JP3944141B2 - Array manifold data interpolation method, arrival direction estimation method, and array manifold data interpolation device - Google Patents

Description

  The present invention relates to an arrival direction estimation method for incident waves, a method for deriving array manifold data used for the estimation method and the like by interpolation, and an interpolation apparatus.

  An MUSIC (MUltiple Signal Classification) algorithm is known as an incident wave arrival estimation method in an antenna apparatus having a plurality of antenna elements (see Non-Patent Document 1), and high-precision azimuth estimation is performed by using the MUSIC algorithm. Is possible.

  In the MUSIC algorithm, the azimuth spectrum is calculated, and the azimuth is estimated from the maximum value. An array manifold is used when calculating such an orientation spectrum.

  The array manifold is data representing the relative reception amplitude and relative reception phase of each antenna element with respect to the direction from which radio waves arrive. The array manifold is determined mainly by three elements such as the radiation pattern of the antenna elements, the coupling between the antenna elements, and the phase amount based on the coordinates of the antenna elements, and is a value unique to the antenna device. Such an array manifold can be obtained by measuring a radiation pattern or performing electromagnetic analysis using a moment method or a FDTD (Finite Difference Time Domain) method.

  By the way, in the arrival direction estimation algorithm such as the MUSIC algorithm as described above, the array manifold is required for all angles for calculating the direction spectrum. In order to improve the azimuth estimation accuracy, it is necessary to calculate the azimuth spectrum for many angles. In this case, an array manifold corresponding to many angles is required.

  Therefore, a device that performs high-precision azimuth estimation requires a storage capacity for storing an array manifold consisting of a large amount of information, and as a preparatory work, a complicated operation such as obtaining a large number of array manifolds using the above-mentioned moment method or the like. Necessary. For example, when an azimuth spectrum is calculated at intervals of 0.1 ° in an azimuth range of 0 to 360 ° for an antenna apparatus having eight antenna elements, 8 (number of elements) × 3601 (number of angles) = It is necessary to derive and hold 28,808 array manifold data. Furthermore, in the case of the two-dimensional case, 28,808 × 901 (number of angles) = 25,956,008 when the orientation spectrum is calculated at intervals of 0.1 ° in the range of elevation 0-90 °. Data is required.

  Therefore, a technique for suppressing the number of array manifolds necessary for azimuth estimation has been proposed (see Patent Document 1). In the technique disclosed in this document, array manifold data corresponding to unequal intervals of angles is derived and stored for each direction, and the number of array manifolds is reduced by using these data. In this technique, while a large number of array manifolds are prepared for directions with good azimuth estimation accuracy, the amount of data is reduced by reducing the number of array manifolds for directions with poor azimuth estimation accuracy.

JP 2002-267728 A RO Schmidt "Multiple emitter location and signal parameter estimation" IEEE Trans. Antennas & Propagation AP-34, no. 3, pp 276-280 March 1986

  However, with the technique described in Patent Document 1, it is possible to reduce the amount of data for the direction with poor azimuth estimation accuracy, but it is not possible to reduce the amount of data for the direction with high accuracy. If the amount of data for a direction with high accuracy is reduced, the direction estimation accuracy will deteriorate. Moreover, since the amount of data is reduced in the direction with poor azimuth estimation accuracy, the accuracy is further deteriorated.

  The present invention has been made in view of the above, and array manifold data that can derive a more accurate array manifold by interpolation without preparing a large amount of array manifolds used for arrival direction estimation or the like in advance. An object is to obtain an interpolation method, an arrival direction estimation method, and an array manifold data interpolation apparatus.

  In order to solve the above-described problems and achieve the object, one aspect of the present invention is a method for deriving array manifold data of an antenna apparatus having a plurality of antenna elements by interpolation, and comprising array manifold data of a plurality of frequencies. Obtaining a subtracted phase value obtained by subtracting the phase value determined by the arrangement of the antenna elements from the phase value, and performing an interpolation operation using the subtracted phase value obtained in the obtaining step, and the plurality of frequencies Is an interpolation step for obtaining an interpolation subtraction phase value corresponding to a different frequency, and an interpolation phase is obtained by adding a phase value determined by an arrangement of antenna elements corresponding to the different frequency to the interpolation subtraction phase value obtained in the interpolation step. An array manifold data interpolation method comprising: an adding step for deriving a value.

  Another aspect of the present invention is a method for deriving array manifold data of an antenna device having a plurality of antenna elements by interpolation, and from the phase values of array manifold data at a plurality of angles, depending on the arrangement of the antenna elements. An acquisition step of acquiring a subtraction phase value obtained by subtracting a fixed phase value, and an interpolation calculation using the subtraction phase value acquired in the acquisition step, and an interpolation subtraction phase value corresponding to an angle different from the plurality of angles. An interpolation step to be obtained; and an addition step for deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different angles to the interpolation subtraction phase value obtained in the interpolation step. Is an array manifold data interpolation method characterized by

  Another aspect of the present invention is a method for estimating the direction of arrival of an incident wave using array manifold data of an antenna device having a plurality of antenna elements, from the phase value of array manifold data of a plurality of frequencies, Acquiring a subtracted phase value obtained by subtracting a phase value determined by the arrangement of the antenna elements, and performing an interpolation operation using the subtracted phase value acquired in the acquiring step, corresponding to a frequency different from the plurality of frequencies An interpolation step for obtaining an interpolation subtraction phase value, and an addition for deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different frequencies to the interpolation subtraction phase value obtained in the interpolation step And an estimation step for estimating the direction of arrival using the interpolation phase value obtained in the addition step. A DOA estimating method comprising and.

  Another aspect of the present invention is a method for estimating the direction of arrival of an incident wave using array manifold data of an antenna device having a plurality of antenna elements, from the phase values of array manifold data at a plurality of angles, An acquisition step of acquiring a subtraction phase value obtained by subtracting a phase value determined by the arrangement of the antenna elements, and an interpolation calculation using the subtraction phase value acquired in the acquisition step, corresponding to an angle different from the plurality of angles An interpolation step for obtaining an interpolation subtraction phase value, and an addition for deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different angles to the interpolation subtraction phase value obtained in the interpolation step And an estimation step for estimating the direction of arrival using the interpolation phase value obtained in the addition step. It is the array manifold data interpolation method to be.

  Another aspect of the present invention is an apparatus for deriving array manifold data of an antenna apparatus having a plurality of antenna elements by interpolation, from a phase value of array manifold data of a plurality of frequencies, depending on the arrangement of the antenna elements. An acquisition means for acquiring a subtraction phase value obtained by subtracting a fixed phase value, and an interpolation calculation using the subtraction phase value acquired by the acquisition means, and an interpolation subtraction phase value corresponding to a frequency different from the plurality of frequencies. Interpolating means to be obtained; and adding means for deriving an interpolating phase value by adding a phase value determined by the arrangement of antenna elements corresponding to the different frequencies to the interpolating subtraction phase value obtained by the interpolating means. An array manifold data interpolating device characterized by the following.

