CN103312346A - Null-steering antenna - Google Patents

Abstract

The invention relates to a null-steering antenna. Input signals of an antenna radiation unit are switched from a high frequency band to a low microwave frequency band by using a down converter; a part of energy is coupled out of each channel of the antenna, a channel in which signals exist is selected via a switch matrix, signals are acquired after orthogonalization, and estimation of the direction of arrival of signals is realized by using multiple signal classification; and a weight is calculated according to the measuring result of the direction of arrival via a conformal null-steering algorithm, and wide-frequency-band null-steering wave beams are formed on the low microwave frequency band by using a microwave weight network. In a direction of arrival detection working mode, the null-steering antenna can be used for actively positioning an incoming wave signal direction; and in a wave beam in-orbit reconstruction working mode, real-time reconstruction of wave beams is realized for the null-steering antenna by using the microwave weight network, so that the flexibility and anti-jamming capabilities of wave beams are further enhanced.

Description

A kind of Nulling antenna

Technical field

The present invention relates to a kind of smart antenna, particularly a kind of Nulling antenna with direction of arrival estimation, zeroing, wave beam reconstruct, passage amplitude and phase error correction ability.

Background technology

Nulling antenna is a kind of form of smart antenna.Smart antenna is comprised of a lot of antenna radiation units, and the feedback of each radiating element to form specific wave beam, realizes beam scanning, enhancing or zeroing with the signal of certain amplitude and phase place (being referred to as amplitude weights and phase place weights).Generally speaking, by the amplitude regulator of control connection radiating element needed wave beam is regulated and formed to the radiating element signal amplitude, by the phase regulator that changes linkage unit the phase place of cell signal is controlled to realize beam scanning.

Smart antenna need to be at certain direction of arrival (Direction of Arrival, when DOA) carrying out wave beam enhancing or zeroing, amplitude weights and phase place weights according to adaptive each radiating element of calculating of direction of arrival, then the weights network (amplitude regulator and phase regulator) that is connected with each radiating element by control is realized the width of cloth phase weights of needs, obtains wave beam enhancing or zeroing directional diagram in the direction of expecting.Present Nulling antenna or incoming wave returned to zero, or incoming wave is strengthened does not have and can return to zero to incoming wave, can carry out to incoming wave again that wave beam strengthens or the ability of wave beam reconstruct.In addition, when the working frequency range of antenna at Ka during with super band, the realization difficulty of high-precision weights network (amplitude regulator and phase regulator) increases.

Smart antenna has dual mode to the zeroing of incoming wave signal, and a kind of is closed-loop fashion, and another kind is open loop approach.Closed-loop fashion does not need to know wave line of propagation, directly incoming wave is returned to zero by the mode that iterates, until come intensity of wave to drop to the level that system can stand.Open loop approach is carried out first the estimation of direction of arrival to incoming wave, the zeroing weights that then obtain on the direction of arrival according to the direction of estimating return to zero with realization.Generally do not consider conformal during zeroing, the directional diagram after the zeroing rises and falls large, can cause the change in signal strength in the service area large.

Owing to having error between the width of cloth of actual each passage of the Nulling antenna phase, can worsen the performance of Nulling antenna.Therefore, need to proofread and correct the amplitude phase error of each passage of Nulling antenna.Error correction is divided into interior correction and outer correction two large class methods.When the working frequency range of antenna reaches the Ka frequency range when above, because the restriction of antenna radiation unit and channel size, interior bearing calibration is difficult to realize, generally adopts outer bearing calibration.The error of bringing in order to reduce bearing calibration self, outer bearing calibration General Requirements are proofreaied and correct distance between antenna and the radiating element at 200 more than the wavelength.When limited space that antenna is installed, this requirement is unappeasable, and therefore general outer bearing calibration is no longer applicable.

Summary of the invention

The object of the invention is to overcome the above-mentioned deficiency of prior art, a kind of new Nulling antenna is provided, reduce on the one hand the realization difficulty of high accuracy weights network, the fluctuating of directional diagram in the rear service area reduces to return to zero, make outer bearing calibration no longer be subjected to the restriction in space, make on the other hand Nulling antenna have simultaneously direction of arrival estimation, zeroing and wave beam re-configurability, further strengthen flexibility and the interference free performance of Nulling antenna, have widely applicability and application value.

