JP2000216620A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a receiver that can conduct both of measurement of an azimuth of a plurality of incoming waves with the same frequency and of elimination of a crosstalk wave from a desired wave. SOLUTION: A signal distributor 2 distributes a plurality of signals with the same frequency received by an antenna element group 1 into two, the one signal is given to an azimuth measurement circuit 3 and the other signal is given to a weight control circuit 8 respectively. The azimuth measurement circuit 3 adopts the super decomposition system to measure the azimuth of each signal. Designated azimuth is selected among the results of the measurement of azimuth and given to an input device 6. A weight arithmetic circuit 7 adopts the DCMP method to provide a null to the azimuth value other than the designated azimuth. The weight control circuit 8 receiving the other signal outputs only the signal with the designated azimuth to a synthesizer 9 and a demodulation circuit 5 because a signal other than the designated signal have a null based on the arithmetic result by the weight arithmetic circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver, and more particularly to a receiver having a function of separating a specified one-way signal wave from a plurality of incoming waves.

[0002]

2. Description of the Related Art Using received signals of a plurality of antenna elements,
MUSIC (Multiple Si) is a super-resolution technique for simultaneously measuring the directions of arrival of a plurality of incoming waves of the same frequency.
A general classification method is known. Details of the MUSIC method are described in O. Schm
"Multiple Emitter Lo by Idt
Cation and Signal Paramet
er Estimation ”(IEEE Tran
s. AP-34 (3), 1986).

[0003] The MUSIC method has been applied to an azimuth measuring device in recent years because it can simultaneously measure the number of incoming waves equal to the number of antenna elements minus one.

On the other hand, as a method for suppressing unnecessary waves from among a plurality of received waves received and separating only a desired wave, a plurality of antenna elements are used to process these received signals to determine the direction of arrival of the unnecessary waves. There is an adaptive array technology for forming a zero point of the total directivity of an antenna element.

[0005] The adaptive array has a frequency of an incoming wave,
When the modulation method is known and a reference signal synchronized with the arriving wave can be generated in the receiver, zero points are formed by the least squares method even if the arrival directions of a plurality of unnecessary waves are unknown. can do. However, the zeros that can be formed are generally limited to the number of antenna elements minus one.

If the desired direction of arrival is known, DC
By the MP algorithm, it is possible to form a zero point for an unnecessary wave without a reference signal.

Further, Japanese Patent Application Laid-Open Nos. 1-142479, 61-219202, and 57-1411
No. 02 and Japanese Patent Laid-Open No. 57-20001 disclose techniques relating to an interference separation circuit and an interference elimination circuit.

[0008]

However, the conventional MUS
The azimuth measuring device using the IC method can measure the arrival direction of a desired wave and an unnecessary wave irrespective of the modulation method, but since the demodulated signal contains unnecessary waves, accurate communication information can be obtained. Was difficult to grasp.

On the other hand, the adaptive array based on the least squares method requires a reference signal of the same modulation scheme synchronized with a modulation signal of a desired signal, so that it is difficult to use it in an actual environment where incoming waves of various modulation schemes exist. It is.

An adaptive array based on the DCMP algorithm requires information on the direction of arrival of an incoming wave for storing signals.

As described above, the conventional techniques are proposed independently of the azimuth measurement technique and the demodulated signal interference elimination technique, and are used to measure the azimuth of a plurality of arriving waves of the same frequency and to eliminate the interference wave from the desired wave. A receiving device that can do both has not yet been proposed.

The same applies to the above four prior arts.

