JP2002221561A - Incoming wave direction estimation device and incoming wave direction estimation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve incoming wave direction estimation accuracy by executing real-time high-precision calibration by using reception data in operation. SOLUTION: When receiving a radio wave by plural antenna elements and estimating the incoming direction of the radio wave by a reception signal corresponding to each antenna element, a deviation of a passage characteristic in a reception system for acquiring the reception signal from each antenna element and a deviation of the reception signal caused by leakage of a signal from another reception system are corrected corresponding to each antenna by using the reception signal acquired by executing reception processing of the radio wave captured by each antenna element, and the incoming direction of the radio wave is estimated by using the corrected reception signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incoming wave direction estimating apparatus and an incoming wave direction estimating method used for mobile communication, private radio, radar equipment, and the like.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for an adaptive antenna apparatus which can transmit and receive signals.
In a DD communication system, since the transmission and reception frequencies match, it is effective to use an adaptive antenna apparatus that forms the same pattern in transmission and reception.

FIG. 12 is a block diagram showing an example of the configuration of a conventional adaptive antenna apparatus for transmission and reception. A plurality of antenna elements 31a forming an adaptive antenna,
, 31n, and each of the antenna elements is connected to a receiving analog section 32a,..., 32n for receiving a signal and a transmitting analog section 33a,.

The reception signals of the reception analog sections 32a,..., 32n are input to a reception pattern forming circuit 34 to become final reception signals. The transmission signal is transmitted by the transmission pattern forming circuit 35.
, And the individual transmission analog units 33a,.
Distributed to

[0005] Such an adaptive antenna apparatus for both transmission and reception uses the individual antenna elements 31a,...
a,..., 31n are determined by the reception pattern forming circuit 34, and the weights are given to the reception signals corresponding to the common antenna element, or the weights are transmitted by the transmission pattern formation circuit 35. To form a desired antenna pattern. Therefore, in principle, the same pattern can be formed for reception and transmission.

However, it is practically difficult to form the same pattern for reception and transmission. In many cases, the reason is that there is a deviation (variation) in the pass characteristics (pass amplitude characteristics, pass phase characteristics) of the transmission analog unit 33 and the reception analog unit 32 for each antenna element in the adaptive antenna. .

[0007] When there is such a deviation, as shown in FIG. 13, the reception pattern 50 and the transmission pattern 60 are different, and the gain in the desired direction decreases, and the gain to the interference user increases. I will.

[0008] Alternatively, a receiving adaptive antenna apparatus may use an adaptive algorithm with directional constraints. Also in this case, if there is a deviation (variation) in the pass characteristic of the reception analog unit, it is impossible to obtain an optimal solution.

Further, the reception adaptive antenna device is used as a part of the radar device for estimating the arrival direction of a radio wave. If there is a deviation (variation) in the passing characteristic of the reception analog section, the reception adaptive antenna device can accurately detect the radio wave. The direction of arrival cannot be estimated.

As a method of removing the above-mentioned deviation,
Generally, calibration is performed. Calibration refers to measuring the deviations of all the analog reception units and the analog transmission units at the time when the production of the adaptive antenna device is completed, and calculating the correction amount (same as the deviation amount) in advance. Then, when actually operating the adaptive antenna apparatus, an amplitude phase (weight) set for each element may be calculated in consideration of the correction amount.

However, there is a case where the initially obtained correction amount changes during operation. For example, it is conceivable that the characteristics of analog parts (amplifiers, frequency converters, filters, etc.) change due to differences in the outside air temperature during the day and night, and the length of the cable connecting them changes. When such a change occurs, the performance of the receiving adaptive antenna apparatus is greatly degraded, and it is impossible to accurately estimate the direction of arrival.
In the worst case, the communication may be disconnected. That is, the calibration is not sufficient at one time, and it is required to perform the calibration in real time during operation.

As a method for solving such a problem, FIG. 14 shows an example of the invention of Japanese Patent Application Laid-Open No. 2000-91833, in which received signals received by antenna elements 41a, 41b and 41c pass through a beamformer 42. Converted to beam space data. The output (beam space data) of the beam former is corrected by the level adjusters 44b and 44c. The corrected data is converted again by the inverse conversion circuit into a reception signal (corrected) received by the antenna element.

The phase correction amount calculating section 43 detects the relative phase difference between the outputs of the beamformers. here,
There is one arriving wave, and the antenna elements 41a, 41b,
.., 41c, the phase difference between the outputs of the beamformer is determined by the angle of arrival. Therefore, the phase correction amount calculation unit 43 calculates the difference between the detected phase difference and the originally obtained value as a correction amount, and adjusts the reception levels of the antenna elements 41b and 41c by the level adjusters 44b and 44c based on the correction amount. Thus, the accuracy of the estimation direction of the incoming wave can be improved. Moreover, this conventional example has an advantage that the above-mentioned correction can be performed in real time during operation.

However, since the number of arriving waves is limited to one and only the phase is corrected, a deviation cannot be guaranteed if there is a change in amplitude. In particular, in the adaptive antenna device, pattern formation is performed while a plurality of incoming waves are being received. Since the number of incoming radio waves must be one, calibration cannot be performed during normal communication.

As described above, the calibration method invented for the conventional adaptive antenna apparatus can be performed in real time, but the number of arriving waves is limited to one and only the phase can be corrected. was there.

