JP2003222665A - Device and method for detecting orientation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a device for detecting an orientation, which generates multiple beams after executing a spatial smoothing process and makes it possible to separately measure angles of a plurality of waves correlating with each other by using an output signal and an angle detection algorithm with a super fine resolution, even in the case a covariance matrix of an input signal is degraded in the rank because a plurality of entering waves are in correlation with each other. <P>SOLUTION: The device for detecting the orientation has a linear array antenna 1 with identical spacings which receives an entering wave having a correlation with a plurality of targets, a spatial smoothing section 5 which processes the entering wave in the spatial smoothing process, a spatial filter 3 which generates the multiple beams in response to the processed signal, and an angle measuring section 6 which computes an estimated entering angle by using the output signal and the angle detection algorithm with super fine resolution. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to estimating the incident angles of a plurality of correlated waves propagating in a medium, for example, after spatial smoothing processing, forming a plurality of beams and measuring their outputs by super-resolution measurement. The present invention relates to an incident angle estimating apparatus and method capable of improving the angle measuring performance of a plurality of incident waves when the angle is measured using an angle algorithm.

[0002]

BACKGROUND ART FIG. 5 is a block diagram showing an angle measuring method in which a conventional beam space processing in FIG, 12 ₁ to 12
_M is the M arranged array antenna, 2 ₁ to 2 _K is wave incidence of K wave, 31 ₁ to 31 _J spatial filter to form a J-number of the orthogonal beams, 10 uniform linear array conversion processing unit, 4 ₁ to 4 _L is subarray, 5 spatial smoothing processing unit, 6 is a angle measuring section obtains the estimated incident angle by super-resolution angle measurement algorithm.

Next, the operation will be described. Currently low S /
It is known to use the beam space processing for the purpose of improving the S / N ratio when performing the angle measurement of the target incident at N. In the beam space processing, since the beam is formed in the desired direction, the S / N ratio can be improved. Here, an angle measurement method using the eigen filter method, which is one method of beam space processing, will be described. The beam space angle measuring method is a method of forming a plurality of beams depending on a received signal and applying a super resolution angle measuring algorithm to the beam output.

The structure of the prior art will be described with reference to FIG. In the figure, 12 _{1 to} 12 _M are M array antennas. Here, the element spacing and the element arrangement do not matter.
It is assumed that K wave incident waves 2 ₁ to 2 _K are incident on these element antennas at an angle of θ _k with respect to the direction in which the element antennas are arranged. Here, it is assumed that the wave number K of the incident wave is smaller than the number M of the element antennas, and the incident wave has a partial or complete correlation. 31 _{1 to} 31 in the figure
_J represents J spatial filters. In these spatial filters, the coefficients for J orthogonal multi-beam forming are calculated, and the input signal is multiplied. However, the beam forming number J is 2 if only the Forward type space smoothing process is performed.
K or more and M or less, and in the Forward / Backward type, (3/2) K or more and M or less. In the figure, reference numeral 10 represents a linear array conversion processing unit for a virtual linear array.
In this processing, the outputs of the spatial filters 31 _{1 to} 31 _J are not generally the same as the covariance matrix of the output signals of the equally-spaced linear array antenna, so that the spatial smoothing processing in the subsequent stage is performed in order to perform the conversion. To use. 4 in the figure
₁ to 4 _L indicate subarrays. The number of elements of the sub-array is set to be the incident wave number K or more. In the figure, in the spatial smoothing processing section 5 the covariance matrix is calculated for each of the 4 ₁ to 4 _L sub-arrays and averaged, and then input to the angle measurement processing section 6 in the figure and the super resolution angle measurement algorithm is used. Estimated incident angle θ
^{Find ^} ₁ , ..., θ ^{^} _k .