SUMMARY OF THE INVENTION An object of the present invention is to provide a receiver capable of performing both azimuth measurement of a plurality of arriving waves of the same frequency and elimination of an interference wave from a desired wave.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a plurality of receiving antennas arranged at arbitrary positions, and a signal distribution means for dividing a high-frequency signal received by these receiving antennas into two. Receiving the high-frequency signal of one of the systems distributed by the signal distribution means, obtaining the covariance matrix of the received signals received by the plurality of antennas, and measuring the azimuths of a plurality of incoming waves based on the matrix. M that outputs a dispersion matrix and direction information of a plurality of incoming waves
Azimuth measuring means using the USIC method, designation signal storage means for storing one azimuth information designated from azimuth information of a plurality of arriving waves obtained as a result of measurement by the azimuth measuring means,
The high-frequency signal of the other system distributed by the signal distribution unit is received, and a weight for suppressing a signal other than one specified direction stored by the specified signal storage unit is calculated based on the covariance matrix. Weighting arithmetic circuit, weighting means for weighting the high-frequency signals received by the plurality of receiving antennas by the weights calculated by the arithmetic circuit, and a signal for synthesizing and outputting the high-frequency signals output from the weighting means And combining means.

[0015]

According to the present invention, a plurality of arriving waves received by a receiving antenna are divided into two by signal distribution means, one of which is input to an azimuth measuring means to measure the azimuth of each arriving wave. You.

Then, a one-way signal designated by the user is stored in the designated signal storage means from the azimuth information of each arriving wave.

On the other hand, the other arriving wave distributed by the signal distributor is weighted by a signal other than the one-way signal specified by the weighting means, that is, a zero point is given, and thereafter the signal includes the specified one-way signal. All signals are synthesized and output by the signal synthesizing means.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a first embodiment of a receiving apparatus according to the present invention.

The receiving apparatus receives a plurality of arriving waves of the same frequency and outputs a high-frequency signal.
An antenna element group 1 composed of a number (n is an integer of 2 or more) of antenna elements, a signal distributor 2 for dividing a high-frequency signal received by the antenna element group 1 into two, and a signal distributor 2 An azimuth measuring circuit 3 to which one of the two signals is input, an interference canceling circuit 4 to which the other signal is input, and a demodulation circuit 5 for demodulating an output signal of the interference canceling circuit 4. .

The interference canceling circuit 4 further includes an input device 6 for storing a signal in one direction designated by a user based on the angle information output from the azimuth measuring circuit 3 and an output from the input device 6. Weight calculation circuit 7 for calculating a weighting value for a signal other than a specified one-way signal based on the signal
And, based on the weight from the weight calculation circuit 7,
A weight control circuit 8 in which a zero point is formed in a signal other than a specified one-way signal of the other signal of the two signals divided by the signal distributor 2, and a signal output from the weight control circuit 8 And a combiner 9 for combining and outputting.

Next, the azimuth measuring circuit 3 will be described.
FIG. 2 is a flowchart showing the operation of the azimuth measuring circuit 3.

The MUSIC method used for the azimuth measuring circuit 3 is based on an antenna element group 1 composed of a plurality of antenna elements.
The reception response (steering vector) for all directions from 0 degrees to 359 degrees is previously measured and stored in a memory (not shown) provided inside the direction measurement circuit 3 (S1). The eigenvalue of the covariance matrix of the received signal received by each antenna element group is obtained (S2), the eigenvector corresponding to the minimum eigenvalue is obtained (S3), and finally the eigenvector corresponding to this minimum eigenvalue and The direction of arrival is estimated from an evaluation function represented by the reciprocal of the square of the Euclidean distance of the steering vector (S4).

Next, the operation of the azimuth measuring circuit 3 will be described in detail. First, a covariance matrix S of received signals x1, x2,..., Xn (n is a positive integer) of each antenna element branched by the signal splitter 1 is calculated.

Received signals x1, x2 of each antenna element
, Xn are represented by a matrix X of n rows and 1 column, a covariance matrix S
Is

[0025]

(Equation 1)

## EQU2 ## Here, the bar (-) indicates the average of the sample values of the received signal, and H indicates the conjugate transpose of X.

Now, let the received signal of the i-th element be xi
If (t) is (t is time), when this is sampled in time series at every Δt seconds, the sampled values are xi (0), xi (Δ
t), xi (2Δt),..., xi ((N−1) Δt). N is the number of samples.