Further, the above-mentioned conventional problems relating to the adaptive antenna apparatus are exactly the same as those in the case where the accuracy of estimating the direction of arrival is improved in an antenna radar apparatus partially having the same configuration as that of the reception adaptive apparatus. Becomes

[0017]

As described above, in the conventional arriving wave direction estimating apparatus, calibration is generally performed as a method of removing the characteristic deviation of the circuit, but the correction amount obtained first is used. The calibration has to be performed in real time, since it may change in the middle. However, in this case, the number of arriving waves is limited to one, and only the phase can be corrected.In addition, calibration cannot be performed during operation in which a plurality of arriving waves are present, which is insufficient for practical use. .

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to carry out high-precision calibration in real time using received data during operation, and to improve the accuracy of estimating the direction of an incoming wave. An object of the present invention is to provide an incoming wave direction estimating apparatus and an incoming wave direction estimating method that can be improved.

[0019]

In order to achieve the above object, a feature of the present invention is that a plurality of antenna elements,
A plurality of receiving units are provided corresponding to the plurality of antenna elements and process reception signals transmitted from the corresponding antenna elements in correspondence with the antenna elements, and the plurality of reception units output from the plurality of reception units. Correction amount calculating means for estimating a relative deviation between signals output from the receiving units, and correcting the received signals output from the plurality of receiving units using the deviation amount obtained by the correction amount calculating means. And estimating the direction of arrival of at least one radio wave arriving at the plurality of antenna elements using the corrected received signals.

According to a second aspect of the present invention, the correction amount calculating means includes:
A deviation amount between the reception analog units is calculated using arrival direction information of one or more radio waves calculated by a calculation algorithm.

According to a third aspect of the present invention, the calculation algorithm is the MUSIC algorithm.

According to a fourth aspect of the present invention, the arrival direction estimating means obtains a received signal containing no deviation by multiplying an output signal of the receiving unit by a reciprocal of the deviation calculated by the correction amount calculating means. And estimating the direction of arrival of one or more radio waves arriving at the plurality of antenna elements using the received signals.

According to a fifth aspect of the present invention, the correction amount calculating means includes:
The process of obtaining three kinds of unknown variables of the arrival directions of one or a plurality of radio waves, the amplitude / phase deviation between signals output from a plurality of receiving units, and the mutual coupling coefficient between the signals output from a plurality of receiving units. Step 1 is performed to estimate the arrival direction by fixing the amplitude / phase deviation and the mutual coupling coefficient.
Assuming that the arrival direction and the mutual coupling coefficient are fixed, the amplitude / phase deviation is estimated. Step 3 is to fix the arrival direction and the amplitude / phase deviation to estimate the mutual coupling coefficient. The deviation amount is obtained by repeatedly executing until the convergence.

According to a sixth aspect of the present invention, the correction amount calculating means includes:
Step 1 is to estimate the arrival direction by fixing the amplitude phase deviation and the mutual coupling coefficient. Step 2 is to estimate the amplitude phase deviation by fixing the arrival direction and the mutual coupling coefficient.
Assuming that the direction of arrival is estimated by fixing the amplitude phase deviation and the mutual coupling coefficient, the mutual coupling coefficient is estimated by fixing the direction of arrival and the amplitude and phase deviation as step 4, and the processing results of steps 1 to 4 are estimated. The deviation amount is obtained by repeatedly executing until the convergence.

The arriving wave direction estimating device of the invention according to claim 7 has one or more radio wave transmitting devices for calculating the deviation amount, and the radio wave transmitting position of the radio wave transmitting device is determined by the arrival time. It is characterized in that the direction relative to the wave estimating device is known.

[0026] The correction amount calculating means of the invention of claim 8 may be arranged such that:
Using a received signal of a radio wave arriving from a known direction emitted from the transmitting device, the arrival direction and the mutual coupling coefficient are fixed to estimate the amplitude / phase deviation in step 1, and the arrival direction and the amplitude / phase deviation in step 2 Is fixed, the mutual coupling coefficient is estimated, and the processing of steps 1 and 2 is repeatedly executed until the estimation result converges, thereby obtaining the deviation amount.

According to a ninth aspect of the present invention, the correction amount calculating means has a correction amount storage device, and stores the deviation amount obtained every time the deviation amount is calculated in the correction amount storage device to update the storage contents. It is characterized by doing.

According to a tenth aspect of the present invention, the correction amount calculating means uses the past deviation amount stored in the correction amount storage device to predict the next deviation amount.

[0029] The correction amount calculating means of the invention of claim 11 uses the past deviation amount stored in the correction amount storage device to predict the next deviation amount by linear interpolation.

According to a twelfth aspect of the present invention, the correction amount storage device includes: a deviation amount calculated by the correction amount calculation device;
It is characterized in that both the outside air temperature at that time are stored.

According to a thirteenth aspect of the present invention, the correction amount storage device comprises: a deviation amount calculated by the correction amount calculation device;
It is characterized in that both temperatures around the reception analog section at that time are stored.

According to a fourteenth aspect of the present invention, the correction amount storage device includes: a deviation amount calculated by the correction amount calculating means;
It is characterized in that both the time and the date and time at that time are stored.

