JPH11326490A - Adaptive antenna device, processing method in this adaptive antenna device and recording medium recording program for practicing this processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adaptive antenna device capable of steadily restraining a jamming signal regardless of weight converging time taken to restrain the jamming signal. SOLUTION: Received signals are once wholly stored in a memory circuit 3 after being digitalized. Data enough to converge a weight related to at least an adaptive beam operation is transferred to a weight operation circuit 4 from the memory circuit 3. Time tt taken for transfer and time taken for an operation of a weight are sped up, and after converging the weight, data on an adaptive beam operation is transferred to an adaptive beam operation circuit 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adaptive antenna device used for a radar device, a radio communication device, or the like and having a function of suppressing an interfering signal, a processing method in the adaptive antenna device, and a program for executing the processing method. The present invention relates to a recording medium on which is recorded.

[0002]

2. Description of the Related Art As an antenna device having a function of effectively suppressing an interference signal, an adaptive antenna device is well known, and by utilizing its characteristics, is widely used as a transmitting / receiving antenna in a radar device.

[0003] Such an adaptive antenna device is
Using a phased array antenna having a plurality of antenna elements, by appropriately setting weights (reception gain, phase, etc.) of each antenna element, and forming a null in the arrival direction of the interference signal, the interference signal is suppressed. There are many things like that.

[0004] The set value of the weight is obtained by performing a predetermined arithmetic processing on the received signal. Although there are various ways of this calculation, in recent years, as the DBF (digital beam forming) technology has developed, the mainstream is to convert a received signal into digital data and obtain a coefficient corresponding to a weight.

FIG. 7A shows the configuration of such an adaptive antenna device in principle. That is, a plurality of antenna elements (not shown) in the array antenna 100
Are converted into digital data by the A / D converter 200, and are subjected to arithmetic processing by the weight arithmetic unit 300, and then the received beam is formed by the beam forming unit 400.

At this time, an output signal is fed back to weight calculating section 300 in order to set the weight to an appropriate value. The weight converges to a certain value each time the number of times of reception signal input has passed, and the level of the interfering signal decreases accordingly. This state is shown in FIG.

By the way, it takes a certain time (convergence time) until the weight values converge and the suppression of the interference signal is completed. Therefore, the interference signal cannot be sufficiently suppressed for the signal received within the convergence time.

[0008] This poses a serious problem in realizing a radar device using the adaptive antenna device. That is, when the target is at a short distance, the timing of receiving the radar reflected wave from the target depends on the convergence time, and the interference signal cannot be sufficiently suppressed with respect to the radar reflected wave.

[0009] Such a decrease in the detection performance in the short range may lead to a loss of the ground target at the time of landing in an aircraft radar, for example, and often causes a fatal defect. is there.

[0010]

As described above, the conventional adaptive antenna apparatus cannot suppress the interference signal until the convergence time of the weight for suppressing the interference signal. For this reason, when used in a radar apparatus, there is a problem that the detection performance in a short range is deteriorated.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide an adaptive antenna device capable of performing steady suppression of a disturbing signal irrespective of a convergence time of a weight for suppressing a disturbing signal, a processing method in the adaptive antenna device, and executing the processing method. It is to provide a recording medium on which a program is recorded.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of synthesizing a plurality of antenna elements and a received signal of each of the plurality of antenna elements by multiplying them by complex weights individually given. Adaptive beam forming means for forming an adaptive beam, and complex weight calculating means for obtaining the complex weight for forming the adaptive beam from received signals of the plurality of antenna elements; and Delay means for delaying the received signal until at least the value of the complex weight calculated by the complex weight calculating means converges and outputting the delayed signal to the adaptive beam forming means.

With this configuration, after the value of the complex weight converges in the complex weight calculating means, the received signal related to the calculation of the weight is again provided to the adaptive beam forming means. That is, it is possible to form an adaptive beam using the weight after convergence as an initial value.

For this reason, it is possible to obtain an adaptive beam in which unnecessary wave components are suppressed from the beginning at the output. When such an adaptive antenna device is used as a transmitting / receiving antenna in a pulse radar device, a clear image can be obtained from the first received pulse.

Also, the present invention provides a plurality of antenna elements, a plurality of analog / digital conversion means for converting respective reception signals of the plurality of antenna elements into digital signals at a predetermined sampling period, and the analog / digital conversion. Storage means for storing the digital signal converted by the means, and adaptive beam forming means for forming the adaptive beam by combining the digital signals transferred from the storage means after multiplying them by complex weights individually given thereto And a complex weight calculating means for obtaining the complex weight for forming the adaptive beam from the digital signal transferred from the storage means; and causing the storage means to transfer the digital signal to the complex weight calculating means. Along with at least this transferred Transfer control means for causing the storage means to transfer the digital signal to the adaptive beam forming means after the value of the complex weight calculated by the complex weight calculation means converges based on the digital signal. And

In the above invention, on the premise of use in a so-called DBF (Digital Beamforming) radar, the reception signals of the respective antenna elements converted into digital signals are temporarily stored in the storage means. Then, the transfer control means causes the complex weight calculation means to transfer the digital signal from the storage means first, and after the complex weight value converges, causes the transfer control means to transfer the digital signal to the adaptive beam forming means. ing.