Above-mentioned purpose of the present invention mainly is achieved by following technical solution: a kind of Nulling antenna comprises antenna array, a N low-converter, a N coupler, (N+1) * M switch matrix, signal orthogonalization device, A/D collector, processor, microwave weights network, beam forming network, composite signal coupler, calibration signal source, boresight antenna that N radiating element forms; The mode of operation of processor control Nulling antenna comprises that zeroing mode of operation, direction of arrival testing pattern, wave beam are in rail reconstruct mode of operation; Wherein:

Under the zeroing mode of operation: the antenna array of N radiating element composition receives external high band microwave signal and is delivered to N low-converter, and N low-converter is transformed to the low-frequency range microwave signal with the high band microwave signal that receives respectively; N coupler is divided into two parts with the microwave signal after the down-conversion respectively, part input microwave weights network, and another part inputs to the 1st～a N input port of (N+1) * M switch matrix; (N+1) * the M switch matrix selects the signal of a noisy M passage, gives the signal orthogonalization device with it from N passage; The signal orthogonalization device carries out orthogonalization with the signal of each passage of M passage, forms M to i/q signal, and is transferred to the A/D collector; After gathering, 6 pairs of i/q signals of A/D collector give processor; Processor is the direction of arrival of estimated disturbance signal at first, forms then according to the definite zeroing of the interference radiating way of estimating wave beam formation weights, and with wave beam and gives microwave weights network after weights deduct passage width of cloth phase distribution error; The signal that microwave weights network is sent coupler here is given beam forming network after microwave frequency band is weighted; The microwave signal of beam forming network after with weighting forms the zeroing wave beam of expectation in its delivery outlet stack, this wave beam is through the straightthrough port output of synthetic signal coupler;

Direction of arrival testing pattern: the antenna array of N radiating element composition receives external high band microwave signal; N low-converter is transformed to the high band microwave signal microwave signal of low-frequency range; The microwave signal of N coupler after with frequency conversion inputs to (N+1) * M switch matrix; (N+1) * the M switch matrix selects the signal of M passage, gives the signal orthogonalization device with it from N passage; The signal orthogonalization device carries out orthogonalization with the signal of each passage of M passage, forms M to i/q signal, and is transferred to the A/D collector; The A/D collector to I Q signal give processor after gathering; Processor is estimated the signal direction of arrival;

Wave beam is in rail reconstruct mode of operation: the antenna array that N radiating element forms receives external high band microwave signal and exports respectively N low-converter to; Each low-converter is transformed to microwave signal than low-frequency range with the high band microwave signal; N coupler inputs to the microwave signal after the frequency conversion respectively microwave weights network; Processor deducts passage width of cloth phase distribution error with predetermined wave beam at rail reconstruct weights and gives microwave weights network; The signal that microwave weights network is sent coupler here is given beam forming network after microwave frequency band is weighted; The signal of beam forming network after with weighting forms the reconstruct wave beam of expectation in its delivery outlet stack, this wave beam is through the straightthrough port output of synthetic signal coupler.

The definite of described passage width of cloth phase distribution error enters calibration mode of operation by processor selection, obtains under calibration mode of operation, and detailed process is as follows:

Calibration signal source sends calibrating signal by boresight antenna to array element; The antenna array of N radiating element composition receives calibrating signal and exports respectively N low-converter to; The microwave signal that each low-converter is transformed to calibrating signal respectively low-frequency range exports coupler to; The microwave signal of coupler after with frequency conversion is divided into two parts, and a part inputs to the 1st～a N input port of (N+1) * M switch matrix; Another part inputs to microwave weights network, microwave weights network is given beam forming network with this part signal, beam forming network is exported to the composite signal coupler with microwave signal, (N+1) input port that the composite signal coupler will be coupled and export to (N+1) * M switch matrix by the composite signal of its coupling aperture; Determine that by processor all passages distribute mutually with respect to the relative Amplitude of the 1st passage coupling output signal, to calibrate again amplitude and phase error that the position difference of an antenna distance N radiating element is brought, in the relative Amplitude of 1～N passage distributes mutually, compensate and normalization, obtain passage width of cloth phase distribution error.

