CN117763832A - Digital array pattern null optimization control method based on channel amplitude and phase error dynamic compensation - Google Patents
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Abstract
本发明公开了一种基于通道幅相误差动态补偿的数字阵列方向图零陷优化控制方法,该方法根据期望零陷深度确定幅相自校准干噪比INR门限ψ,在基于二维傅里叶变换FFT加速的干扰检测与角度估计,以及基于施密特正交化的正交投影算法的基础上,对干扰子空间进行幅相补偿,从而动态进行方向图抗干扰零陷深度和宽度的优化控制。本发明能够动态校准幅相误差,实现干扰零陷深度和宽度的优化控制;通过施密特正交化避免干扰子空间投影矩阵中的矩阵求逆,降低了运算复杂度;通过期望零陷深度确定幅相自校准门限,采用二维FFT干扰检测和施密特正交化正交投影算法,利用满足门限的强干扰源并行计算幅相误差自校准,达到一边工作,一边实时更新幅相误差的目的。
The invention discloses a digital array pattern null optimization control method based on dynamic compensation of channel amplitude and phase errors. This method determines the amplitude-phase self-calibration dry-noise ratio INR threshold ψ according to the expected null depth. Based on the two-dimensional Fourier Based on the interference detection and angle estimation accelerated by transform FFT, and the orthogonal projection algorithm based on Schmidt orthogonalization, the interference subspace is compensated for the amplitude and phase, thereby dynamically optimizing the depth and width of the pattern anti-interference null. control. The present invention can dynamically calibrate the amplitude and phase errors and achieve optimal control of the interference null depth and width; avoid matrix inversion in the interference subspace projection matrix through Schmidt orthogonalization, and reduce the computational complexity; and achieve the desired null depth through Schmidt orthogonalization. Determine the amplitude and phase self-calibration threshold, use two-dimensional FFT interference detection and Schmidt orthogonalization orthogonal projection algorithm, and use strong interference sources that meet the threshold to calculate the amplitude and phase error self-calibration in parallel, so as to update the amplitude and phase error in real time while working. the goal of.
Description
技术领域Technical Field
本发明属于数字阵列天线空域抗干扰技术领域,特别是涉及一种基于通道幅相误差动态补偿的数字阵列方向图零陷优化控制方法。The invention belongs to the technical field of digital array antenna spatial domain anti-interference, and in particular relates to a digital array pattern nulling optimization control method based on dynamic compensation of channel amplitude and phase errors.
背景技术Background Art
数字阵列天线可以通过控制方向图在干扰方向形成零陷实现空域抗干扰,同时具有波束切换快速、波束方向图控制灵活以及空域干扰抑制能力较强等优点。由于数字阵列天线每个射频通道都是由混频器、放大器和滤波器等线性或者非线性有源器件组成。射频通道间不可避免的存在幅相误差,并且随着环境温度的变化和通道间温度的差异,会缓慢变化。通道幅相误差会影响信号源角度估计精度和阵列增益,严重影响阵列方向图的干扰零陷深度以及旁瓣电平等。因此,对于低旁瓣和深零陷抗干扰需求的数字阵列天线,必须进行动态的通道幅相误差校准。Digital array antennas can achieve spatial anti-interference by controlling the radiation pattern to form a null in the interference direction. They also have the advantages of fast beam switching, flexible beam pattern control, and strong spatial interference suppression capabilities. Since each RF channel of a digital array antenna is composed of linear or nonlinear active devices such as mixers, amplifiers, and filters. There are inevitably amplitude and phase errors between RF channels, and they will change slowly with changes in ambient temperature and temperature differences between channels. Channel amplitude and phase errors will affect the accuracy of signal source angle estimation and array gain, and seriously affect the interference null depth and sidelobe level of the array radiation pattern. Therefore, for digital array antennas with low sidelobe and deep null anti-interference requirements, dynamic channel amplitude and phase error calibration must be performed.
现有的校准算法主要分为有源校准法和自校准法两大类。有源校准法需要在系统正常工作前进入专门的校准模式,利用空间位置精确已知的辅助信号源进行校准,无法“边工作边校准”。自校准法则可以同时进行通道幅相误差参数与信源到达方向(DirectionofArrival,DOA)的联合估计值。自校准法大多是通过幅相校准得到更精确的DOA估计,对于干扰角度快速变化的情况,不能动态实现幅相补偿的抗干扰方向图零陷深度和宽度的优化控制。The existing calibration algorithms are mainly divided into two categories: active calibration and self-calibration. The active calibration method requires entering a special calibration mode before the system works normally, and uses an auxiliary signal source with a precisely known spatial position for calibration. It is not possible to "calibrate while working". The self-calibration method can simultaneously perform a joint estimate of the channel amplitude and phase error parameters and the direction of arrival (DOA) of the source. Most self-calibration methods obtain more accurate DOA estimates through amplitude and phase calibration. For situations where the interference angle changes rapidly, it is not possible to dynamically achieve the optimization control of the depth and width of the anti-interference pattern null of amplitude and phase compensation.