[0017] Even in this case, it is possible to obtain an adaptive beam in which unnecessary wave components are suppressed from the beginning with complex convergence weights. Further, the present invention is characterized in that the transfer control means repeatedly transmits the digital data to the complex weight calculating means and the adaptive beam forming means at an arbitrary timing.

With this configuration, as time elapses, the digital signals stored in the storage unit are sequentially transferred to the complex weight calculation unit at each pulse emission timing, for example, and the calculation of the complex weight is repeated. Thus, even when the radio wave environment changes and the state (strength, direction, etc.) of the interfering signal changes, the complex weight is updated, so that the unnecessary wave suppressing ability can be always maintained.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1A shows a basic configuration of an adaptive antenna device according to an embodiment of the present invention. In the following description, it is assumed that the pulse radar device is used as a transmission / reception antenna.
In FIG. 1A, the same parts as those in FIG. 6A are denoted by the same reference numerals.

The adaptive antenna apparatus according to the present embodiment guides a received signal converted into digital data to each of weight calculating section 300 and delay section 500, and firstly, weight calculating section 300 causes the weight to converge to a certain value. wait. The delay unit 500 gives the digital data to the beam forming unit 400 after the lapse of the time required for the convergence. Then, the beam forming unit 400 performs beam forming using the converged weight value as an initial value.

FIG. 2 shows a specific configuration of the adaptive antenna device according to the embodiment of the present invention. Received signal X1 received by N antenna elements (not shown)
To XN are converted into reception intermediate frequency signals by frequency converters 11 to 1N, and then converted to reception digital signals DX1 to DXN by analog / digital converters (A / D converters) 21 to 2N, respectively. You.

The received digital signals DX1 to DXN
Is provided to a memory circuit 3 implemented by, for example, a RAM, and all the received digital signals related to one radar pulse transmission are temporarily stored in the memory circuit 3.

Of the stored data, sampling data x1 to xN corresponding to a predetermined sampling interval ts (ie, a plurality of reception data are sampled for one radar pulse transmission) are sent to the weight calculation circuit 4. The data is immediately transferred, and a weight operation is performed.

The complex weight W calculated here is supplied to an adaptive beam calculation circuit 5, where a weighting process is performed on the sampling data x1 to xN related to the weight calculation, and an adaptive beam output L in which an interference signal is suppressed is applied. Is obtained.

Here, a high-speed data transfer path (not labeled) from the memory circuit 3 to the wait operation circuit 4 is used, and at least within a time shorter than the sampling interval ts, the sampling data x1 to xN The transfer to the wait operation circuit 4 is completed. The time required for this transfer is tt. On the other hand, sampling data x1 to x
N is transferred from the memory circuit 3 to the adaptive beam operation circuit 5 at a sampling interval ts.

Next, a specific configuration of the weight calculation circuit 4 and the adaptive beam calculation circuit 5 is shown in FIG. The configuration shown in FIG. 3 substantially follows that shown in Japanese Patent Publication No. 5-25311. The sampling data x1 to xN transferred to the weight calculation circuit 4 are:
It is provided to main beam forming circuit 6 and preprocessor circuit 7. The main beam forming circuit 6 includes N × N operation cells A
(Not shown) are connected in a systolic array manner, and each arithmetic element A performs an arithmetic operation represented by the following equation (1).

[0027]

(Equation 1)

That is, as shown in FIG. 4A, the arithmetic cell A multiplies the beam forming weight W for each of the sampling data x1 to xN by the multiplier A1, and adds the output Yin of the preceding arithmetic cell A to this. The signal is added by the unit A2 and input to the next operation cell A. The output of the operation cell A corresponding to the final stage, that is, the sampling data xN is supplied to the cancellation circuit 8 in FIG.

On the other hand, each of the preprocessor circuits 7
An operation cell B and an operation cell C having the configuration shown in FIG. 4B and FIG. 4C are provided. Operation cell B (7B1-7B
m) includes a normalization unit B1 and a complex conjugate unit B2 connected in series, and outputs the sampled data x1 to xN as they are as output Yout1 and obtains a normalized complex conjugate output Yout2. The calculation formula is represented by the following formula (2).

[0030]

(Equation 2)

The operation cell C (8C11-8CmL) includes a subtractor C1, multipliers C2 and C3, an adder C4, a sampling delay C5, coefficient units C6 and C7, and a limiter C
8 for performing the calculation shown in the following equation (3).