Processor determines that all passages are as follows with respect to the step that the relative Amplitude of the 1st passage coupling output signal distributes mutually under the described calibration mode of operation:

The first step, processor first the microwave weights network of the 1st passage is set to undamped with without the phase shift state, the microwave weights network of other passage is set to the maximum attenuation state;

Second step, (N+1) * the M switch matrix gives the signal orthogonalization device with the coupling output signal of the 1st passage as the coupled signal of reference signal and 12 outputs of composite signal coupler; The signal orthogonalization device carries out orthogonalization with this two-way letter, forms two pairs of i/q signals, and is transferred to the A/D collector; The A/D collector to 2 couples of I Q signal give processor after gathering; Processor carries out the width of cloth to the two paths of signals of A/D collector collection compares, and obtains the 1st passage and distributes mutually with respect to the relative Amplitude of the 1st passage coupling output signal;

The 3rd step, processor then successively the microwave weights network of the 2nd～N passage is set to undamped with without the phase shift state, the microwave weights network of other passage is set to the maximum attenuation state, (N+1) * and the M switch matrix gives the signal orthogonalization device with the coupling output signal of the 1st passage as the coupled signal of reference signal and the output of composite signal coupler; The signal orthogonalization device carries out orthogonalization with this two-way letter, forms two pairs of i/q signals, and is transferred to the A/D collector; The A/D collector to I Q signal give processor after gathering; Processor carries out the width of cloth to the two paths of signals of A/D collector collection compares, and obtains respectively passage 2～N and distributes mutually with respect to the relative Amplitude of the 1st passage coupling output signal.

Described N 〉=3, M 〉=3.

Described low-frequency range is microwave frequency band.

Described microwave weights network is operated in microwave frequency band.

Described (N+1) * M switch matrix is operated in microwave frequency band.

The direction of arrival of described interference signal estimates to adopt multiple signal classification algorithm to realize.

Really it is as follows that zero wave beam of setting the tone under the described zeroing mode of operation forms the weights implementation algorithm:

$\left\{\begin{array}{c}\min \left(\mathrm{\Δ\ϵ}\right)=\min \left\{\right|W-W_q\left|\right\}\\ W^H\mathrm{\β}=0\end{array}\right.$

Wherein, W _qThe weight vector of the microwave weights network when being noiseless the existence claims again static weight vector; β is the unit direction matrix that disturbs angle to form, and W is that zeroing wave beam to be asked forms weights, and weight vector namely returns to zero; W ^HBe the associate matrix of W, △ ε waits to ask zeroing weight vector W and static weight vector W _qBetween the absolute value of error; In glitch-free situation, by changing static weight vector, the needed directional diagram of the signal formation that array received is arrived;

Adopting lagrange's method of multipliers to find the solution the W that obtains is based on conformal (maintenance W _qMinimum change) the resulting zeroing weight vector of design is used W _NullExpression, for:

W _null=(I-β(β ^Hβ) ^-1β ^H)W _q

In the formula, I is the one battle array, β ^HIt is the associate matrix of β.

The present invention compared with prior art beneficial effect is:

(1) the lower microwave frequency band that the high band microwave signal is down-converted to that the present invention proposes carries out the scheme that wave beam forms, both guaranteed the radio frequency operation bandwidth of antenna, reduce again difficulty and complexity (adopting present existing weights network implementation to get final product) that the weights network is realized, and had higher weights realization precision;

(2) the outer bearing calibration that compensates mutually of the space width of cloth that proposes of the present invention, make outer bearing calibration no longer be subjected to the restriction in space, the difficulty that has reduced the outer bearing calibration realization of high band has guaranteed again precision, can promote the use of the passage amplitude and phase error correction of the array antenna of small-scale and limited space, have widely applicability and application value;

(3) the present invention proposes the zeroing scheme of conformal, has reduced the fluctuating of directional diagram in the service area after the zeroing, and the excursion of signal strength signal intensity in the service area is dwindled, and has reduced the difficulty that signal link is realized.

(4) the direction of arrival estimation that proposes of the present invention, zeroing, wave beam make Nulling antenna have greater flexibility and stronger antijamming capability at the multi-operation mode of rail reconstruct.