  Another aspect of the present invention is an apparatus for deriving array manifold data of an antenna apparatus having a plurality of antenna elements by interpolation, and from the phase values of array manifold data at a plurality of angles, depending on the arrangement of the antenna elements. An acquisition means for acquiring a subtraction phase value obtained by subtracting a fixed phase value, and an interpolation calculation using the subtraction phase value acquired by the acquisition means, and an interpolation subtraction phase value corresponding to an angle different from the plurality of angles. Interpolating means to be obtained, and adding means for deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different angles to the interpolating subtraction phase value obtained by the interpolating means. An array manifold data interpolating device characterized by the following.

  According to the present invention, there is an effect that a more accurate array manifold can be derived by interpolation without preparing a large number of array manifolds used for arrival direction estimation or the like in advance.

  Exemplary embodiments of an array manifold data interpolation method, an arrival direction estimation method, and an array manifold data interpolation apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a flowchart showing the procedure of an array manifold data interpolation method according to the first embodiment of the present invention. By following such a procedure, array manifold data corresponding to an unprepared angle can be derived by interpolation from array manifold data having an angle prepared in advance. Prior to the description of the interpolation processing procedure, the array manifold data can be derived. The manifold will be described.

  The array manifold is data representing the relative reception amplitude and relative reception phase of each antenna element with respect to the direction in which radio waves arrive, and is derived for each angle by performing a radiation pattern measurement as described above. be able to.

  As shown in FIG. 2, the array manifold is an entire data set of amplitude values and phase values for each of the plurality of antennas # 1, # 2, # 3, # 4,. Expressed. In the illustrated example, the amplitude value of the array manifold data of the azimuth angle φ = 1 ° for the antenna element # 2 is 1.2, and the phase value is 10 °. That is, it is represented by the relative reception amplitude and phase value between the antenna elements with the origin as a reference. In this specification, the above-described array manifold data indicating the amplitude value and phase value for each angle is referred to as array manifold data. For example, the array manifold data for an angle of 1 ° is used. .

  The array manifold data interpolation method according to the present embodiment uses a plurality of array manifold data for each angle of each antenna element that is derived in advance and held in a recording medium such as a memory or a hard disk, and is not held. This is a method of deriving angular array manifold data by interpolation. Hereinafter, array manifold data of antenna element # 2 having an angle of 2.5 ° (an angle not prepared in FIG. 2) is prepared in advance. The case of deriving from is described.

  When array manifold data is derived by interpolation for many angles such as 2.5 °, 3.5 °, and 4.5 °, the following procedure is performed in parallel for each angle to be derived. However, in order to simplify the description, a case where only 2.5 ° is targeted will be described as an example.

  As shown in FIG. 1, in the array manifold data interpolation method according to the present embodiment, interpolation is performed from among a plurality of angles prepared in advance (in the example shown in FIG. 2, every angle of 1 ° in the range of 360 °). Identify array manifold data of multiple angles required to interpolate the target angle (= 2.5 °), separate the phase value and amplitude value of those array manifold data, and obtain the phase value (Step Sa1).

  In the present embodiment, array manifold data corresponding to two angles (2 ° and 3 °) in the vicinity of the angle to be interpolated of antenna element # 2 to be interpolated is specified as array manifold data used for interpolation. Then, the phase value and amplitude value of these array manifold data are separated to obtain phase values (15 ° and 20 °) (see FIG. 2).

  In addition, if the phase value and the amplitude value of each array manifold data are separated in advance and only the phase value is recorded and held separately in a storage medium, the phase value can be obtained without performing such separation processing. Can do. When the phase and amplitude of the array manifold data are recorded and held in the form of complex numbers, the phases can be separated by calculating the absolute values of the complex numbers and the phases of the complex numbers.

  When the phase values of the two array manifold data are acquired as described above, the phase amount based on the coordinates of the antenna element # 2 is derived for the acquired angles (2 ° and 3 °), and the angle to be interpolated (= 2) .5 °), a phase amount based on the coordinates of the antenna element # 2 is derived (step Sa2). As described above, the array manifold is a value mainly determined by three elements such as a radiation pattern of antenna elements, coupling between antenna elements, and a phase amount based on the coordinates of the antenna elements. The phase amount based on it is calculated.

Here, the coordinates of the antenna element, that is, the phase amount a based on the arrangement is obtained by the following equation (1).
a = 2π / λ × (x sin θ cos φ + y sin θ sin φ) (1)

  Each variable in the above equation (1) will be described with reference to FIG. As shown in the figure, x and y are arrangement position coordinates based on the origin of the target antenna element (# 2), θ is an elevation angle, and φ is an azimuth angle. For simplicity of explanation, only the azimuth angle φ is considered. Further, λ is a wavelength corresponding to the frequency to be interpolated.

  As described above, when the phase amount based on the coordinates of the antenna element in the phase component of the array manifold data for the angle used for interpolation is derived, the antenna derived for each angle from the phase value of the array manifold data for these angles. The phase amount based on the element coordinates is subtracted, and a subtraction phase value is derived and acquired (step Sa3).

  That is, the value obtained by removing the phase amount based on the coordinates of the antenna element from the phase of the array manifold data determined mainly by three elements such as the radiation pattern of the antenna elements, the coupling between the antenna elements, and the phase amount based on the coordinates of the antenna elements. The subtraction phase value which is a value mainly determined by two elements such as the radiation pattern of the element and the coupling between the antenna elements is obtained.

  When the subtraction phase values for the two angles used for interpolation are obtained in this way, interpolation processing is performed using these subtraction phase values, and the subtraction phase value is obtained for the angle (= 2.5 °) that is the interpolation target ( Step Sa4). The interpolation processing method here may be an interior method or an exterior method, and any method such as primary interpolation, secondary interpolation, or spline interpolation can be used.

  In this way, when the subtraction phase value for the angle to be interpolated (= 2.5 °) is derived by the interpolation processing, the interpolation target angle (= 2.5) obtained in step Sa2 is obtained as the interpolated subtraction phase value. The phase amount based on the antenna element coordinates for (°) is added to derive an interpolation phase value (step Sa5).

  As described above, when the interpolation phase value for the angle to be interpolated (= 2.5 °) is obtained, it becomes the object to be interpolated from the amplitude value of the array manifold data for the angles (2 ° and 3 °) used for the interpolation. The interpolation amplitude value for the angle (= 2.5 °) is obtained by an arbitrary interpolation method such as linear interpolation. The amplitude value interpolation process need not be performed at this stage, and may be performed in parallel with other steps.

  Through the above process, the phase value and the amplitude value of the array manifold data for an arbitrary angle not held in advance can be obtained by interpolation processing. By using array manifold data derived by interpolation in this way, the arrival direction can be estimated by an arrival direction estimation algorithm such as the MUSIC method. As described above, the accuracy of the interpolation value obtained by the method including the process of performing the interpolation process using the subtraction phase value obtained by subtracting the phase amount based on the antenna element coordinates is high. This will be described with reference to FIG.

