JPH10288659A - Interference-wave suppressing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to suppress interference waves by forming the null beam, which satisfies the requirement in each direction of an arbitrary specified liquid and an unwanted wave, by obtaining the ideal common variance matrix from an unwanted-wave arriving angle and computing the optimum load vector. SOLUTION: K pieces of arriving waves, which have arrived to an m<th> element antenna 1 undergo phase detection. Thereafter, an anglemeasuring-signal processor 8 computes the arriving angles (θ1 , θ2 ...θk ) of the K pieces of the arriving waves. The optimum load is computed in an optimum-load operating part 20 from the arriving angle 9, and an optimum load vector 12 is outputted. A signal synthesizer 14 forms the null-beam antenna pattern. At this time, in the optimum-load operating part 20, an operator 23 obtains the matrix, which is constitued of the steering vectors of M rows and K-1 lines having the antenna information in the directions of (K-1) pieces of unnecessary-wave arriving angles 22. Then, an operator 25 obtains the ideal common variance matrix from the output of the operator 23 and the unit matrix of M rows and M lines. The optimum load vector of M rows and one line is computed by both outputs of the operator 15 and the operator 25 in an operator 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interference wave suppressing apparatus for extracting a specific radio wave by suppressing an antenna gain in an unnecessary wave direction from a plurality of incoming waves and maintaining an antenna gain in a desired wave direction. About.

[0002]

2. Description of the Related Art In a radio wave monitoring system for controlling a rapidly increasing number of illegal or illegal radio stations, among the arrival directions of a plurality of radio waves in the same frequency band radiated from a plurality of radio sources,
As an interference wave suppression processing method for suppressing a radio wave from an unnecessary radio source and specifying a desired radio source, for example, an antenna gain in a direction of arrival of a desired radio source is maintained, and a null beam antenna is provided for the arrival direction of the unnecessary radio source. A null beam forming method for forming a pattern is used.

Here, as a method of forming a null beam, a principle of a method of determining a load of an array antenna based on a least-squares method with constraints will be described.

FIG. 6 is a diagram showing a conventional interference wave suppressing device, wherein 1 is an element antenna, 2 is an RF amplifier / filter, 3
Is a local oscillator, 4 is a mixer, 5 is an IF amplifier / filter, 6 is an A / D converter, 7 is a phase detector, 8 is an angle measurement signal processor, and 9 is an output from the 8 angle measurement signal processor. Angle of arrival, 10 is a branch reception signal output from the 7 phase detector, 11 is an optimal load calculator A, 12 is an optimal load vector output from the 11 optimal load calculator A, 13
Is a branch signal of the IF output received signal from the IF amplifier / filter of 5, and 14 is a signal synthesizer.

Next, the operation will be described. The symbols used here are defined below. k is an incoming wave number, K is the number of incoming waves, m is an element antenna number, M is the number of element antennas, and K <M. Further, the M element antennas are arbitrarily arranged.

In FIG. 6, K arriving waves arriving at the m-th element antenna 1 from K radio wave sources (not shown) are output from the reception channel by the phase detector 7 in phase detection. In the angle measurement signal processor 8, K
The angle of arrival of each arriving wave is calculated, and the optimum load calculator A1
In step 1, the optimum load is calculated. In the signal combiner 14, the optimal load vector 12 and the IF branch signal 1
3, the antenna gain in the direction of arrival of the desired radio source is maintained, a null beam antenna pattern is formed in the direction of arrival of the unnecessary radio source, and finally the interference wave is suppressed and the desired specific radio wave is suppressed. Extract.

[0007] Here, the angle measuring signal processor 8 is provided with a known paper, Schmidt, "Multiple Emitt".
er Location and Signal Pa
meter Estimation ”, IEEE
Trance, AP-34, 3, pp. 276-280
(1986). The MUSIC algorithm disclosed in US Pat.

FIG. 7 shows the processing contents of the optimum load calculator A11. In the figure, reference numeral 15 denotes a computing unit A for calculating a steering vector of M rows and 1 column having antenna information of a desired wave direction among the K arrival angles calculated by the angle measurement signal processor 8, and 16 denotes a branch signal. Arithmetic units B and 17 for obtaining the received signal covariance matrix of M rows and M columns from 10 are arithmetic units for calculating an optimal load vector based on the least-squares method with constraints from the output of the arithmetic unit A15 and the output of the arithmetic unit B16. C.

