimation of the wave source.

<Fifth Embodiment>
Hereinafter, the receiving system 1 according to the fifth embodiment of the present invention will be described.
In the receiving system 1 according to the fifth embodiment of the present invention, in the case of an application in which the number of wave sources does not change, the estimation unit 204 calculated last time is used as the assumed number of wave sources L'input by the wave source number input unit 201. The number of spectra above the threshold value of the spectrum used to specify the estimated true wave source, that is, the number of wave sources L estimated by the estimation unit 204 as the true wave source last time is adopted. That is, the estimation unit 204 adopts the true number of wave sources L (k) as the assumed number of wave sources L'(k + 1).
Alternatively, in the receiving system 1 according to the fifth embodiment of the present invention, in the case of an application in which the number of wave sources constantly changes, the estimation unit calculated last time as the assumed number of wave sources L'input by the wave source number input unit 201. The number of wave sources obtained by adding the number of wave sources ΔL increased by the change in the number of wave sources to the number L of the spectrum above the threshold value of the spectrum used to specify the true wave source estimated by 204 is adopted. That is, the estimation unit 204 adopts the number of wave sources as the assumed number of wave sources L'(k + 1), which is the sum of the true number of source numbers L (k) and the increased number of wave sources ΔL. Note that ΔL is a positive integer.

The receiving system 1 according to the fifth embodiment of the present invention has been described above.
In the directional estimation device 20 of the receiving system 1, in the case of an application in which the number of wave sources does not change, the wave source number input unit 201 adopts the true wave source number L (k) as the assumed wave source number L'(k + 1). .. Further, in the case of an application in which the number of wave sources is constantly changing, the estimation unit 204 calculates the number of wave sources obtained by adding the increased number of wave sources ΔL to the true number of wave sources L (k) as the assumed number of wave sources L'(k + 1). adopt.
By doing so, the directional estimation device 20 can reduce unnecessary calculations and shorten the calculation time.

<Sixth Embodiment>
Hereinafter, the receiving system 1 according to the sixth embodiment of the present invention will be described.
If the accuracy of the arrival angle calculated by the angle calculation unit 202 using the root-MUSIC method is poor, the spectrum corresponding to the arrival angle deviates from the maximum spectrum, and in some cases, the true wave source is specified. May fall below the threshold of the spectrum used to do this.
Therefore, in the sixth embodiment of the present invention, the spectrum calculation unit 203 determines the spectrum with respect to the arrival angle calculated by the angle calculation unit 202 using the root-MUSIC method and an angle in a predetermined range before and after the angle. calculate. For example, as shown in FIG. 11, the spectrum calculation unit 203 has a spectrum corresponding to each of the arrival angles θ ₁ , θ ₂ , θ ₃ , and θ ₄ calculated by the angle calculation unit 202 using the root-MUSIC method. Calculate the spectrum corresponding to each of the arrival angles θ ₁ , θ ₂ , θ ₃ , and θ ₄ before and after ± Δθ. Note that Δθ is set to a small value so that a maximum value can be found even when the change in the spectrum is large.

The receiving system 1 according to the sixth embodiment of the present invention has been described above.
In the directional estimation device 20 of the receiving system 1, the spectrum calculation unit 203 calculates a spectrum with respect to the arrival angle calculated by the angle calculation unit 202 using the root-MUSIC method and an angle in a predetermined range before and after the angle. ..
In this way, the directional estimation device 20 can correctly estimate the directional estimation of the wave source.

In the processing according to the embodiment of the present invention, the order of the processing may be changed as long as the appropriate processing is performed.

Each of the storage unit 206 and the other storage devices in the embodiment of the present invention may be provided anywhere within the range in which appropriate information is transmitted and received. Further, each of the storage unit 206 and the other storage devices may exist in a plurality of areas within a range in which appropriate information is transmitted and received, and the data may be distributed and stored.

Although the embodiment of the present invention has been described, the above-mentioned receiving system 1, directional estimation device 20, and other control devices may have a computer system inside. The process of the above-mentioned processing is stored in a computer-readable recording medium in the form of a program, and the above-mentioned processing is performed by the computer reading and executing this program. A specific example of a computer is shown below.
FIG. 12 is a schematic block diagram showing the configuration of a computer according to at least one embodiment.
As shown in FIG. 12, the computer 5 includes a CPU 6, a main memory 7, a storage 8, and an interface 9.
For example, each of the above-mentioned receiving system 1, orientation estimation device 20, and other control devices is mounted on the computer 5. The operation of each of the above-mentioned processing units is stored in the storage 8 in the form of a program. The CPU 6 reads a program from the storage 8, expands it into the main memory 7, and executes the above processing according to the program. Further, the CPU 6 secures a storage area corresponding to each of the above-mentioned storage units in the main memory 7 according to the program.