  4 shows the relationship between the phase value of the array manifold data actually obtained by performing radiation pattern measurement and the like and the azimuth angle, and FIG. 5 shows the array manifold data held in advance for each discrete angle. The relationship between the phase value and the azimuth angle is shown. As shown in FIG. 5, in this example, it is assumed that phase values α3 and α3 of array manifold data corresponding to two angles such as an azimuth angle of 2 ° and an azimuth angle of 3 ° are held. Note that the broken line in FIG. 5 indicates the measured value of the array manifold phase value (see FIG. 4).

  In the present embodiment, the phase value αx of the array manifold data corresponding to the azimuth angle x ° (for example, 2.5 °) is derived from α2 and α3 held discretely. At this time, as described above, a phase amount based on the coordinates of the antenna element at the held angle is derived, and a subtracted phase value obtained by subtracting it from the phase values α2 and α3 is obtained.

  That is, the relationship between the phase amount based on the coordinates of the antenna element and the azimuth angle is expressed by a function expressed by the above equation (1), as shown in FIG. Therefore, phase amounts β2 and β3 based on the antenna element coordinates corresponding to the angles of 2 ° and 3 ° are derived, and are subtracted from the held phase values as shown in FIG. That is, the subtraction phase value γ2 (= α2−β2) corresponding to the azimuth angle of 2 °. A subtraction phase value γ2 (= α3-β3) corresponding to 3 ° is derived.

  Then, the subtraction phase value γx at the azimuth angle x is interpolated using these subtraction phase values γ2 and γ3. Here, FIG. 8 shows the relationship between the azimuth angle x in the range of 2 to 3 ° determined from the two subtraction phase values by linear interpolation and the subtraction phase value of the array manifold data.

  When the subtraction phase value γx of an arbitrary angle x within the range of 2 to 3 ° is obtained in this way, the phase amount βx based on the coordinates of the antenna element corresponding to the azimuth angle x is added to the subtraction phase value γx. Thus, the phase value αx of the array manifold data at an arbitrary azimuth angle x is derived. Here, since the relationship between the phase amount based on the coordinates of the antenna element and the azimuth angle is as shown in FIG. 6, the relationship between the azimuth angle and the subtraction phase value derived by interpolation shown in FIG. 8 is shown in FIG. If the relationships shown are added, as shown in FIG. 9, the correspondence between an arbitrary angle x and the phase value αx of the array manifold data can be acquired.

  As described above, the relationship between the azimuth angle obtained by the interpolation method according to this embodiment and the phase value of the array manifold data (see FIG. 9), and the relationship between the azimuth angle actually obtained and the phase value of the array manifold data (see FIG. 9). 4), it can be seen that they are in an approximate relationship, and that the accuracy of the phase value of the array manifold data derived by the interpolation method is high.

  On the other hand, FIG. 10 shows the relationship between the azimuth angle obtained by the primary interpolation using the phase values α2 and α3 of the array manifold data held discretely shown in FIG. 5 and the phase value of the array manifold data. Show. As is clear from the comparison between the relationship shown in FIG. 10 and the relationship shown in FIG. 4 (actual measurement data), when interpolation is performed using the phase value of the array manifold data as it is, a value greatly different from the actual measurement value is derived. It can be seen that the accuracy is low.

  As described above, in the present embodiment, the phase amount based on the coordinates of the antenna element, which is one main component of the phase value of the array manifold data, is not simply interpolated using the phase value of the array manifold data. 1) The value derived by the equation is subtracted to obtain a subtraction phase value, and interpolation is performed using the subtraction phase value. Then, the phase value of the array manifold data is interpolated and derived by adding the phase amount based on the coordinates of the antenna element corresponding to the angle to the subtraction phase value derived by the interpolation. The phase value of accurate array manifold data can be derived.

  Therefore, by deriving and holding a certain amount of array manifold data, it is possible to acquire array manifold data that is close to the actual measurement value even for angles that are not held, so a large number of array manifold data can be measured in advance. The arrival direction can be estimated by an arrival direction estimation algorithm such as the MUSIC algorithm using a large number of array manifolds without being derived and stored in a recording medium.

  As described above, in the arrival direction estimation algorithm, the estimation accuracy is improved by using a large amount of array manifolds, that is, array manifold data for each angle with a denser angular interval, but the interpolation method of this embodiment is used. By using it, it is possible to estimate the direction with higher accuracy without deriving and holding a large number of array manifolds.

  What has been described above is the array manifold data interpolation method according to the first embodiment. Next, there is an array manifold data interpolation device for executing the array manifold data interpolation method, and the array manifold data interpolation method is included. The configuration of the antenna device that realizes the azimuth estimation method will be described with reference to FIG.

  As shown in the figure, an antenna device 100 includes a plurality of antenna elements 101, a reception analog processing unit 102, an A / D conversion unit 103, an arrival direction estimation processing unit 104, an array manifold storage unit 105, an antenna, A coordinate storage unit 106 and an array manifold data interpolation device 107 are provided.

  The antenna element 101 is an element that receives incoming radio waves, and various antennas such as a dipole antenna, a horn antenna, and a loop antenna can be used. Further, even if each antenna element 101 is the same, a plurality of different types of antenna elements 101 may be arranged.

  The reception analog processing unit 102 is provided corresponding to each antenna element 101 and performs the following processing on the analog signal received by the corresponding antenna element 101. That is, the reception analog processing unit 102 includes an amplifier, a filter, a frequency converter, and the like, and performs amplification processing, filter processing, frequency conversion processing, and the like on the received signal.

  The A / D conversion unit 103 is provided corresponding to the reception analog processing unit 102, converts the analog signal supplied from the corresponding reception analog processing unit 102 into a digital signal, and sends it to the arrival direction estimation processing unit 104. Output.

  The array manifold storage unit 105 stores an array manifold that is a set of array manifold data for each discrete angle for each antenna element 101 (see FIG. 2). In such an antenna device 100, since the above-described interpolation processing is performed by the array manifold data interpolation device 107, the number of array manifold data stored in the array manifold storage unit 105 may be relatively small, for example, every 1 ° interval. For example, array manifold data corresponding to the angle may be held.

  The antenna coordinate storage unit 106 stores the arrangement coordinates of each antenna element 101, and in the present embodiment, stores the x coordinate, y coordinate, and z coordinate of each antenna element 101. These coordinate values are used when deriving the phase amount based on the coordinates of the antenna element described above.

  The array manifold data interpolation device 107 uses the array manifold data stored in the array manifold storage unit 105 and the antenna coordinate values stored in the antenna coordinate storage unit 106 to perform interpolation processing according to the above-described array manifold data interpolation method. (See FIG. 1), an array manifold having an angle necessary for processing in the arrival direction estimation processing unit 104 is derived. That is, the array manifold data interpolation device 107 includes means for obtaining a subtraction phase value for an angle required for interpolation, means for performing an interpolation calculation process using these, and deriving an interpolation subtraction phase value. And a function as means for deriving an interpolation phase value corresponding to an arbitrary angle by adding a phase amount based on the antenna element coordinates.

  For example, when an arrival manifold corresponding to an angle of 0.1 ° interval is required in the arrival direction estimation processing in the arrival direction estimation processing unit 104, 1 ° stored in the array manifold storage unit 105 as described above. Using array manifold data for each angle of the interval, array manifold data corresponding to the angle for each 0.1 ° interval is derived by interpolation.