[0032]

(Equation 3)

That is, the arithmetic cell C is provided with a complex weight W of the current sample by a multiplier C3, an adder C4, a sampling delay C5, coefficient units C6 and C7, and a limiter C8.
(N), the multiplier C2 multiplies the output Yout1 (n-1) of the immediately preceding sample by the complex weight W (n-1) of the immediately preceding sample, and multiplies this by the subtractor C1. Output Xout (n-1) is subtracted from sampling data xin (n-1). That is, the operation cell C removes a signal component having a correlation with Yin among components of the input xin.

When these operation cells B and C are connected in a systolic array as shown in FIG. 3, an output similar to that obtained by resolving an input signal by using a so-called Gram-Schmidt orthogonalization method can be obtained. These decomposed signals are applied to each operation cell C (8C11-8C) of the cancellation circuit 8.
CmL).

Then, in the cancellation circuit 8, unnecessary wave components included in each output of the main beam forming circuit 6 are suppressed by the decomposition signal from the preprocessor circuit 7.

In the above process, when the same processing is performed on the plurality of sampling data x1 to xN, the operation cells A,
The values of the B and C internal parameters gradually converge. After the convergence is completed, the transfer of the sampling data x1 to xN to the adaptive beam operation circuit 5 of FIG. 2 is completed.

Thus, the adaptive beam operation circuit 5
In this case, the adaptive beam can be formed from the beginning with the weight value already converged. Thus, in the present embodiment, the received signal is digitized and then all stored in the memory circuit 3 once. Then, data enough to converge at least the weights related to the adaptive beam calculation are transferred from the memory circuit 3 to the weight calculation circuit 4. The time tt required for the transfer and the time required for the calculation of the weight are set to be high-speed so that the data relating to the adaptive beam calculation is transferred to the adaptive beam calculation circuit 5 after the weight has converged.

[0038] With this configuration, an adaptive beam can be formed with the converged value of the weight from the beginning, so that unnecessary wave components can be suppressed for all received signals.

The present invention is not limited to the above embodiment. In the above-described embodiment, the transfer time tt and the sampling interval ts are appropriately set so that the data transfer to the adaptive beam arithmetic circuit 5 is completed after the convergence of the weights. May be provided for exclusive use. This transfer control means is realized as a control function recorded on a recording medium such as a floppy disk or a program memory.

In this transfer control means, for example, FIG.
Is performed according to the flowchart of FIG. That is,
After transferring the sampling data x1 to xN to the weight calculation circuit 4 in step ST51, the value of the weight is directly monitored in step ST52, and after it is determined that the weight has converged, the sampling data x1 is determined in step ST53. To xN may be transferred to the adaptive beam arithmetic circuit 5. Even in this case, since the weight value converged from the beginning can be used, the same effect as described above can be obtained.

Further, as a control function of the transfer control means, the process of FIG. 5 may be repeatedly performed at a predetermined timing. That is, as shown in the time chart of FIG. 6, a plurality of sampled signals sampled at intervals of the pulse emission interval T are divided into several groups, and the processes from data transfer to weight calculation and beam forming are repeated one after another. .

Thus, the value of the weight is reset every predetermined time in accordance with the radio wave environment.
Therefore, it is possible to well follow changes in the radio wave environment, such as changes in the direction of arrival of the interference signal.

Although not shown in the above embodiment, a reflector for reflecting an incoming radio wave and directing the reflected radio wave toward each of the plurality of antenna elements may be provided.
In addition, various modifications can be made without departing from the spirit of the present invention.

[0044]

As described above in detail, according to the present invention, the adaptive beam is formed from the first received data with the converged value of the complex weight, so that the convergence of the weight for suppressing the interfering signal is achieved. It is possible to provide an adaptive antenna device capable of steadily suppressing an interference signal regardless of time, a processing method in the adaptive antenna device, and a recording medium storing a program for executing the processing method. Become.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle configuration and an effect of an adaptive antenna device according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a specific configuration of the adaptive antenna device according to the embodiment of the present invention.

FIG. 3 is a circuit block diagram showing a portion related to weight calculation of the adaptive antenna device according to the embodiment of the present invention.

FIG. 4 is a circuit block diagram showing a configuration of each computation cell of the adaptive antenna device according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a control procedure of a transfer control unit according to another example of the embodiment of the present invention.

FIG. 6 is a diagram showing processing timing in another example of the embodiment of the present invention.

FIG. 7 is a diagram showing a principle configuration of a conventional adaptive antenna apparatus and a state of suppressing an interference signal.