Description of drawings

Fig. 1 is composition frame chart of the present invention.

Embodiment

Below in conjunction with accompanying drawing antenna of the present invention is described in detail, as shown in Figure 1, specific as follows:

One, antenna structure introduction

Nulling antenna comprises: N antenna array 1, a N low-converter 2, a N coupler 3, (N+1) * M switch matrix 4, signal orthogonalization device 5, A/D collector 6, processor 7, microwave weights network 8, beam forming network 9, composite signal coupler 12, calibration signal source 11, the boresight antenna 10 that radiating element forms; Above-mentioned N 〉=3, M 〉=3.The mode of operation of processor 7 control Nulling antennas comprises that zeroing mode of operation, direction of arrival testing pattern, wave beam are in rail reconstruct mode of operation and calibration mode of operation; Specific implementation under each mode of operation is as follows:

1) under the zeroing mode of operation, the signal of the external high band of antenna array 1 reception that is formed by N radiating element; N low-converter 2 is transformed to microwave signal than low-frequency range (microwave frequency band) with the high band microwave signal; N coupler 3 is divided into two parts with the microwave signal after the down-conversion, part input microwave weights network 8, and another part inputs to (N+1) * M switch matrix 4; (N+1) * M switch matrix 4 selects the signal of a noisy M passage, gives signal orthogonalization device 5 with it from N passage; Signal orthogonalization device 5 carries out orthogonalization with the signal of each passage of M passage, forms M to i/q signal, and is transferred to A/D collector 6; 6 couples of I of A/D collector Q signal give processor 7 after gathering; The multiple signal classification method (Multiple Signal Classification, MUSIC) of utilizing processor 7 realizes the estimation to interference signal direction of arrival (Direction of Arrival, DOA); Utilize the nulling algorithm of conformal to calculate the zeroing wave beam according to interference radiating way again and form weights, and wave beam is formed weights give microwave weights network 8; The signal that microwave weights network 8 is sent coupler 3 here carries out giving beam forming network 9 after the weighting of width of cloth phase at microwave frequency band; Beam forming network 9 forms the microwave signal after the weighting zeroing wave beam of expectation in its delivery outlet stack, and through synthesizing the straightthrough port output of signal coupler 12.

2) under the direction of arrival testing pattern, the antenna array 1 that is comprised of N radiating element receives extraneous signal; N low-converter 2 is transformed to microwave signal than low-frequency range with the high band microwave signal; N coupler 3 inputs to (N+1) * M switch matrix 4 with the microwave signal after the frequency conversion; (N+1) * M switch matrix 4 selects the signal of M passage, gives signal orthogonalization device 5 with it from N passage; Signal orthogonalization device 5 carries out orthogonalization with the signal of each passage of M passage, forms M to i/q signal, and is transferred to A/D collector 6; 6 couples of I of A/D collector Q signal give processor 7 after gathering; The multiple signal classification method (Multiple Signal Classification, MUSIC) of utilizing processor 7 realizes the estimation to signal direction of arrival (Direction of Arrival, DOA).

3) wave beam is under rail reconstruct mode of operation, and the antenna array 1 that is comprised of N radiating element receives extraneous signal; N low-converter 2 is transformed to microwave signal than low-frequency range with the high band microwave signal; N coupler 3 inputs to microwave weights network 8 with the microwave signal after the frequency conversion; Processor 7 is given microwave weights network 8 with predetermined wave beam at rail reconstruct weights; After being weighted, the signal that microwave weights network 8 is sent coupler 3 here gives beam forming network 9; Beam forming network 9 forms the signal after the weighting reconstruct wave beam of expectation in its delivery outlet stack, and through synthesizing the straightthrough port output of signal coupler 12.