According to a fifteenth aspect of the present invention, there is provided a method for estimating a direction of arrival of a radio wave by receiving a radio wave by a plurality of antenna elements and estimating a direction of arrival of the radio wave by a plurality of reception signals corresponding to the antenna elements. For the received signal obtained by performing the reception processing of the radio wave captured by the above, the received signal generated due to the deviation of the pass characteristic between the receiving systems until the receiving signal is obtained from each antenna element and the leakage of the signal from the other receiving system. And a step of estimating the direction of arrival of the radio wave using the corrected received signal.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a first embodiment of an incoming wave direction estimation device of the present invention. The arriving wave direction estimating apparatus includes a plurality of antenna elements 1a,
, 1n and a plurality of reception analog sections 2a,..., 2n provided corresponding to the plurality of antenna elements 1a,.
, 3n for digitally converting the output signals of the reception analog sections 2a,..., 2n, and a correction amount calculation for estimating the relative deviation between the plurality of reception analog sections 2a,. .., 1n using the correction amount output from the correction amount calculating unit 4. The arrival direction estimating unit 5 estimates the direction of arrival of one or more radio waves arriving at the plurality of antenna elements 1a,. .

Here, the reception analog section 2 (collectively referred to as reception analog sections 2a,..., 2n) includes a low noise amplifier 21 for amplifying a desired signal, a filter 22 for extracting only a desired frequency band, and a frequency band. From RF (radio frequency) to BB
(Baseband) or IF (intermediate frequency). The receiving analog section 2 may be replaced with any other component having a function of extracting a received signal, converting the frequency, and amplifying the received signal.

Next, the operation of this embodiment will be described.
The correction amount calculation means 4 uses one or a plurality of incoming radio wave reception signals to generate a MUSIC (Multiple Signal) signal.
The first embodiment employs the method of calculating the correction amount using the arrival direction information of a plurality of radio waves estimated by a Classification algorithm.

Here, the plurality of antenna elements 1a, 1n may be of any type. For example, if a dipole antenna is used, a substantially omnidirectional property can be obtained in a horizontal plane, so that one arriving wave direction estimating device can cover 360 degrees. For example, if a horn antenna is used, each antenna has directivity, and the arriving wave direction estimating means 5 covers only a limited area. In this way, although the area is limited, the direction of the radio wave can be estimated without being affected by the incoming wave from behind. Here, it is assumed that the radiation pattern of the antenna is measured in advance and used in the arrival direction estimation means 5 and the correction amount calculation means 4.

Next, regarding the reception analog section 2, here, the reception signal is amplified by the low noise amplifier 21, only the desired frequency band is extracted by the filter 22, and the frequency is converted to the baseband (BB) by the frequency converter 23. ) Or an intermediate frequency (IF). Here, each of the reception analog units 2a,..., 2n has a deviation (variation).
Each branch has a different passing characteristic. Further, mutual coupling may occur between the reception analog units 2a,..., 2n when the shield is not perfect. That is, a phenomenon occurs in which a signal received by a certain reception analog unit leaks into another reception analog unit.

Next, each received signal is output to each A / D converter 3a,
.. Are converted into digital signals by 3n and processed by the arrival direction estimating means 5 to estimate the direction of the arriving wave.

On the other hand, the correction amount calculating means 4 calculates a correction amount using the received signal converted into a digital signal by each of the A / D converters 3a,..., 3n. If this correction amount is accurately obtained, no matter what deviation is present (except when the cable is cut and the amplitude becomes 0), it can be corrected, and the direction of the incoming wave can be accurately determined. Be able to estimate. The arriving wave direction estimating means 5 may estimate the direction by any method.
Even if the MUSIC algorithm is used, ESPRIT (Es
timation of Signal Parameters via Rotational In ra
riance Techniques) algorithm, a monopulse side angle, or a beamformer method.

FIG. 2 is a diagram showing a deviation of the reception analog unit 2 in a circuit model. The signals received by the plurality of antennas 1a,..., 1n are Γii (i = 1 to n) (n is the number of elements)
Multiplied. Here, Γii is a complex number representing a pass characteristic, and means a deviation between amplitude and phase. In other words, if all {ii are lex (j0}), it means that the pass characteristics are the same in all the reception analog units 2a,..., 2n. On the other hand, Γii is the reception analog unit 2a,
.., 2n, it is necessary to correct the passing characteristic.

Next, the received signal multiplied by Γii is represented by Cij
(I = 1 to n, j = 1 to n) times, and leaks to another reception analog unit 2. Cij is the i-th and j-th mutual coupling coefficient of the reception analog unit. Here, Cii is always 1
It is. If Cij (i ≠ j) = 0, it means that no coupling has occurred. As described above, in the reception analog units 2a,..., 2n, there are unknown variables that need to be corrected for the amplitude / phase deviation and the mutual coupling.

It does not matter in which part of the reception analog sections 2a,..., 2n the amplitude phase deviation and the mutual coupling occur. That is, it is important to determine the deviation of the entire reception analog section 2. Also, the order of the circuit model of the amplitude and phase deviation and the mutual coupling does not matter.
This is because, even if the order is reversed, an equivalent deviation can be obtained as the overall deviation of the reception analog unit 2.

Next, the correction amount calculating means 4 uses a received signal of one or a plurality of incoming radio waves. That is, since any incoming radio wave can be used, calibration can be performed in real time during operation of the adaptive antenna apparatus, and no special transmission source for calibration is required. Then, the correction amount is calculated using the arrival direction information of a plurality of radio waves estimated by the MUSIC algorithm.