When the sample value of the received signal of the t = 0, n-element array is represented by a vector,

[0029]

(Equation 2)

## EQU2 ## Expressing this as a transposed matrix X ^T ,

[0031]

(Equation 3)

## EQU1 ## Then, the covariance matrix S is

[0033]

(Equation 4)

## EQU1 ## That is,

[0035]

(Equation 5)

## EQU1 ## Here, * indicates a complex conjugate.

Next, the minimum eigenvalue and the maximum
Eigenvector E corresponding to small eigenvalue _N Is calculated.

Next, for each direction,

[0039]

(Equation 6)

The evaluation function E (θ) represented by The reception response (steering vector （(θ); θ is the azimuth) corresponding to each azimuth of the antenna element group 1 is stored in the memory in the azimuth measuring circuit 3 in advance as described above.

FIG. 3 is a waveform diagram showing the calculation result of the evaluation function. For example, when the number of incoming waves is two, the evaluation function E
(Θ) indicates an angle corresponding to the arrival direction, that is, a peak point P1 of the arriving wave 1 appears at an angle θ1, and a peak point P2 of the arriving wave 2 appears at an angle θ2, as shown in FIG. Therefore,
By reading the angle corresponding to the peak point, the arrival direction of the incoming wave can be estimated.

Next, the operation of the interference removal circuit 4 using the adaptive array algorithm will be described. In the present invention, the direction of arrival of the arriving wave is known by the azimuth measuring circuit 3, and the covariance matrix of the received signal of each antenna element is calculated during the azimuth measurement (S2 in FIG. 2) by using the MUSIC method. Therefore, the use of the DCMP algorithm is appropriate.

The DCMP method is based on the principle of minimizing the output power of the array, and protects the desired wave by applying a constraint. For details of the DCMP method, see K.K. "A" by Takano
nAdaptive Array under Dir
electronic Constraint "(IEEE
Trans. AP-24 (5), 1976).

The optimum weight Wopt obtained by the DCMP method is an azimuth constraint in one direction (an incoming wave in which this direction is preserved, and other arriving waves are suppressed by the zero point).

[0045]

(Equation 7)

[0046]

(Equation 8)

Is given by Where C is a constraint matrix, M
Is the restraint response. For example, in the case of an equally-spaced linear array of omni-directional elements, the constraint matrix C is as follows: if the constraint direction is θc, the element interval is d, and the wave number is k.

[0048]

(Equation 9)

[0049]

(Equation 10)

Is represented by When a response of a signal having an amplitude A and a phase φ is desired in an array output with respect to an incoming wave from θc, the constraint response M is

[0051]

[Equation 11]

Is represented by

The element Ψi (θc) of the constraint vector C of the circumferential array of radius D is

[0054]

(Equation 12)

Is represented by

The input device 6 reads the covariance matrix S of the received signal from the azimuth measuring circuit 3 and uses the signal of the azimuth (constraint direction θc) to be preserved among the arriving azimuths obtained by the azimuth measuring circuit 3. The signal of the direction desired to be stored is manually input to the input device 6 by the operator (operator).

The user selects the direction of arrival from the evaluation function E (θ) of Equation 6. The evaluation function E (θ) is an evaluation function as an array, and is not output for each element.

Next, the weight calculation circuit 7 calculates the covariance matrix S
And the constraint weight θc to obtain the optimum weight W according to Equation 7.
Calculate opt.

Next, the weight control circuit 8 controls the amplitude and phase of the received signal input from the signal distributor 2 based on the calculation result of the optimum weight Wopt.

FIG. 4 is a directional characteristic diagram after weight control. The figure shows that a gain is provided in the desired direction (θc) and zeros are formed in other unnecessary directions.

The received signals whose amplitude and phase are controlled are combined by the combiner 9 and input to the demodulator 5. Since the zero point is formed in the input signal to the demodulator 5 in the arrival direction of the unnecessary wave, the unnecessary wave is suppressed, and the output signal of the demodulator 9 is a signal in a designated one direction only.

Next, a second embodiment of the present invention will be described. FIG. 5 is a configuration diagram of the second embodiment. The same components as those in the first embodiment (FIG. 1) are denoted by the same reference numerals, and description thereof will be omitted.