4) under the calibration mode of operation, calibration signal source 11 sends calibrating signal by boresight antenna 10 to radiating element; The antenna array 1 that is comprised of N radiating element receives calibrating signal; N low-converter 2 is transformed to microwave signal than low-frequency range with the calibrating signal of high band; N coupler 3 is divided into two parts with the microwave signal after the frequency conversion, and a part inputs to the 1st～a N input port of (N+1) * M switch matrix 4; Another part inputs to microwave weights network 8, microwave weights network 8 is given beam forming network 9 with this part signal, beam forming network 9 is exported to composite signal coupler 12 with microwave signal, (N+1) input port that composite signal coupler 12 is exported to (N+1) * M switch matrix 4 by its coupling aperture with the part coupling of composite signal; The outer correcting algorithm that processor 7 compensates mutually according to the space width of cloth, amplitude and phase error that the position difference of calibration antenna distance N radiating element is brought, in the relative Amplitude of 1～N passage distributes mutually, compensate and normalization, obtain real passage width of cloth phase distribution error.

Two, algorithm introduction

1, the nulling algorithm of the conformal under the zeroing mode of operation is as follows:

$\left\{\begin{array}{c}\min \left(\mathrm{\Δ\ϵ}\right)=\min \left\{\right|W-W_q\left|\right\}\\ W^H\mathrm{\β}=0\end{array}\right.$

Wherein, W _qThe weight vector of the microwave weights network when being noiseless the existence claims again static weight vector; β is the unit direction matrix that disturbs angle to form, and W is that zeroing wave beam to be asked forms weights, and weight vector namely returns to zero; W ^HBe the associate matrix of W, △ ε waits to ask zeroing weight vector W and static weight vector W _qBetween the absolute value of error; In glitch-free situation, by changing static weight vector, the needed directional diagram of the signal formation that array received is arrived;

Adopting lagrange's method of multipliers to find the solution the W that obtains is based on conformal (maintenance W _qMinimum change) the resulting zeroing weight vector of design is used W _NullExpression, for:

W _null=(I-β(β ^Hβ) ^-1β ^H)W _q

In the formula, I is the one battle array, β ^HIt is the associate matrix of β.

2, the external calibration algorithm that compensates mutually of the space width of cloth under the calibration mode of operation is as follows:

Distance between boresight antenna and the antenna array (being the antenna array that N radiating element forms) does not satisfy the general desired condition that is not less than 200 wavelength of outer correcting algorithm; Physical distance between boresight antenna phase center and the radiating element phase center is accurately known, is respectively d _j(j=1～N), the spatial extent that it brings and phase error are:

$\mathrm{\Δ}{A}_j=20\log \left(\frac{d_j}{\mathrm{\λ}}\right)-20\log \left(\frac{d_1}{\mathrm{\λ}}\right),i=1~N$

Open calibration signal source, the weights phase and magnitude of the microwave weights network of j passage all is set to 0 (being undamped without phase shift), the microwave weights network amplitude of other passage is set to maximum attenuation or closes, utilize (N+1) * M switch matrix to give the signal orthogonalization device with the coupling output signal (as the reference signal) of the 1st passage with the coupled signal of composite signal coupler output, obtained real, the imaginary part of the coupler output signal of the 1st passage by the A/D collector

And real, the imaginary part of j channel signal

Calculate j channel signal poor with respect to the phase and magnitude of the coupler output signal of the 1st passage:

$B_1=\sqrt{{\left(A_1^I\right)}^2+{\left(A_1^Q\right)}^2}$

${\mathrm{\φ}}_1=\mathrm{arctg}\left(\frac{A_1^Q}{A_1^I}\right)$

$B_j=\sqrt{{\left(A_j^I\right)}^2+{\left(A_j^Q\right)}^2},j=1~N$

${\mathrm{\φ}}_j=\mathrm{arctg}\left(\frac{A_j^Q}{A_j^I}\right),j=1~N$

ΔB _j=20log(B _j)-20log(B ₁) j=1～N

In the formula, B ₁, φ ₁, B _j, φ _jBe respectively the coupling output signal of the 1st passage and the amplitude of synthetic wave beam coupled signal (unit is dB) and phase place (unit for °); Δ B _j, Δ φ _jBe respectively j channel signal poor with respect to the phase and magnitude of the coupling output signal of the 1st passage.