Generally, if the calibration is performed correctly, the arrival direction estimated by the MUSIC algorithm has a sharp peak as shown by the solid line in FIG. In addition, MUSIC
The spectrum is calculated from the radiation pattern of the antenna, the received signal, and the correction amount (calibration data). However, when there is a deviation, the peak in the estimation direction becomes dull as shown by the broken line in FIG. 3, and the estimation accuracy is degraded.

The correction amount calculating means 4 here is a MUSIC
Correction amount (Γii and Cij in FIG. 2) so as to sharpen the peak of the MUSIC spectrum obtained by
Is calculated. The calculation method may be any method. For example, the correction amount of the sharpest spectrum may be selected from the correction amounts of all conceivable combinations. Alternatively, a method using a genetic algorithm (a genetic method) or a method using a neuro may be used. Hereinafter, an example of a calculation method for obtaining Γ will be described. This calculation method is described in the literature (B. Friedlander, et a
l., "Direction finding in the presence of mutual co
upling, "IEEE Trans.Antenna and Propagation, vol.39,
No.3, pp.273-284, March 1991.).

A plurality of antennas (here, n elements) 1a,
.., The reception vector received at 1n is given by the following equation.

X (t) = AS (t) + N (t) where X (t) is a reception vector, A is an array manifold in the arrival direction, S (t) is a signal vector, and N (t) is a signal vector.
(T) is a noise vector.

The reception vector X "(t) after passing through the reception analog section 2 having a deviation is as follows.

X "(t) = C {AS (t) + N (t)} = diag {11, {22,..., {Nn} C is the reception analog unit 2 whose element Cij is the i-th and j-th
Is a matrix that means the mutual coupling coefficient of.

In this example, a method for calculating the amplitude phase Γii will be described. In this calculation, the following evaluation function Jc is minimized. This evaluation function is represented by MUS1C in the direction of arrival.
It represents the reciprocal of the total value of the spectrum. That is, M
The aim is to maximize the value of the USIC spectrum, but for the sake of calculation, we aim to minimize it using the reciprocal.

[0052]

(Equation 1) Here, N is the number of incoming waves, θm is the direction of arrival of the mth wave, and a (θm) is the θm direction.

[Outside 1] This is a matrix composed of the noise eigenvectors of the correlation matrix of the previous).

Also, δ = [Γ11, ， 22, ..., Γm
m] T, Q1 (m) = diag {a (θm)}.
However, T is transposed.

At this time, Γii that minimizes Jc is given by the following equation.

[0055]

(Equation 2) The correction amount for sharpening the MUSIC spectrum represents the actual correction amount. Therefore, by reflecting this correction amount to the arrival direction estimating means 5, an optimal arrival direction can be estimated. That is, when the direction-of-arrival estimating means 5 receives the correction amount calculated by the correction amount calculating means 4, it multiplies its reciprocal by the output of the A / D converters 3a,. The reception error caused by the mutual coupling coefficient Cij with the other reception analog unit 2 is eliminated, and the input reception level is made the same as the original reception level of the corresponding antenna element.

As described above, the arriving wave direction estimating apparatus according to the present embodiment calculates the correction amount (that is, the calibration amount) by using the arriving direction information obtained by the MUSIC algorithm using only the received signals of a plurality of radio waves. Can). Here, the reception signals of a plurality of radio waves do not need to be specially prepared for calibration, and only reception signals that are actually used may be used.

Also, the amplitude, phase, and even mutual coupling can be calibrated in real time. Further, the apparatus can be configured at low cost without requiring new analog parts.

Next, the calculation method of the second embodiment in the correction amount calculation means 4 will be described with reference to the flowchart of FIG. First, the amplitude phase Γii and the mutual coupling coefficient Ci
An initial value is given to j (step 401). As the initial value, if there is the previous calibration data, the value may be given under the condition that there is no deviation or mutual coupling if it is completely unknown. Next, the arrival direction is estimated by the MUSIC algorithm while fixing the amplitude / phase deviation and the mutual coupling coefficient (step 402). Here, the amplitude phase Γi
i and the mutual coupling coefficient Cij are fixed.

Next, the amplitude direction deviation Γii is estimated by fixing the arrival direction and the mutual coupling coefficient (step 403). Here, the arrival direction and the mutual coupling coefficient are fixed. Γii
Is set so that the peak of the MUSIC spectrum becomes sharper (has a larger value) in the direction of arrival.

Further, the direction of arrival and the amplitude / phase deviation are fixed, and the mutual coupling coefficient Cij is estimated (step 404). Here, the direction of arrival and the amplitude and phase are fixed. Cij is
The peak of the MUSIC spectrum is set so as to be sharp (a large value) in the arrival direction. The processing from step 402 to step 404 is repeatedly performed. When the estimation result converges and the value of the unknown variable does not change, the calculation is terminated (step 405), and the correction amount is output to the arrival direction estimation means 5 (step 405). Step 406). It should be noted that any method may be used as the calculation method in the processing of steps 403 and 404.

This embodiment describes a method for efficiently calculating a correction amount. As unknown parameters,
There are three types: the arrival direction of the radio wave, the amplitude / phase deviation, and the mutual coupling coefficient. Simultaneous estimation of these results in a huge number of unknown parameters, which poses a problem when performing calibration in real time. Therefore, these three types of unknown variables are not calculated at the same time, but are calculated in order, and are repeatedly obtained until the result converges.