  The arrival direction estimation processing unit 104, based on the reception signal of each antenna element supplied from the A / D conversion unit 103 and the array manifold supplied from the array manifold data interpolation device 107 as described above, Performs processing to estimate the direction of arrival. The arrival direction estimation processing unit 104 in the present embodiment performs the direction estimation processing using the MUSIC algorithm, but may be processing using another direction estimation algorithm.

  The arrival direction estimation processing unit 104 performs direction estimation processing using the MUSIC method disclosed in the above-mentioned document (Non-patent Document 1). A brief description will be given by taking an example of measuring the angle.

When an incident wave having a wave number K is incident on the antenna element 101, it is assumed that the kth wave is incident at an angle θ. It is assumed that the number K of incident waves is smaller than the number M of antenna elements 101, and the incident waves are uncorrelated with each other. When incident under such conditions, the received signal x (t) output from each antenna element 101 is derived by the following equation.

Here, a (θ _k) is the steering vector, g _m (θ _k) is the complex directivity pattern of the m-th antenna element 101, p _m is the position vector from the phase reference point of the m-th antenna element 101, q (Θ _k ) represents an incident direction unit vector of the k-th incident wave. Further, s _k represents a signal representing the amplitude and frequency of each incident wave, n (t) represents a noise vector, and T represents transposition.

The received signal vector x (t) can be expressed by the following equation using an M × k matrix A in which steering vectors are arranged, an incident signal vector s (t), and a noise vector n (t).

In the arrival direction estimation processing unit 104, an M × M dimensional covariance matrix R for the received signal vector x expressed as described above is obtained by the following equation.

Here, ￣ represents the sample average, H represents the complex conjugate transpose, and R ₀ represents the covariance matrix of the incident signal vector s (t). Also, σ ² is noise power, and I is a unit matrix. Although there are M eigenvalues of the covariance matrix R, this is expressed as λ _m, and the M eigenvectors of the covariance matrix R corresponding thereto are expressed as e _m as shown in the following equation. Can do.

Next, the estimated incident wave number is obtained. More specifically, since the incident wave is assumed to be a K wave, it is considered that there are K eigenvalues λ _m that are not equal to the noise power. Therefore, the estimated incident wave number can be obtained from the number of λ _m > σ ² among the eigenvalues λ _m of R.

Next, the incident angle is estimated. When the estimation of the radio wave incident angle theta _k, a λ _m = σ ² the following expression evaluation function using the M × (M-K) matrix E _N to the eigenvector e _m elements (M-K) Use.

When θ is changed in the above evaluation function, the denominator becomes 0 only when θ coincides with the radio wave incident angle θ _k (k = 1, 2,..., K), and a high peak is actually obtained. Therefore, it is possible to estimate the incident angle by searching for the peak of P _MU (θ).

  When performing such a peak search, an array manifold (a set of steering vectors) is used. In this embodiment, the array manifold supplied from the array manifold data interpolating device 107 as described above is used. It will be.

The above is the processing of the MUSIC algorithm taking the one-dimensional angle measurement as an example. However, when this angle measurement method is used for the two-dimensional angle measurement of the incident wave, the following evaluation function may be used.

When (θ, φ) is changed in the evaluation function, the denominator is set to 0 only when (θ, φ) matches the radio wave incident angle (θ _k , φ _k ) (k = 1, 2,..., K). And show a high peak. Therefore, the incidence angle can be estimated by searching for the peak of P _MU (θ, φ).

  The processing procedure by the arrival direction estimation processing unit 104 is as described above, and the arrival direction estimation process is performed using the many array manifold data interpolated by the array manifold data interpolation device 107 as described above.

  As described above, the antenna device 100 configured as described above can perform the arrival direction estimation process using the array manifold data interpolated by the array manifold data interpolation device 107. Therefore, it is possible to perform highly accurate arrival direction estimation processing using a large amount of array manifold data without deriving and storing a large amount of array manifold in advance. As a result, the capacity of the storage medium used as the array manifold storage unit 106 can be reduced, which contributes to downsizing and cost reduction of the apparatus.

(Second Embodiment)
FIG. 12 is a flowchart showing the procedure of the array manifold data interpolation method according to the second embodiment of the present invention. The array manifold data interpolation method according to the present embodiment corresponds to an angle that is not prepared, in that array manifold data corresponding to an unprepared frequency is derived by interpolation from array manifold data for each frequency prepared in advance. This is different from the first embodiment in which array manifold data to be interpolated is interpolated.

  That is, in this embodiment, as shown in FIG. 13, when array manifold data for each discrete angle is prepared for each discrete frequency such as frequencies f1, f2,... The array manifold data for frequencies not prepared is interpolated using the array manifold data that is provided. Hereinafter, a case where the array manifold data of the angle 2 ° of the antenna element # 2 for the frequency f1.5 (frequency not prepared in FIG. 13) is derived from the array manifold data prepared in advance will be described as an example. To do.

  As shown in FIG. 12, in the array manifold data interpolation method according to the present embodiment, a frequency (f1.5 (f1 and f1) to be interpolated is selected from a plurality of frequencies (f1, f2,...) Prepared in advance. The array manifold data of a plurality of frequencies necessary for the interpolation derivation is specified, and the phase value and the amplitude value of the array manifold data are separated (step Sb1).

  In the present embodiment, array manifold data corresponding to an angle of 2 ° at two frequencies (f1 and f2) in the vicinity of the frequency to be interpolated by antenna element # 2 to be interpolated is specified as array manifold data used for interpolation. . Then, the phase value and amplitude value of these array manifold data are separated to obtain phase values (15 ° and 18 °).

  In addition, if the phase value and the amplitude value of each array manifold data are separated in advance and only the phase value is recorded and held separately in a storage medium, the phase value can be obtained without performing such separation processing. Can do.

  When the phase values of the two array manifold data are acquired as described above, for each of the acquired frequencies f1 and f2, a phase amount based on the coordinates of the antenna element # 2 at an angle of 2 ° is derived, and the frequency to be interpolated A phase amount based on the coordinates of antenna element # 2 at an angle of 2 ° is derived for (f1.5) (step Sb2). The phase amount based on the antenna coordinates can be derived from the above equation (1).

  As described above, when the phase amount based on the coordinates of the antenna element in the phase component of the array manifold data for the frequency used for the interpolation is derived, the antenna derived for each angle from the phase value of the array manifold data of these frequencies. The phase amount based on the element coordinates is subtracted to derive and obtain a subtraction phase value (step Sb3).

  When the subtraction phase values for the two frequencies used for interpolation are obtained in this way, interpolation processing is performed using these subtraction phase values, and the subtraction phase value is obtained for an angle of 2 ° at the frequency (f1.5) to be interpolated. Obtained (step Sb4).

  As described above, when the subtraction phase value for the frequency (f1.5) to be interpolated is derived by the interpolation process, the interpolation subtraction phase value for the interpolation target frequency (f1.5) obtained in step Sb2 is obtained. The phase amount based on the antenna element coordinates is added to derive an interpolation phase value (step Sb5).