Prior art on mutually orthogonal beam forming methods is known in the art (KM Buckley, XL.
Xu, "Spatial-Spectrum Esti
mation in a Location Sect
or, “IEEE Trans. on Acoustic
cs Speech and Signal Proc
essing, Vol. 38, No. 11, pp. 18
42-1852, 1990. ) Is an eigenfilter method. This method is used to calculate the spatial filter coefficient matrix W _BS for multi-beam formation.

Covariance matrix R _BS of the output signal of the spatial filter
Is the spatial filter coefficient matrix W _BS and the received signal vector x
Using (i),

[Equation 1] Is expressed as Here, E [] represents an expected value calculation. H represents the conjugate transpose.

However, when there is a correlation between the incident waves, it may be impossible to estimate the incident angle depending on the angle measurement algorithm. For example, when the MUSIC algorithm is used as the angle measurement algorithm and the incident angles of a plurality of correlated waves are to be estimated, the rank of the covariance matrix of the received signal is equal to or smaller than the incident wave number, and the MUSIC
Since the algorithm does not hold, it becomes impossible to estimate the incident angle.

In such a case, a method of recovering the rank of the covariance matrix of the received signal by spatial smoothing preprocessing is known. In order for the spatial smoothing process to be established, the covariance matrix R _BS of the output signal of the spatial filter obtained after the beam space process needs to be the same as the covariance matrix of the output signal of the equally-spaced linear array antenna.
However, generally obtained by the formula (1) R _BS does not correspond thereto. Therefore, the J spatial filters 31 _{1 to} 3
The output signal of 1 _J is once converted into a reception signal in a virtual evenly-spaced linear array antenna.

Letting C be the conversion matrix from the output of the spatial filter to the virtual equidistant linear array, the covariance matrix R _virtual of the received signal of the virtual equidistant linear array is

[Equation 2] It can be expressed as. In addition, the transformation matrix C is also used for the matrix B in which the steering vectors of the spatial filters in the angle range Θ of interest and the matrix A _{virtual in} which the steering vectors of the virtual equally-spaced linear array are arranged.

[Equation 3] Is expressed as

A method for determining the transformation matrix C is described in a known document (Fri).
edlander, Weiss, "Direction
Finding Using Spatial Sm
loosing with Interpolated
Arrays, "IEEE Trans. AES-2
8, No. 2, pp. 574-587, 1992. ).

Subsequently, spatial smoothing processing is performed on the received signal converted into the output signal from the virtual linear array by the obtained conversion matrix. Here, for the sake of simplicity, the Forward type space smoothing process will be described.

Assuming that the covariance matrix S of the incident signal vector is S and the noise power is σ ² , equation (2) is

[Equation 4] It can be expressed as. Since the equation (4) can be described by the steering vector of the virtual evenly spaced linear array, the spatial smoothing processing that is established only by the equally spaced linear array can be applied.

It is considered that the present invention is applied to the MUSIC algorithm using the output signal subjected to the spatial smoothing processing. This operation is given by the following equation.

[Equation 5] Where L is the average number of subarrays and * is the complex conjugate
Represent Also, Z_iIs from the i-th column to the i + j-th column₀Up to the column is single
Construct a rank matrix (j₀Xj) matrix. j ₀Is a sub
Represents the dimension of the array.

[Equation 6]

Expanding equation (5),

[Equation 7] To get

Since the (j ₀ × j) matrix G of the second term on the right side of the equation (7) is generally not a unit matrix, the MUSIC algorithm cannot be applied. Therefore, R _virtual is transformed so that G becomes a unit matrix (pre-whitening).

[Equation 8] If the average number of subarrays in equation (8), that is, the number L of subarrays is set to satisfy L ≧ K, R _{virtual Since} the rank of _s is K, equation (10)
The first term on the right side of the modified covariance matrix R ′ _virtual shown in FIG. Therefore, even if the covariance matrix S of the incident signals is rank-decreased because all or some of the incident signals are correlated with each other, the MUSIC is applied by applying the spatial smoothing process in the virtual evenly-spaced linear array.
Angle measurement is possible. A matrix defined by the noise space eigenvector e ″ _N corresponding to the smallest eigenvalue of R ′ _virtual

[Equation 9] Using, the estimated incident angle is obtained from the peak of the azimuth evaluation function of the following equation.