Next, FIG. 8 shows the processing contents of the signal synthesizer 14. In the figure, 18 is the optimal load vector 1
2 multiplied by the IF branch signal 13
Reference numeral 9 denotes an arithmetic unit D that combines the M signals output from the mixer B18 to form a null beam antenna pattern.

[0010]

However, in the conventional null beam forming method as described above, a null beam satisfying the requirements may not be formed depending on the desired wave direction and the unnecessary wave direction, and the interference wave cannot be suppressed well. There was a problem.

The present invention solves the above-mentioned problems. The present invention solves the problem that the covariance matrix is obtained by using the actual received signal in the optimal load calculation. By finding the ideal covariance matrix using the steering vector with information and calculating the optimal load vector based on the constrained least squares method, a null beam that satisfies the requirements in any desired wave direction and unnecessary wave direction can be obtained. It is formed and intended to suppress interference waves.

[0012]

According to a first aspect of the present invention, there is provided an interference wave suppressing apparatus comprising: a receiving element; a receiver connected to the receiving element; and an A / D converter connected to the receiver. And m is a number from 1 to M, and the output signals of the m-th reception channel are divided into two, and the phases are shifted by π / 2 from each other. An m-th phase detector for performing phase detection, a digital signal output from each of the M phase detectors, and an angle measurement signal processor for estimating arrival directions of a plurality of incident waves; The processor inputs the estimated arrival angle values of the plurality of incident waves output from the processor and calculates an M-column optimal load vector for holding the antenna gain in the arrival direction of the desired wave and suppressing the antenna gain in the arrival direction of the unnecessary wave. An optimal load calculator and the M
Null beam that holds the antenna gain in the direction of arrival of the desired wave and suppresses the antenna gain in the direction of arrival of the unwanted wave by combining and multiplying the output signals of the number of reception channels by the optimum weight vector of the M columns output by the optimum weight calculator. And a signal synthesizer for forming an antenna pattern.

Further, the interference wave suppression device of the second invention uses an optimum load calculation device for performing the optimum load calculation by generating pseudo noise as the optimum load calculation device of the interference wave suppression device of the first invention. It was what was.

Further, the interference wave suppressing apparatus according to the third invention uses an optimum load calculator provided with a calculator for normalizing the M columns of optimum load vectors as the optimum load calculator. .

The interference wave suppression device according to a fourth aspect of the present invention is an optimal load arithmetic unit that performs an optimal load operation by generating pseudo noise to perform an operation for normalizing an M column optimal load vector. This uses an optimum load calculator provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a diagram showing Embodiment 1 of the present invention. The difference between Embodiment 1 of the present invention and FIG. 6 showing a conventional example is that the antenna gain of the desired wave arrival direction is maintained and the unnecessary wave arrival direction is maintained. In the optimal load calculation process for forming a null beam antenna pattern that suppresses the antenna gain of the antenna, the covariance matrix was calculated from the actual received wave received signal, and then the optimal load vector was calculated. After calculating an ideal covariance matrix from the angle of arrival of, the optimal load vector is calculated.

In the drawing, 1 is an element antenna, 2 is an RF amplifier / filter, 3 is a local oscillator, 4 is a mixer, 5 is an I / O
F amplifier / filter, 6 an A / D converter, 7 a phase detector, 8 an angle measurement signal processor, 9 an angle of arrival output from the angle measurement signal processor 8, 12 an optimal load calculator B20 Is the optimum load vector output from the IF amplifier /
A branch signal of the IF output received signal from the filter 5, and 14 is a signal synthesizer.

Next, the operation of FIG. 1 will be described. The symbols used here are defined below. k is the number of incoming waves, K is the number of incoming waves, m is the element antenna number, M is the number of element antennas, and K <M. Further, the M element antennas are arbitrarily arranged.

In FIG. 1, K arriving waves arriving at the m-th element antenna 1 from K radio sources (not shown) are output from the reception channel by the phase detector 7 in phase detection. In the angle measurement signal processor 8, K
Arrival angles (θ ₁ , θ ₂ ,..., Θ _K ) of the arriving waves are calculated, an optimum load is calculated in the optimum load calculator B20, and the calculated optimum load vector 12 is output.
In the signal combiner 14, the optimal load vector 12
And the branch signal 13 to form a null beam antenna pattern. Here, a configuration diagram of the optimal load calculator B20 is shown in FIG.