The space amplitude phase error that physical distance between boresight antenna phase center and the radiating element phase center is brought compensates, and obtains each passage poor with respect to the normalization phase and magnitude of the 1st passage, and algorithm is as follows:

ΔB _j—Nor=ΔB _j-ΔA _j j=1～N

In the formula, Δ B _J-Nor, Δ φ _J-Nor, to be respectively j channel signal poor with respect to the normalization phase and magnitude of the 1st passage.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (9)

1. a Nulling antenna is characterized in that: comprise antenna array (1), a N low-converter (2), a N coupler (3), (N+1) * M switch matrix (4), signal orthogonalization device (5), A/D collector (6), processor (7), microwave weights network (8), beam forming network (9), composite signal coupler (12), calibration signal source (11), boresight antenna (10) that N radiating element forms; The mode of operation of processor (7) control Nulling antenna comprises that zeroing mode of operation, direction of arrival testing pattern, wave beam are in rail reconstruct mode of operation; Wherein:

Under the zeroing mode of operation: the antenna array (1) of N radiating element composition receives external high band microwave signal and is delivered to N low-converter (2), and N low-converter (2) is transformed to the low-frequency range microwave signal with the high band microwave signal that receives respectively; N coupler (3) is divided into two parts with the microwave signal after the down-conversion respectively, part input microwave weights networks (8), and another part inputs to the 1st～a N input port of (N+1) * M switch matrix (4); (N+1) * M switch matrix (4) selects the signal of a noisy M passage, gives signal orthogonalization device (5) with it from N passage; Signal orthogonalization device (5) carries out orthogonalization with the signal of each passage of M passage, forms M to i/q signal, and is transferred to A/D collector (6); After gathering i/q signal, gives by A/D collector (6) processor (7); Processor (7) is the direction of arrival of estimated disturbance signal at first, forms then according to the definite zeroing of the interference radiating way of estimating wave beam formation weights, and with wave beam and gives microwave weights network (8) after weights deduct passage width of cloth phase distribution error; The signal that microwave weights network (8) is sent coupler (3) here is given beam forming network (9) after microwave frequency band is weighted; Beam forming network (9) forms the microwave signal after the weighting zeroing wave beam of expectation in its delivery outlet stack, this wave beam is through the straightthrough port output of synthetic signal coupler (12);

Direction of arrival testing pattern: N the external high band microwave signal of antenna array (1) reception that radiating element forms; N low-converter (2) is transformed to the high band microwave signal microwave signal of low-frequency range; N coupler (3) inputs to (N+1) * M switch matrix (4) with the microwave signal after the frequency conversion; (N+1) * M switch matrix (4) selects the signal of M passage, gives signal orthogonalization device (5) with it from N passage; Signal orthogonalization device (5) carries out orthogonalization with the signal of each passage of M passage, forms M to i/q signal, and is transferred to A/D collector (6); 6 couples of I of A/D collector Q signal give processor (7) after gathering; Processor (7) is estimated the signal direction of arrival;

Wave beam is in rail reconstruct mode of operation: the antenna array (1) that N radiating element forms receives external high band microwave signal and exports respectively N low-converter (2) to; Each low-converter (2) is transformed to microwave signal than low-frequency range with the high band microwave signal; N coupler (3) inputs to the microwave signal after the frequency conversion respectively microwave weights network (8); Processor (7) deducts passage width of cloth phase distribution error with predetermined wave beam at rail reconstruct weights and gives microwave weights network (8); The signal that microwave weights network (8) is sent coupler (3) here is given beam forming network (9) after microwave frequency band is weighted; Beam forming network (9) forms the signal after the weighting reconstruct wave beam of expectation in its delivery outlet stack, this wave beam is through the straightthrough port output of synthetic signal coupler (12).

2. a kind of Nulling antenna according to claim 1 is characterized in that: the determining of described passage width of cloth phase distribution error enters calibration mode of operation by processor (7) selection, obtains under calibration mode of operation, and detailed process is as follows:

Calibration signal source (11) sends calibrating signal by boresight antenna (10) to array element; The antenna array (1) of N radiating element composition receives calibrating signal and exports respectively N low-converter (2) to; The microwave signal that each low-converter (2) is transformed to calibrating signal respectively low-frequency range exports coupler (3) to; Coupler (3) is divided into two parts with the microwave signal after the frequency conversion, and a part inputs to the 1st～a N input port of (N+1) * M switch matrix (4); Another part inputs to microwave weights network (8), microwave weights network (8) is given beam forming network (9) with this part signal, beam forming network (9) is exported to composite signal coupler (12) with microwave signal, (N+1) input port that composite signal coupler (12) will be coupled and export to (N+1) * M switch matrix 4 by the composite signal of its coupling aperture; Determine that by processor (7) all passages distribute mutually with respect to the relative Amplitude of the 1st passage coupling output signal, to calibrate again amplitude and phase error that the position difference of an antenna distance N radiating element is brought, in the relative Amplitude of 1～N passage distributes mutually, compensate and normalization, obtain passage width of cloth phase distribution error.