[Equation 10] Here, the steering vector a ′ (θ) is

[Equation 11] Given in.

Up to this point, orthogonal multi-beams have been formed by the eigen-filter method, the output signals thereof have been converted into virtual equal-spaced linear arrays, and the spatially smoothed signals have been applied to a super-resolution angle-measuring algorithm to obtain a plurality of correlated waves. The method of estimating the incident angle of is described.

[0017]

Since the conventional incident angle estimating apparatus is constructed as described above, it is possible to disperse the energy concentrated on a specific beam by the beam space processing at the time of conversion of the virtual linear array at equal intervals. Therefore, there is a problem that the separation and angle measurement performance of a plurality of waves that are partially or wholly correlated with each other is deteriorated.

The present invention has been made to solve the above problems, and even when all or some of a plurality of incident waves have a correlation with each other, the covariance matrix of the incident signals drops in rank. An object of the present invention is to obtain an azimuth detecting apparatus and method capable of performing multi-beam formation after spatial smoothing processing and using the output signals thereof to separate and measure a plurality of correlated waves by a super-resolution angle measurement algorithm.

[0019]

An azimuth detecting apparatus according to the present invention is a linear array antenna for receiving incident waves having a correlation from a plurality of targets and a spatial smoothing for spatially smoothing the received incident waves. A processing unit,
A spatial filter that forms a multi-beam according to the processed signal, and an angle measurement processing unit that obtains an estimated incident angle by a super-resolution angle measurement algorithm using an output signal from the spatial filter are provided.

The azimuth detecting apparatus according to the present invention includes an array antenna for receiving correlated incident waves from a plurality of targets,
An equal-spaced linear array conversion processing unit that converts the received incident wave into a virtual linear array output, a spatial smoothing processing unit that performs spatial smoothing processing on the converted incident wave, and a multi-beam according to the processed signal. It is provided with a spatial filter to be formed, and an angle measurement processing section for obtaining an estimated incident angle by a super-resolution angle measurement algorithm using an output signal from the spatial filter.

The azimuth detecting apparatus according to the present invention is configured to form orthogonal multi-beams in the spatial filter according to the signal processed by the spatial smoothing processing section.

In the azimuth detecting method according to the present invention, when the incident waves having a correlation from a plurality of targets are separated by radio wave angle measurement using a linear array antenna with equal intervals, first,
The incident wave is spatially smoothed, then a multi-beam is formed, and the output signal thereof is used to obtain an estimated incident angle by a super-resolution angle-measuring algorithm.

In the azimuth detecting method according to the present invention, when the correlated incident waves from a plurality of targets are separated by radio wave angle measurement using an array antenna, first, the incident waves are subjected to linear array conversion processing, and then the incident waves are incident. The waves are spatially smoothed, then multi-beams are formed, and the output signals are used to obtain the estimated incident angle by a super-resolution angle-measuring algorithm.

The azimuth detecting method according to the present invention forms an orthogonal multi-beam.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below.
explain. Embodiment 1. FIG. 1 shows an embodiment of the present invention.
Spatial smoothing using a linear array of 1s
FIG. 3 is a configuration diagram showing an angle measuring method for forming a beam later.
Then 1₁~ 1_MIs an evenly spaced linear array with M
Antenna, 2₁~ 2_KIs the incident wave of K wave, 4 ₁~ 4_LIs L
Sub-arrays, 5 are spatial smoothing processing units, 3₁~
Three_JIs J spatial filters, 6 is super-resolution angle measurement algorithm
Is an angle measurement processing unit that obtains an estimated incident angle by using the rhythm.