In FIG. 2, reference numeral 21 denotes a desired wave arrival angle θ _{S of} the nine K arrival angles (θ ₁ , θ ₂ ,..., Θ _K ), and 22 denotes the nine K arrival angles. Angle (θ ₁ , θ ₂ , ...
, Θ _K ) of (K−1) unwanted wave arrival angles (θ
_{1, θ 2, ···, θ} S-1, θ S + 1, ···, θ K),
23 denotes the (K-1) unnecessary wave arrival angles (θ ₁ ,
_{θ 2, ···, θ S-} 1, θ S + 1, ···, θ K) calculator E for obtaining the direction of the matrix composed of steering vectors M rows K-1 column with antenna information, Numeral 24 denotes an arithmetic unit F constituting a unit matrix of M rows and M columns, and 25 denotes the arithmetic unit E2
3, an arithmetic unit G for obtaining an ideal covariance matrix from the arithmetic unit F24, the output of the arithmetic unit A15 and the arithmetic unit G25.
Calculates the optimal load vector of M rows and 1 column by the computing unit C17 from the output of (1).

Next, the operation of FIG. 2 will be described. First, the 22 (K-1) unwanted wave arrival angles (θ ₁ , θ ₂ ,...)
, Θ _S−1 , θ _{S + 1} ,..., Θ _K )
23, (K-1) unnecessary wave arrival angles (θ ₁ , θ ₂ ,..., Θ _S-1 , θ _{S + 1} ,.
θ _K ) is represented as a matrix composed of M rows and K−1 columns of steering vectors having antenna information in the direction.

[0022]

(Equation 1)

Further, the M-row, 1-column steering vector a (θ _S ) of the desired wave arrival angle θ _{S in} the arithmetic unit A15 is shown in “Equation 2”.

[0024]

(Equation 2)

Next, a unit matrix of M rows and M columns is constructed in the arithmetic unit F24, and is shown in "Formula 3".

[0026]

(Equation 3)

In the arithmetic unit G25, an ideal covariance matrix is obtained from "Equation 1" and "Equation 3" as shown in "Equation 4".

[0028]

(Equation 4)

In the arithmetic unit C17, an optimal load vector of M rows and 1 column is calculated from "Equation 2" and "Equation 4" using the least squares method with the constraint condition, and is shown in "Equation 5".

[0030]

(Equation 5)

Next, the processing contents of the signal combiner 14 of FIG. 8 will be described. In FIG. 8, a reception signal vector of M rows and 1 column is formed from the 13 branch signals, and is shown in "Formula 6".

[0032]

(Equation 6)

From the equations (5) and (6), the mixer B1
In step 8, the optimum load vector is multiplied by the received signal vector, and the arithmetic unit D19 performs a synthesizing process to calculate a null beam antenna pattern.

[0034]

(Equation 7)

Thus, the antenna gain G in the desired wave direction
(Θ _S ), and the antenna gain G (θ
_k ) (k = 1, 2,..., S-1, S + 1,.
K) can be suppressed.

Embodiment 2 FIG. 3 is a block diagram showing a second embodiment of the present invention. In the first embodiment of the present invention, a unit matrix of M rows and M columns is formed. However, as shown in FIG. The same effect as in the first embodiment can be obtained by generating the pseudo noise vector n in the first row and calculating the noise covariance matrix の in the M rows and the M columns by the 27 arithmetic unit H. Equation 8 shows the derivation of the noise covariance matrix.

[0037]

(Equation 8)

Embodiment 3 FIG. 4 is a block diagram showing a third embodiment of the present invention. In the first embodiment of the present invention, signal synthesis is performed after calculating an optimal load vector of M rows and 1 column. As shown in FIG. The same effect as in the first embodiment can be obtained even if the arithmetic unit I28 for performing signal synthesis after normalizing the optimal load vector in the first row is provided. “Equation 9”
The optimal load vector normalized is shown in FIG.

[0039]

(Equation 9)

Embodiment 4 FIG. FIG. 5 is a block diagram showing Embodiment 4 of the present invention. FIG. 5 is a diagram showing Embodiment 2 of the present invention, in which the arithmetic unit I28 is provided, and the signal after standardizing the optimal load vector of M rows and 1 column. Embodiment 1 Even with Synthesis
The same effect as described above can be obtained.

