CN109188366A - Broadband emission Adaptive beamformer method based on subband maximum signal noise ratio principle - Google Patents

Abstract

Translated fromChinese

本发明公布了一种基于子带最大信噪比准则的宽带发射自适应波束形成方法，包括如下步骤：步骤一、设计宽带发射天线阵列，计算宽带阵列的输出信号；步骤二、设计子带滤波器组；步骤三、利用子带滤波器组中的分析滤波器组完成宽带信号的子带划分；步骤四、基于子带最大信噪比准则计算各个子带自适应波束形成权矢量；步骤五、利用子带滤波器组中的综合滤波器组将经过处理的宽带信号进行重构。本发明方法能够在期望位置形成深度很深且方向不随频率变化的零陷，并且计算量较小，利于工程实现。

The invention discloses a broadband transmission adaptive beam forming method based on the sub-band maximum signal-to-noise ratio criterion, comprising the following steps: step 1, design a broadband transmission antenna array, and calculate the output signal of the broadband array; step 2, design a sub-band filter Step 3, use the analysis filter bank in the subband filter bank to complete the subband division of the broadband signal; Step 4, calculate each subband adaptive beamforming weight vector based on the subband maximum signal-to-noise ratio criterion; Step 5 . The processed wideband signal is reconstructed using the synthesis filter bank in the subband filter bank. The method of the present invention can form a deep-deep null at a desired position and the direction does not change with frequency, and the calculation amount is small, which is favorable for engineering realization.

Description

Broadband emission Adaptive beamformer method based on subband maximum signal noise ratio principle

Technical field

The invention belongs to array signal processing fields, and in particular to a kind of broadband hair based on subband maximum signal noise ratio principlePenetrate Adaptive beamformer method.

Background technique

The null for the interference signal that is used to decay often is placed in receiving end by the adaptive array disposed in modern radar system,Such as hostile interference, it is not intended to which electromagnetic interference or environment clutter etc., the antenna of this scheme is usually on aperture with uniform amplitudeWeighting is sent, to maximize main beam gain.It is this to be gradually improved in radar receiving end signal processing technique, by excellentIt is more and more difficult to change radar return signal Processing Algorithm promotion detection performance, therefore, nearest more and more research institutions areThe technology for the transmitting terminal creation null in radar is developed, benefit is that antenna can apply significant pair to interference signalTo loss.So far, the most of transmitting zero setting algorithms developed are suitable for narrowband application, and assume unlimited phase andAmplitude precision.

Under normal circumstances, weighted value applied by each array element only calculates in the centre frequency of array signal, corresponds toHalf-wave long spacing between array element.In addition, each subsequent phase shifter of array element is only corrected signal center frequency.Therefore,The actual phase shift of the broadband signal of each array element transmitting can be deviated with actual frequency, so as to cause in entire signal bandwidth,The null of transmitting signal can deviate pointing direction.

To solve the above-mentioned problems, Peter G.Vouras proposes a kind of wideband array Robust Transmission zero setting (RobustTransmit Nulling, RTN) beamforming algorithm, the algorithm is maximum in order to make to emit Signal-to-Noise (SINR), derivesSINR function about frequency integrator, and SINR function is solved by being conjugated iterative algorithm, to obtain optimal pumpingHead delay line coefficient.Due to the algorithm conjugation iterative initial value setting there are some problems and iteration step length calculate it is complicated, in order toIt obtains optimal solution, generally requires repeatedly to be conjugated iteration, increase considerably calculation amount, increase the load of system, be unfavorable for workJourney is implemented.

Summary of the invention

The broadband emission Adaptive beamformer method based on subband maximum signal noise ratio principle that the present invention provides a kind of, hairEjected wave beam can form that depth is very deep and direction null not varying with frequency in desired locations, and calculation amount is smaller, is conducive to engineeringIt realizes.