Next, the operation will be described. In the first embodiment, a plurality of orthogonal beams depending on the received signal after the spatial smoothing process are formed, and the angle is measured using the beam output. In FIG. 1, ₁₁ to 1 _M are M linearly-spaced linear array antennas. It is assumed that the K-wave incident waves 2 ₁ to 2 _K enter the element antenna at an angle of azimuth θ _K with respect to the direction in which the element antenna is arranged. Here, it is assumed that the wave number K of the incident wave is smaller than the number M of the element antennas, and the incident wave has a partial or complete correlation. In Fig, 4 ₁ to 4 _L represents a configuration of the L subarrays. However, the sub-array number L is set to be the incident wave number K or more. The output of the covariance matrix of this sub-array is averaged in the spatial smoothing processing unit 5 in the figure.

The spatial smoothing processing is performed because when the incident waves have a correlation, the covariance matrix of the received signal drops in rank, and MUSIC or the like cannot be applied as the angle measurement algorithm. As a technique for avoiding this constitutes a subarray 4 ₁ to 4 _L, obtains a covariance matrix for each sub-array, to restore the rank by averaging them.

In the figure, 3 _{1 to} 3 _J are spatial filters.
In the spatial filter, the coefficient matrix W _BS for orthogonal multi-beam formation is calculated, and the covariance matrix after the spatial smoothing process is multiplied. However, the beam forming number J is not less than the incident wave number K and not more than the number of element antennas M _{0 of the} sub array. Then, in the figure, it is input to the angle measurement processing unit 6 and the estimated incident angles θ ^{^} ₁ , ..., θ ^{^} _k are _obtained by the super-resolution angle measurement algorithm.

Unlike the conventional method, the spatial smoothing process is performed before the beam formation. Therefore, the element array of the receiving antenna is assumed to be a linear array with equal intervals.

The following shows that the rank of the covariance matrix of the input signal applied to the angle measurement processing unit 6 is restored when the beam space processing is performed by the eigen filter method after the spatial smoothing processing.

Of the M element antennas, 1 ₁ , ...
.., the element of 1 ₁ + M _0-1 is called the l-th sub-array. The received signal vector x _{l of} this sub-array 4 ₁ , ..., 4 _L
Is

[Equation 12] It can be expressed as. Here, A ′ is a matrix in which steering vectors a ′ (θ _k ) are arranged, and

[Equation 13] Is. The matrix B is

[Equation 14] Is a Kth-order diagonal matrix defined by s represents an incident signal vector, and n _l represents a noise vector of the sub array l. Further, T represents transposition.

Here, for simplicity, let us consider a case where only the Forward type space smoothing process is performed. In the spatial smoothing processing, the covariance matrix R ′ _l of x ₁ is processed as in the following equation to obtain the covariance matrix R after smoothing.

[Equation 15] However, from equation (14), the covariance matrix R ′ _{l of the} sub-array
Is

[Equation 16] It can be expressed as. Here, R _s is the covariance matrix of only the incident signal, I ′ is the unit matrix, L is the average number of subarrays,
H represents the complex conjugate transpose.

Substituting equation (16) into equation (15)R
Is

[Equation 17] It can be expressed as.

Here, as orthogonal multi-beam forming,
For example, the eigen filter method is applied and the coefficient matrix W _BS of the spatial filter is obtained by the method described above.

Co-division of received signal after spatial smoothing processing
Dispersal matrixRAnd the coefficient matrix W_BSAnd multiply it by the angle measurement algorithm
Covariance matrix after orthogonal multi-beam formation, if applicable
R _BSThe following shows that the rank has been recovered in
YouR _BSIs equation (17) and W _BS ^HW_BS= I
,

[Equation 18] It can be expressed as. W_BS ^HRank is R_ΘThe unique
The J and A'ranks are K because J cuttles are arranged side by side.
Therefore, W_BS ^HThe rank of A'is K.R _BSFor
In order to establish the MUSIC algorithm,

[Formula 19] If the rank of is K. It is established when L satisfies L ≧ K.