In the first embodiment, the weight is directly applied to the high-frequency signal received by the antenna element group 1. However, if the frequency range of the signal to be received is wide, it is difficult to realize a wide-band weight control circuit.

Therefore, in the second embodiment, a receiver 10 (10-1 to 10-n) for converting a high-frequency signal received by the antenna element group 1 in advance into an intermediate frequency is provided for each antenna element. , The weight of the signal converted to the intermediate frequency is controlled.

In the first embodiment, the azimuth measurement circuit 3 and the demodulation circuit 5 have an intermediate frequency conversion function. However, the azimuth measurement circuit 3 and the demodulation circuit 5 in the second embodiment are excluded from the intermediate frequency conversion function. ing.

The signal converted to the intermediate frequency is supplied to the signal distributor 3
Are distributed to the azimuth measurement circuit 3 and the phase detection circuit 11. The operation of the azimuth measuring circuit 3 is the same as that of the first embodiment, and will not be described.

In the phase detection circuit 11, the intermediate frequency signal from the signal distributor 3 is subjected to quadrature detection, and I and Q video signals (two color difference signals in an NTSC color television).
Is converted to

The I and Q video signals are input to the weight control circuit 8, and the phases and amplitudes of the I and Q video signals are controlled based on the calculation result of the optimum weight Wopt.

The calculation of the optimum weight Wopt is the first
The description is omitted because it is similar to the embodiment.

Next, the I and Q video signals whose phases and amplitudes have been controlled by the combiner 9 are combined, and a video signal of an incoming wave in a designated one direction is output.

Finally, the video signal is demodulated by the demodulation circuit 5.

[0072]

According to the present invention, a high frequency signal received by a plurality of receiving antennas is divided into two by signal distribution means, one of the divided signals is measured by a direction measurement means, and the direction is measured based on the direction information. Since the other distributed signal is weighted by the weighting means, there is an effect that both the azimuth measurement of a plurality of incoming waves of the same frequency and the interference wave removal from the desired wave can be performed by one receiver. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of a receiving device according to the present invention.

FIG. 2 is a flowchart illustrating an operation of the azimuth measuring circuit according to the first embodiment.

FIG. 3 is a waveform chart showing a calculation result of an evaluation function according to the first embodiment.

FIG. 4 is a directional characteristic diagram after weight control of the first embodiment.

FIG. 5 is a configuration diagram of a second embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna element group 2 signal distributor 3 azimuth measuring circuit 4 interference elimination circuit 5 demodulation circuit 6 input device 7 weight calculation circuit 8 weight control circuit 9 combiner 10 receiver 11 phase detection circuit

Claims (3)

[Claims] 1. A plurality of receiving antennas arranged at arbitrary positions, signal distribution means for dividing a high-frequency signal received by these receiving antennas into two, and high-frequency signals of one system distributed by the signal distribution means. Receive the signal, determine the covariance matrix of the received signals received by the plurality of antennas and measure the direction of a plurality of incoming waves based on this,
Azimuth measuring means using the MUSIC method for outputting this covariance matrix and azimuth information of a plurality of arriving waves, and one azimuth designated by azimuth information of a plurality of arriving waves obtained as a result of measurement by the azimuth measuring means. A designation signal storage unit for storing orientation information; and a high-frequency signal of the other system distributed by the signal distribution unit is received, and signals other than the designated one orientation saved by the designation signal storage unit are suppressed. Weighting circuit for calculating a weight for the calculation based on the covariance matrix and the one specified azimuth information, and weighting the high-frequency signals received by the plurality of receiving antennas by the weight calculated by the calculation circuit A receiving apparatus comprising: a weighting unit; and a signal combining unit that combines and outputs a high-frequency signal output from the weighting unit. 2. The receiving apparatus according to claim 1, wherein said weighting means is means for giving a zero point to a signal other than one designated azimuth stored in said designated signal storing means. 3. The receiving apparatus according to claim 1, wherein said weighting means includes a coefficient vector calculating means using an adaptive array algorithm.