In order to solve the above-mentioned technical problem, using following technical scheme:

Broadband emission Adaptive beamformer method based on subband maximum signal noise ratio principle, includes the following steps:

Step 1: design broadband emission aerial array, calculates the output signal of wideband array；

Step 2: design sub-filter group；

Step 3: completing the sub-band division of broadband signal using the analysis filter group in sub-filter group；

Step 4: calculating each sub-band adaptive Wave beam forming weight vector based on subband maximum signal noise ratio principle；

Step 5: treated broadband signal is reconstructed using the synthesis filter group in sub-filter group.

Further, the broadband emission aerial array is the uniform linear array that element number of array is M, after each array elementFace is the tapped delay line (Tapped Delay Line, TDL) for being equivalent to Discrete Finite impact response filter, TDL systemNumber is J, and the low-limit frequency of the primary output signal x (n) of wideband array is f_L, highest frequency f_H, n=0, ± 1, ± 2 ....

The response of TDL array meets following formula:

Wherein, j is imaginary unit, θ₀For the array signal direction of the launch, ω is numerical frequency, w_m[k] is m-th of array elementThe weighted value of k-th of tap, m=0,1 ..., M-1, k=0,1 ..., J-1, T_sFor the sampling time interval of two neighboring tap,φ is the phase difference that two neighboring array element transmits signal, and φ meets formula:

Wherein, d is array element spacing, and f is instantaneous frequency, and c is the light velocity.

Space is mixed in order to prevent, and d=c/ (2f is arranged_H), in order to avoid being instantaneously mixed, T is set_s=1/ (2f_H)。

The output signal of m-th of array element are as follows:

Wherein, x_mIt (n) is the output signal of m-th of array element, x (n-k) indicates input discrete signal x (n) to left kUnit.

Further, the sub-filter group selects discrete Fourier transform filtering device group (DiscreteFourier Transform Filter Bank, DFTFB), sub-filter group generally includes two groups of filter groups, wherein oneGroup is analysis filter group, and for the decomposition of broadband signal, each way band after decomposing can be carried out individually at required signalReason；Another set is synthesis filter group, for the reconstruct of broadband signal, obtains system after reconstruct treated output letterNumber.

Further, there is Q sub-band processing channel behind each array element, there is an analysis filter in each sub-band processing channelWave device and a synthesis filter.Analysis filter in each subband channel is filtered by the low-pass prototype that a length is PDevice H₀(z) translation obtains, and is f in sample frequency_sWhen, length is the filter H of P_q(z) broadband signal that bandwidth is B can be filteredIt is f at bandwidth_sThe subband signal of/P, therefore the length P=f of filter_s/(B/M).Q-th of Subband Analysis Filter shock responseMeet following formula:

H_q(z)=H₀(zW^q+i) (4)

H₀(z)=1+z^-1+…+z^-(P-1) (5)

Wherein, H_q(z) z-transform of q-th of multichannel analysis filter impulse response, q=1 ..., Q and complex variable z are indicated=e^jω, W=e^-j2π/P, q+i q-th of Subband Analysis Filter of expression is relative to low-pass filter H₀(z) frequency shift (FS), and i=f_L/(B/M)-0.5。

Q-th of sub-band synthesis filter shock response meets following formula:

F_q(z)=W^-(q+i)F₀(zW^q+i) (6)

F₀(z)=1+z^-1+…+z^-(P-1) (7)

Wherein, F_q(z) z-transform of q-th of channel synthesis filter shock response is indicated.

By above formula, it can be concluded that, each synthesis filter and corresponding analysis filter have identical amplitude response, broadbandIt is by sub-band division and reconstruct if signal is the frequency information that will not change original signal by sub-band division and reconstructObtained output signal meets formula:

Y (n)=Qx (n-Q+1) (8)

Wherein, y (n) is the output signal by sub-band division and reconstruct, and x (n-Q+1) indicates discrete signal x (n) to the rightTranslate Q-1 unit.

Further, when the broadband signal direction of the launch is θ₀When, the array steering vector of signal meets formula:

v(θ₀, f) and=[1, exp (j2 π fdsin θ₀/c),…,exp(j2πfd(M-1)sinθ₀/c)]^T (9)

Wherein, []^TFor transposition operator, v (θ₀, f) and the expression direction of the launch is θ₀, frequency be f signal array guideVector.

