JP2006125985A - Arrival direction estimation method and arrival direction estimation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arrival direction estimation device and an arrival direction estimation method capable of surely discriminating between the direct wave and reflected wave without complicating the constitution of hardware. <P>SOLUTION: The vector r representing the set of wave signals arrived from the transmission terminal to a plurality of branches arranged as elements for receiving wave signals including sound waves and radio waves are determined. The matrix R representing the correlation of wave signals arrived from the transmission terminal is determined from the vector r and by processing the specific matrix operation on the matrix R, the intrinsic value of matrix R including the index relating to the reception power of arrived waves to the site and intrinsic vector corresponding to the intrinsic value is determined. The incoming wave to be estimated with its arrival direction is discriminated whether the incoming wave is directly incident on the site from the transmission terminal or not based on the value of the intrinsic value satisfies the condition or not which should be satisfied by receiving intensity of the direct incident wave signal. Only for the direct wave to be estimated, its arrival direction is estimated by using the intrinsic vector of the matrix R and its corresponding intrinsic value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention estimates the direction or position of the transmitting end by performing predetermined signal processing on the wave signal arriving at the site, and simultaneously determines whether the wave signal whose arrival direction is estimated is a direct wave. The present invention relates to an arrival direction estimation method and an arrival direction estimation device.

There are various processing algorithms that can be applied to the estimation of the direction of arrival of electromagnetic waves and sound waves arriving at multiple branches (receiving elements that receive wave signals such as radio waves, sound waves, and light), and there are many different algorithms than before. Proposals have been made.
Moreover, the apparatus which estimates said arrival direction based on such an algorithm is published by the nonpatent literature 1 mentioned later, for example, is comprised as an antenna system shown in FIG.

  Here, the antenna system shown in FIG. 11 is configured as an array antenna 11 (a plurality of N antenna elements 12-1 to 12-N arranged in the site 10 and these antenna elements 12-1 to 12-N. Are arranged in a straight line at a common interval d.), And at the site 10, the signal processing circuit 13 is connected to the feeding points of the antenna elements 12-1 to 12-N.

  In the antenna system having such a configuration, for example, as shown in FIG. 11, an incoming wave that arrives at the array antenna 11 from the direction of the azimuth angle θ and is an object of estimation of the arrival direction has an amplitude a of the incoming wave. And the phase difference φ determined according to the azimuth angle θ and the distance d described above, and the number N (≧ 2) of the antenna elements 12-1 to 12-N, Denoted as the vector r shown.

r = [a a · e ^jφ ... a · e ^{j (N-1) φ} ] ^T (1)
For example, the signal processing circuit 13 estimates the arrival direction by performing processing including the following steps (a) to (c) based on a MUSIC (MUltiple SIgnal Classification) algorithm.
(A) The range that this direction of arrival can take (here, for the sake of simplicity, it is assumed that it is expressed by an azimuth angle θ equal to either minus 90 degrees or plus 90 degrees) with a specified accuracy (for example, 1 Scan every hour).
(B) Direction vectors of incoming waves that should arrive at the antenna elements 12-1 to 12-N from the direction of the azimuth angle θ assumed as appropriate under the scan (all the components of the mode vector indicating these incoming waves) It is obtained by normalizing the amplitude component to “1.”) a (θ), the number L of incoming waves arriving at the array antenna 11, and the number K of antenna elements of the array antenna 11 (= N) and the eigenvalue EN (≡ [e _{L + 1} ,..., E _K ]) of the thermal noise component contained in the vector r described above, the MUSIC spectrum PMU ( θ) is obtained collectively.

(C) The direction indicated by the azimuth angle θ at which the MUSIC spectrum PMU (θ) obtained in this way is maximized is estimated as the direction of arrival.
JP 2000-199784 A "Adaptive signal processing by array antenna", pages 173 to 268, Science and Technology Publishers http://www.mobile.ss.titech.ac.jp/mobile/seminar/ohp-011015_hungchin.pdf http://www.cybernet.co.jp/matlab/support/3vent/conf97/tsuji.pdf http://maxwell.elcom.nitech.ac.jp/~kikuma/source.html

When the position of the transmitting end is identified and searched using a technique for estimating the direction of the arriving wave that has arrived at the array antenna, it is essential to estimate the direction of arrival of the direct wave that directly arrives from the transmitting end.
However, in the above-described prior art, the direction of arrival is determined without determining whether the incoming wave that has arrived at the array antenna 11 disposed at the site 10 is a direct wave or a reflected wave that has undergone first-order or higher-order reflection. Had been estimated. For this reason, there is a case where the arrival direction of the reflected wave is erroneously estimated, which is insufficient as an arrival direction estimation function for transmitting terminal position identification or search.

As a technique for estimating the arrival direction of an incoming wave at a site for position identification or search of a transmission end, a technique disclosed in Patent Document 1 has been proposed.
In the technique of Patent Document 1, a wave source transmits a prescribed signal group twice or more, and a receiving side obtains a cross-correlation corresponding to the repetition of the signal group, and estimates the direction of arrival by a MUSIC algorithm using a cross-correlation matrix. Is used to estimate the direction of arrival of direct waves.

However, this method assumes that a direct wave is always incident on the antenna, so if for some reason the direct wave is blocked and only the reflected wave is incident on the antenna. Is not applicable.
In order to realize this method, it is necessary to provide a function for repeatedly transmitting a prescribed signal group on the wave source side, and a function for obtaining a cross-correlation for a repeatedly arrived signal group on the receiving side. It is necessary and the hardware becomes complicated.

  An object of the present invention is to provide an arrival direction estimation method and an arrival direction estimation apparatus that can reliably discriminate between a direct wave and a reflected wave without complicating the hardware configuration.

The first direction-of-arrival estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, a reception strength determination step, and an arrival direction estimation step.
The principle of the first direction of arrival estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the reception strength discrimination step, the incoming wave that is the target of the arrival direction is directly incident on the site from the transmission end based on whether the eigenvalue value satisfies the condition that the reception intensity of the wave signal that is directly incident on the site should satisfy. It is determined whether or not it is a direct wave. The arrival direction estimation step estimates the arrival direction of an incoming wave using the eigenvector of the matrix R and the eigenvalue corresponding thereto only when the arrival wave to be estimated is a direct wave.

The operation of the first direction-of-arrival estimation method configured as described above is as follows.
For the matrix R indicating the correlation of the wave signals obtained by executing the correlation calculation step, for example, the eigenvalue of the matrix R obtained by performing eigenvalue analysis processing in the matrix calculation step is used as an index indicating the received power of the incoming wave. Can be caught.
Here, since the intensity of the wave signal incident on the site through one or more reflections naturally decreases significantly due to scattering due to reflection or an increase in propagation distance, the received power corresponding to the reflected wave is directly This is considered to be significantly lower than the lower limit of wave signal attenuation due to propagation. Therefore, whether or not the maximum value of the eigenvalue obtained as described above in the reception strength determination means is equal to or greater than a threshold value relating to reception power that is determined in advance based on, for example, the lower limit of attenuation of the wave signal due to direct propagation. By determining, it is possible to determine whether or not the incoming wave that is the target of the arrival direction estimation is a direct wave that is directly incident on the site.

In this way, only for the incoming wave determined as a direct wave, in the arrival direction estimation step, for example, by performing the arrival direction estimation process by the arrival direction estimation method such as the MUSIC algorithm, regardless of the presence of the reflected wave, It is possible to selectively estimate the direction of arrival of a useful incoming wave and use it for the transmission end position identification and search processing.
A second arrival direction estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, an arrival direction estimation step, an eigenvalue correction step, a reception intensity determination step, and an estimated value output step. It consists of.

The principle of the second direction-of-arrival estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the arrival direction estimation step, the arrival direction of the incoming wave to the site is estimated using the eigenvector of the matrix R and the eigenvalue corresponding thereto. The eigenvalue correction step corrects at least one of the eigenvalues obtained by the matrix calculation processing on the matrix R based on the estimated arrival direction and the arrangement and characteristics of each branch at the site. Based on whether the corrected eigenvalue value satisfies the condition that the received signal intensity of the wave signal directly incident on the site should satisfy, the received strength determination step determines whether the incoming wave to be estimated for the arrival direction is transmitted from the transmitting end to the site. It is discriminated whether or not it is a direct wave directly incident on the. The estimated value output step outputs the estimation result as the arrival direction of the arrival wave directly propagated to the site only when the arrival wave whose arrival direction is estimated is a direct wave.

The operation of the second direction-of-arrival estimation method configured as described above is as follows.
First, for the matrix R indicating the correlation of the wave signals obtained by the execution of the correlation calculation step, for example, in the arrival direction estimation step using the eigenvector of the matrix R obtained by performing eigenvalue analysis processing in the matrix calculation step. For example, the direction of arrival of the wave signal arriving at the site is estimated by performing the direction-of-arrival estimation process by the direction of arrival estimation method such as the MUSIC algorithm. Next, the eigenvalue obtained in the eigenvalue analysis process described above is corrected in the eigenvalue correction step based on the estimation result and characteristics such as the arrangement and directivity of each branch in the site. Thereby, it is possible to obtain an index indicating the received power of the incoming wave in consideration of an error due to the directivity of the site.

The maximum eigenvalue obtained as described above is compared with a predetermined threshold value based on the lower limit of the attenuation of the wave signal due to direct propagation, for example, in the reception strength determination step. Regardless of this, it is possible to accurately determine whether or not the incoming wave whose direction of arrival has been estimated is a direct wave directly incident on the site.
In this way, only the arrival direction estimation result obtained for the incoming wave determined as a direct wave is output as the arrival direction of the incoming wave in the estimated value output step, regardless of the presence of the reflected wave. The direction of arrival of a new incoming wave can be used for transmitting end position identification and search processing.

A third direction-of-arrival estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, an arrival direction estimation step, a vector correction step, a matrix correction step, an eigenvalue recalculation step, The reception intensity determination step and the estimated value output step.
The principle of the third direction of arrival estimation method according to the present invention is as follows.

  In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmitting end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the arrival direction estimation step, the arrival direction of the incoming wave to the site is estimated using the eigenvector of the matrix R and the eigenvalue corresponding thereto. Based on the vector correction step, the estimated direction of arrival, and the arrangement and characteristics of each branch at the site, the value of each element constituting the vector r is corrected. In the matrix correction step, a correction matrix Ra indicating the correlation of the wave signal that has arrived at the site is obtained based on the corrected vector r. In the eigenvalue recalculation step, a predetermined matrix calculation process is performed on the correction matrix Ra to obtain an eigenvector of the correction matrix Ra and an eigenvalue corresponding thereto. In the reception strength discrimination step, the incoming wave to be estimated for the arrival direction is directly incident on the site from the transmission end based on whether the eigenvalue satisfies the condition that the reception intensity of the wave signal directly incident on the site should satisfy. It is determined whether or not it is a direct wave. The estimated value output step outputs the estimation result as the arrival direction of the arrival wave directly propagated to the site only when the arrival wave whose arrival direction is estimated is a direct wave.