3. a kind of Nulling antenna according to claim 2 is characterized in that: processor under the described calibration mode of operation (7) determines that all passages are as follows with respect to the step that the relative Amplitude of the 1st passage coupling output signal distributes mutually:

The first step, processor (7) first the microwave weights network of the 1st passage is set to undamped with without the phase shift state, the microwave weights network of other passage is set to the maximum attenuation state;

Second step, (N+1) * M switch matrix (4) gives signal orthogonalization device (5) with the coupling output signal of the 1st passage as the coupled signal of reference signal and composite signal coupler (12) output; Signal orthogonalization device (5) carries out orthogonalization with this two-way letter, forms two pairs of i/q signals, and is transferred to A/D collector (6); A/D collector (6) to 2 couples of I Q signal give processor (7) after gathering; The two paths of signals that processor (7) gathers A/D collector (6) carries out the width of cloth compares, and obtains the 1st passage and distributes mutually with respect to the relative Amplitude of the 1st passage coupling output signal;

The 3rd step, processor (7) then successively the microwave weights network of the 2nd～N passage is set to undamped with without the phase shift state, the microwave weights network of other passage is set to the maximum attenuation state, (N+1) * and M switch matrix (4) gives signal orthogonalization device (5) with the coupling output signal of the 1st passage as the coupled signal of reference signal and composite signal coupler (12) output; Signal orthogonalization device (5) carries out orthogonalization with this two-way letter, forms two pairs of i/q signals, and is transferred to A/D collector (6); 2 couples of I of A/D collector Q signal give processor (7) after gathering; The two paths of signals that processor (7) gathers A/D collector (6) carries out the width of cloth compares, and obtains respectively passage 2～N and distributes mutually with respect to the relative Amplitude of the 1st passage coupling output signal.

4. Nulling antenna according to claim 1 is characterized in that: described N 〉=3, M 〉=3.

5. Nulling antenna according to claim 1, it is characterized in that: described low-frequency range is microwave frequency band.

6. Nulling antenna according to claim 1, it is characterized in that: microwave weights network (8) is operated in microwave frequency band.

7. Nulling antenna according to claim 1 is characterized in that: (N+1) * and M switch matrix (4) is operated in microwave frequency band.

8. Nulling antenna according to claim 1 is characterized in that: the direction of arrival estimation employing multiple signal classification algorithm realization of described interference signal.

9. Nulling antenna according to claim 1 is characterized in that: it is as follows that zero wave beam of really setting the tone under the described zeroing mode of operation forms the weights implementation algorithm:

$\left\{\begin{array}{c}\min \left(\mathrm{\Δ\ϵ}\right)=\min \left\{\right|W-W_q\left|\right\}\\ W^H\mathrm{\β}=0\end{array}\right.$

Wherein, W _qThe weight vector of the microwave weights network when being noiseless the existence claims again static weight vector; β is the unit direction matrix that disturbs angle to form, and W is that zeroing wave beam to be asked forms weights, and weight vector namely returns to zero; W ^HBe the associate matrix of W, Δ ε waits to ask zeroing weight vector W and static weight vector W _qBetween the absolute value of error; In glitch-free situation, by changing static weight vector, the needed directional diagram of the signal formation that array received is arrived;

Adopting lagrange's method of multipliers to find the solution the W that obtains is based on conformal (maintenance W _qMinimum change) the resulting zeroing weight vector of design is used W _NullExpression, for:

W _null=(I-β(β ^Hβ) ^-1β ^H)W _q

In the formula, I is the one battle array, β ^HIt is the associate matrix of β.