After analysis filter carries out sub-band division, the tap sampling frequency of TDL is reduced to original 1/Q, subband TDL delayChain vector meets formula:

Steering vector meets formula when relevant to signal frequency empty:

In formula,Indicate the Kronecker product of vector, V_st(θ₀, f) the expression direction of the launch be θ₀, frequency be f sky when leadDraw vector.

Further, if broadband signal bandwidth is uniformly divided into K frequency point by analysis filter, then there is { f₁,f₂,...,f_K}∈[f_L,f_H], signal variance matrix and interference noise covariance matrix meet following formula:

Wherein, []^HFor transposition conjugate operation symbol, R_st-qIt is the signal variance matrix of q-th of subband signal, N_st-qIt is qThe interference noise covariance matrix of a subband signal, K are frequency point sum, V_st-q(θ₀,f_l) expression frequency be f_lWhen sky when guideVector, H_q(f_l) expression frequency be f_lWhen q-th of Subband Analysis Filter frequency response, F_q(f_l) expression frequency be f_lWhen qThe frequency response of a sub-band synthesis filter, β are the power of interference signal, σ²It is the function of zero-mean additive white noise Gaussian processRate, I are unit matrix, θ₀It is main lobe direction, θ₁It is the direction for desirably forming null, f_l∈{f₁,f₂,...,f_KAnd l=1,2,...,K。

Further, the signal-to-noise ratio SINR of q-th of subband signal_qMeet formula:

Wherein, W_qIt is the dimension TDL weight vector of NJ × 1 of q-th of subband signal, works as SINR_qWhen maximum, it is optimal to obtain weight vectorSolution:

Wherein, W_opt-qIt is subband optimal T DL weight vector, λ_maxIt isMaximum eigenvalue, W_opt-qIt is λ_maxIt is correspondingFeature vector.

Further, according to the reconstruct of synthesis filter group, by emitting Adaptive beamformer, m-th of array element outputSignal frequency-domain expression are as follows:

Wherein, Y_m(e^jω) indicate m-th of array element output signal frequency domain, w_qm[k] indicates m-th of array element, q-th of subbandK-th of tap weightings, X (e^jω) indicate original wideband signal frequency domain, H_q(e^jω) indicate that the analysis of q-th of subband filtersThe frequency response of device, F_q(e^jω) indicate q-th of subband synthesis filter frequency response.

Further, the Broadband emission signal launching beam antenna radiation pattern after the reconstruct of synthesis filter group are as follows:

Wherein, P (θ, f) indicates broadband signal launching beam antenna radiation pattern, v_st(θ, f) indicates the broadband signal direction of the launchSteering vector when sky when for θ, frequency being f, H_q(f) frequency response of q-th of Subband Analysis Filter when frequency is f, F are indicated_q(f) frequency response of q-th of sub-band synthesis filter when frequency is f is indicated.

By above-mentioned technological means, following technical effect can be obtained:

The broadband emission Adaptive beamformer method based on subband maximum signal noise ratio principle that the invention discloses a kind of is led toThe full bandwidth covariance matrix and interference noise covariance matrix of Maximum-likelihood estimation (MEL) broadband signal are crossed, based on maximum letterDry make an uproar finds out optimal T DL weight vector than (MSINR) criterion, not only greatly reduces the operand of method, also has good propertyEnergy.It being handled by sub-band division, the deeper null that can be formed in desired direction is stronger to the inhibiting effect of interference, andAnd the tap sampling frequency of TDL is reduced, it is more conducive to Project Realization

Detailed description of the invention

Fig. 1 is the flow chart of the method for the present invention.

Fig. 2 is wideband array TDL processing structure schematic diagram of the present invention.

Fig. 3 is the ARRAY PROCESSING structural schematic diagram the present invention is based on sub-band division.

Fig. 4 is broadband RTN algorithm launching beam antenna radiation pattern.

Fig. 5 is subband RTN algorithm broadband emission beam antenna directional diagram.