Therefore, even if all or some of the incident signals are correlated with each other and therefore the rank of the covariance matrix of the incident signals is lowered, by setting L to L ≧ K, the orthogonal multi-path after the spatial smoothing process is performed. Beam formation is performed, and using the output signal, it is possible to separate and measure the angle of a plurality of correlated waves by a subspace super resolution algorithm such as MUSIC.

As described above, according to the first embodiment, because of the S / N ratio improving effect by the multi-beam formation,
It is possible to improve the probability of successful separation of multiple waves.

Further, applying only the output of the beam directed in the desired direction to the angle measuring algorithm has the effect of reducing the amount of calculation as compared with applying all the beam outputs to the angle measuring algorithm. It is considered that the reduction of the amount of calculation enables real-time processing. For example, in the case of the MUSIC algorithm, since the calculation amount is proportional to the cube of the number of input signals, it is considered that the effect of reducing the amount of calculation by reducing the number of input signals by multi-beam formation is great.

Embodiment 2. FIG. 2 is a block diagram showing an angle measuring method for forming orthogonal beams after spatial smoothing using an evenly-spaced linear array according to Embodiment 2 of the present invention.
In the figure, 31 _{1 to} 31 _J are spatial filters that form J orthogonal multi-beams. Other configurations are the same as those in FIG.

Next, the operation will be described. In the second embodiment, for example, an eigen filter method or the like is used for multi-beam formation. In this case, the beams formed are orthogonal to each other, unlike the first embodiment.
In FIG. 2, 31 _{1 to} 31 _J are spatial filters that form orthogonal multi-beams. In the spatial filter, the coefficient matrix W _BS for orthogonal multi-beam formation is calculated and multiplied by the covariance matrix after the spatial smoothing process. However,
The beam forming number J is set to K or more and M ₀ or less. Then, in the figure, it is input to the angle measurement processing unit 6 and the estimated incident angle is obtained by the super resolution angle measurement algorithm.

As described above, according to the second embodiment, since the same effect as that of the first embodiment can be obtained, it is possible to improve the separation angle measuring performance of a plurality of waves having a mutual correlation.
By using only the beam output in the desired direction and reducing the number of multi-beam outputs applied to the angle measurement algorithm,
The calculation amount of the angle measurement algorithm can be reduced.

Embodiment 3. FIG. 3 is a configuration diagram showing an angle measuring method for forming a beam after spatial smoothing using an array antenna according to a third embodiment of the present invention. In the figure, 12 _{1 to} 12 _M are array antennas in which M pieces are arranged,
Reference numeral 10 is a uniform interval linear array conversion processing unit. Other configurations are the same as those in FIG.

Next, the operation will be described. In FIG. 3, when the array antenna is not a uniform linear array such as 12 _{1 to} 12 _M in FIG. 3, the uniform linear array conversion processing unit 10 in the drawing converts the output into a virtual linear array, The spatial smoothing process of 5 becomes possible. After that, multi-beams are formed in the spatial filters 3 _{1 to} 3 _J and angle measurement processing is performed.

As described above, according to the third embodiment, since the beam space processing is performed after the linear array conversion, the effect of improving the S / N ratio in the beam space processing seen in the conventional example is not reduced. For this reason, the separation angle measurement performance can be improved. It is possible to reduce the amount of calculation of the angle measurement algorithm by reducing the number of outputs of the multi-beam applied to the angle measurement algorithm using only the beam output in the desired direction.

Fourth Embodiment FIG. 4 is a block diagram showing an angle measuring method for forming orthogonal beams after spatial smoothing using an array antenna according to a fourth embodiment of the present invention. In the figure, 31 _{1 to} 31 _J form J orthogonal multi-beams. It is a spatial filter. Other configurations are the same as those in FIG.