The operation of the third direction-of-arrival estimation method configured as described above is as follows.
First, for the matrix R indicating the correlation of the wave signals obtained by executing the correlation calculation step, for example, using the eigenvector of the matrix R obtained by performing eigenvalue analysis processing in the matrix calculation step, for example, the MUSIC algorithm The direction of arrival of the wave signal arriving at the site is estimated by performing the direction-of-arrival estimation process using the direction-of-arrival estimation method. Next, in the vector correction step, the value of each component of the vector r described above is corrected based on this estimation result and characteristics such as the arrangement and directivity of each branch at the site. Thereafter, in the matrix correction step, a correction matrix Ra indicating the correlation is newly calculated for the vector r corrected as described above, and eigenvalue analysis processing is again performed on the correction matrix Ra in the eigenvalue recalculation step. By performing the calculation of the eigenvalues of the correction matrix Ra, it is possible to obtain an index indicating the received power of the incoming wave in consideration of errors due to site directivity.

The maximum eigenvalue obtained as described above is compared with a predetermined threshold value based on the lower limit of the attenuation of the wave signal due to direct propagation, for example, in the reception strength determination step. Regardless of this, it is possible to accurately determine whether or not the incoming wave whose direction of arrival has been estimated is a direct wave directly incident on the site.
In this way, only the direction of arrival estimation result obtained for the incoming wave determined as a direct wave. In the estimated value output step, by outputting the arrival direction of the incoming wave, the arrival direction of the useful incoming wave can be used for the transmission end position identification and search processing regardless of the presence of the reflected wave.

A fourth direction of arrival estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, a significant difference determination step, and an arrival direction estimation step.
The principle of the fourth direction-of-arrival estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the significant difference determination step, whether the incoming wave to be estimated is a direct wave incident on the site by direct propagation based on whether there is a significantly larger eigenvalue than other eigenvalues. Determine. The arrival direction estimation step estimates the arrival direction of an incoming wave using the eigenvector of the matrix R and the eigenvalue corresponding thereto only when the arrival wave to be estimated is a direct wave.

The operation of the fourth direction-of-arrival estimation method configured as described above is as follows.
For the matrix R indicating the correlation of the wave signals obtained by executing the correlation calculation step, for example, in the matrix calculation step, an eigenvalue analysis process is performed to obtain an eigenvalue of the matrix R, thereby obtaining an index indicating the received power of the incoming wave. be able to.
Here, since the wave signal incident on the site through one or more reflections is naturally considered to have a significantly reduced intensity due to scattering due to reflection or an increase in propagation distance, the direct wave and the reflected wave Are simultaneously arriving at the site, it is considered that there is a large variation in the value of the eigenvalue of the matrix R. Therefore, in the significant difference determination step, for example, by determining whether or not the maximum eigenvalue V ₁ is significantly larger than the next largest eigenvalue V ₂ , the arrival wave that is the target of arrival direction estimation is a direct wave. It can be determined whether or not there is. In this case, for example, as a result of comparing the predetermined threshold value based on the degree of attenuation of the wave signal due to reflection and the ratio of the eigenvalues of a value obtained by dividing the eigenvalue V ₁ eigenvalue V _2, the largest eigenvalue When it is shown that the intensity of the incoming wave corresponding to V ₁ is sufficiently higher than the intensity of the other incoming waves, it is determined that there is an incoming wave that has directly propagated to the site.

In this way, only for the incoming wave determined as a direct wave, in the arrival direction estimation step, for example, by performing the arrival direction estimation process by the arrival direction estimation method such as the MUSIC algorithm, regardless of the presence of the reflected wave, It is possible to selectively estimate the direction of arrival of a useful incoming wave and use it for the transmission end position identification and search processing.
A fifth arrival direction estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, an arrival direction estimation step, an eigenvalue correction step, a significant difference determination step, and an estimated value output step. It consists of.

The principle of the fifth direction of arrival estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the arrival direction estimation step, the arrival direction of the incoming wave to the site is estimated using the eigenvector of the matrix R and the eigenvalue corresponding thereto. The eigenvalue correction step corrects the value of the eigenvalue obtained as a result of the matrix calculation processing based on the estimated arrival direction and the arrangement and characteristics of each branch at the site. The significant difference determining step determines whether or not there is a significant difference between the corrected eigenvalue related to the arrival wave whose arrival direction is estimated and other corrected eigenvalues. The estimated value output step determines that the arrival wave whose arrival direction is estimated is a direct wave when there is a significant difference between the eigenvalue related to the arrival wave whose arrival direction is estimated and other eigenvalues. The result is output as the arrival direction of the incoming wave that propagated directly to the site.

The operation of the fifth arrival direction estimation method configured as described above is as follows.
First, for the matrix R indicating the correlation of the wave signal obtained by executing the correlation calculation step, using the eigenvector of the matrix R obtained by executing the matrix calculation step, in the arrival direction estimation step, for example, a MUSIC algorithm or the like The direction of arrival of the wave signal arriving at the site is estimated by performing the direction of arrival estimation process using the direction of arrival estimation method. Next, in the eigenvalue correction step, each eigenvalue obtained in the eigenvalue analysis process described above is corrected based on this estimation result and characteristics such as the arrangement and directivity of each branch in the site. As a result, it is possible to obtain an index indicating the received power of each incoming wave in consideration of errors due to site directivity.

For the eigenvalue corrected as described above, in the significant difference determination step, for example, it is determined whether or not the eigenvalue V ₁ corresponding to the incoming wave whose arrival direction is estimated is significantly larger than the next largest eigenvalue V _2. If determined, it is possible to accurately determine whether or not the incoming wave whose arrival direction has been estimated is a direct wave directly incident on the site, regardless of errors due to the directivity of the site.

In this way, only the arrival direction estimation result obtained for the incoming wave determined as a direct wave is output as the arrival direction of the incoming wave in the estimated value output step, regardless of the presence of the reflected wave. The direction of arrival of a new incoming wave can be used for transmitting end position identification and search processing.
A sixth arrival direction estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, an arrival direction estimation step, a vector correction step, a matrix correction step, an eigenvalue recalculation step, , A significant difference determination step and an estimated value output step.

The principle of the sixth direction-of-arrival estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the arrival direction estimation step, the arrival direction of the incoming wave to the site is estimated using the eigenvector of the matrix R and the eigenvalue corresponding thereto. In the vector correction step, the value of each component constituting the vector r is corrected based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site. In the matrix correction step, a correction matrix Ra indicating the correlation of the wave signal that has arrived at the site is obtained based on the corrected vector r. In the eigenvalue recalculation step, a predetermined matrix calculation process is performed on the correction matrix Ra to obtain eigenvectors of the correction matrix Ra and eigenvalues corresponding to the respective elements. The significant difference determining step determines whether or not there is a significant difference between the eigenvalues of the correction matrix Ra and the other eigenvalues regarding the incoming wave whose arrival direction is estimated. The estimated value output step determines that the incoming wave is a direct wave when there is a significant difference between the eigenvalues of the correction matrix Ra related to the incoming wave whose direction of arrival has been estimated and other eigenvalues, and the estimation result Is output as the direction of arrival of the incoming wave directly propagating to the site.

The operation of the sixth direction-of-arrival estimation method configured as described above is as follows.
First, for the matrix R indicating the correlation of the wave signal obtained by executing the correlation calculation step, using the eigenvector of the matrix R obtained by executing the matrix calculation step, in the arrival direction estimation step, for example, a MUSIC algorithm or the like The direction of arrival of the wave signal arriving at the site is estimated by performing the direction of arrival estimation process using the direction of arrival estimation method. Next, in the vector correction step, the value of each component of the vector r described above is corrected based on this estimation result and characteristics such as the arrangement and directivity of each branch at the site. Thereafter, in the matrix correction step, a correction matrix Ra indicating the correlation of the corrected vector r is calculated, and for this correction matrix Ra, eigenvalue analysis processing is performed in the eigenvalue recalculation step, for example, to obtain the eigenvalue of the correction matrix Ra. Thus, it is possible to obtain an index indicating the received power of the incoming wave in consideration of an error due to the directivity of the site.

For the eigenvalues obtained anew as described above, in the significant difference determination step, for example, whether or not the eigenvalue V ₁ corresponding to the incoming wave whose direction of arrival has been estimated is significantly larger than the next largest eigenvalue V ₂ . , It is possible to accurately determine whether or not the incoming wave whose arrival direction is estimated is a direct wave that is directly incident on the site, regardless of errors due to the directivity of the site.

In this way, only the arrival direction estimation result obtained for the incoming wave determined as a direct wave is output as the arrival direction of the incoming wave in the estimated value output step, regardless of the presence of the reflected wave. The direction of arrival of a new incoming wave can be used for transmitting end position identification and search processing.
A seventh direction-of-arrival estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, a received intensity determination step, a significant difference determination step, a direct wave determination step, and an arrival direction estimation. It consists of steps.

The principle of the seventh arrival direction estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the correlation calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the reception intensity determination step, a first determination value indicating whether or not the eigenvalue value satisfies a condition to be satisfied by the reception intensity of the wave signal directly incident on the site is obtained. The significant difference determination step obtains a second determination value indicating whether or not there is a significantly larger value from the eigenvalue than other eigenvalues. In the direct wave discrimination step, it is discriminated based on the first determination value and the second determination value whether or not the arrival wave to be estimated for the arrival direction is a direct wave that directly enters the site from the transmission end. The arrival direction estimation step estimates the arrival direction of an incoming wave using the eigenvector of the matrix R and the eigenvalue corresponding thereto only when the arrival wave to be estimated is a direct wave.

The operation of the seventh arrival direction estimation method configured in this way is as follows.
For the matrix R indicating the correlation of the wave signal obtained by executing the correlation calculation step, in the matrix calculation step, for example, an eigenvalue analysis process is performed to obtain an eigenvalue of the matrix R, thereby obtaining an index indicating the received power of the incoming wave. be able to.
Here, as described above, the reception intensity of the reflected wave is considered to be significantly lower than the lower limit of the attenuation of the wave signal by direct propagation, and also corresponds to the reception intensity and the reflected wave corresponding to the direct wave. It is considered that there is a large variation in the value of the eigenvalue of the matrix R because of the large difference that occurs between the received intensity and the received intensity.

Therefore, for example, the first determination is that any of the eigenvalues obtained as described above is equal to or greater than a predetermined threshold based on the lower limit of the attenuation of the wave signal due to direct propagation in the reception intensity determination step. If the second determination value indicates that the largest eigenvalue V ₁ is significantly larger than the next largest eigenvalue V ₂ in the significant difference determination step, the direct wave determination step It can be confirmed more reliably that there is a direct wave directly incident on.

  In this case, for example, when the direct wave is shielded and, instead, the reflected wave due to the secondary reflection and the reflected wave due to the secondary reflection enter the site, the intensity of the reflected wave due to the primary reflection is due to the secondary reflection. Despite the fact that the second judgment value indicates that the intensity is significantly greater than the intensity of the reflected wave, the intensity indicated by the maximum eigenvalue is smaller than the intensity estimated from the attenuation assumed by direct propagation. It can be determined that there is no direct wave with the first determination value indicating.

In this way, only when a direct wave has arrived at the site, in the direction of arrival estimation step, for example, by performing the direction of arrival estimation process by the direction of arrival estimation method such as the MUSIC algorithm, the presence of the reflected wave is confirmed. Regardless, it is possible to selectively estimate the direction of arrival of a useful incoming wave and use it for the position identification and search processing of the transmitting end.
An eighth arrival direction estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, an arrival direction estimation step, an eigenvalue correction step, a reception intensity determination step, and a significant difference determination step. And a direct wave discrimination step and an estimated value output step.