Fig. 6 is the unallocated subband of the present invention based on broadband MSINR algorithm broadband emission Adaptive beamformer figure；ItsIn, (a) is broadband MSINR algorithm launching beam antenna direction, is (b) the broadband algorithm null direction MSINR with frequency variation diagram.

Fig. 7 is present invention division subband based on subband MSINR algorithm broadband emission Adaptive beamformer figure；Wherein,(a) it is subband MSINR algorithm launching beam antenna direction, is (b) the algorithm null direction subband MSINR with frequency variation diagram.

Specific embodiment

Technical solution of the present invention is described in detail with reference to the accompanying drawing:

A kind of broadband emission Adaptive beamformer method based on subband maximum Signal to Interference plus Noise Ratio criterion, as shown in Figure 1, mainIt wants including the following steps:

Step 1: design broadband emission aerial array, calculates the output signal of wideband array.The letter of m-th of array element outputNumber x_m(n) meet formula:

Wherein, x (n-k) refers to the discrete signal x (n) of output to k unit of left, w_m[k] refers to the kth of m-th of array elementThe weighted value of a tap, m=0,1 ..., M-1, k=0,1 ..., J-1, M are array element sums, and J is tapped delay line coefficient.

Step 2: design sub-filter group, sub-filter group can be divided into analysis filter group and synthesis filterGroup, analysis filter group are used for the sub-band division of broadband signal, and synthesis filter group is used for signal reconstruction, the choosing of sub-filter groupDiscrete Fourier transform filtering device group.

Step 3: completing the sub-band division of broadband signal using the analysis filter group in sub-filter group.Assuming that everyThere is Q sub-band processing channel behind a array element, broadband signal bandwidth is uniformly divided into K frequency point, signal by analysis filterVariance matrix and interference noise covariance matrix meet following formula:

Wherein, []^HFor transposition conjugate operation symbol, R_st-qIt is the signal variance matrix of q-th of subband signal, N_st-qIt is qThe interference noise covariance matrix of a subband signal, K are frequency point sum, V_st-q(θ₀,f_l) expression frequency be f_lWhen sky when guideVector, H_q(f_l) expression frequency be f_lWhen q-th of Subband Analysis Filter frequency response, F_q(f_l) expression frequency be f_lWhen qThe frequency response of a sub-band synthesis filter, β are the power of interference signal, σ²It is the function of zero-mean additive white noise Gaussian processRate, I are unit matrix, θ₀It is main lobe direction, θ₁It is the direction for desirably forming null, f_l∈{f₁,f₂,...,f_KAnd l=1,2,...,K。

Step 4: calculating each sub-band adaptive Wave beam forming weight vector based on subband maximum signal noise ratio principle.Q-th of sonThe signal-to-noise ratio SINR of band signal_qMeet formula:

Wherein, W_qIt is the dimension TDL weight vector of NJ × 1 of q-th of subband signal.Work as SINR_qWhen maximum, available weight vectorOptimal solution:

Wherein, subband optimal T DL weight vector W_opt-qIt isMaximum eigenvalue λ_maxCorresponding feature vector.

Step 5: treated broadband signal is reconstructed using the synthesis filter group in sub-filter group.The optimal T DL weight vector for finding out each subband, according to the reconstruct of synthesis filter group, by emitting Adaptive beamformer, mThe frequency-domain expression of the signal of a array element output are as follows:

Wherein, Y_m(e^jω) indicate m-th of array element output signal frequency domain, w_qm[k] indicates m-th of array element, q-th of subbandK-th of tap weightings, X (e^jω) indicate original wideband signal frequency domain, H_q(e^jω) indicate that the analysis of q-th of subband filtersThe frequency response of device, F_q(e^jω) indicate q-th of subband synthesis filter frequency response.

The main lobe direction of final output is θ₀Broadband signal launching beam antenna radiation pattern are as follows:

Wherein, P (θ, f) indicates broadband signal launching beam antenna radiation pattern, v_st(θ, f) indicates the broadband signal direction of the launchSteering vector when sky when for θ, frequency being f, H_q(f) frequency response of q-th of Subband Analysis Filter when frequency is f, F are indicated_q(f) frequency response of q-th of sub-band synthesis filter when frequency is f is indicated.