An example of the correction amount calculation result when this algorithm is used is shown. The antenna was a circular array of six elements, and the amplitude and phase shown in FIG. 5 were set as errors. FIG. 5 shows a result obtained by repeating the processing from step 402 to step 404 using the above algorithm at this time.
As an initial value of the amplitude and phase, a value without error is used. The calculation for obtaining the amplitude and phase was performed by the method described in the first embodiment. From FIG. 5, it can be seen that the correction amount has been calculated despite the use of the condition without error as the initial value. Although the value is not 100% true, it is a value that can be sufficiently used as calibration data.

As described above, according to this embodiment, the unknown variables are repeatedly calculated, so that the calculation can be performed efficiently, and an expensive high-speed computer can be used for real-time calibration. It does not need to be used, which greatly contributes to the configuration of the apparatus at low cost.

Next, the calculation method of the third embodiment by the correction amount calculation means will be described with reference to the flowchart of FIG. First, initial values are given to the amplitude phase Γii and the mutual coupling coefficient Cij (step 601). As the initial value, if there is the previous calibration data, the value may be given under the condition that there is no deviation or mutual coupling if it is completely unknown. Next, the arrival direction is estimated by the MUSIC algorithm while fixing the amplitude / phase deviation and the mutual coupling coefficient (step 602). Here, the amplitude phase Γii and the mutual coupling coefficient Cij are fixed. Next, the amplitude and phase deviation Γii is estimated with the arrival direction and the mutual coupling coefficient fixed (step 603). Here, the arrival direction and the mutual coupling coefficient are fixed. Γii is set so that the peak of the MUSIC spectrum becomes sharper (larger value) in the direction of arrival. Next, the arrival direction is estimated by the MUSIC algorithm while fixing the amplitude / phase deviation and the mutual coupling coefficient (step 604). Here, the amplitude phase Γii and the mutual coupling coefficient Cij are fixed.

Further, the direction of arrival and the amplitude / phase deviation are fixed, and the mutual coupling coefficient Cij is estimated (step 605). Here, the direction of arrival and the amplitude and phase are fixed. Cij is
The peak of the MUSIC spectrum is set so as to be sharp (a large value) in the arrival direction. The processing from step 602 to step 605 is repeatedly performed. When the estimation result converges and the value of the unknown variable does not change, the calculation is terminated (step 606), and the correction amount is output to the arrival direction estimating means 5 (step 606). Step 607).

In the present embodiment, the order of calculation is changed, and especially the calculation of the direction of arrival wave estimation is performed twice in the processing of steps 602 and 604 as compared with the second embodiment shown in FIG.

In this embodiment, as shown in FIG. 6, arrival direction estimation → amplitude / phase calculation → arrival direction estimation →
Calculation of mutual coupling coefficient → ... This way,
Although it seems that the number of steps of arrival direction estimation increases by one and the calculation amount increases, the effect of reducing the number of repetitions can be expected. The reason will be described below.

In FIG. 4, the correction amount is calculated in step 403. However, when the arrival direction is re-estimated using the corrected data, the direction may change. That is, when the steps as shown in FIG. 4 are taken, the arrival direction estimated in step 402 may be different from the arrival direction newly estimated using the data corrected in step 403. Here, the correction is performed in step 404 as it is,
Arrival direction data in step 402 and step 403
Step 4
The correction amount obtained in step 04 may include an error.

Therefore, in this embodiment, after calculating the correction amount of the amplitude and phase, the arrival direction is estimated in step 604. Then, the mutual coupling coefficient is calculated. As a result, in calculating the mutual coupling coefficient, the correction coefficient can be obtained by reducing the number of repetitions, since the mutual coupling coefficient can be obtained without error.

As described above, according to the present embodiment,
After calculating the correction amount, the direction of arrival is re-estimated every time.
An error-free calculation of the correction amount can be realized. As a result, the calculation result converges with a small number of repetitions, and the real-time calibration can be performed more quickly.

If the amplitude / phase correction amount is clearly larger than the mutual coupling correction amount, steps 602 and 60 are performed.
3, 602, 603, 602, 604, 602, 60
3, 602, 603, 602, 604,..., And by increasing the number of times of obtaining the amplitude / phase correction amount, an effect of further reducing the number of repetitions can be expected.

FIG. 7 shows a second embodiment of the arriving wave direction estimating apparatus according to the present invention.
It is a figure showing composition of an embodiment. As shown in FIG. 7, the direction-of-arrival-wave estimating apparatus 100 includes one or a plurality of radio wave transmitting devices 9a and 9b for calculating a correction amount. The relative directions of the radio wave transmitting devices 9a and 9b with respect to the incoming wave estimating device 100 are known. Note that the direction-of-arrival-wave estimation device 100 of this example is the same as that of the first embodiment shown in FIG.
This will be described with reference to FIG.

FIG. 8 is a flow chart showing an embodiment of the correction amount calculating method of the correction amount calculating means 4 of the arrival wave direction estimating apparatus shown in FIG. The correction amount calculating means 4 of the present embodiment is configured as shown in FIG.
The transmitting devices 9a, 9 arriving from known directions as shown in FIG.
b, the amplitude and phase 電波
The correction amount is calculated by repeatedly calculating ii and the mutual coupling coefficient Cij.