  As described above, when the interpolation phase value for the frequency (f1.5) to be interpolated is obtained, the frequency (f1...) To be interpolated from the amplitude value of the array manifold data for the frequencies (f1 and f2) used for interpolation. For 5), the interpolation amplitude value is obtained by an arbitrary interpolation method such as linear interpolation.

  The above is the array manifold data interpolation method according to the second embodiment. The antenna element is not a simple interpolation using the phase value of the array manifold data, but is one main component of the phase value of the array manifold data. Based on these coordinates, a value derived from the above equation (1) called phase amount is subtracted to obtain a subtracted phase value, and interpolation is performed using the subtracted phase value. Then, the phase value of the array manifold data is interpolated and derived by adding the phase amount based on the coordinates of the antenna element corresponding to the angle to the subtraction phase value derived by the interpolation. The phase value of accurate array manifold data can be derived.

  Therefore, even when performing azimuth estimation processing over a wide frequency band, the orientation using the array manifold for a large number of frequencies is maintained without storing and storing the array manifold for a large number of frequencies belonging to these frequency bands. An estimation process can be performed.

  In addition, it can also provide as an antenna apparatus which has the array manifold interpolation apparatus which implements the array manifold data interpolation method concerning 2nd Embodiment, and was provided with the arrival direction estimation function. The configuration in this case is almost the same as that of the antenna device 100 in the first embodiment. The array manifold storage unit 105 stores an array manifold for each discrete frequency (see FIG. 13), and the processing performed by the array manifold data interpolation device 107 is a process according to the procedure shown in FIG. Although it is different from the first embodiment in a certain point, the other configurations are the same and will not be described.

(Third embodiment)
Next, FIG. 14 is a flowchart showing the procedure of the array manifold data interpolation method according to the third embodiment of the present invention. The array manifold data interpolation method in the present embodiment is array manifold data corresponding to an unprepared frequency and array manifold data corresponding to an unprepared angle from array manifold data for each frequency prepared in advance. Is different from the above embodiments in this respect.

  That is, in the present embodiment, array manifold data for each discrete angle is prepared for each discrete frequency such as frequencies f1, f2,... As in the second embodiment (see FIG. 13). ). In such a case, by using these prepared array manifold data, it is array manifold data for a frequency that is not prepared and an angle that is not prepared (for example, 2.5 °, 3.5 °). Etc.) is derived by interpolation.

  Hereinafter, the array manifold data of the angle 2.5 ° (angle not prepared) of the antenna element # 2 with respect to the frequency f1.5 (frequency not prepared in FIG. 13) is obtained from the array manifold data prepared in advance. The case of deriving will be described as an example.

  As shown in FIG. 14, in the array manifold data interpolation method according to the present embodiment, a frequency (f1.5 (f1 and f1) to be interpolated is selected from a plurality of frequencies (f1, f2,...) Prepared in advance. f2)) and angle (2.5 °) array manifold data required to interpolate and derive the array manifold data of multiple frequencies, and the phase value and amplitude of those array manifold data The phase is separated from the value (step Sc1).

  Here, array manifold data corresponding to angles 2 ° and 3 ° for each of two frequencies (f1 and f2) in the vicinity of the frequency to be interpolated of antenna element # 2 to be interpolated, that is, four array manifold data. Is specified as array manifold data used for interpolation. Then, the phase value and amplitude value of these array manifold data are separated to obtain the phase value.

  In addition, if the phase value and the amplitude value of each array manifold data are separated in advance and only the phase value is recorded and held separately in a storage medium, the phase value can be obtained without performing such separation processing. Can do.

  When the phase values of the two array manifold data are acquired as described above, the phase amount based on the coordinates of the antenna element # 2 at the angles 2 ° and 3 ° is derived for each of the acquired frequencies f1 and f2, and the interpolation target A phase amount based on the coordinates of the antenna element # 2 at an angle of 2.5 ° with respect to the frequency (f1.5) is derived (step Sc2). The phase amount based on the antenna coordinates can be derived from the above equation (1).

  As described above, when the phase amount based on the coordinates of the antenna element in the phase component of the array manifold data for the frequency used for the interpolation is derived, the antenna derived for each angle from the phase value of the array manifold data of these frequencies. The phase amount based on the element coordinates is subtracted, and the subtraction phase value is derived and obtained (step Sc3).

  Thus, when subtraction phase values corresponding to two angles are obtained for each of the two frequencies used for interpolation, that is, when four subtraction phase values are obtained, interpolation processing is performed using these subtraction phase values, and an interpolation target is obtained. A subtraction phase value is obtained for an angle of 2 ° at a frequency (f1.5) (step Sc4).

  In such an interpolation process, first, a subtraction phase value corresponding to an angle 2 ° of frequency 1.5 (== a subtraction phase value corresponding to an angle 2 ° of frequency f2 and a subtraction phase value corresponding to an angle 2 ° of frequency f2). G1.5 · 2) is derived by interpolation. Further, from the subtraction phase value corresponding to the angle 3 ° of the frequency f1 and the subtraction phase value corresponding to the angle 3 ° of the frequency f2, the subtraction phase value corresponding to the angle 2 ° of the frequency f1.5 (= G1.5 · 3) is derived by interpolation.

  From the subtraction phase value G1.5 · 2 corresponding to the angle 2 ° of the frequency f1.5 and the subtraction phase value G1.5 · 3 corresponding to the angle 3 ° of the frequency f1.5, the frequency f1. The subtraction phase value corresponding to the angle 2.5 of 5 is derived by interpolation.

  The interpolation is not limited to the above procedure, and may be performed by the following procedure. First, from the subtraction phase value corresponding to the angle 2 ° of the frequency f1 and the subtraction phase value corresponding to the angle 3 ° of the frequency f1, the subtraction phase value corresponding to the angle 2.5 ° of the frequency f1 (= G1 · 2.5 ) Is derived by interpolation. Further, from the subtraction phase value corresponding to the angle 2 ° of the frequency f2 and the phase value corresponding to the angle 3 ° of the frequency f2, the subtraction phase value corresponding to the angle 2.5 ° of the frequency f2 (= G2 · 2.5 ) Is derived by interpolation. Then, from the subtraction phase value G1 · 2.5 corresponding to the angle 2.5 ° of the frequency f1 and the subtraction phase value G2 · 2.5 corresponding to the angle 2.5 ° of the frequency f2, the frequency f1. Alternatively, the subtraction phase value corresponding to the angle 2.5 of 5 may be derived by interpolation.

  In this way, when the subtraction phase value for the angle 2.5 ° to be interpolated at the frequency (f1.5) to be interpolated is derived by the interpolation processing, the interpolated subtraction phase value is obtained in step Sc2 above. A phase amount based on the antenna element coordinates for the interpolation target angle of the interpolation target frequency is added to derive an interpolation phase value (step Sc5).

  As described above, when the interpolation phase value for the interpolation target angle (2 °) of the frequency (f1.5) to be interpolated is obtained, the angles 2 ° and 3 ° for each of the frequencies (f1 and f2) used for interpolation. The interpolation amplitude value for the angle 2.5 ° of the frequency (f1.5) to be interpolated is obtained by an arbitrary interpolation method such as linear interpolation from the array manifold data corresponding to the above, that is, the amplitude values of the four array manifold data. .