The principle of the eighth arrival direction estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the arrival direction estimation step, the arrival direction of the incoming wave to the site is estimated using the eigenvector of the matrix R and the eigenvalue corresponding thereto. The eigenvalue correction step corrects the value of the eigenvalue obtained as a result of the matrix calculation processing based on the estimated arrival direction and the arrangement and characteristics of each branch at the site. In the reception intensity determination step, a first determination value indicating whether or not the value of the corrected eigenvalue corresponding to the arrival wave whose arrival direction has been estimated satisfies a condition that the reception intensity of the wave signal directly incident on the site should satisfy is satisfied. Ask. The significant difference determination step obtains a second determination value indicating whether or not the corrected eigenvalue corresponding to the incoming wave whose arrival direction is estimated is significantly larger than other eigenvalues. The direct wave determining step determines whether or not the incoming wave whose arrival direction is estimated is a direct wave that directly enters the site from the transmission end based on the first determination value and the second determination value. The estimated value output step outputs the estimated direction of arrival only when the arrival wave whose direction of arrival is estimated is a direct wave.

The operation of the eighth arrival direction estimation method configured as described above is as follows.
First, for the matrix R indicating the correlation of the wave signal obtained by executing the correlation calculation step, using the eigenvector of the matrix R obtained by executing the matrix calculation step, for example, in the direction of arrival estimation step, for example, the MUSIC algorithm The direction of arrival of the wave signal arriving at the site is estimated by performing the direction-of-arrival estimation process using the direction-of-arrival estimation method. Next, in the eigenvalue correction step, each eigenvalue obtained in the eigenvalue analysis process described above is corrected based on this estimation result and characteristics such as the arrangement and directivity of each branch in the site. As a result, it is possible to obtain an index indicating the received power of each incoming wave in consideration of errors due to site directivity.

  Since the eigenvalue obtained as described above has already corrected the error due to the directivity of the site, it is based on the first judgment value obtained in the reception strength judgment step and the second judgment value obtained in the significant difference judgment step. By executing the direct wave discrimination step, it is possible to accurately determine whether the incoming wave whose direction of arrival is estimated is a direct wave directly incident on the site, taking into account the influence of the site orientation, etc. be able to.

According to this determination result, in the estimated value output step, by outputting only the arrival direction estimation result obtained for the incoming wave determined as the direct wave as the arrival direction of the incoming wave, regardless of the presence of the reflected wave, Useful arrival directions of incoming waves can be used for transmitting end position identification and search processing.
A ninth arrival direction estimation method according to the present invention includes a signal vector collection step, a correlation calculation step, a matrix calculation step, an arrival direction estimation step, a vector correction step, a matrix correction step, and an eigenvalue recalculation step. , A reception intensity determination step, a significant difference determination step, a direct wave determination step, and an estimated value output step.

The principle of the ninth direction of arrival estimation method according to the present invention is as follows.
In the signal vector collection step, a vector r indicating a set of wave signals arriving from the transmission end is obtained for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves. In the correlation calculation step, a matrix R indicating the correlation of the wave signal arriving at the site is obtained based on the vector r. In the matrix calculation step, predetermined matrix calculation processing is performed on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves arriving at the site and eigenvectors corresponding to these eigenvalues. In the arrival direction estimation step, the arrival direction of the incoming wave to the site is estimated using the eigenvector of the matrix R and the eigenvalue corresponding thereto. In the vector correction step, the value of each component constituting the vector r is corrected based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site. In the matrix correction step, a correction matrix Ra indicating the correlation of the wave signal that has arrived at the site is obtained based on the corrected vector r. In the eigenvalue recalculation step, a predetermined matrix calculation process is performed on the correction matrix Ra to obtain eigenvectors of the correction matrix Ra and eigenvalues corresponding to the respective elements. The reception strength determination step is a first determination indicating whether or not the value of the eigenvalue newly obtained corresponding to the arrival wave whose arrival direction is estimated satisfies a condition to be satisfied by the reception strength of the wave signal directly incident on the site. Find the value. In the significant difference determination step, a second determination value indicating whether or not the eigenvalue newly obtained corresponding to the arrival wave whose arrival direction is estimated is significantly larger than other eigenvalues is obtained. The direct wave determining step determines whether or not the incoming wave whose arrival direction is estimated is a direct wave that directly enters the site from the transmission end based on the first determination value and the second determination value. The estimated value output step outputs the estimated direction of arrival only when the arrival wave whose direction of arrival is estimated is a direct wave.

The operation of the ninth arrival direction estimation method configured as described above is as follows.
First, for the matrix R indicating the correlation of the wave signals obtained by executing the correlation calculation step, using the eigenvector of the matrix R obtained by executing the matrix calculation step, for example, in the direction of arrival estimation step, for example, MUSIC The direction of arrival of the wave signal arriving at the site is estimated by performing the direction-of-arrival estimation process using an arrival direction estimation method such as an algorithm. Next, in the vector correction step, the value of each component of the vector r described above is corrected based on this estimation result and characteristics such as the arrangement and directivity of each branch at the site. Thereafter, in the matrix correction step, a correction matrix Ra indicating the correlation of the corrected vector r is calculated, and for this correction matrix Ra, eigenvalue analysis processing is performed in the eigenvalue recalculation step, for example, to obtain the eigenvalue of the correction matrix Ra. Thus, it is possible to obtain an index indicating the received power of the incoming wave in consideration of an error due to the directivity of the site.

  In the eigenvalue newly obtained as described above, the error due to the directivity of the site is already corrected. Therefore, by performing the direct wave discrimination step based on the first judgment value obtained in the reception strength discrimination step and the second judgment value obtained in the significant difference discrimination step, there is an error due to site preference or the like. Regardless of whether or not the arrival wave whose direction of arrival is estimated is a direct wave directly incident on the site, it can be accurately determined.

According to this determination result, in the estimated value output step, by outputting only the arrival direction estimation result obtained for the incoming wave determined as the direct wave as the arrival direction of the incoming wave, regardless of the presence of the reflected wave, Useful arrival directions of incoming waves can be used for transmitting end position identification and search processing.
A first arrival direction estimation apparatus according to the present invention includes sampling means, correlation calculation means, matrix calculation means, reception intensity determination means, arrival direction estimation means, and output control means.

The principle of the first direction of arrival estimation apparatus according to the present invention is as follows.
The sampling means samples incoming waves to a plurality of branches installed at the site as elements that receive wave signals including sound waves and electromagnetic waves, and obtains a vector r indicating a set of wave signals that have arrived from the transmitting end. The correlation calculation means obtains a matrix R indicating the correlation of the wave signal arriving at the site based on the vector r. The matrix calculation means performs predetermined matrix calculation processing on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves that have arrived at the site, and eigenvectors corresponding to these eigenvalues. The reception strength determining means determines whether or not the eigenvalue satisfies a predetermined condition regarding the reception strength corresponding to the direct wave directly incident on the site from the transmission end. The arrival direction estimation means estimates the arrival direction of the incoming wave to the site using the eigenvector of the matrix R and the eigenvalue corresponding thereto. The output control unit determines that the arrival wave to be estimated is a direct wave when the determination result that the condition is satisfied is obtained by the reception strength determination unit, and the estimation result by the arrival direction estimation unit is Is output as the direction of arrival of the incoming wave that arrived directly by.

The operation of the first direction-of-arrival estimation apparatus configured as described above is as follows.
Based on the vector r obtained by sampling by the sampling means, the correlation calculation means obtains a matrix R indicating the correlation of the wave signal, and the matrix calculation means performs, for example, an eigenvalue analysis process on the matrix R. By obtaining the eigenvalue of R, an index indicating the received power of the incoming wave can be obtained.

  As described above, the reception intensity corresponding to the reflected wave is considered to be significantly lower than the lower limit of the attenuation of the wave signal due to direct propagation. Therefore, in the reception strength discriminating means, the maximum value of the eigenvalue obtained as described above is compared with a predetermined threshold based on the lower limit of the attenuation of the wave signal due to direct propagation, for example, to estimate the direction of arrival. It can be determined whether the incoming wave of interest is a direct wave directly incident on the site.

  Further, the arrival direction estimation means estimates the arrival direction of the arrival wave at the site by an arrival direction estimation method such as a MUSIC algorithm. The estimation result by the arrival direction estimation means is output via the output control means only when it is confirmed by the discrimination result obtained by the reception intensity discrimination means that a direct wave has arrived. Therefore, according to the first arrival direction estimation device, it is possible to selectively output the estimation result of the arrival direction of a useful arrival wave and use it for the transmission end position identification and search processing.

A second arrival direction estimation apparatus according to the present invention is configured by including eigenvalue correction means and condition determination means in the reception intensity determination means provided in the first arrival direction estimation apparatus described above.
The principle of the second arrival direction estimating apparatus according to the present invention is as follows.
In the reception strength determination means provided in the first arrival direction estimation device described above, the eigenvalue correction means performs matrix calculation based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch at the site. The value of the eigenvalue obtained by the means is corrected. The condition determining means determines the condition regarding the reception intensity corresponding to the direct wave when the corrected eigenvalue corresponding to the incoming wave whose direction of arrival is estimated satisfies a predetermined relationship with respect to the predetermined threshold. Outputs the determination result to satisfy.

The operation of the second arrival direction estimation apparatus configured as described above is as follows.
In the reception intensity discrimination means, first, the eigenvalue value obtained by the matrix operation means is corrected by the eigenvalue correction means using the estimation result obtained by the arrival direction estimation means. As a result, it is possible to obtain an index indicating the received power of each incoming wave in consideration of errors due to site directivity.
Since the error due to the directivity of the site has already been corrected in the eigenvalue obtained as described above, the eigenvalue V ₁ corresponding to the incoming wave whose direction of arrival is estimated, for example, is attenuated by direct propagation by the condition determining means. By determining whether or not the condition relating to the reception intensity corresponding to the direct wave is satisfied by determining whether or not the threshold is greater than the threshold obtained in advance from the lower limit, the arrival wave whose arrival direction is estimated is determined. It is possible to accurately determine whether the wave is a direct wave directly incident on the site.

A third direction-of-arrival estimation apparatus according to the present invention includes a vector correction means, a matrix correction means, a corrected eigenvalue calculation means, a condition determination, and a reception intensity determination means provided in the first arrival direction estimation apparatus described above. Means.
The principle of the third arrival direction estimation apparatus according to the present invention is as follows.
In the reception strength determination means provided in the first arrival direction estimation device described above, the vector correction means is configured to calculate the vector r based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch at the site. Is corrected. The correction correlation calculation means obtains a correction matrix Ra indicating the correlation of the wave signal that has arrived at the site, based on the corrected vector r. The corrected eigenvalue calculating means performs a predetermined matrix calculation process on the correction matrix Ra and calculates eigenvalues of the correction matrix Ra and eigenvectors corresponding to these eigenvalues, thereby obtaining corrected eigenvalues. The condition determining means determines the condition regarding the reception intensity corresponding to the direct wave when the corrected eigenvalue corresponding to the incoming wave whose direction of arrival is estimated satisfies a predetermined relationship with respect to the predetermined threshold. Outputs the determination result to satisfy.