发明内容Summary of the invention
本发明目的在于解决上述背景技术中提出的问题,提供一种基于通道幅相误差动态补偿的数字阵列方向图零陷优化控制方法,根据期望的方向图零陷深度和宽度需求,利用满足自校准干噪比门限的非合作干扰源动态校准通道幅相误差,进而有效控制方向图零陷深度和宽度。The purpose of the present invention is to solve the problems raised in the above-mentioned background technology, and to provide a digital array pattern nulling optimization control method based on dynamic compensation of channel amplitude and phase errors. According to the desired pattern nulling depth and width requirements, the channel amplitude and phase errors are dynamically calibrated using a non-cooperative interference source that meets the self-calibration interference-to-noise ratio threshold, thereby effectively controlling the pattern nulling depth and width.
为了实现本发明目的,本发明公开了一种基于通道幅相误差动态补偿的数字阵列方向图零陷优化控制方法,包括以下步骤:In order to achieve the purpose of the present invention, the present invention discloses a digital array pattern nulling optimization control method based on dynamic compensation of channel amplitude and phase errors, comprising the following steps:
步骤1、对阵列接收数据矢量x(k)进行二维FFT处理,根据二维FFT输出与波束形成输出的关系以及计算得到的干扰检测门限T,进行快速干扰检测,估计出干扰个数P、干扰角度以及INRp,(p=1,…,P);Step 1: Perform two-dimensional FFT processing on the array received data vector x(k). According to the relationship between the two-dimensional FFT output and the beamforming output and the calculated interference detection threshold T, perform fast interference detection and estimate the number of interferences P and the interference angle. and INR p ,(p=1,…,P);
步骤2(a)、当P=1且INRP≥ψ时,通过乘幂法计算x(k)的协方差矩阵的主特征向量利用与干扰导向性矢量的差异估计幅相误差 Step 2(a), when P = 1 and INR P ≥ ψ, calculate the covariance matrix of x(k) by the power method The principal eigenvector of use Interference-oriented vector The difference in the estimated amplitude and phase error
步骤2(b)、当P>0,即存在有效干扰时,根据P、和u,v方向的零陷展宽宽度Δu,Δv构建具有零陷展宽特性的干扰子空间C,并利用步骤2(a)中计算得到的幅相误差进行修正C,得到 Step 2(b): When P>0, that is, there is effective interference, according to P, The interference subspace C with null-sinking characteristics is constructed by using the null-sinking widths Δu and Δv in the u and v directions, and the amplitude and phase errors calculated in step 2(a) are used to By making correction C, we get
步骤3、对进行施密特正交化处理,采用正交投影算法计算零陷深度和零陷宽度优化控制的空域零陷抗干扰权重w。Step 3: Schmidt orthogonalization is performed, and the spatial nulling anti-interference weight w of the nulling depth and nulling width optimization control is calculated using the orthogonal projection algorithm.
其中,辅助的幅相自校准门限计算模块,通过分析期望零陷深度与通道幅相误差、通道幅相误差与校准源INR的关系,确定幅相误差自校准的INR门限ψ。The auxiliary amplitude-phase self-calibration threshold calculation module determines the INR threshold ψ of the amplitude-phase error self-calibration by analyzing the relationship between the expected null depth and the channel amplitude-phase error, and between the channel amplitude-phase error and the calibration source INR.