Examples of the storage 8 include HDD (Hard Disk Drive), SSD (Solid State Drive), magnetic disk, optical magnetic disk, CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versaille Disk) Read , Semiconductor memory and the like. The storage 8 may be an internal medium directly connected to the bus of the computer 5 or an external medium connected to the computer 5 via the interface 9 or a communication line. Further, when this program is distributed to the computer 5 by a communication line, the distributed computer 5 may expand the program to the main memory 7 and execute the above processing. In at least one embodiment, the storage 8 is a non-temporary tangible storage medium.

Further, the above program may realize a part of the above-mentioned functions. Further, the program may be a file that can realize the above-mentioned functions in combination with a program already recorded in the computer system, a so-called difference file (difference program).

Although some embodiments of the present invention have been described, these embodiments are examples and do not limit the scope of the invention. Various additions, omissions, replacements, and changes may be made to these embodiments without departing from the gist of the invention.

1 ... Receiving system 5 ... Computer 6 ... CPU
7 ... Main memory 8 ... Storage 9 ... Interface 10 ... Sensor 20 ... Direction estimation device 201 ... Wave source number input unit 202 ... Angle calculation unit 203 ... Spectrum calculation unit 204 ... estimation unit 205 ... threshold value setting unit 206 ... storage unit 207 ... threshold value calculation unit

Claims (9)

Based on the received signals received by multiple sensors, the number of wave sources input section that inputs the specified number of wave sources on the assumption that the number of wave sources will be greater than or equal to the true number.
An angle calculation unit that calculates the arrival angle indicating the wave source direction of each wave source of the number of wave sources input by the wave source number input unit, and an angle calculation unit.
A spectrum calculation unit that calculates the intensity spectrum for each arrival angle and the intensity spectrum in a predetermined range that is small enough to find a maximum value even when the change in the intensity spectrum before and after each arrival angle is large .
The wave source direction is estimated based on the intensity spectrum for each arrival angle and the intensity spectrum in a predetermined range of angles small enough to find a maximum value even when the change in the intensity spectrum before and after each arrival angle is large. And the estimation part to do
A directional estimation device equipped with. The threshold value between the intensity spectrum for each arrival angle and the intensity spectrum in a predetermined range of angles small enough to find a maximum value even when the change in the intensity spectrum before and after each arrival angle is large is stored in the storage unit. Threshold setting part,
Equipped with
The estimation unit
Intensity higher than the threshold value in the intensity spectrum in a predetermined range of angles small enough to find a maximum value even when the change in the intensity spectrum for each arrival angle and the intensity spectrum before and after each arrival angle is large. Estimate the source direction corresponding to the spectrum,
The directional estimation device according to claim 1. The threshold value is calculated based on the intensity spectrum calculated by the spectrum calculation unit for an angle that is unlikely to be the arrival angle and the maximum intensity spectrum among the intensity spectra calculated for each arrival angle. Threshold calculation unit,
2. The directional estimation device according to claim 2. Threshold value calculation unit for calculating the threshold value,
2. The directional estimation device according to claim 2. The threshold value calculation unit is
When the difference between the maximum intensity spectrum and the minimum intensity spectrum among the intensity spectra calculated for each arrival angle is smaller than a predetermined difference, the threshold value is calculated again .
The directional estimation device according to claim 4. The angle calculation unit is
The sample-phase matrix of the entire array is calculated by dividing the sum of the sample-phase matrices for each sub-array composed of the plurality of sensors by a predetermined range of sensors by the number of sub-arrays.
The directional estimation device according to any one of claims 1 to 5. The angle calculation unit is
The arrival angle is calculated based on the eigenvectors of the sample phase matrix .
The directional estimation device according to claim 6 . Based on the received signals received by multiple sensors, input the specified number of wave sources assuming that the number will be greater than or equal to the true number of wave sources.
To calculate the arrival angle indicating the wave source direction of each wave source of the input wave source number,
To calculate the intensity spectrum for each arrival angle and the intensity spectrum in a predetermined range of angles small enough to find a maximum value even when the change in the intensity spectrum before and after each arrival angle is large .
Estimating the wave source direction based on the calculated intensity spectrum,
Direction estimation method including. On the computer
Based on the received signals received by multiple sensors, input the specified number of wave sources assuming that the number will be greater than or equal to the true number of wave sources.
To calculate the arrival angle indicating the wave source direction of each wave source of the input wave source number,
To calculate the calculated intensity spectrum for each arrival angle and the intensity spectrum in a predetermined range of angles small enough to find a maximum value even when the change in the intensity spectrum before and after each arrival angle is large .
Estimating the direction of the wave source based on the calculated intensity spectrum,
A program to execute.

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