In this embodiment, the validity of this method is further verified by Computer Simulation, and is utilizedThe RTN beamforming algorithm of Peter G.Vouras is compared with algorithm of the invention.The parameter setting of this emulation experimentIt is as shown in table 1:

1 system emulation parameter of table

Parameter name	Parameter values
		Array number (M)	32
Subband port number (Q)	5
		Signal center frequency (fc)	1250MHz
Signal bandwidth (B)	500MHz
		Array element spacing (d)	0.1m
Main beam direction (θ0)	0°
		Interference radiating way (θ1)	20°
Original tap sampling frequency (Ts)	3000MHz
		It divides frequency points (K)	96

In addition, time domain broadband when in order to ensure unallocated subband Wave beam forming and the time domain width phase after division subbandTogether, TDL order J is 15 when unallocated subband, and it is wideband array TDL processing of the present invention that TDL order J, which is 5, Fig. 2, when dividing subbandStructural schematic diagram.

This ARRAY PROCESSING structure of emulation based on sub-band division is as shown in figure 3, broadband signal x (n) is filtered by analysisDevice, each subband after division individually carry out TDL processing, and treated, and signal is reconstructed by synthesis filter, are finally locatedOutput signal y after reason_m(n)。

According to theory analysis and emulation experiment, it is deeper that RTN algorithm can form depth in broadband emission wave beam assigned directionNull, null direction does not change with frequency.The launching beam antenna radiation pattern of broadband RTN algorithm and subband RTN algorithmLaunching beam antenna radiation pattern difference is as shown in Figure 4 and Figure 5, it can be seen that compares wider band RTN algorithm, subband RTN algorithm canTo obtain deeper null.

The beam antenna directional diagram based on broadband MSINR broadband emission adaptive beam-forming algorithm of subband is not dividedAs shown in (a) in Fig. 6, null direction with shown in (b) of the frequency variation such as in Fig. 6, divide subband based on subband MSINRShown in (a) in the beam antenna directional diagram such as Fig. 7 of broadband emission adaptive beam-forming algorithm, null direction becomes with frequencyChange as shown in (b) in Fig. 7.As can be seen that being interfered when angle is 20 ° from (b) in (b) and Fig. 7 in Fig. 6It is a vertical lines on direction, this illustrates that broadband MSINR algorithm and subband MSINR algorithm can inhibit aperture to get overEffect, the null direction formed on broadband emission wave beam do not change with frequency.

The null depth correlation that algorithms of different emulation experiment obtains is as shown in table 2:

2 algorithms of different of table forms null depth correlation (dB)

Algorithm	Most	Center	Highest
				Broadband RTN algorithm	36.4	41.8	42.6
Subband RTN algorithm	33.2	45.9	38.4
				Broadband MSINR algorithm	57.6	73.0	66.2
Subband MSINR algorithm	76.2	86.6	69.7

From table 2 it can be seen that the null depth formed based on MSINR criterion algorithm is obviously than the depth of RTN algorithm, and subbandThe broadband emission adaptive beam-forming algorithm performance based on MSINR criterion divided is most strong.Broadband MSINR algorithm is formed byWave beam null depth improves 20dB or so in low-limit frequency, centre frequency, highest frequency, and in centre frequency, depth is reachable73dB, performance are substantially better than RTN algorithm.Meanwhile subband MSINR algorithm, relative to broadband MSINR algorithm, null depth is furtherIt is promoted, centre frequency null depth reaches 86.2dB, further strengthens to the rejection of interference, and relative to broadbandThe tap sampling frequency of MSINR algorithm, TDL is reduced to original 1/5, more conducively Project Realization.

Embodiments of the present invention are explained in detail above in conjunction with attached drawing, but the invention is not limited to above-mentionedEmbodiment within the knowledge of a person skilled in the art can also be before not departing from present inventive conceptIt puts and makes a variety of changes.