进一步地,步骤1的具体过程为:Furthermore, the specific process of step 1 is:
步骤1-1、二维FFT干扰检测与角度估计;Step 1-1, two-dimensional FFT interference detection and angle estimation;
对于二维矩形栅格平面阵,阵列接收数据矢量x(k)进行二维FFT处理得到For a two-dimensional rectangular grid array, the array receives the data vector x(k) and performs two-dimensional FFT processing to obtain
其中,为第n个阵元的输出信号,Nx,Ny分别为x轴和y轴方向上阵元个数;in, is the output signal of the nth array element, N x , N y are the number of array elements in the x-axis and y-axis directions respectively;
二维FFT输出通道(lx,ly)和角度(up,vp)对应关系为The corresponding relationship between the two-dimensional FFT output channel (l x , ly ) and the angle ( up ,v p ) is:
其中,dx,dy分别为x轴和y轴方向的阵元间距,λ为波长;Where dx and dy are the array element spacings in the x-axis and y-axis directions respectively, and λ is the wavelength;
步骤1-2、计算干扰检测门限T;Step 1-2, calculate the interference detection threshold T;
首先,计算噪声功率Pn First, calculate the noise power Pn
其中,I为二维FFT行列点数,IP为剔除的较大峰值的个数,I0为剔除点位置集合;Where, I is the number of two-dimensional FFT row and column points, I P is the number of large peaks to be eliminated, and I 0 is the set of eliminated point positions;
接着,计算虚警概率为PF时的恒虚警检测门限因子αNext, calculate the constant false alarm detection threshold factor α when the false alarm probability is PF
最后,根据上面的Pn与α计算干扰检测门限TFinally, the interference detection threshold T is calculated based on the above Pn and α
T=αPn T= αPn
步骤1-3、估计干扰个数P、干扰角度以及INRp,(p=1,…,P);Step 1-3: Estimate the number of interferences P and the interference angle and INR p ,(p=1,…,P);
当dx,dy大于λ/2,由于存在周期性模糊,在可视区域(u2+v2≤1)内,二维FFT处理后一个干扰对应的所有可能出现的位置数量为When d x , d y is greater than λ/2, due to the existence of periodic blur, in the visible area (u 2 +v 2 ≤1), the number of all possible positions corresponding to an interference after two-dimensional FFT processing is
其中,为向下取整符号;in, is the floor rounding symbol;
搜索二维FFT处理后数据中超过干扰检测门限T的峰值,根据峰值对应通道位置(lx,ly)估计出干扰角度并将估计结果分组;同组干扰角度估计值之间相差整数倍模糊间距,仅需要选择该组干扰模糊角度中的任意一个角度。最终确定不相关的干扰个数P;Search for the peak value that exceeds the interference detection threshold T in the data after two-dimensional FFT processing, and estimate the interference angle according to the channel position (l x , ly ) corresponding to the peak value The estimation results are grouped; the difference between the interference angle estimation values in the same group is an integer multiple of the fuzzy spacing, and only one angle in the group of interference fuzzy angles needs to be selected. Finally, the number of irrelevant interferences P is determined;
根据干扰对应的峰值位置(lx,ly),计算干扰功率Calculate the interference power according to the peak position (l x , ly ) corresponding to the interference
Pp=|F(lx,ly,k)|2 P p = |F(l x , ly ,k)| 2
对应的干噪比为INRp=10log(Pp/Pn)。The corresponding interference-to-noise ratio is INR p =10log(P p /P n ).
进一步地,步骤2为两个并行计算的子步骤,具体为:Furthermore, step 2 consists of two parallel computing sub-steps, specifically:
步骤2(a)、当P=1且INRP≥ψ时,计算并更新幅相误差 Step 2(a): When P = 1 and INR P ≥ ψ, calculate and update the amplitude and phase errors.
计算x(k)的协方差矩阵通过乘幂法迭代估计的主特征向量干扰导向性矢量为:其中,xn,yn为阵元位置,n=1,2,…,N,N为阵元个数, Calculate the covariance matrix of x(k) Iterative estimation by power method The principal eigenvector of The interference directivity vector is: Where x n , y n are array element positions, n = 1, 2, ..., N, N is the number of array elements,
与的关系为 and The relationship is
其中,计算得到其他阵元除以参考阵元(第一个阵元)归一化后的幅相误差估计值in, Calculate the normalized amplitude and phase error estimates of other array elements divided by the reference array element (the first array element)
其中, in,
步骤2(b)、当P>0时,计算补偿幅相误差的干扰子空间 Step 2(b): When P>0, calculate the interference subspace for compensating the amplitude and phase errors
根据P、以及u,v方向的零陷展宽宽度Δu,Δv构建具有零陷展宽特性的干扰子空间C=[C1,C2,…,CP],其中According to P. And the null-sinking widths Δu and Δv in the u and v directions are used to construct the interference subspace C = [C 1 ,C 2 ,…,C P ] with null-sinking characteristics, where
利用步骤2(a)计算得到的幅相误差进行修正C,得到 The amplitude and phase errors calculated using step 2(a) are By making correction C, we get
进一步地,步骤3具体为:Furthermore, step 3 is specifically as follows:
对的列向量进行施密特正交化处理,得到 right The column vector of is Schmidt orthogonalized to obtain
干扰正交子空间投影矩阵Z⊥为The interference orthogonal subspace projection matrix Z ⊥ is
采用正交投影算法计算零陷深度和宽度优化控制的空域零陷抗干扰权重Orthogonal projection algorithm is used to calculate the spatial nulling anti-interference weights for nulling depth and width optimization control
其中,w0为无零陷的静态权重。Among them, w0 is a static weight without zero sink.