First, the amplitude phase Δii and the mutual coupling coefficient C
An initial value is given to ij (step 801). As the initial value, if there is the previous calibration data, the value may be given under the condition that there is no deviation or mutual coupling if it is completely unknown.

Next, the direction of arrival (which is known) and the mutual coupling coefficient are fixed, and the amplitude / phase deviation Δii is estimated (step 802). Here, the arrival direction and the mutual coupling coefficient are fixed. Γii is set such that the peak of the MUSIC spectrum becomes sharper (larger value) in the direction of arrival.

Further, the direction of arrival and the amplitude / phase deviation are fixed, and the mutual coupling coefficient Cij is estimated (step 803). Here, the direction of arrival and the amplitude and phase are fixed. Cij is
The peak of the MUSIC spectrum is set so as to be sharp (a large value) in the arrival direction. The processing from step 802 to step 803 is repeatedly performed. When the estimation result converges and the value of the unknown variable does not change, the calculation is terminated (step 804), and the correction amount is output to the arrival direction estimation means 5 (step 804). Step 805).

This embodiment describes a method for efficiently calculating the correction amount. In this example, since a received signal of a radio wave from a wave source in a known direction is used, there are only two types of unknown parameters: an amplitude / phase deviation and a mutual coupling coefficient. That is, the arrival direction, which is an unknown parameter, becomes a known condition, and the correction amount is estimated under this condition. Therefore, the calculation of the direction estimation becomes extremely unnecessary, and the processing amount is reduced. In addition, since the direction is known, improvement in the accuracy of the finally obtained correction amount can be expected.

FIG. 9 shows the calculation result of the correction amount when the direction is known. The simulation conditions are the same as in FIG. It can be seen that the correction amount can be calculated more accurately than when the received signal from the unknown direction shown in FIG. 5 is used.

In this example, the correction amount can be calculated even if only one transmitting device is used. However, by using a plurality of transmitting devices, it becomes possible to cope with a position shift of the transmitting device, a change in a propagation environment between the transmitting device and the arriving wave estimating device, a failure of the transmitting device, and the like, and the correction amount can be stably and further improved. It can be calculated with high accuracy.

As described above, according to the present embodiment, the processing amount can be significantly reduced by calculating the correction amount using the radio wave transmitting device for calculating the correction amount, and the accuracy can be reduced. Calibration for obtaining a high correction amount can be performed in real time.

FIG. 10 is a block diagram showing the configuration of the third embodiment of the direction-of-arrival-wave estimating apparatus of the present invention. However,
The same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted as appropriate. The arriving wave direction estimating device is provided corresponding to the plurality of antenna elements 1a,..., 1n, and the plurality of reception elements for processing the reception signals transmitted from the corresponding antenna elements. , 2n; A / D converters 3a,..., 3n for digitally converting output signals of the reception analog units 2a,.
... Correction amount calculating means 4 for estimating the relative deviation of 2n
, An arrival direction estimating means 5 for estimating an arrival direction of one or a plurality of radio waves arriving at the plurality of antenna elements 1a,..., 1n using the correction amount output from the correction amount calculating means 4, and a correction amount is calculated. Each time, a correction amount storage device 6 for storing a new correction amount and updating the storage content is provided.

Next, the operation of the present embodiment will be described.
The arriving wave direction estimating operation of this example, in particular, the operation of calculating the correction amount by the correction amount calculating means 4 is the same as that of the first embodiment. The different operation is that the correction amount calculated by the correction amount calculating means 4 is stored in the correction amount storage device 6.

In this embodiment as well, the correction amount can be corrected in real time, but if the fluctuation in a short time is small, it is sufficient to correct at a certain time interval.
In this case, the direction of the incoming wave may be estimated intermittently using the correction amount stored in the correction amount storage device 6, and the load on the device and the system including the present device can be reduced.
If the correction amount in the correction amount storage device 6 is used as the initial value when calculating the correction amount, the convergence time of the correction amount calculation algorithm can be shortened.

Hereinafter, an embodiment of the operation of estimating an incoming wave using the correction amount in the correction amount storage device 6 will be described.

The correction amount calculating means 4 of the present embodiment predicts the next correction amount by using the past correction amounts stored in the correction amount storage device 6.

Here, calculating the correction amount in real time is important for improving the accuracy. But,
Reducing the number of times the correction amount is calculated, and using the calculation resources for calculating the correction amount in the arriving time in the direction-of-arrival estimation algorithm, and shortening the calculation time related to the direction estimation is very important for real-time processing. is important.

Therefore, in this example, the correction amount at the present time is predicted from the past correction amount stored in the correction amount storage device 6, and
The direction of arrival of the radio wave is estimated using the correction amount.

A specific example of a method for estimating the correction amount will be described below. As a first example, the correction amount is predicted by linear interpolation. Figure 1
1 is an example showing a method of predicting the amplitude of the amplitude phase by linear interpolation. The horizontal axis represents the number of corrections, and the vertical axis represents the amount of correction amplitude. The current correction amount is predicted by primary linear interpolation from the past two amplitude correction amounts. Here, it is also possible to make a prediction from a second-order approximation using past three or more data.