  The above is the array manifold data interpolation method according to the third embodiment. The antenna element is one main component of the phase value of the array manifold data rather than simply using the phase value of the array manifold data. Based on these coordinates, a value derived from the above equation (1) called phase amount is subtracted to obtain a subtracted phase value, and interpolation is performed using the subtracted phase value. Then, the phase value of the array manifold data is interpolated and derived by adding the phase amount based on the coordinates of the antenna element corresponding to the angle to the subtraction phase value derived by the interpolation. The phase value of accurate array manifold data can be derived.

  Therefore, even when performing azimuth estimation processing over a wide frequency band, the orientation using the array manifold for a large number of frequencies is maintained without storing and storing the array manifold for a large number of frequencies belonging to these frequency bands. An estimation process can be performed. In addition, array manifold data for a larger number of angles can be used without holding array manifold data for many angles in advance, and arrival direction estimation with higher accuracy can be performed.

  In addition, it can also provide as an antenna apparatus which has the array manifold interpolation apparatus which performs the array manifold data interpolation method concerning 3rd Embodiment, and was provided with the arrival direction estimation function. The configuration in this case is substantially the same as that of the antenna device 100 in the first embodiment, and the array manifold storage unit 105 stores an array manifold for each discrete frequency (see FIG. 13). The processing performed by the array manifold data interpolation device 107 is different from that of the first embodiment in that it is processing according to the procedure shown in FIG. Omit.

(Modification)
In addition, this invention is not limited to each embodiment mentioned above, The various deformation | transformation which is illustrated below is possible.

(Modification 1)
In each of the above-described embodiments, when phase values of array manifold data are prepared for a plurality of angles and frequencies in advance, a case where the phase values of array manifold data of unprepared angles and frequencies are derived by interpolation is described. However, instead of the phase value of the array manifold data, the subtracted phase value may be prepared in advance (for example, stored in the array manifold storage unit 106).

  In this way, the phase value and amplitude value separation performed in each of the above embodiments (step Sa1, step Sb1, step Sc1), and phase amount derivation based on antenna coordinates (step Sa2, step Sb2, step Sc1) are performed. ) And derivation of the subtraction phase value (step Sa3, step Sb3, step Sc3) may be omitted, and a step of obtaining a predetermined subtraction phase value prepared instead may be performed.

  The arrival direction estimation process uses not the subtracted phase value but array manifold data composed of the phase value and the amplitude value. Therefore, when only the subtraction phase value is recorded and held as described above, when using the array manifold data corresponding to the held subtraction phase value, the subtraction phase value is used for the arrival direction estimation process. The phase value is obtained by adding the phase amount based on the antenna coordinates derived by the above equation (1). Then, the phase value and the amplitude value separately held may be used in combination for the azimuth estimation process.

(Modification 2)
Further, in each of the above-described embodiments, one-dimensional angle measurement for only the azimuth angle θ is assumed. However, the present invention can be applied to an array manifold used for two-dimensional angle measurement. . For example, as shown in FIG. 15, the array manifold used for two-dimensional angle measurement is array manifold data including phase values and amplitude values of the antenna elements # 1, # 2,... For each set of azimuth φ and elevation θ. It is.

  Even in such a case, the phase manifold based on the antenna coordinates is subtracted using the array manifold data of the two-dimensional angle necessary for the interpolation of the two-dimensional angle (θ, φ) to be interpolated, as in the above embodiments. The phase value corresponding to the two-dimensional angle to be interpolated may be derived by performing processing such as interpolating the subtracted phase value.

  For example, as shown in FIG. 16, when array manifold data corresponding to three angles such as an angle (θ1, φ1), an angle (θ1, φ2), and an angle (θ2, φ2) are prepared, By using the three array manifold data, the array manifold data corresponding to an arbitrary angle (θ, φ) in the triangular area shown by the oblique lines in FIG. 16 can be derived by interpolation.

(Modification 3)
Further, in each of the above-described embodiments, when array manifold data is prepared for each uniform angle (every 1 ° in the examples of FIGS. 2 and 13), the array manifold data is prepared using these array manifold data. Interpolated the array manifold data with no angle. As described above, the angle at which the array manifold data is prepared in advance need not be uniform, and may be varied depending on the direction. For example, the direction from 0 to 90 ° is every 1 °, and the direction from 90 to 180 ° is every 0.5 °.

(Modification 4)
In addition, when the number of array manifold data prepared per unit angle varies depending on the direction as described above, the number may be determined based on the arrangement state of the antenna elements 101. That is, the arrival direction estimation accuracy for each direction tends to be determined according to the arrangement state of each antenna element in the antenna device. For example, in the case of the linear array antenna apparatus shown in FIG. 17, the accuracy of the relative accuracy is seen for each direction in which the direction of θ = 90 ° has poor estimation accuracy and the direction of θ = 0 ° has high estimation accuracy. .

  Therefore, the number of array manifold data prepared per unit angle for a direction with good estimation accuracy determined by the arrangement of antenna elements is less than the number of array manifold data prepared per unit angle for a direction with poor estimation accuracy. To do. This makes it possible to balance the azimuth estimation error due to the antenna element placement status and the azimuth estimation error due to the interpolation of the array manifold data for the following reasons. Without increasing the number, stable estimation accuracy can be obtained regardless of the direction.

  That is, according to the interpolation method of each of the above embodiments, it is possible to derive an interpolation value with high accuracy, but even in this case, the interpolation accuracy decreases when the amount of data prepared is small. It will be. Therefore, in order to improve the accuracy of the interpolation value, as much data as possible should be prepared. However, in this case, there arises a problem that the capacity of the recording medium is increased.

  As described above, since it is possible to estimate the direction with high accuracy as a whole even if the interpolation error is slightly increased for the direction with high accuracy of estimation as described above, the amount of data held for the direction is reduced. On the other hand, in the direction where the estimation accuracy is originally poor, if the error due to interpolation becomes large, the direction estimation accuracy may be greatly deteriorated. Therefore, for such a direction, a relatively large amount of array manifold data is prepared in order to minimize the interpolation error.

  In the case of the antenna apparatus as shown in FIG. 17, for example, in the direction of θ = 0 ° to 30 °, 0.5 array manifold data is held per unit angle (for example, 1 °), that is, one for every 2 °. While the array manifold data is held, in the direction of θ = 60 to 90 °, two array manifold data are held per unit angle. In the direction of θ = 30 to 60 °, if one array manifold data is held per unit angle, stable direction estimation accuracy can be obtained for all directions without increasing the amount of data to be prepared. Will be able to.

  In this modification, in order to obtain stable azimuth estimation accuracy for all directions, a number of data corresponding to the quality of azimuth estimation accuracy determined from the antenna element arrangement status for each direction is prepared. When it is desired to realize stable azimuth estimation accuracy in a partial (for example, 0-30 °) direction, an antenna is provided for each direction (0-10 °, 10-20 °, 20-30 °, etc.) of the portion. A number of data corresponding to the arrangement state of the elements may be prepared.