The operation of the third direction-of-arrival estimation apparatus configured as described above is as follows.
In the reception strength discrimination means, first, the value of each component of the vector r described above is corrected by the vector correction means using the estimation result by the arrival direction estimation means. Thereafter, a correction matrix Ra indicating the correlation of the corrected vector r is calculated by the correction correlation calculation means, and an eigenvalue of the correction matrix Ra is calculated by the correction eigenvalue calculation means.

In the eigenvalue newly obtained as described above, the error due to the directivity of the site is already corrected. Therefore, the condition determining means, for example, by the eigenvalues V ₁ the incoming direction corresponds to the estimated arrival wave to determine whether greater than a previously determined threshold value from the lower limit of the attenuation due to the direct propagation, the direct wave It is possible to more accurately determine whether or not the condition regarding the corresponding reception intensity is satisfied, and to accurately determine whether or not the incoming wave whose arrival direction is estimated is a direct wave that is directly incident on the site.

A fourth arrival direction estimation apparatus according to the present invention includes sampling means, correlation calculation means, matrix calculation means, significant difference determination means, arrival direction estimation means, and output control means.
The principle of the fourth arrival direction estimating apparatus according to the present invention is as follows.
The sampling means samples incoming waves to a plurality of branches installed at the site as elements that receive wave signals including sound waves and electromagnetic waves, and obtains a vector r indicating a set of wave signals that have arrived from the transmitting end. The correlation calculation means obtains a matrix R indicating the correlation of the wave signal arriving at the site based on the vector r. The matrix calculation means performs predetermined matrix calculation processing on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves that have arrived at the site, and eigenvectors corresponding to these eigenvalues. The significant difference discriminating unit determines whether there is a significant value among eigenvalues compared to other eigenvalues. The arrival direction estimation means estimates the arrival direction of the incoming wave to the site using the eigenvector of the matrix R and the eigenvalue corresponding thereto. The output control means determines that the arrival wave to be estimated is a direct wave when the determination result that the significantly large eigenvalue exists is obtained by the significant difference determination means, and the estimation result by the arrival direction estimation means Output as the arrival direction of the desired arrival wave.

The operation of the fourth direction-of-arrival estimation apparatus configured as described above is as follows.
Based on the vector r obtained by sampling by the sampling means, the correlation calculation means obtains a matrix R indicating the correlation of the wave signal, and the matrix calculation means performs, for example, an eigenvalue analysis process on the matrix R. By obtaining the eigenvalue of R, an index indicating the received power of the incoming wave can be obtained.

Here, since the wave signal incident on the site through one or more reflections is naturally considered to have a significantly reduced intensity due to scattering due to reflection or an increase in propagation distance, the direct wave and the reflected wave Are simultaneously arriving at the site, it is considered that there is a large variation in the value of the eigenvalue of the matrix R. Therefore, for example, by determining whether or not the maximum eigenvalue V ₁ is significantly larger than the next largest eigenvalue V ₂ , it is determined whether or not the incoming wave that is the target of arrival direction estimation is a direct wave. can do. In other words, a significant difference determining means, by comparing the predetermined threshold value based on the degree of attenuation of the wave signal due to reflection and the ratio of the eigenvalues of a value obtained by dividing the eigenvalue V ₁ eigenvalue V _2, maximum intensity of the incoming wave corresponding to the eigenvalues V ₁ is determined whether sufficiently larger than the intensity of other incoming waves. If it is indicated, it is determined that there is an incoming wave that has directly propagated to the site.

  Further, the arrival direction estimation means estimates the arrival direction of the arrival wave at the site by an arrival direction estimation method such as a MUSIC algorithm. The estimation result by the arrival direction estimation means is output via the output control means only when it is confirmed by the discrimination result obtained by the significant difference discrimination means that a direct wave has arrived. Therefore, according to the first arrival direction estimation device, it is possible to selectively output the estimation result of the arrival direction of a useful arrival wave and use it for the transmission end position identification and search processing.

A fifth arrival direction estimation apparatus according to the present invention is configured by including eigenvalue correction means and comparison means in the significant difference determination means provided in the fourth arrival direction estimation apparatus described above.
The principle of the fifth arrival direction estimating apparatus according to the present invention is as follows.
In the significant difference discriminating means provided in the fourth direction-of-arrival estimation apparatus described above, the eigenvalue correcting means performs matrix calculation based on the arrival direction estimated by the arrival direction estimating means and the arrangement and characteristics of each branch at the site. The value of the eigenvalue obtained by the means is corrected. The comparing means determines whether or not the value of the corrected eigenvalue corresponding to the incoming wave whose direction of arrival has been estimated is significantly larger than other corrected eigenvalues.

The operation of the fifth arrival direction estimation apparatus configured as described above is as follows.
In the significant difference discriminating means, first, the eigenvalue value obtained by the matrix computing means is corrected by the eigenvalue correcting means using the estimation result obtained by the arrival direction estimating means. As a result, it is possible to obtain an index indicating the received power of each incoming wave in consideration of errors due to site directivity.
Since the error due to the directivity of the site has already been corrected in the eigenvalue obtained as described above, for example, the eigenvalue V ₁ corresponding to the incoming wave whose arrival direction has been estimated by the comparing means is the next largest eigenvalue V _2. If it is determined whether or not it is significantly larger than the, it is possible to accurately determine whether the incoming wave whose direction of arrival has been estimated is a direct wave directly incident on the site, regardless of errors due to the directivity of the site. can do.

A sixth arrival direction estimation device according to the present invention includes a vector correction unit, a matrix correction unit, a corrected eigenvalue calculation unit, and a comparison unit, as a significant difference determination unit provided in the fourth arrival direction estimation device described above. And is configured.
The principle of the sixth arrival direction estimating apparatus according to the present invention is as follows.
In the significant difference discriminating means provided in the fourth arrival direction estimation device described above, the vector correction means is configured to calculate the vector r based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch at the site. Is corrected. The correction correlation calculation means obtains a correction matrix Ra indicating the correlation of the wave signal that has arrived at the site, based on the corrected vector r. The corrected eigenvalue calculating means performs a predetermined matrix calculation process on the correction matrix Ra and calculates eigenvalues of the correction matrix Ra and eigenvectors corresponding to these eigenvalues, thereby obtaining corrected eigenvalues. The comparing means determines whether or not the value of the corrected eigenvalue corresponding to the incoming wave whose direction of arrival has been estimated is significantly larger than other corrected eigenvalues.

The operation of the sixth arrival direction estimation apparatus configured as described above is as follows.
In the significant difference discriminating means, first, the value of each component of the vector r described above is corrected by the vector correcting means using the estimation result by the arrival direction estimating means. Thereafter, a correction matrix Ra indicating the correlation of the corrected vector r is calculated by the correction correlation calculation means, and an eigenvalue of the correction matrix Ra is calculated by the correction eigenvalue calculation means.

In the eigenvalue newly obtained as described above, the error due to the directivity of the site is already corrected. Therefore, for example, if it is determined by the comparison means whether or not the eigenvalue V ₁ corresponding to the arrival wave whose direction of arrival has been estimated is significantly larger than the next largest eigenvalue V ₂ , an error due to the directivity of the site is caused. Regardless, it is possible to accurately determine whether the incoming wave whose direction of arrival has been estimated is a direct wave directly incident on the site.

A seventh arrival direction estimation apparatus according to the present invention includes a sampling means, a correlation calculation means, a matrix calculation means, a reception intensity determination means, a significant difference determination means, an arrival direction estimation means, and an output control means. Composed.
The principle of the seventh arrival direction estimation device according to the present invention is as follows.
The sampling means samples incoming waves to a plurality of branches installed at the site as elements that receive wave signals including sound waves and electromagnetic waves, and obtains a vector r indicating a set of wave signals that have arrived from the transmitting end. The correlation calculation means obtains a matrix R indicating the correlation of the wave signal arriving at the site based on the vector r. The matrix calculation means performs predetermined matrix calculation processing on the matrix R, thereby obtaining eigenvalues of the matrix R including indices related to the received power of the waves that have arrived at the site, and eigenvectors corresponding to these eigenvalues. The reception intensity determination means determines whether or not the eigenvalue value satisfies a predetermined condition regarding the reception intensity corresponding to the direct wave directly incident on the site from the transmission end, and outputs a first determination value indicating the determination result To do. The significant difference discriminating means determines whether or not there is an eigenvalue that is significantly larger than other eigenvalues, and outputs a second determination value indicating the determination result. The arrival direction estimation means estimates the arrival direction of the incoming wave to the site using the eigenvector of the matrix R and the eigenvalue corresponding thereto. The output control means determines whether or not the arrival wave to be estimated is a direct wave based on the first determination value and the second determination value, and only when the arrival wave is a direct wave, the estimation by the arrival direction estimation means The result is output as the direction of arrival of the desired incoming wave.

The operation of the seventh arrival direction estimation apparatus configured as described above is as follows.
Based on the vector r obtained by sampling by the sampling means, the correlation calculation means obtains a matrix R indicating the correlation of the wave signal, and the matrix calculation means performs, for example, an eigenvalue analysis process on the matrix R. By obtaining the eigenvalue of R, an index indicating the received power of the incoming wave can be obtained.

Here, the wave signal incident on the site through one or more reflections is naturally considered to have a significantly reduced intensity due to scattering due to reflection and an increase in propagation distance, and also to direct waves. From the large difference that occurs between the received intensity corresponding to the reflected wave and the received intensity corresponding to the reflected wave, the values of the eigenvalues of the matrix R are considered to vary greatly. Therefore, for example, the reception intensity determination unit obtains that any of the eigenvalues obtained as described above is equal to or greater than a predetermined threshold based on the lower limit of the attenuation of the wave signal due to direct propagation. indicated by 1 decision value, and the maximum is possible eigenvalues V ₁ is greater significantly larger than the next largest eigenvalue V _2, if indicated by the second judgment value obtained by significant difference determining means, to the site It can be confirmed more reliably that there is a direct wave directly incident.

  In this case, for example, when the direct wave is shielded and, instead, the reflected wave due to the secondary reflection and the reflected wave due to the secondary reflection enter the site, the intensity of the reflected wave due to the primary reflection is due to the secondary reflection. Despite the fact that the second judgment value indicates that the intensity is significantly greater than the intensity of the reflected wave, the intensity indicated by the maximum eigenvalue is smaller than the intensity estimated from the attenuation assumed by direct propagation. It can be determined that there is no direct wave with the first determination value indicating.

  Further, the arrival direction estimation means estimates the arrival direction of the arrival wave at the site by an arrival direction estimation method such as a MUSIC algorithm. The estimation result by the arrival direction estimation means is output via the output control means only when it is confirmed by the discrimination result obtained by the significant difference discrimination means that a direct wave has arrived. Therefore, according to the seventh arrival direction estimation device, it is possible to selectively output the estimation result of the arrival direction of a useful arrival wave and to use it for the transmission end position identification and search processing.

An eighth arrival direction estimation apparatus according to the present invention is configured by including eigenvalue correction means in the seventh arrival direction estimation apparatus described above.
The principle of the eighth arrival direction estimation apparatus according to the present invention is as follows.
In the seventh arrival direction estimating device described above, the eigenvalue correcting means is a value of the eigenvalue obtained by the matrix computing means based on the arrival direction estimated by the arrival direction estimating means and the arrangement and characteristics of each branch at the site. , And the corrected eigenvalue is used for the processing of the reception intensity determination unit and the significant difference determination unit.