As a second example, prediction can be made by storing both the correction amount calculated by the correction amount calculation means 4 and the outside air temperature at that time in the correction amount storage device 6. In some cases, the deviation of the reception analog unit 2 has a correlation with the outside air temperature. That is, if the outside air temperature is known, the deviation of the reception analog unit 2 can be predicted in some cases. In such a case, the correction amount can be predicted by monitoring the outside air temperature. Alternatively, there is a case where the reception analog section 2 has no relation to the outside air temperature but has a relation to the temperature inside the apparatus including the reception analog section 2. That is, the temperature difference between the outside air and the inside of the apparatus may be different due to the heat generated by the equipment in the apparatus. In this case, it is effective to store the temperature in the apparatus and the correction amount in the correction amount storage device 6.

As a third example, both the correction amount calculated by the correction amount calculating means 4 and the time at that time are stored in the correction amount storage device 6. For example, there is a correlation between the use time and the use frequency in a private radio or a mobile communication base station. That is, in the case of indoor radio in a factory, it is frequently used in the daytime, and in outdoor base stations, it is frequently used in the time period when the work of members of society ends. If the frequency of use is high, the amount of heat generated in the device also increases, and the temperature in the device increases. That is, there is also a correlation between time and temperature. As described above, there is a correlation between the temperature and the correction amount. That is, there is a correlation between time and temperature. That is, it is effective to store the time and the correction amount in the correction amount storage device 6. In addition, the temperature of the outside air changes with time. In addition, there is a difference in outside air depending on the season. Therefore, it is effective to store the date and time in addition to the time.

It is also effective to predict the correction amount at a time or date and time that is not stored by linear interpolation from the stored discrete time or date and time and the value of the correction amount.

Similarly, it is also effective to predict the correction amount at an unstored temperature by linear interpolation from the stored discrete temperature and the value of the correction amount.

Further, the initial value at the time of calculating the correction amount can be set more appropriately based on the above-mentioned air temperature, temperature inside the apparatus, time and date and time.

In each of the above embodiments, the description has been given of the direction-of-arrival estimation apparatus. However, similarly, the correction of the receiving system of the adaptive antenna apparatus can be used in the same manner.

Further, based on the correction amount obtained in each of the above embodiments and the weight of the adaptive antenna apparatus used for reception,
It is of course possible to reverse the weight to be used for transmission. At this time, separately prepared calibration data for transmission is required. In particular, the TDMA / TDD system is effective because the same pattern is required for transmission and reception. In the above description, the correction amount of the mutual coupling coefficient is calculated. However, when the shield of the reception analog unit is configured with high accuracy, the mutual coupling coefficient can be ignored. In such a case, only the correction amount of the amplitude and phase needs to be calculated. In addition, it is of course possible to configure the arrival direction estimating apparatus by combining a plurality of embodiments used in the above description.

Furthermore, the present invention is not limited to the above-described embodiment, and can be embodied in other various forms in specific configurations, functions, operations, and effects without departing from the gist thereof. .

[0097]

As described in detail above, according to the present invention, highly accurate calibration can be performed in real time using received data in operation, and the accuracy of estimating the direction of an incoming wave can be improved. it can. Further, by using the transmission device for calibration, it becomes possible to perform more accurate correction. Further, by storing the past correction amount, the correction amount at the present time can be easily predicted by linear interpolation or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration according to a first embodiment of an incoming wave direction estimation device of the present invention.

FIG. 2 is an equivalent circuit diagram showing a deviation of a reception analog unit shown in FIG. 1 in a circuit model.

FIG. 3 is a diagram showing a MUSI used in a correction amount calculating unit shown in FIG. 1;
FIG. 4 is a characteristic diagram showing characteristics of a C spectrum.

FIG. 4 is a flowchart showing a second embodiment of the correction amount calculating method in the correction amount calculating means shown in FIG. 1;

FIG. 5 is a table showing set values and calculated values of an amplitude phase Γii calculated by a correction amount calculating unit shown in FIG. 1;

FIG. 6 is a flowchart showing a third embodiment of a correction amount calculating method in the correction amount calculating means shown in FIG. 1;

FIG. 7 is a block diagram showing a configuration of a second embodiment of an arrival wave direction estimation device of the present invention.

FIG. 8 is a flowchart showing an embodiment of a correction amount calculating method in the correction amount calculating means shown in FIG. 7;

9 is a table showing setting values and calculated values of amplitude and phase Γii calculated by the correction amount calculating means shown in FIG. 7;

FIG. 10 is a block diagram showing a configuration according to a third embodiment of the arrival wave direction estimation device of the present invention.

11 is a diagram illustrating a method of linearly interpolating the amplitude amount obtained by the correction amount calculation unit in FIG.

FIG. 12 is a block diagram showing a configuration example of a conventional adaptive antenna device.

13 is a diagram showing an example of a transmission pattern and a reception pattern in the device of FIG.

FIG. 14 is a block diagram showing a configuration example of a conventional arriving wave direction estimating apparatus.