[0041]

According to the first aspect of the invention, a null beam that satisfies the requirements in any desired wave direction and unnecessary wave direction, which is difficult with the conventional interference wave suppressing device, is formed, and the interference wave can be suppressed well.

According to the second invention, even when the noise covariance matrix calculated from the pseudo noise vector is used in place of the unit matrix, it is difficult for the conventional interference wave suppression device to perform the same as in the first invention. A null beam that satisfies the requirements in any desired wave direction and unnecessary wave direction is formed, and the interference wave can be suppressed well.

According to the third invention, even when the optimum load vector is standardized, as in the case of the first invention, the demand in any desired wave direction and unnecessary wave direction, which is difficult with the conventional interference wave suppression device, is obtained. Is formed, and the interference wave can be suppressed well.

According to the fourth aspect, even when the noise covariance matrix calculated from the pseudo noise vector is used in place of the unit matrix and the optimal weight vector is further normalized,
As in the first invention, a null beam satisfying the requirements in any desired wave direction and unnecessary wave direction, which is difficult with the conventional interference wave suppression device, is formed, and the interference wave can be suppressed well.

[Brief description of the drawings]

FIG. 1 is a diagram showing Embodiment 1 of an interference wave suppressing apparatus according to the present invention.

FIG. 2 is a configuration diagram of an optimum load calculator B for explaining an interference wave suppressing apparatus according to Embodiment 1 of the present invention;

FIG. 3 is a configuration diagram of an optimum load calculator B for explaining an interference wave suppressing apparatus according to a second embodiment of the present invention;

FIG. 4 is a configuration diagram of an optimum load calculator B for explaining an interference wave suppressing apparatus according to a third embodiment of the present invention;

FIG. 5 is a configuration diagram of an optimum load calculator B for explaining an interference wave suppressing apparatus according to a fourth embodiment of the present invention;

FIG. 6 is a diagram illustrating a conventional interference wave suppression device.

FIG. 7 is a configuration diagram of an optimum load calculator A for explaining a conventional interference wave suppression device.

FIG. 8 is a diagram showing a signal combiner for explaining a conventional interference wave suppressing apparatus and an interference wave suppressing apparatus according to the present invention.

[Explanation of symbols]

1 element antenna, 2 RF amplifier / filter, 3 local oscillator, 4 mixer A, 5 IF amplifier / filter,
Reference Signs List 6 A / D converter, 7 phase detector, 8 angle measurement signal processor, 9 angle measurement value output from angle measurement signal processor, 10 branch reception signal output from phase detector, 11 optimal load calculator A , 14 signal synthesizer, 15 operation unit A, 16 operation unit B, 17 operation unit C, 18 mixer B, 19 operation unit D, 20 optimum load operation unit B, 23 operation unit E, 24
Computing units F, 25 Computing units G, 26 Pseudo-noise generators, 27 Computing units H, 28 Computing units I.

Claims (4)

[Claims] 1. A first to an M-th reception apparatus comprising a receiving element, a receiver connected to the receiving element, and an A / D converter connected to the receiver. Channel and m
Is a number from 1 to M, the output signal of the m-th reception channel is divided into two, and the m-th phase detector performs phase detection so that the phases are shifted from each other by π / 2, and the M phase detectors Angle measuring signal processor for inputting digital signals output by the respective devices and estimating the arrival directions of a plurality of incident waves,
Optimum load of M columns for inputting the estimated arrival angle values of the plurality of incident waves output by the angle measurement signal processor and holding the antenna gain in the desired wave arrival direction and suppressing the antenna gain in the unwanted wave arrival direction An optimal load calculator for calculating the vector,
By multiplying and combining the output signals of the M reception channels and the M columns of optimum load vectors output by the optimum load calculator, the antenna gain in the desired wave arrival direction is maintained and the antenna gain in the unnecessary wave arrival direction is suppressed. And a signal combiner for forming a null beam antenna pattern. 2. The interference wave suppression device according to claim 1, wherein the optimum load calculator is an optimum load calculator for performing an optimum load calculation by generating pseudo noise. 3. The interference wave suppression device according to claim 1, wherein the optimum load calculator is an optimum load calculator that performs a calculation for normalizing the M columns of optimum load vectors. 4. The optimum load calculator according to claim 1, wherein the optimum load calculator performs an optimum load calculation by generating pseudo noise and performs a calculation for normalizing an optimum load vector of M columns. 2. The interference wave suppression device according to 1.