The operation of the eighth arrival direction estimation apparatus configured as described above is as follows.
The eigenvalue correction means corrects the value of the eigenvalue obtained by the matrix calculation means using the estimation result obtained by the arrival direction estimation means, and the corrected eigenvalue is calculated for each incoming wave in consideration of errors due to site directivity. As an index indicating the received power, it is used for the processing of the received intensity determining means and the significant difference determining means.

As a result, the first determination value and the second determination value can be obtained after correcting the error due to the directivity of the site. Instead, it is possible to accurately determine whether or not the arrival wave whose arrival direction is estimated is a direct wave that is directly incident on the site.
A ninth arrival direction estimation apparatus according to the present invention is configured by adding the vector correction means, the matrix correction means, and the corrected eigenvalue calculation means to the seventh arrival direction estimation apparatus described above.

The principle of the ninth arrival direction estimation apparatus according to the present invention is as follows.
In the seventh arrival direction estimation device described above, the vector correction means calculates the value of each component constituting the vector r based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch at the site. to correct. The correction correlation calculation means obtains a correction matrix Ra indicating the correlation of the wave signal that has arrived at the site, based on the corrected vector r. The corrected eigenvalue calculation means performs a predetermined matrix calculation process on the correction matrix Ra, calculates eigenvalues of the correction matrix Ra and eigenvectors corresponding to these eigenvalues, thereby obtaining corrected eigenvalues, and the obtained corrected eigenvalues. The eigenvalues are used for the processing of the reception strength discrimination means and the significant difference discrimination means.

The operation of the ninth arrival direction estimation apparatus configured as described above is as follows.
The value of each component of the vector r described above is corrected by the vector correction unit using the estimation result by the arrival direction estimation unit, and then the correction matrix Ra indicating the correlation of the corrected vector r is calculated by the correction correlation calculation unit. Calculated. Then, the eigenvalue of the correction matrix Ra is calculated by the correction eigenvalue calculating means, and used for the processing of the reception intensity determining means and the significant difference determining means.

In the eigenvalue newly obtained as described above, the error due to the directivity of the site is already corrected. Therefore, for example, if it is determined by the comparison means whether or not the eigenvalue V ₁ corresponding to the arrival wave whose direction of arrival has been estimated is significantly larger than the next largest eigenvalue V ₂ , an error due to the directivity of the site is caused. Regardless, it is possible to accurately determine whether the incoming wave whose direction of arrival has been estimated is a direct wave directly incident on the site.

  As described above, the eigenvalue is obtained again based on the vector r in which the error due to the directivity of the site is corrected, thereby removing the influence of the error due to the directivity of the site from the index regarding the received power corresponding to the incoming wave. Above, it can use for the process of a receiving strength discrimination | determination means and a significant difference discrimination means. As a result, the first determination value and the second determination value can be obtained without being affected by the error due to the directivity of the site, etc. Therefore, the error depends on the error due to the relationship between the directivity of the site and the estimated arrival direction. Instead, it is possible to accurately determine whether or not the arrival wave whose arrival direction is estimated is a direct wave that is directly incident on the site.

  According to the first direction-of-arrival estimation method and apparatus according to the present invention, whether a direct wave has arrived at a site based on the value of the eigenvalue of the matrix R indicating the correlation of the wave signals used in the direction-of-arrival estimation process. Whether or not can be determined by an extremely simple process. By using the fact that the received power corresponding to the direct wave can be expected to be greater than or equal to a predetermined threshold, it is determined whether or not the direct wave has arrived at the site. The result of estimating the direction of arrival of can be provided as information useful for identifying and searching for the position of the transmitting end.

  In addition, according to the fourth direction-of-arrival estimation method and apparatus according to the present invention, based on whether there is a significant difference between eigenvalue values of the matrix R indicating the correlation of the wave signals used in the direction-of-arrival estimation process. Thus, it is possible to determine whether or not a direct wave has arrived at the site. By using the fact that there is a large difference between the received power corresponding to the direct wave and the received power corresponding to the reflected wave, it is determined whether or not the direct wave has arrived at the site, and the direct wave has arrived. Only occasionally, the result of estimating the direction of arrival of an incoming wave can be provided as information useful for position identification and search of the transmitting end.

  On the other hand, according to the seventh direction-of-arrival estimation method and apparatus according to the present invention, there is a significant difference between the eigenvalue values themselves of the matrix R indicating the correlation of the wave signals used in the direction-of-arrival estimation process and the eigenvalue values. Based on whether or not there is, it can be determined whether or not a direct wave has arrived at the site. As a result, it can be expected that the received power corresponding to the direct wave is greater than or equal to a predetermined threshold, and that there is a large difference between the received power corresponding to the direct wave and the received power corresponding to the reflected wave. Use this to determine whether there is a direct wave arriving at the site, and to estimate the arrival direction of the incoming wave only when the direct wave is arriving, as useful information for position identification and search of the transmitting end Can be provided.

  Further, in each of the arrival direction estimation methods and apparatuses described above, using the arrival direction estimation result, the corrected eigenvalue obtained by correcting the error due to the directivity of the site for the calculated eigenvalue itself, or By using the eigenvalues newly calculated from the matrix indicating the correlation of the set of wave signals corrected for errors due to site directivity, etc., to determine whether there is direct wave arrival at the site, the site directivity, etc. Regardless of such hardware limitations, it is possible to reliably determine whether a direct wave has arrived at the site.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First Embodiment) Comparison between Received Intensity and Threshold Value FIG. 1 shows a first embodiment of an arrival direction estimating apparatus according to the present invention.
Note that among the components shown in FIG. 1, the same components as those shown in FIG. 11 are denoted by the reference numerals shown in FIG.

  A sampling processing unit 201 provided in the signal processing circuit 13 shown in FIG. 1 samples the outputs of the antenna elements 12-1 to 12-N constituting the array antenna 11, thereby a vector r indicating a set of wave signals. To get. Based on the vector r, the correlation calculation processing unit 202 obtains a matrix R indicating the correlation of the wave signal, and the matrix calculation processing unit 203 performs eigenvalue expansion processing on the matrix R to obtain an array antenna. 11, the same number of eigenvalues as the number N of antenna elements 12-1 to 12 -N constituting the antenna 11 and eigenvectors corresponding to these eigenvalues are obtained.

The arithmetic control unit 206 shown in FIG. 1 passes the eigenvalues and eigenvectors obtained by the matrix arithmetic processing unit 203 to the arrival direction estimation processing unit 204 for use in the arrival direction estimation process, and uses the eigenvalues described above as the direct wave determination unit 207. To the direct wave discrimination process described later.
In the direct wave discriminating unit 207 shown in FIG. 1, the maximum value detecting unit 208 detects the maximum value from the N eigenvalues received from the arithmetic control unit 206 and sends the maximum value V _{1 of the} eigenvalue to the comparing unit 209. pass and subjected to comparison process with a predetermined threshold Th _1. The comparison result by the comparison unit 209 is returned to the arithmetic control unit 206 as an output of the direct wave discrimination unit 207, and used for output processing related to the arrival direction estimation result.

  On the other hand, the arrival direction estimation processing unit 204 shown in FIG. 1 performs arrival direction estimation processing according to the MUSIC algorithm, for example, based on the eigenvalue and eigenvector received from the arithmetic control unit 206, and the arrival direction θ that maximizes the MUSIC spectrum. Is passed to the arithmetic control unit 206 as an estimation result. Further, the phase correction register 205 shown in FIG. 1 corresponds to the azimuth angle θ indicating the direction in which the wave signal can arrive at the site 10, and the azimuth angle θ and the antenna elements 12-1 to 12-1 in the array antenna 11. The phase correction value related to the phase difference φ determined by the 12-N arrangement interval d is stored. For example, when the arrival direction of the wave signal arriving at the site 10 is estimated with an accuracy of 1 degree in an azimuth angle range of −90 degrees to +90 degrees, the azimuth angle θ is changed by 1 degree within the above range. It is necessary to calculate a phase correction value related to the assumed phase difference φ and store it in the phase correction register 205.

FIG. 2 is a flowchart showing the direction of arrival estimation operation.
First, by sampling the output signal of the array antenna 11 corresponding to the wave signal arriving at the site 10 by the sampling processing unit 201, information on the amplitude and phase of the wave signal arriving at the site 10 is collected and obtained. Based on the obtained information, a vector r indicating a set of wave signals arriving at the site 10 is formed (step 301).

Here, when a wave signal transmitted from the transmitting end whose arrival direction is unknown is incident on the site 10, the arrival wave has an amplitude b, an unknown azimuth angle θ and an antenna element arrangement when arriving at the site 10. Using the phase difference φ determined by the interval d (see FIG. 11) and the number N of antenna elements, it is expressed as a vector r as shown in Equation (3).
r = [b b · e ^jφ ... b · e ^{j (N-1) φ} ] ^T (3)
Next, the correlation calculation processing unit 202 performs a correlation calculation on the vector r indicating the set of wave signals formed in step 301 described above to obtain a matrix R indicating the correlation of the vector r indicating the set of wave signals (step 302).

For the matrix R obtained in this manner, the matrix calculation processing unit 203 performs eigenvalue expansion processing to obtain the same number of eigenvalues as the number N of antenna elements provided in the array antenna 11 and eigenvectors corresponding to these eigenvalues. (Step 303).
The arrival direction estimation processing unit 204 receives the eigenvalues and eigenvectors obtained by the processing of the matrix operation processing unit 203 via the operation control unit 206, and based on these eigenvalues and eigenvectors, for example, the arrival direction estimation process according to the MUSIC algorithm And the azimuth angle θ that maximizes the MUSIC spectrum is returned to the arithmetic control unit 206 as an estimated value of the direction of arrival (step 304).

The N eigenvalues obtained by the matrix calculation processing unit 203 in step 303 described above are passed to the maximum value detection unit 208 of the direct wave determination unit 207 via the calculation control unit 206, and the maximum value detection unit 208 The largest eigenvalue V ₁ is detected from the N eigenvalues (step 305), and is used for comparison processing with the threshold Th ₁ by the comparison unit 209.
Here, as described above, among the N eigenvalues obtained for the matrix r indicating the correlation of the vector R indicating the set of arriving waves, the value corresponding to L (L <N) arriving waves is: Closely related to the received power of the corresponding incoming wave, other eigenvalues are related to thermal noise. Therefore, the largest one among the N eigenvalues is considered to be related to the wave signal having the highest received power among the wave signals arriving at the site 10.

  In addition, when the wave signal radiated from the transmission end arrives at the site 10 by direct propagation, for example, when the transmission end and the site 10 whose direction of arrival should be estimated are installed in a limited area. Can be predicted, a lower limit can be assumed for the received power of the wave signal that arrives by this direct propagation. And the received power when the wave signal radiated | emitted from the transmission end mentioned above injects into the site 10 via primary or higher-order reflection is naturally much smaller than the lower limit of the received power regarding the direct wave mentioned above. Can be expected. This is because the propagation path of the reflected wave incident through the first-order or higher-order reflection is very long compared to the direct wave propagation path, and is also surely attenuated by scattering during reflection. .