[Explanation of symbols]

 1a, 1n Antenna element 2a, 2n Receive analog unit 3a, 3n A / D converter 4 Correction amount calculation unit 5 Arrival direction estimation unit 6 Correction amount storage device 9a, 9n Transmission device 21 Low noise amplifier 22 Filter 23 Frequency converter 100 Arrival wave direction estimation device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04B 7/26 H04B 7/26 DF term (Reference) 5J021 AA05 AA06 CA06 DB02 DB03 EA04 FA17 FA20 FA26 FA29 FA32 GA02 HA05 5K059 CC03 CC04 DD31 5K067 CC24 GG11 HH23 KK03

Claims (15)

[Claims] A plurality of antenna elements; a plurality of reception units provided corresponding to the plurality of antenna elements, for processing a reception signal transmitted from the corresponding antenna element in correspondence with the antenna element; Correction amount calculation means for estimating a relative deviation between signals output from the plurality of reception units from a reception signal output from the reception unit; and calculating the correction amount based on reception signals output from the plurality of reception units. Means for correcting using the amount of deviation obtained by the means, and using these corrected received signals to estimate the direction of arrival of at least one radio wave arriving at the plurality of antenna elements. Characteristic incoming wave direction estimation device. 2. The apparatus according to claim 1, wherein the correction amount calculating unit calculates a deviation amount between the reception analog units using one or a plurality of arrival direction information of radio waves calculated by a calculation algorithm. 2. The incoming wave direction estimating apparatus according to 1. 3. The apparatus according to claim 2, wherein the calculation algorithm is a MUSIC algorithm. 4. The receiving direction estimating means multiplies the reciprocal of the deviation amount calculated by the correction amount calculating means to an output signal of the receiving unit to obtain a received signal containing no deviation. The direction-of-arrival-wave estimating device according to any one of claims 1 to 3, wherein the direction of arrival of one or a plurality of radio waves arriving at the plurality of antenna elements is estimated by using the following. 5. The correction amount calculating means according to claim 1, wherein the direction of arrival of one or a plurality of radio waves, the amplitude / phase deviation between signals output from a plurality of receiving units, and the mutual direction between signals output from the plurality of receiving units. A process for obtaining three kinds of unknown variables of the coupling coefficient is performed. As a step 1, the arrival direction is estimated by fixing the amplitude / phase deviation and the mutual coupling coefficient. As a step 2, the arrival direction and the mutual coupling coefficient are fixed, and the amplitude / phase deviation is fixed. Is estimated as a step 3, the direction of arrival and the amplitude / phase deviation are fixed to estimate the mutual coupling coefficient, and the processing from the step 1 to the step 3 is repeatedly executed until the estimation result converges, thereby obtaining the deviation amount. The direction-of-arrival-wave estimating device according to any one of claims 1 to 4, wherein: 6. The correction amount calculating means estimates the direction of arrival by fixing the amplitude phase deviation and the mutual coupling coefficient in step 1 and estimates the amplitude phase deviation by fixing the arrival direction and the mutual coupling coefficient in step 2 In step 3, the arrival direction is estimated by fixing the amplitude phase deviation and the mutual coupling coefficient. In step 4, the mutual coupling coefficient is estimated by fixing the arrival direction and the amplitude / phase deviation. The direction of arrival wave estimating device according to any one of claims 1 to 4, wherein the deviation amount is obtained by repeatedly executing the above until the estimation result converges. 7. The arriving wave direction estimating device includes one or a plurality of radio wave transmitting devices for calculating a deviation amount, and a radio wave transmitting position of the radio wave transmitting device is determined by the arriving wave estimating device. 2. The arriving wave direction estimating apparatus according to claim 1, wherein a direction relative to the arriving wave direction is known. 8. The correction amount calculating means uses an incoming signal of a radio wave arriving from a known direction emitted from the transmitting device to fix an arrival direction and a mutual coupling coefficient and to calculate an amplitude / phase deviation in step 1. Estimating, as step 2, estimating the mutual coupling coefficient by fixing the arrival direction and amplitude / phase deviation, and repeatedly executing the processing of steps 1 and 2 until the estimation result converges, thereby obtaining the deviation amount The direction-of-arrival-wave estimation apparatus according to claim 7, characterized in that: 9. The correction amount calculating means has a correction amount storage device, and stores a deviation amount obtained every time a deviation amount is calculated in the correction amount storage device to update the storage content. The arriving wave direction estimating device according to claim 1. 10. The arriving wave direction according to claim 9, wherein the correction amount calculating means predicts the next deviation amount by using the past deviation amount stored in the correction amount storage device. Estimation device. 11. The apparatus according to claim 9, wherein the correction amount calculating means uses a past deviation amount stored in the correction amount storage device to predict a next deviation amount by linear interpolation. Arrival wave direction estimation device. 12. The incoming wave direction according to claim 9, wherein the correction amount storage device stores both the deviation amount calculated by the correction amount calculation device and the outside air temperature at that time. Estimation device. 13. The apparatus according to claim 9, wherein the correction amount storage device stores both the deviation amount calculated by the correction amount calculation device and the temperature around the reception analog unit at that time. Arrival wave direction estimation device. 14. The correction amount storage device stores a deviation amount calculated by the correction amount calculation means, a time at that time,
The arrival wave direction estimating apparatus according to claim 9, wherein both the date and time are stored. 15. A method for estimating a direction of arrival of a radio wave based on a plurality of reception signals corresponding to each antenna element, wherein the radio wave is received by a plurality of antenna elements. For the received signal obtained by the above, the deviation of the pass characteristic between the receiving systems until the received signal is obtained from each antenna element and the deviation of the received signal caused by the leakage of the signal from the other receiving system for each antenna. Correcting, and estimating the direction of arrival of the radio wave using the corrected received signal.