(Modification 5)
Further, when the number of array manifold data prepared per unit angle is varied depending on the direction as described above, the number may be determined based on the amplitude value of the array manifold. That is, the angle (direction) with a large amplitude value of the array manifold has a relatively good estimation accuracy, and the angle (direction) with a small amplitude value of the array manifold has a relatively poor estimation accuracy. A number of data corresponding to the accuracy of the estimation accuracy in each direction is prepared.

  This is due to the following reason. That is, when the antenna element has directivity, the reception intensity of the radio wave changes according to the directivity gain. For example, when a received signal from a direction where the gain is 5 dB is compared with a received signal from the direction where the gain is 0 dB, there is a received power difference of 5 dB. The estimation accuracy in the direction estimation method such as the MUSIC method changes depending on the S / N (signal to noise ratio) of the received signal. When the S / N is large, the estimation accuracy is good, and when the S / N is small, the estimation accuracy is high. bad. That is, the estimation accuracy is good when the antenna gain, that is, the amplitude value of the array manifold is large, and the estimation accuracy is poor when the amplitude value of the array manifold is small.

  Therefore, as described above, the number of array manifold data prepared per unit angle for each direction is determined based on the amplitude value of the array manifold. For example, the average value of the amplitude value of the array manifold data in the direction of 0 to 40 ° is compared with the average value of the amplitude value of the array manifold data in the direction of 40 to 60 °, and the array manifold in the direction of 0 to 40 ° is compared. When the average value of the amplitude values of data is large, the number of array manifold data prepared per unit angle in the direction of 40 to 60 ° is larger than the number of array manifold data prepared per unit angle in the direction of 0 to 40 °. Increase the number.

  In this way, as in the case of determining the number of data according to the arrangement state of the antenna element, the direction estimation error determined by the antenna device configuration (antenna element configuration, etc.) and the array manifold data are interpolated. Thus, stable estimation accuracy can be obtained regardless of the direction without increasing the amount of array manifold data to be recorded and held.

  Also in this modification, when it is desired to realize stable azimuth estimation accuracy in a partial (for example, 0 to 30 °) direction, each direction (0 to 10 °, 10 to 20 °, 20 to 20) of that portion is desired. The number of data corresponding to the amplitude value of the array manifold data may be prepared every 30 °).

(Modification 6)
In each of the above-described embodiments, the angle at which array manifold data is prepared in advance is the same for all antenna elements # 1, # 2,... (See FIGS. 2 and 13). For example, in the example shown in FIGS. 2 and 13, array manifold data is prepared for each antenna element for each angle of 1 °, such as 1 °, 2 °, and 3 °, and prepared from the prepared array manifold data. It was designed to interpolate array manifold data that was not performed.

  In this way, an array manifold having the same angle may be prepared for all antenna elements. However, as shown in FIG. 18, an array manifold having a different angle may be prepared for each antenna element. . As shown in the figure, in this example, array manifold data is prepared for angles of 0 °, 1 °, 2 °, 3 °,... For antenna element # 1, and 0 for antenna element # 2. Array manifold data is prepared for angles such as .25 °, 1.25 °, 2.25 °, etc., and for antenna element # 3, 0.5 °, 1.5 °, 2.5 °, etc. Array manifold data is provided for angles.

  Thus, by varying the angle at which the array manifold data is prepared for each antenna element, it is possible to achieve stable direction estimation accuracy in all directions when the antenna apparatus as a whole composed of a plurality of antenna elements is evaluated.

  That is, according to the interpolation method of each of the above embodiments, array manifold data at an unprepared angle can be more accurately interpolated, but even though some interpolation errors still occur, actually measured values are prepared. The error in the array manifold data is zero. Therefore, the direction estimation accuracy is better when data prepared in advance is used than when interpolated data is used.

  Therefore, if the angle for preparing the array manifold is made different for each antenna element as described above, the array array prepared in advance for a larger number of angles when observed as a whole antenna apparatus having a plurality of antenna elements. Since direction estimation can be performed using the manifold data, stable direction estimation can be performed for all directions.

(Modification 7)
In the second and third embodiments described above, the angle at which array manifold data is prepared in advance is the same for all frequencies (f1, f2). For example, in the example shown in FIG. 13, array manifold data is prepared at intervals of 1 ° such as 1 °, 2 °, and 3 ° for frequencies f1 and f2, and array manifold data that is not prepared from the prepared array manifold data is prepared. The data was derived by interpolation.

  In this way, an array manifold having the same angle may be prepared for all frequencies, but an array manifold having a different angle for each frequency may be prepared as shown in FIG. As shown in the figure, in this example, array manifold data is prepared for angles such as 0 °, 1 °, 2 °, 3 °... For frequency f1, and 0.5 ° for frequency f2. Array manifold data is prepared for angles of 1.5 °, 2.5 °, etc.

  Thus, by varying the angle at which the array manifold data is prepared for each frequency, stable direction estimation accuracy can be realized in all directions when performing direction estimation for a wide frequency band.

(Modification 8)
In each of the above-described embodiments, the array manifold data interpolation device 107 interpolates the array manifold data of the angle and frequency according to the request from the arrival direction estimation processing unit 104, for each array manifold data request. The angle and frequency of interpolation may be varied.

  For example, when the frequency that is the target of arrival direction estimation is low, the direction estimation accuracy is low due to the long wavelength. Thus, when targeting the low frequency region, there are cases where improvement in the direction estimation accuracy cannot be expected even if a large amount of array manifold data is used. In such a case, since it is not necessary to derive a lot of array manifold data by interpolation, the number of required angles is reduced.

  On the other hand, when performing azimuth estimation for a high frequency region, the accuracy tends to be improved, and the accuracy can be further improved by using a lot of array manifold data. Therefore, in such a case, array manifold data is derived by interpolation for more angles.

  As described above, the number of data to be interpolated by the array manifold data interpolating device 107 may be changed in accordance with the frequency region for which the direction is to be estimated. In addition, when it is required to perform direction estimation processing quickly, the number of array manifolds derived by interpolation is reduced, and in the case where accuracy is given priority over time, the number of array manifolds derived by interpolation is reduced. You may make it increase.

(Modification 9)
Also, the array manifold data derived by the array manifold data interpolation method and apparatus according to each of the above embodiments is used not only for the arrival direction estimation process using the MUSIC method as described above but also for other arrival direction estimation processes. It can also be used when calculating the beam pattern in an adaptive antenna.

  As described above, the array manifold data interpolation method, the arrival direction estimation method, and the array manifold interpolation device according to the present invention are useful for direction estimation using the MUSIC method and the like, in particular, a radar device having a plurality of antenna elements, etc. It is suitable as a technique used for the above.