Therefore, for example, if a value related to the lower limit of the received power is set as the threshold Th _{1 in} the comparison unit 209 shown in FIG. 1, the comparison unit 209 compares the threshold Th ₁ with the maximum eigenvalue V ₁ as a comparison result. The determination result as to whether or not the incoming wave is a direct wave can be obtained.
That is, when the maximum eigenvalue V ₁ is equal to or greater than the above-described threshold value Th ₁ (affirmative determination in step 306), the arrival direction estimated in the above-described step 304 is the arrival of the wave signal that has arrived directly at the site 10 Since it is considered to be a direction, the calculation control unit 206 outputs the estimation result obtained by the arrival direction estimation processing unit 204 as the direction of the transmitting end (step 307), and ends the arrival direction estimation process.

On the other hand, when the maximum eigenvalue V ₁ is smaller than the above-described threshold value Th ₁ (negative determination in step 306), the arrival direction estimated in the above-described step 304 has arrived at the site 10 via primary or higher-order reflection. Since it is considered to be the arrival direction of the wave signal, the arithmetic control unit 206 outputs a message indicating that no direct wave is detected (step 308), and ends the arrival direction estimation process.

  In this way, using the fact that the eigenvalue value inevitably calculated for use in the direction of arrival estimation process is closely related to the received power of the incoming wave, based on the eigenvalue value described above, Determine whether the arrival wave whose direction of arrival has been estimated is a direct wave, and output the arrival direction estimation result as the direction of the transmitting end only when it is confirmed that the direct wave has arrived. Can do.

  Note that the direct wave discrimination technique described above can be applied regardless of the algorithm type as long as it is an algorithm that estimates the arrival direction of the incoming wave using the eigenvalues and eigenvectors of the matrix R indicating the correlation of the set of wave signals. Is possible. Therefore, instead of the arrival wave estimation processing unit 204 shown in FIG. 1, for example, an arrival direction estimation processing unit that performs estimation processing according to the Beamformer algorithm may be provided, or estimation processing according to the Capon algorithm, LP algorithm, or minimum norm algorithm An arrival direction estimation processing unit may be provided.

It is also possible to determine the presence or absence of a direct wave by comparing all eigenvalues with the threshold Th ₁ and determining whether or not there is one or more eigenvalues having a value equal to or greater than the threshold.
In addition, the value of the threshold value Th ₁ described above can be determined according to the environment where the site 10 and the transmission end exist, the parameters of the wave signal that can be transmitted from the transmission end, and a plurality of threshold values are set in advance. The presence or absence of a direct wave can also be determined based on the relationship between the range indicated by these threshold values and the maximum value of the eigenvalue V1.

Furthermore, as described above, the arrival direction estimation processing by the arrival direction estimation processing unit 204 can be executed after confirming that a direct wave has arrived based on the eigenvalue.
(Second Embodiment)
FIG. 3 shows a second embodiment of the arrival direction estimation apparatus according to the present invention.

3 that are the same as those shown in FIG. 1 and FIG. 11 are denoted by the same reference numerals as those shown in FIG. 1 and FIG. 11, and description thereof is omitted.
The eigenvalue correction unit 211 shown in FIG. 3 receives the azimuth angle θ indicating the estimated value of the arrival direction obtained by the arrival direction estimation processing unit 204 from the arithmetic control unit 206 and the eigenvalue of the matrix R described above, and receives the correction coefficient register. After correcting the eigenvalues of the matrix R using the information held in 212, the information is provided for discrimination processing by the direct wave discrimination unit 207.

The correction coefficient register 212 illustrated in FIG. 3 is, for example, −90 degrees to +90 degrees with respect to the normal direction to the arrangement plane of the antenna elements 12-1 to 12-N in the array antenna 11 provided in the site 10. Corresponding to the azimuth angle θ of the range, a correction coefficient C for correcting the influence of the characteristic that changes depending on the azimuth angle θ, such as the sensitivity of the array antenna 11 to the wave signal coming from the azimuth angle θ. holds _θ .

In the direction-of-arrival estimation apparatus configured in this way, as shown in FIG. 4, eigenvalue correction processing is performed by the eigenvalue correction unit 211 prior to the direct wave discrimination processing in step 305 and step 306 (step 311). .
In this case, the eigenvalue correction unit 211, for example, receives the L azimuth angle theta ₁ through? _L that gives a peak value of the MUSIC spectrum obtained in the arrival direction estimation processing unit 204 from the operation controller 206, these azimuth the eigenvalues corresponding to each of theta ₁ through? _L, is corrected by multiplying a correction coefficient C _.theta.1 -C _.theta.L held in the correction coefficient register 212 in correspondence with the azimuth angle theta ₁ through? _L.

  Such correction processing corrects the influence of the directivity of the array antenna 11 and the like, so that the intensity of the wave signal arriving from the corresponding arrival direction is faithfully shown by the corrected eigenvalue. Therefore, by performing the process by the direct wave discriminating unit 207 based on the eigenvalue corrected as described above, the arrival wave whose arrival direction is estimated regardless of the influence of the directivity of the array antenna 11 or the like. Whether it is a direct wave can be determined more reliably.

When the influence of the directivity of the array antenna 11 is small, the eigenvalue correction process and the process for determining the presence or absence of a direct wave can be simplified as described below.
That is, the eigenvalue correcting unit 211 corrects the eigenvalue corresponding to the azimuth angle θ giving the maximum value of the MUSIC spectrum (that is, the maximum eigenvalue V ₁ ), and the direct wave discriminating unit 207 corrects the corrected eigenvalue. The presence / absence of a direct wave is determined by determining whether V ₁ is greater than or equal to the threshold Th ₁ .
(Third embodiment)
FIG. 5 shows a third embodiment of the arrival direction estimation apparatus according to the present invention.

5 that are the same as those shown in FIG. 1 and FIG. 11 are denoted by the same reference numerals as those shown in FIG. 1 and FIG.
The vector correction unit 213 illustrated in FIG. 5 receives the azimuth angle θ, which is the estimation result of the arrival direction, from the arithmetic control unit 206, and is obtained by the sampling processing unit 201 using the information held in the correction coefficient register 214. The value of each element constituting the signal vector R is corrected and again subjected to correlation calculation processing by the correlation calculation processing unit 202.

The correction coefficient register 214 illustrated in FIG. 5 is, for example, −90 degrees to +90 degrees with respect to the normal direction to the arrangement plane of the antenna elements 12-1 to 12-N in the array antenna 11 provided in the site 10. Corresponding to the azimuth angle θ of the range, a correction coefficient K for correcting the influence of the characteristics that change depending on the azimuth angle θ, such as the sensitivity of the array antenna 11 to the wave signal coming from the azimuth angle θ. holds _θ .

In the arrival direction estimating apparatus configured as described above, as shown in FIG. 6, the correction processing described below is performed prior to the direct wave discrimination processing in step 305 and step 306.
First, the arithmetic control unit 206 passes the estimated value θ of the arrival direction to the vector correction unit 213, and the vector correction unit 213 is based on the correction coefficient K _θ held in the correction coefficient register 214 corresponding to the estimated value θ. Correction processing is executed (step 312).

  In accordance with the input of the correction signal vector obtained in this way, the correlation calculation processing unit 202 obtains a correction matrix Ra indicating the correlation of the correction signal vector (step 313). Further, the matrix calculation processing unit 203 By performing eigenvalue expansion processing on the correction matrix Ra, errors determined by the arrangement of the antenna elements 12-1 to 12-N and the direction in which the transmitting end can be located, such as the directivity of the array antenna 11, are corrected. The obtained eigenvalue is obtained (step 314).

Such correction processing corrects the influence of the directivity of the array antenna 11 and the like, so that the corrected eigenvalue faithfully indicates the intensity of the wave signal arriving from the corresponding arrival direction. Therefore, by performing the process by the direct wave discriminating unit 207 based on the eigenvalue corrected as described above, the arrival wave whose arrival direction is estimated regardless of the influence of the directivity of the array antenna 11 or the like. Whether it is a direct wave can be determined more reliably.
(Fourth embodiment)
FIG. 7 shows a fourth embodiment of the arrival direction estimating apparatus according to the present invention.

7 that are the same as those shown in FIG. 1 and FIG. 11 are denoted by the same reference numerals as those shown in FIG. 1 and FIG. 11, and description thereof is omitted.
The arrival direction estimation apparatus illustrated in FIG. 7 includes a direct wave determination unit 220 instead of the direct wave determination unit 207 illustrated in FIG.
In the direct wave discriminating unit 220 shown in FIG. 7, the eigenvalue extracting unit 221 extracts the maximum eigenvalue V ₁ and the eigenvalue V ₂ having the next largest value from the eigenvalues received from the arithmetic control unit 206, and performs division. These eigenvalues are passed to instrument 222. The divider 222 divides the maximum eigenvalue V ₁ by the second largest eigenvalue V ₂ and uses the division result for comparison processing with the threshold Th ₂ by the comparison unit 223. The comparison result by the comparison unit 223 is returned to the arithmetic control unit 206 as an output of the direct wave discrimination unit 220, and used for output processing related to the arrival direction estimation result.

In the arrival direction estimating apparatus configured as described above, the following processing is performed instead of the direct wave discrimination processing in steps 305 and 306 shown in FIG. 2 (see FIG. 8).
The N eigenvalues obtained by the matrix operation processing unit 203 shown in FIG. 7 are passed to the eigenvalue extraction unit 221 of the direct wave discrimination unit 220 via the operation control unit 206, and the eigenvalue extraction unit 221 generates N The largest eigenvalue V ₁ and the first largest eigenvalue V ₂ are extracted from among the eigenvalues (step 321), and the divider 222 obtains the ratio between the largest eigenvalue V ₁ and the second largest eigenvalue V _2. (Step 322).

Here, as described above, among the N eigenvalues obtained for the matrix r indicating the correlation of the vector R indicating the set of arriving waves, the value corresponding to L (L <N) arriving waves is: Closely related to the received power of the corresponding incoming wave, other eigenvalues are related to thermal noise. Therefore, the two eigenvalues V ₁ and V ₂ extracted from the N eigenvalues are related to the wave signal that has arrived at the site 10 with the highest received power and the next highest received power. Conceivable.

  Also, for example, the received power when the wave signal radiated from the transmitting end whose direction of arrival is to be estimated is incident on the site 10 via first-order or higher reflection is, of course, directly propagated from the transmitting end to the site 10. Can be expected to be much smaller than the received power for the direct wave incident on. This is because the propagation path of the reflected wave incident through the first-order or higher-order reflection is very long compared to the direct wave propagation path, and is also surely attenuated by scattering during reflection. .

Therefore, if there is one transmission end, the ratio of the eigenvalues obtained in step 322 described above is considered to be a value corresponding to the degree to which the wave signal is attenuated by the first-order or higher-order reflection. Therefore, if a value corresponding to the degree to which the wave signal is attenuated by the first-order reflection or more is set as the threshold Th _{2 in} the comparison unit 223 shown in FIG. 7, the threshold Th ₂ by the comparison unit 223 and the value obtained in Step 322 are obtained. Depending on the comparison result with the ratio of the eigenvalues, the two eigenvalues extracted by the eigenvalue extraction unit 221 shown in FIG. 7 differ to an extent corresponding to the eigenvalue corresponding to the direct wave and the eigenvalue corresponding to the reflected wave. It can be determined whether or not.