Next, the operation will be described. In FIG. 4, when the array antenna is not a linear array such as 12 _{1 to} 12 _M in FIG. 4, the linear array conversion processing unit of 10 in the figure performs conversion into an output of a virtual linear array. The spatial smoothing process of 5 becomes possible. After that, orthogonal multi-beams are formed in the spatial filters 31 _{1 to} 31 _J and the angle measurement processing is performed.

As described above, according to the fourth embodiment, since the beam space processing is performed after the linear array conversion, the effect of the beam space processing seen in the conventional example is not reduced. Also in this case, it is possible to improve the separation angle measurement performance by improving the S / N ratio in beam forming. It is possible to reduce the amount of calculation of the angle measurement algorithm by reducing the number of outputs of the multi-beam applied to the angle measurement algorithm using only the beam output in the desired direction.

[0048]

As described above, according to the present invention, an equally-spaced linear array antenna for receiving correlated incident waves from a plurality of targets, and a spatial smoothing processing unit for spatially smoothing the received incident waves. And a spatial filter that forms a multi-beam according to the processed signal, and an angle measurement processing unit that obtains an estimated incident angle by a super-resolution angle measurement algorithm using the output signal from the spatial filter. Therefore, even if the covariance matrix of the incident signal drops in rank because all or some of the multiple incident waves are correlated with each other, multibeam formation is performed after the spatial smoothing process, and the superresolution measurement is performed using the output signal. It becomes possible to separate and measure multiple waves with correlation by the angle algorithm. In addition, since the S / N ratio is improved by the multi-beam formation, the probability of successful separation of a plurality of waves can be improved. Furthermore, since only the output of the beam directed in the desired direction is applied to the super resolution angle measurement algorithm, there is an effect that the amount of calculation can be reduced as compared with the case where all beam outputs are applied to the super resolution angle measurement algorithm.

According to the present invention, an array antenna for receiving correlated incident waves from a plurality of targets, an equal-interval linear array conversion processing unit for converting the received incident waves into a virtual linear array output, and its conversion. A spatial smoothing processing unit that performs spatial smoothing processing on the incident wave, a spatial filter that forms a multi-beam according to the processed signal, and an estimated incident angle by a super-resolution angle measurement algorithm using the output signal from the spatial filter. Since it is configured to include the angle measurement processing unit to be obtained, even if the covariance matrix of the incident signal drops due to the correlation of all or some of the multiple incident waves, the multi-beam formation is performed after the spatial smoothing process. Then, using the output signal, the separation angle measurement of multiple waves with correlation by the super resolution angle measurement algorithm is performed. The ability. In addition, since the S / N ratio is improved by the multi-beam formation, the probability of successful separation of a plurality of waves can be improved. Furthermore, since only the output of the beam directed in the desired direction is applied to the super resolution angle measurement algorithm, there is an effect that the amount of calculation can be reduced as compared with the case where all beam outputs are applied to the super resolution angle measurement algorithm.

According to the present invention, in the spatial filter, the orthogonal multi-beam is formed according to the signal processed by the spatial smoothing processing unit, so that the spatial filter forming the orthogonal multi-beam can be applied. There is an effect that can be done.

According to the present invention, when separating incident waves having a correlation from a plurality of targets by radio wave angle measurement using a linear array antenna with equal intervals, first, the incident waves are subjected to spatial smoothing processing, and thereafter, Forming a multi-beam,
Since the output signal is used to calculate the estimated incident angle by the super-resolution angle measurement algorithm, if the covariance matrix of the incident signal drops due to the correlation of all or some of the multiple incident waves. However, it is possible to perform multi-beam formation after the spatial smoothing process and use the output signal to separate and measure a plurality of correlated waves by a super-resolution angle measurement algorithm. In addition, since the S / N ratio is improved by the multi-beam formation, the probability of successful separation of a plurality of waves can be improved. Furthermore, since only the output of the beam directed in the desired direction is applied to the super resolution angle measurement algorithm, there is an effect that the amount of calculation can be reduced as compared with the case where all beam outputs are applied to the super resolution angle measurement algorithm.