Claims (9)

Translated fromChinese

1.基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，包括如下步骤：1. the broadband transmission adaptive beamforming method based on the subband maximum signal-to-noise ratio criterion, is characterized in that, comprises the steps:步骤一、设计宽带发射天线阵列，计算宽带阵列的输出信号；Step 1: Design a broadband transmitting antenna array, and calculate the output signal of the broadband array;步骤二、设计子带滤波器组；Step 2, design a subband filter bank;步骤三、利用子带滤波器组中的分析滤波器组完成宽带信号的子带划分；Step 3, utilize the analysis filter bank in the subband filter bank to complete the subband division of the wideband signal;步骤四、基于子带最大信噪比准则计算各个子带自适应波束形成权矢量；Step 4. Calculate the adaptive beamforming weight vector of each subband based on the subband maximum signal-to-noise ratio criterion;步骤五、利用子带滤波器组中的综合滤波器组将经过处理的宽带信号进行重构。Step 5: Reconstruct the processed wideband signal by using the synthetic filter bank in the subband filter bank.2.根据权利要求1所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，步骤一中的宽带发射天线阵列是阵元个数为M的均匀直线阵列，每个阵元后面是一个等效于离散有限冲激响应滤波器的抽头延迟线，抽头延迟线系数为J，宽带阵列的输出信号x(n)的最低频率为f_L，最高频率为f_H，n＝0,±1,±2,…；第m个阵元输出的信号x_m(n)满足公式：2. the broadband transmission adaptive beamforming method based on the sub-band maximum signal-to-noise ratio criterion according to claim 1, is characterized in that, the broadband transmission antenna array in step 1 is the uniform linear array that array element number is M, Behind each array element is a tapped delay line equivalent to a discrete finite impulse response filter. The tapped delay line coefficient is J, and the output signal x(n) of the wideband array has the lowest frequency f_L and the highest frequency f_H , n=0,±1,±2,…; the signal x_m (n) output by the mth array element satisfies the formula:其中，x(n-k)指输出的离散信号x(n)向左平移k个单位，w_m[k]指第m个阵元的第k个抽头的加权值，m＝0,1,…,M-1，k＝0,1,…,J-1。Among them, x(nk) refers to the output discrete signal x(n) shifted to the left by k units, w_m [k] refers to the weighted value of the k-th tap of the m-th array element, m=0,1,…, M-1, k=0,1,...,J-1.3.根据权利要求1所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，所述的子带滤波器组选用离散傅里叶变换滤波器组。3 . The broadband transmission adaptive beamforming method based on the sub-band maximum signal-to-noise ratio criterion according to claim 1 , wherein the sub-band filter bank selects a discrete Fourier transform filter bank. 4 .4.根据权利要求2所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，每个阵元后面有Q个子带处理通道，每个子带处理通道中有一个分析滤波器和一个综合滤波器。4. the broadband transmission adaptive beamforming method based on the subband maximum signal-to-noise ratio criterion according to claim 2, is characterized in that, each array element has Q subband processing channels behind, and each subband processing channel has a Analysis filters and a synthesis filter.5.根据权利要求4所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，每个子带通道的分析滤波器是由一个长度为P的低通原型滤波器H₀(z)平移获得，在采样频率为f_s时，P＝f_s/(B/M)，其中，B是该子带通道中信号的带宽，M是阵元总数；分析滤波器满足以下公式：5. The broadband transmission adaptive beamforming method based on the subband maximum signal-to-noise ratio criterion according to claim 4, wherein the analysis filter of each subband channel is a low-pass prototype filter whose length is P H₀ (z) is obtained by translation. When the sampling frequency is f_s , P=f_s /(B/M), where B is the bandwidth of the signal in the subband channel, and M is the total number of array elements; the analysis filter satisfies The following formula:H_q(z)＝H₀(zW^q+i)H_q (z)=H₀ (zW^q+i )H₀(z)＝1+z^-1+…+z^-(P-1)H₀ (z)=1+z^-1 +...