[Explanation of symbols]

Reference Signs List 100 array antenna 200 A / D conversion unit 300 weight calculation unit 400 beam forming unit 500 delay unit 11 to 1N frequency converter 21 to 2N analog / digital converter (A / D converter) 3 Memory circuit 4 ... Weight operation circuit 5 ... Adaptive beam operation circuit X1 to XN ... Reception signal DX1 to DXN ... Reception digital signal x1 to xN ... Sampling data W ... Complex weight L ... Adaptive beam output ts ... Sampling interval tt ... Sampling data x1転 送 xN transfer time required for transfer to the weight calculation circuit 4 A: calculation cell A A1: multiplier A2: adder B (7B1 to 7Bm): calculation cell B B1: standardization unit B2: complex conjugate unit C ( 8C11-8CmL) arithmetic cell C C1 subtractor C2, C3 multiplier C4 adder C ... sample delay unit C6, C7 ... coefficient multiplier C8 ... limiter 6 ... main beam-forming circuit 7 ... preprocessor circuit 8 ... cancellation circuit

Continuing from the front page (72) Inventor Shinichi Takeya No. 1 Komukai Toshiba-cho, Saiyuki-ku, Kawasaki-shi, Kanagawa Inside the Toshiba Komukai Plant

Claims (7)

[Claims] A plurality of antenna elements; an adaptive beam forming unit configured to multiply received signals of the plurality of antenna elements by individually given complex weights and combine them to form an adaptive beam; Complex weight calculating means for obtaining the complex weight for forming the adaptive beam from the received signals of the plurality of antenna elements, and receiving signals from the plurality of antenna elements, at least, calculating by the complex weight calculating means A delay means for delaying the value of the complex weight to be converged and outputting the result to the adaptive beam forming means. 2. The apparatus according to claim 1, further comprising: a plurality of analog / digital conversion means for converting respective reception signals of said plurality of antenna elements into digital signals at a predetermined sampling period, wherein said delay means comprises: Storage means for storing the digital signal converted by the means at least until the value of the complex weight calculated by the complex weight calculation means converges, wherein the weight calculation means is converted by the analog / digital conversion means. Calculating the complex weight from the digital signal obtained by the adaptive beam forming means, the adaptive beam forming means reads the digital signal stored in the storage means, and individually converts the read digital signal into the converged complex signal. That the weight is multiplied and then synthesized. Adaptive antenna apparatus according to claim 1, symptoms. 3. A plurality of antenna elements; a plurality of analog / digital conversion means for converting respective reception signals of the plurality of antenna elements into digital signals at a predetermined sampling cycle; Storage means for storing the converted digital signal; adaptive beam forming means for forming the adaptive beam by multiplying the digital signals transferred from the storage means by complex weights individually given thereto and forming an adaptive beam; From the digital signal transferred from the storage means,
Complex weight calculating means for obtaining the complex weight for forming the adaptive beam, and the storage means for transferring the digital signal toward the complex weight calculating means, and at least, based on the transferred digital signal, An adaptive antenna, comprising: transfer control means for transferring the digital signal to the adaptive beam forming means in the storage means after the value of the complex weight calculated by the complex weight calculation means converges. apparatus. 4. The transmission control unit according to claim 3, wherein the transmission of the digital signal to the complex weight calculation unit and the adaptive beam forming unit is repeated at an arbitrary timing. Adaptive antenna device. 5. The adaptive antenna device according to claim 2, further comprising a reflector that reflects an incoming radio wave and guides the reflected radio wave toward the plurality of antenna elements. 6. An adaptive beam forming means for forming an adaptive beam by multiplying received signals of the plurality of antenna elements by complex weights individually given thereto, and forming an adaptive beam; A complex weight calculating unit for obtaining the complex weight for forming the adaptive beam from the received signals of the plurality of antenna elements, the adaptive weight forming method in the adaptive antenna apparatus, comprising: A first step of determining whether or not the value of the calculated complex weight has converged; and, in the first step, when it is determined that the value of the complex weight has converged, Output to the adaptive beam forming means. Adaptive beamforming method characterized by comprising the steps. 7. A plurality of antenna elements, a plurality of analog / digital conversion means for converting respective reception signals of the plurality of antenna elements into digital signals at a predetermined sampling cycle, and the analog / digital conversion means. Storage means for storing the converted digital signal; adaptive beam forming means for forming the adaptive beam by multiplying the digital signals transferred from the storage means by complex weights individually given thereto and forming an adaptive beam; From the digital signal transferred from the storage means,
A complex weight calculating means for calculating the complex weight for forming the adaptive beam, wherein the processing function in the adaptive antenna device is recorded, wherein the storage means, the digital signal to the complex weight calculating means At least after the value of the complex weight calculated by the complex weight calculating means converges based on the transferred digital signal, the digital signal is sent to the adaptive beam forming means. A recording medium on which a program for executing a transfer control means for causing a transfer is recorded.