According to the present invention, when separating incident waves having a correlation from a plurality of targets by radio wave angle measurement using an array antenna, first, the incident waves are subjected to linear array conversion processing, and then the incident waves are spatially converted. Since the smoothing process is performed and then the multi-beam is formed and the output signals are used to obtain the estimated incident angle by the super-resolution angle measurement algorithm, all or some of the multiple incident waves are correlated with each other. Even if the covariance matrix of the incident signal drops in rank, multibeam formation is performed after spatial smoothing processing, and the output signals can be used to separate and measure the correlative multiple waves by the super-resolution angle measurement algorithm. In addition, since the S / N ratio is improved by the multi-beam formation, the probability of successful separation of a plurality of waves can be improved. Furthermore, since only the output of the beam directed in the desired direction is applied to the super resolution angle measurement algorithm, there is an effect that the amount of calculation can be reduced as compared with the case where all beam outputs are applied to the super resolution angle measurement algorithm.

According to the present invention, since the multi-beam is formed so as to form the orthogonal multi-beam,
There is an effect that a spatial filter that forms orthogonal multi-beams can be applied.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an angle measuring method for forming a beam after spatial smoothing by using an evenly-spaced linear array according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing an angle measuring method for forming orthogonal beams after spatial smoothing by using an evenly-spaced linear array according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing an angle measuring method for forming a beam after spatial smoothing using an array antenna according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing an angle measuring method for forming orthogonal beams after spatial smoothing using an array antenna according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional angle measuring method for performing beam space processing.

[Explanation of symbols]

1 ₁ to 1 _M evenly spaced linear array antenna, 2 ₁ to 2 _K
Incident _{wave, 3 1 ~3 J, 31 1} ~31 J spatial filter, 4 ₁ to 4 _L subarray, 5 spatial smoothing processing unit, 6 the angle measuring unit, 10 uniform linear array conversion processing section, 12 ₁ to 12 _M array antenna.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) (72) Inventor Takashi Sekiguchi 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Denki Co., Ltd.

Claims (6)

[Claims] 1. An equally-spaced linear array antenna for receiving correlated incident waves from a plurality of targets, a spatial smoothing processing unit for spatially smoothing incident waves received by the equally-spaced linear array antenna, and the spatial smoothing. Azimuth finding apparatus including a spatial filter that forms a multi-beam according to the signal processed by the processing unit, and an angle measurement processing unit that obtains an estimated incident angle by a super-resolution angle measurement algorithm using the output signal from the spatial filter . 2. An array antenna for receiving correlated incident waves from a plurality of targets, an equidistant linear array conversion processing unit for converting incident waves received by the array antenna into a virtual linear array output, and the equidistant linear array. A spatial smoothing processing unit that spatially smoothes the incident wave converted by the conversion processing unit, a spatial filter that forms a multi-beam according to the signal processed by the spatial smoothing processing unit, and an output signal from the spatial filter are used. Azimuth detection device including an angle measurement processing unit that obtains an estimated incident angle using a super-resolution angle measurement algorithm. 3. The azimuth detecting apparatus according to claim 1, wherein the spatial filter forms an orthogonal multi-beam according to the signal processed by the spatial smoothing processing unit. 4. When separating correlated incident waves from a plurality of targets by radio wave angle measurement using an equally spaced linear array antenna, first, the incident waves are spatially smoothed and then a multi-beam is formed. Then, the azimuth detection method is characterized in that the estimated incident angle is obtained by a super-resolution angle measurement algorithm using the output signal. 5. When separating correlated incident waves from a plurality of targets by radio angle measurement using an array antenna, first, the incident waves are subjected to linear array conversion processing, and
A direction finding method characterized by spatially smoothing an incident wave, then forming a multi-beam, and using the output signals thereof to obtain an estimated incident angle by a super-resolution angle-measuring algorithm. 6. The method according to claim 4, wherein forming the multi-beam forms an orthogonal multi-beam.
Direction detection method described.