+z^-(P-1)其中，H_q(z)表示第q个通道分析滤波器冲击响应的z变换，q＝1,...,Q且复变量z＝e^jω，W＝e^-j2π/P，q+i表示第q个子带分析滤波器相对于低通滤波器H₀(z)的频率偏移，i＝f_L/(B/M)-0.5，f_L是宽带信号的最低频率。Among them, H_q (z) represents the z-transform of the impulse response of the qth channel analysis filter, q=1,...,Q and the complex variable z=e^jω , W=e^-j2π/P , q+i represents The frequency offset of the qth subband analysis filter relative to the low-pass filter H₀ (z), i=f_L /(B/M)-0.5, where f_L is the lowest frequency of the wideband signal.6.根据权利要求5所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，综合滤波器满足以下公式：6. The broadband transmission adaptive beamforming method based on the subband maximum signal-to-noise ratio criterion according to claim 5, wherein the synthesis filter satisfies the following formula:F_q(z)＝W^-(q+i)F₀(zW^q+i)F_q (z)=W^-(q+i) F₀ (zW^q+i )F₀(z)＝1+z^-1+…+z^-(P-1)F₀ (z)=1+z^-1 +...+z^-(P-1)其中，F_q(z)表示第q个通道综合滤波器的z变换。Among them, F_q (z) represents the z-transform of the q-th channel synthesis filter.7.根据权利要求1所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，满足子带最大信噪比准则的子带最优权矢量W_opt-q满足公式：7. The broadband transmission adaptive beamforming method based on the sub-band maximum signal-to-noise ratio criterion according to claim 1, wherein the sub-band optimal weight vector W_opt-q satisfying the sub-band maximum signal-to-noise ratio criterion satisfies formula:其中，λ_max是最大特征值，R_st-q是第q个子带信号的信号方差矩阵，N_st-q是第q个子带信号的干扰噪声协方差矩阵。where_λmax is The largest eigenvalue,_Rst-q is the signal variance matrix of the qth subband signal, and_Nst-q is the interference noise covariance matrix of the qth subband signal.8.根据权利要求1所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，综合滤波器组重构后第m个阵元输出的信号的频域表达式为：8. The broadband transmission adaptive beamforming method based on the sub-band maximum signal-to-noise ratio criterion according to claim 1, wherein the frequency domain expression of the signal output by the mth array element after the comprehensive filter bank reconstruction for:其中，Y_m(e^jω)表示第m个阵元输出的信号的频域，Q是子带处理通道总数，J是抽头延迟线系数，q＝1,...,Q，k＝0,1,…,J-1，w_qm[k]表示第m个阵元第q个子带的第k个抽头加权值，X(e^jω)表示原始宽带信号的频域，H_q(e^jω)表示第q个子带的分析滤波器的频率响应，F_q(e^jω)表示第q个子带的综合滤波器的频率响应。Among them, Y_m (e^jω ) represents the frequency domain of the signal output by the mth array element, Q is the total number of sub-band processing channels, J is the tapped delay line coefficient, q=1,...,Q, k=0,₁^,_.^_ represents the frequency response of the analysis filter for the qth subband, and F_q (e^jω ) represents the frequency response of the synthesis filter for the qth subband.9.根据权利要求8所述的基于子带最大信噪比准则的宽带发射自适应波束形成方法，其特征在于，综合滤波器组重构后的宽带输出信号发射波束天线方向图为：9. The broadband transmission adaptive beamforming method based on the subband maximum signal-to-noise ratio criterion according to claim 8, is characterized in that, the broadband output signal transmission beam antenna pattern after the comprehensive filter bank reconstruction is:其中，P(θ,f)表示宽带信号发射波束天线方向图，v_st(θ,f)表示宽带信号发射方向为θ、频率为f时的空时导引矢量，W_opt-q是最优权矢量，H_q(f)表示频率为f时第q个子带分析滤波器的频率响应，F_q(f)表示频率为f时第q个子带综合滤波器的频率响应。Among them, P(θ, f) represents the beam antenna pattern of the broadband signal transmission, v_st (θ, f) represents the space-time steering vector when the broadband signal transmission direction is θ and the frequency is f, and W_opt-q is the optimal Weight vector, H_q (f) represents the frequency response of the qth subband analysis filter at frequency f, and F_q (f) represents the frequency response of the qth subband synthesis filter at frequency f.