That is, (affirmative determination in Step 323) if the ratio of eigenvalues calculated in step 322 is the threshold value Th ₂ or more as described above, it is determined that there is a significant difference between the eigenvalues V ₁ and the other eigenvalues. In this case, since the arrival direction estimated in step 304 described above is considered to be the arrival direction of the wave signal that has arrived at the site 10 by direct propagation, the arithmetic control unit 206 obtains the arrival direction estimation processing unit 204. The obtained estimation result is output as the direction of the transmitting end (step 307), and the arrival direction estimation process is terminated.

On the other hand, when the ratio of the eigenvalues calculated in step 322 is smaller than the threshold Th ₂ described above (negative determination in step 323), it is determined that there is no significant difference between the eigenvalues V ₁ and the other eigenvalues. In this case, since the arrival direction estimated in the above-described step 304 is considered to be the arrival direction of the reflected wave that has arrived at the site 10, the arithmetic control unit 206 displays a message indicating that the direct wave has not been detected. Output (step 308), and the direction of arrival estimation process ends.

  In this way, the value of the eigenvalue that is inevitably calculated for use in the direction-of-arrival estimation processing is closely related to the received power of the incoming wave, and the received power corresponding to the direct wave and the received wave corresponding to the reflected wave. Based on the value of the eigenvalue described above, it is possible to determine whether or not the arrival wave whose arrival direction is estimated is a direct wave by using the fact that there is a large difference with the power. Only when it is confirmed that a direct wave has arrived, the arrival direction estimation result can be output as the direction of the transmitting end.

This direct wave discrimination method is particularly effective when the amount of attenuation cannot be estimated when the wave signal radiated from the transmitting end is incident by direct propagation.
Note that the direct wave discrimination technique described above can be applied regardless of the type of algorithm as long as it is an algorithm that estimates the arrival direction of an incoming wave using the eigenvalues and eigenvectors of the matrix R indicating the correlation of a set of wave signals. Is possible. Therefore, instead of the arrival wave estimation processing unit 204 shown in FIG. 1, for example, an arrival direction estimation processing unit that performs estimation processing according to the Beamformer algorithm may be provided, or estimation processing according to the Capon algorithm, LP algorithm, or minimum norm algorithm An arrival direction estimation processing unit may be provided.

Also, the distribution of values of N eigenvalues is examined, and from this distribution, the difference between the received power corresponding to the direct wave and the received power corresponding to the reflected wave is equivalent to one or more eigenvalues and other eigenvalues. It is also possible to determine whether or not there is a significant difference to the extent that it is, and to determine the presence or absence of a direct wave based on the result.
Furthermore, as described above, the arrival direction estimation processing by the arrival direction estimation processing unit 204 can be executed after confirming that a direct wave has arrived based on the eigenvalue.

Of course, the eigenvalue correction method described in the second and third embodiments can be applied to determine whether or not a direct wave has arrived based on the corrected eigenvalue.
(Fifth embodiment)
FIG. 9 shows a fifth embodiment of the arrival direction estimation apparatus according to the present invention.
In addition, among the components shown in FIG. 9, the same components as those shown in FIG. 1, FIG. 7 and FIG. 11 are denoted by the reference numerals shown in FIG. 1, FIG. Is omitted.

In the direct wave discriminating unit 230 shown in FIG. 9, the eigenvalue extracting unit 221 receives N eigenvalues obtained by the matrix operation processing unit 203 via the operation control unit 206, and receives the maximum eigenvalue V ₁ and the second eigenvalue V _1. Eigenvalue V ₂ is extracted, and eigenvalue V ₁ is passed to comparison section 231 as it is, and eigenvalues V ₁ and V ₂ are passed to divider 222 as dividend and divisor, respectively.
The comparison section 231 shown in FIG. 9, threshold eigenvalues _{V 1} received from the eigenvalue extractor 221 is compared with a threshold value Th ₁ described above, the above-described divider 222 ratio _V 1 / _{V 2} of the eigenvalues received from Compared with Th ₂ , these comparison results are returned to the calculation control unit 206 as the output of the direct wave discrimination unit 230.

In the direction-of-arrival estimation apparatus configured as described above, as illustrated in FIG. 10, the calculation control unit 206 executes step 331 instead of step 323 illustrated in FIG. The direct wave discrimination method and the direct wave discrimination method described in the fourth embodiment are applied in combination.
That is, the maximum eigenvalue V ₁ is equal to or greater than the threshold Th ₁ corresponding to the minimum received power assumed for the direct wave, and the ratio V _{1/2 of the second} largest eigenvalue V _{2 to} the maximum eigenvalue V ₁ . When V ₂ is equal to or greater than the threshold Th ₂ corresponding to the ratio of the received power of the direct wave and the received power of the reflected wave (affirmative determination in step 331), the arithmetic control unit 206 determines that the incoming wave corresponding to the eigenvalue V1 is It is determined that there is a significant difference between the eigenvalue V ₁ and another eigenvalue, and the estimation result obtained by the direction-of-arrival estimation processing unit 204 is received. The direction of the transmission end is output (step 307), and the arrival direction estimation process is terminated.

On the other hand, when the maximum eigenvalue V ₁ is smaller than the threshold Th ₁ or the ratio V ₁ / V _{2 of the second} largest eigenvalue V _{2 to} the maximum eigenvalue V ₁ is smaller than the threshold Th ₂ (in step 331). (No determination), the arithmetic control unit 206 outputs a message indicating that the direct wave has not been detected (step 307), and ends the arrival direction estimation process.
Thus, by applying the above-described two direct wave discrimination methods in combination, for example, the direct wave is shielded while the primary reflected wave and the secondary reflected wave are incident on the site 10. Even in this case, a correct determination result that the direct wave is not detected can be obtained.

This is because, in the case described above, although the ratio value obtained for the eigenvalue corresponding to the primary reflected wave and the eigenvalue corresponding to the secondary reflected wave is equal to or greater than the above-described threshold Th ₂ , the primary reflected wave the value itself of the corresponding eigenvalues, of course, is because clear that does not exceed the threshold Th _1.
Note that the direct wave discrimination technique described above can be applied regardless of the type of algorithm as long as it is an algorithm that estimates the arrival direction of an incoming wave using the eigenvalues and eigenvectors of the matrix R indicating the correlation of a set of wave signals. Is possible. Therefore, instead of the arrival wave estimation processing unit 204 shown in FIG. 1, for example, an arrival direction estimation processing unit that performs estimation processing according to the Beamformer algorithm may be provided, or estimation processing according to the Capon algorithm, LP algorithm, or minimum norm algorithm An arrival direction estimation processing unit may be provided.

It is also possible to compare all eigenvalues with the threshold value Th ₁ and determine whether or not there is one or more eigenvalues having a value equal to or greater than the threshold value. Further, the distribution of values of N eigenvalues is examined, and the difference between the received power corresponding to the direct wave and the received power corresponding to the reflected wave is found between one or more eigenvalues and other eigenvalues from this distribution. It is also possible to determine whether or not there is a significant difference to the extent that this is possible, and to set this result as the determination value 2.

Furthermore, as described above, the arrival direction estimation processing by the arrival direction estimation processing unit 204 can be executed after confirming that a direct wave has arrived based on the eigenvalue.
Of course, the eigenvalue correction method described in the second and third embodiments can be applied to determine whether or not a direct wave has arrived based on the corrected eigenvalue.

As described above, according to the arrival direction estimation device according to the present invention, the arrival wave whose arrival direction is estimated based on the value of the eigenvalue inevitably calculated for the arrival direction estimation process is a direct wave. Only when it is confirmed that the direct wave has arrived, the arrival direction estimation result can be output as the direction of the transmitting end.
As a result, it is possible to provide only the direction of arrival of the direct wave for processing such as position identification and search of the transmission end. It is extremely useful in fields such as searching for rescue signal sources.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the arrival direction estimation apparatus concerning this invention. It is a flowchart showing an arrival direction estimation operation | movement. It is a figure which shows 2nd Embodiment of the arrival direction estimation apparatus concerning this invention. It is a flowchart showing an arrival direction estimation operation | movement. It is a figure which shows 3rd Embodiment of the arrival direction estimation apparatus concerning this invention. It is a flowchart showing an arrival direction estimation operation | movement. It is a figure which shows 4th Embodiment of the arrival direction estimation apparatus concerning this invention. It is a flowchart showing an arrival direction estimation operation | movement. It is a figure which shows 5th Embodiment of the arrival direction estimation apparatus concerning this invention. It is a flowchart showing an arrival direction estimation operation | movement. It is explanatory drawing of an antenna system.

Explanation of symbols

10 Site 11 Array antenna 12-1 to 12-N Antenna element 13 Signal processing circuit 201 Sampling processing unit 202 Correlation calculation processing unit 203 Matrix calculation processing unit 204 Arrival direction estimation processing unit 205 Phase correction register 206 Calculation control units 207, 220, 230 Direct wave discriminating unit 208 Maximum value detecting unit 209, 223, 231 Comparing unit 211 Eigen value correcting unit 212, 214 Correction coefficient register 213 Vector correcting unit 221 Eigen value extracting unit 222 Divider

Claims (18)

Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Based on whether the value of the eigenvalue satisfies the condition to be satisfied by the reception intensity of the wave signal directly incident on the site, the incoming wave to be estimated for the arrival direction is directly incident on the site from the transmitting end. Whether it ’s a wave or not,
Only when the arrival wave to be estimated is a direct wave, the arrival direction of the arrival wave is estimated using the eigenvector of the matrix R and the corresponding eigenvalue. Estimation method. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Using the eigenvectors of the matrix R and the corresponding eigenvalues, the arrival direction of the incoming wave to the site is estimated,
Based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site, correct at least one of the eigenvalues obtained by the matrix calculation processing on the matrix R,
Based on whether or not the corrected eigenvalue value satisfies the condition to be satisfied by the reception intensity of the wave signal directly incident on the site, the arrival wave to be estimated for the arrival direction is directly transmitted from the transmitting end to the site. Determine whether it is a direct wave incident,
The arrival direction estimation method, wherein the estimation result is output as the arrival direction of the arrival wave directly propagated to the site only when the arrival wave whose arrival direction is estimated is a direct wave. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Using the eigenvectors of the matrix R and the corresponding eigenvalues, the arrival direction of the incoming wave to the site is estimated,
Based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site, correct the value of each element constituting the vector r,
Based on the corrected vector r, a correction matrix Ra indicating the correlation of the wave signal arriving at the site is obtained,
A predetermined matrix calculation process is performed on the correction matrix Ra to obtain an eigenvector of the correction matrix Ra and an eigenvalue corresponding thereto,
Based on whether the value of the eigenvalue satisfies the condition to be satisfied by the reception intensity of the wave signal directly incident on the site, the incoming wave to be estimated for the arrival direction is directly incident on the site from the transmitting end. Whether it ’s a wave or not,
The arrival direction estimation method, wherein the estimation result is output as the arrival direction of the arrival wave directly propagated to the site only when the arrival wave whose arrival direction is estimated is a direct wave. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Based on whether or not the eigenvalue is significantly larger than other eigenvalues, it is determined whether the incoming wave to be estimated is a direct wave incident on the site by direct propagation,
Only when the arrival wave to be estimated is a direct wave, the arrival direction of the arrival wave is estimated using the eigenvector of the matrix R and the corresponding eigenvalue. Estimation method. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Using the eigenvectors of the matrix R and the corresponding eigenvalues, the arrival direction of the incoming wave to the site is estimated,
Based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site, correct the value of the eigenvalue obtained as a result of the matrix calculation process,
Determining whether there is a significant difference between a corrected eigenvalue for the incoming wave whose direction of arrival is estimated and other corrected eigenvalues;
When there is a significant difference between the eigenvalues related to the arrival wave whose direction of arrival is estimated and other eigenvalues, it is determined that the arrival wave whose direction of arrival is estimated is a direct wave, and the estimation result is An arrival direction estimation method characterized by outputting the arrival direction of an incoming wave that has directly propagated to a site. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Using the eigenvectors of the matrix R and the corresponding eigenvalues, the arrival direction of the incoming wave to the site is estimated,
Based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site, correct the value of each component constituting the vector r,
Based on the corrected vector r, a correction matrix Ra indicating the correlation of the wave signal arriving at the site is obtained,
A predetermined matrix calculation process is performed on the correction matrix Ra to determine eigenvectors of the correction matrix Ra and eigenvalues corresponding to the elements thereof,
Determining whether there is a significant difference between eigenvalues of the correction matrix Ra and other eigenvalues with respect to an incoming wave whose direction of arrival is estimated;
If there is a significant difference between the eigenvalues of the correction matrix Ra and other eigenvalues relating to the arrival wave whose direction of arrival has been estimated, it is determined that the arrival wave is a direct wave, and the estimation result is An arrival direction estimation method characterized by outputting the arrival direction of an incoming wave directly propagated to a site. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Obtaining a first determination value indicating whether the value of the eigenvalue satisfies a condition to be satisfied by a reception intensity of a wave signal directly incident on the site;
Obtaining a second determination value indicating whether or not there is a significantly larger value than the other eigenvalues from the eigenvalue;
Based on the first determination value and the second determination value, it is determined whether or not the arrival wave to be the direction of arrival estimation is a direct wave directly incident on the site from the transmission end,
Only when the arrival wave to be estimated is a direct wave, the arrival direction of the arrival wave is estimated using the eigenvector of the matrix R and the corresponding eigenvalue. Estimation method. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Using the eigenvectors of the matrix R and the corresponding eigenvalues, the arrival direction of the incoming wave to the site is estimated,
Based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site, correct the value of the eigenvalue obtained as a result of the matrix calculation process,
Obtaining a first determination value indicating whether or not the corrected eigenvalue corresponding to the incoming wave whose direction of arrival is estimated satisfies a condition that the reception intensity of the wave signal directly incident on the site should satisfy;
Obtaining a second determination value indicating whether or not the corrected eigenvalue corresponding to the incoming wave whose direction of arrival is estimated is significantly larger than other eigenvalues;
Based on the first determination value and the second determination value, it is determined whether the arrival wave whose arrival direction is estimated is a direct wave directly incident on the site from the transmission end,
The direction of arrival estimation method characterized by outputting the estimated direction of arrival only when the arrival wave whose direction of arrival has been estimated is a direct wave. Obtaining a vector r indicating a set of wave signals arriving from the transmitting end for a plurality of branches installed at the site as elements for receiving wave signals including sound waves and electromagnetic waves,
Based on the vector r, a matrix R indicating the correlation of the wave signals arriving at the site is obtained,
By performing a predetermined matrix calculation process on the matrix R, eigenvalues of the matrix R including an index related to the received power of the wave arriving at the site and eigenvectors corresponding to these eigenvalues are obtained,
Using the eigenvectors of the matrix R and the corresponding eigenvalues, the arrival direction of the incoming wave to the site is estimated,
Based on the estimated direction of arrival and the arrangement and characteristics of each branch at the site, correct the value of each component constituting the vector r,
Based on the corrected vector r, a correction matrix Ra indicating the correlation of the wave signal arriving at the site is obtained,
A predetermined matrix calculation process is performed on the correction matrix Ra to determine eigenvectors of the correction matrix Ra and eigenvalues corresponding to the elements thereof,
Obtaining a first determination value indicating whether or not the value of the eigenvalue newly obtained corresponding to the arrival wave whose direction of arrival is estimated satisfies a condition that the reception intensity of the wave signal directly incident on the site should satisfy,
Obtaining a second determination value indicating whether or not the eigenvalue newly obtained corresponding to the arrival wave whose direction of arrival is estimated is significantly larger than other eigenvalues;
Based on the first determination value and the second determination value, it is determined whether the arrival wave whose arrival direction is estimated is a direct wave directly incident on the site from the transmission end,
The direction of arrival estimation method characterized by outputting the estimated direction of arrival only when the arrival wave whose direction of arrival has been estimated is a direct wave. Sampling means for sampling incoming waves to a plurality of branches installed at a site as elements for receiving wave signals including sound waves and electromagnetic waves, and obtaining a vector r indicating a set of wave signals arriving from the transmission end;
Correlation calculation means for obtaining a matrix R indicating the correlation of the wave signal arriving at the site based on the vector r;
Matrix calculation means for obtaining eigenvalues of the matrix R including indices related to received power of waves arriving at the site and eigenvectors corresponding to these eigenvalues by performing predetermined matrix calculation processing on the matrix R;
A reception strength determination means for determining whether or not the value of the eigenvalue satisfies a predetermined condition with respect to a reception strength corresponding to a direct wave directly incident on the site from the transmission end;
Direction-of-arrival estimation means for estimating the direction of arrival of an incoming wave to the site using the eigenvector of the matrix R and the corresponding eigenvalue;
When the determination result that the condition is satisfied is obtained by the reception strength determination unit, it is determined that the arrival wave to be estimated is a direct wave, and the estimation result by the arrival direction estimation unit is transmitted to the site. An output direction estimation device comprising: output control means for outputting the arrival direction of an incoming wave that arrived by direct propagation. The direction-of-arrival estimation apparatus according to claim 10,
The reception strength determination means includes
Eigenvalue correction means for correcting the value of the eigenvalue obtained by the matrix calculation means based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch in the site;
Judgment that the condition regarding the reception intensity corresponding to the direct wave is satisfied when the value of the corrected eigenvalue corresponding to the incoming wave whose direction of arrival is estimated satisfies a predetermined relationship with respect to a predetermined threshold value A direction-of-arrival estimation apparatus comprising: a condition determination unit that outputs a result. The direction-of-arrival estimation apparatus according to claim 10,
The reception strength determination means includes
Vector correction means for correcting the value of each component constituting the vector r based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch in the site;
A corrected correlation calculating means for obtaining a correction matrix Ra indicating the correlation of the wave signal arriving at the site based on the corrected vector r;
A corrected eigenvalue calculating means for obtaining a corrected eigenvalue by performing a predetermined matrix operation on the correction matrix Ra and calculating eigenvalues of the correction matrix Ra and eigenvectors corresponding to these eigenvalues;
Judgment that the condition regarding the reception intensity corresponding to the direct wave is satisfied when the value of the corrected eigenvalue corresponding to the incoming wave whose direction of arrival is estimated satisfies a predetermined relationship with respect to a predetermined threshold value A direction-of-arrival estimation apparatus comprising: a condition determination unit that outputs a result. Sampling means for sampling incoming waves to a plurality of branches installed at a site as elements for receiving wave signals including sound waves and electromagnetic waves, and obtaining a vector r indicating a set of wave signals arriving from the transmission end;
Correlation calculation means for obtaining a matrix R indicating the correlation of the wave signal arriving at the site based on the vector r;
Matrix calculation means for obtaining eigenvalues of the matrix R including indices related to received power of waves arriving at the site and eigenvectors corresponding to these eigenvalues by performing predetermined matrix calculation processing on the matrix R;
Significant difference discriminating means for determining whether or not there is a significantly larger value than the other eigenvalues among the eigenvalues;
Direction-of-arrival estimation means for estimating the direction of arrival of an incoming wave to the site using the eigenvector of the matrix R and the corresponding eigenvalue;
When the determination result that a significantly large eigenvalue exists is obtained by the significant difference determination means, it is determined that the arrival wave to be estimated is a direct wave, and the estimation result by the arrival direction estimation means is determined as a desired arrival And an output control means for outputting the direction of arrival of the wave. The direction of arrival estimation apparatus according to claim 13,
The significant difference determining means includes
Eigenvalue correction means for correcting the value of the eigenvalue obtained by the matrix calculation means based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch in the site;
Comparing means for determining whether or not the value of the corrected eigenvalue corresponding to the incoming wave whose direction of arrival has been estimated is significantly larger than the other corrected eigenvalues. Direction estimation device. The direction of arrival estimation apparatus according to claim 13,
The significant difference determining means includes
Vector correction means for correcting the value of each component constituting the vector r based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch in the site;
A corrected correlation calculating means for obtaining a correction matrix Ra indicating the correlation of the wave signal arriving at the site based on the corrected vector r;
A corrected eigenvalue calculating means for obtaining a corrected eigenvalue by performing a predetermined matrix operation on the correction matrix Ra and calculating eigenvalues of the correction matrix Ra and eigenvectors corresponding to these eigenvalues;
Comparing means for determining whether or not the value of the corrected eigenvalue corresponding to the incoming wave whose direction of arrival has been estimated is significantly larger than the other corrected eigenvalues. Direction estimation device. Sampling means for sampling incoming waves to a plurality of branches installed at a site as elements for receiving wave signals including sound waves and electromagnetic waves, and obtaining a vector r indicating a set of wave signals arriving from the transmission end;
Correlation calculation means for obtaining a matrix R indicating the correlation of the wave signal arriving at the site based on the vector r;
Matrix calculation means for obtaining eigenvalues of the matrix R including indices related to received power of waves arriving at the site and eigenvectors corresponding to these eigenvalues by performing predetermined matrix calculation processing on the matrix R;
It is determined whether or not the value of the eigenvalue satisfies a predetermined condition regarding a reception intensity corresponding to a direct wave directly incident on the site from the transmission end, and a reception intensity that outputs a first determination value indicating the determination result Discrimination means;
A significant difference discriminating means for determining whether or not any of the eigenvalues is significantly larger than other eigenvalues, and outputting a second determination value indicating the determination result;
Direction-of-arrival estimation means for estimating the direction of arrival of an incoming wave to the site using the eigenvector of the matrix R and the corresponding eigenvalue;
Based on the first determination value and the second determination value, it is determined whether the arrival wave to be estimated is a direct wave. Only when the arrival wave is a direct wave, the estimation result by the arrival direction estimation means is An output direction estimation device comprising: output control means for outputting the direction of arrival of a desired arrival wave. The direction-of-arrival estimation apparatus according to claim 16,
Based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch in the site, the eigenvalue value obtained by the matrix calculation means is corrected, and the corrected eigenvalue is determined by the reception strength determination. And an eigenvalue correcting means for use in processing of the significant difference discriminating means. The direction-of-arrival estimation apparatus according to claim 16,
Vector correction means for correcting the value of each component constituting the vector r based on the arrival direction estimated by the arrival direction estimation means and the arrangement and characteristics of each branch in the site;
A corrected correlation calculating means for obtaining a correction matrix Ra indicating the correlation of the wave signal arriving at the site based on the corrected vector r;
A predetermined matrix calculation process is performed on the correction matrix Ra, and eigenvalues of the correction matrix Ra and eigenvectors corresponding to these eigenvalues are calculated to obtain corrected eigenvalues. A direction-of-arrival estimation apparatus comprising: a received intensity determining unit; and a corrected eigenvalue calculating unit for use in processing of the significant difference determining unit.

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