It is a flowchart which shows the procedure of the array manifold data interpolation method concerning the 1st Embodiment of this invention. It is a figure for demonstrating the said array manifold. It is a figure for demonstrating the parameter used in order to calculate the phase amount based on the coordinate of an antenna element. It is a figure which shows an example of the relationship between the phase of the array manifold data actually derived | led-out about the antenna element of a certain antenna apparatus, and azimuth. It is a figure which shows the phase of the azimuth and array manifold data which are actually derived | led-out and prepared about the antenna element of a certain antenna apparatus. It is a figure which shows the relationship between the phase amount based on an antenna element coordinate, and azimuth. It is a figure which shows the relationship between the subtraction phase value which subtracted the phase amount based on an antenna element coordinate from the phase of the array manifold data corresponding to the said prepared azimuth, and azimuth. It is a figure which shows the relationship between the azimuth interpolated using the said subtraction phase value, and the subtraction phase of array manifold data. It is a figure which shows the relationship between a phase value and azimuth after adding the phase amount based on an antenna element coordinate to the interpolation value using the said subtraction phase value. It is a figure which shows the relationship between the phase after interpolation by the conventional interpolation method, and azimuth. It is a block diagram which shows the structure of the antenna apparatus which has an interpolation apparatus for implementing the array manifold data interpolation method concerning 1st Embodiment. It is a flowchart which shows the procedure of the array manifold interpolation method concerning the 2nd Embodiment of this invention. It is a figure which shows an example of the array manifold prepared previously used with the interpolation method concerning 2nd Embodiment. It is a flowchart which shows the procedure of the array manifold data interpolation method concerning the 3rd Embodiment of this invention. It is a figure which shows an example of the array manifold used for interpolation in the modification of each embodiment of this invention. It is a figure for demonstrating the array manifold data used for interpolation when performing two-dimensional angle measurement. It is a figure for demonstrating the number of the data for every direction of the array manifold used for interpolation in the modification of each embodiment of this invention. It is a figure which shows an example of the array manifold used for interpolation in the modification of each embodiment of this invention. It is a figure which shows an example of the array manifold used for the interpolation in the 2nd Embodiment of this invention, and the modification of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Antenna apparatus 101 Antenna element 102 Reception analog processing part 103 A / D conversion part 104 Arrival direction estimation processing part 105 Array manifold memory | storage part 106 Antenna coordinate memory | storage part 107 Array manifold data interpolation apparatus

Claims (11)

A method of deriving array manifold data of an antenna device having a plurality of antenna elements by interpolation,
An acquisition step of acquiring a subtraction phase value obtained by subtracting a phase value determined by arrangement of the antenna element from a phase value of array manifold data of a plurality of frequencies;
An interpolation step is performed using the subtraction phase value acquired in the acquisition step to obtain an interpolation subtraction phase value corresponding to a frequency different from the plurality of frequencies;
An addition step of deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different frequencies to the interpolation subtraction phase value obtained in the interpolation step. Manifold data interpolation method. A method of deriving array manifold data of an antenna device having a plurality of antenna elements by interpolation,
An acquisition step of acquiring a subtraction phase value obtained by subtracting a phase value determined by the arrangement of the antenna elements from a phase value of array manifold data of a plurality of angles;
An interpolation step is performed using the subtraction phase value acquired in the acquisition step to obtain an interpolation subtraction phase value corresponding to an angle different from the plurality of angles;
An addition step of deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different angles to the interpolation subtraction phase value obtained in the interpolation step. Manifold data interpolation method. In the obtaining step, further obtaining a subtraction phase value obtained by subtracting a phase value determined by the arrangement of the antenna element from a phase value of array manifold data of a plurality of angles for each of a plurality of frequencies,
In the interpolation step, an interpolation operation is performed using subtraction phase values corresponding to a plurality of angles for each of the plurality of frequencies acquired in the acquisition step, and the angles different from the plurality of angles and the plurality of frequencies. And the interpolation subtraction phase value corresponding to the frequency,
In the addition step, an interpolation phase value is derived by adding a phase value determined by an arrangement of antenna elements corresponding to the different angle and frequency to the interpolation subtraction phase value obtained in the interpolation step. Item 3. The array manifold data interpolation method according to Item 2. 4. The array manifold according to claim 2, wherein, in the obtaining step, the number of subtraction phase values to be obtained per unit angle is made different for each direction based on an arrangement state of the plurality of antenna elements. 5. Data interpolation method. 5. The acquisition step according to claim 2, wherein in the direction in which the amplitude value of the array manifold is small, the subtracted phase value per unit angle is acquired more than in the direction in which the amplitude value of the array manifold is large. The array manifold data interpolation method according to any one of the above. 6. The acquisition step according to claim 2, wherein when the array manifold phase value for each of the plurality of antenna elements is interpolated, the subtraction phase value corresponding to a different angle is acquired for each antenna element. The array manifold data interpolation method according to any one of the above. 4. The array manifold data according to claim 1, wherein in the obtaining step, when interpolating array manifold phase values for a plurality of frequencies, the subtracting phase values corresponding to different angles are obtained for each frequency. 5. Interpolation method. A method of estimating the direction of arrival of an incident wave using array manifold data of an antenna device having a plurality of antenna elements,
An acquisition step of acquiring a subtraction phase value obtained by subtracting a phase value determined by arrangement of the antenna element from a phase value of array manifold data of a plurality of frequencies;
An interpolation step is performed using the subtraction phase value acquired in the acquisition step to obtain an interpolation subtraction phase value corresponding to a frequency different from the plurality of frequencies;
An addition step of deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different frequencies to the interpolation subtraction phase value obtained in the interpolation step;
An arrival direction estimation method comprising: an estimation step of estimating an arrival direction using the interpolated phase value obtained in the addition step. A method of estimating the direction of arrival of an incident wave using array manifold data of an antenna device having a plurality of antenna elements,
An acquisition step of acquiring a subtraction phase value obtained by subtracting a phase value determined by the arrangement of the antenna elements from a phase value of array manifold data of a plurality of angles;
An interpolation step is performed using the subtraction phase value acquired in the acquisition step to obtain an interpolation subtraction phase value corresponding to an angle different from the plurality of angles;
An addition step of deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different angles to the interpolation subtraction phase value obtained in the interpolation step;
An array manifold data interpolation method comprising: an estimation step of estimating an arrival direction using the interpolation phase value obtained in the addition step. An apparatus for deriving array manifold data of an antenna apparatus having a plurality of antenna elements by interpolation,
Obtaining means for obtaining a subtraction phase value obtained by subtracting a phase value determined by arrangement of the antenna element from a phase value of array manifold data of a plurality of frequencies;
Interpolation using the subtraction phase value acquired by the acquisition means to obtain an interpolation subtraction phase value corresponding to a frequency different from the plurality of frequencies;
Addition means for deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different frequencies to the interpolation subtraction phase value obtained by the interpolation means. Manifold data interpolation device. An apparatus for deriving array manifold data of an antenna apparatus having a plurality of antenna elements by interpolation,
Obtaining means for obtaining a subtraction phase value obtained by subtracting a phase value determined by the arrangement of the antenna elements from a phase value of array manifold data of a plurality of angles;
Interpolation using the subtraction phase value acquired by the acquisition unit to perform an interpolation calculation, and obtaining an interpolation subtraction phase value corresponding to an angle different from the plurality of angles;
And an addition means for deriving an interpolation phase value by adding a phase value determined by an arrangement of antenna elements corresponding to the different angles to the interpolation subtraction phase value obtained by the interpolation means. Manifold data interpolation device.

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