与现有技术相比,本发明的显著进步在于:1)能够根据期望的方向图零陷深度和宽度,动态的估计和补偿通道幅相误差,实现方向图抗干扰零陷深度和宽度的优化控制;2)通过施密特正交化计算避免了干扰子空间投影矩阵中的矩阵求逆运算,降低了运算复杂度;3)通过期望零陷深度确定幅相自校准门限,采用基于二维FFT干扰检测与角度估计算法和基于施密特正交化的正交投影算法,利用满足自校准门限的强干扰源并行计算幅相误差自校准,达到一边工作,一边实时更新幅相误差的目的。Compared with the prior art, the significant progress of the present invention is that: 1) it can dynamically estimate and compensate for channel amplitude and phase errors according to the expected null depth and width of the directional pattern, and realize the optimization control of the anti-interference null depth and width of the directional pattern; 2) the matrix inversion operation in the interference subspace projection matrix is avoided through Schmidt orthogonalization calculation, thereby reducing the calculation complexity; 3) the amplitude and phase self-calibration threshold is determined by the expected null depth, and an orthogonal projection algorithm based on two-dimensional FFT and an orthogonal projection algorithm based on Schmidt orthogonalization are adopted. The amplitude and phase error self-calibration is calculated in parallel using strong interference sources that meet the self-calibration threshold, so as to achieve the purpose of updating the amplitude and phase errors in real time while working.
为更清楚说明本发明的功能特性以及结构参数,下面结合附图及具体实施方式进一步说明。In order to more clearly illustrate the functional characteristics and structural parameters of the present invention, further description is given below in conjunction with the accompanying drawings and specific implementation methods.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
此处所说明的附图用来提供对本发明的进一步理解,构成本申请的一部分,本发明的示意性实施例及其说明用于解释本发明,并不构成对本发明的不当限定。在附图中:The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
图1是本发明的算法实现流程图;Fig. 1 is a flow chart of algorithm implementation of the present invention;
图2是采用64阵元矩形栅格平面阵的阵面分布示意图;FIG2 is a schematic diagram of the array surface distribution of a 64-element rectangular grid plane array;
图3是本发明的一种实施例中通过仿真分析零陷深度与幅相误差、幅相误差与干扰源INR的关系示意图;3 is a schematic diagram of the relationship between the null depth and the amplitude-phase error, and the amplitude-phase error and the interference source INR through simulation analysis in one embodiment of the present invention;
图4是本发明的一种实施例中不同阵元间距,存在一个旁瓣干扰时的二维FFT干扰检测与角度估计结果示意图;4 is a schematic diagram of two-dimensional FFT interference detection and angle estimation results when there is one sidelobe interference at different array element spacings in an embodiment of the present invention;
图5是本发明的一种实施例中是否幅相补偿的干扰方向图零陷对比和输出信干噪比随快拍数目的变化情况对比图。FIG. 5 is a comparison diagram of interference pattern nulling with and without amplitude and phase compensation and output signal to interference noise ratio changes with the number of snapshots in an embodiment of the present invention.
具体实施方式DETAILED DESCRIPTION
下面将结合本发明实施例中的附图,对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅是本发明一部分实施例,而不是全部的实施例;基于本发明中的实施例,本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例,都属于本发明保护的范围。The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
结合图1,一种基于通道幅相误差动态补偿的数字阵列方向图零陷优化控制方法,包括以下主要步骤:In conjunction with FIG1 , a digital array pattern nulling optimization control method based on dynamic compensation of channel amplitude and phase errors includes the following main steps:
步骤1,对阵列接收数据矢量x(k)进行二维FFT处理,根据二维FFT输出与波束形成输出的关系以及计算得到的干扰检测门限T,将二维FFT处理后数据进行恒虚警检测、峰值检测与角度模糊判别等,估计出干扰个数P、干扰角度以及INRp,(p=1,…,P);Step 1: Perform two-dimensional FFT processing on the array received data vector x(k). According to the relationship between the two-dimensional FFT output and the beamforming output and the calculated interference detection threshold T, perform constant false alarm detection, peak detection, and angle ambiguity discrimination on the two-dimensional FFT processed data to estimate the number of interferences P and the interference angle and INR p ,(p=1,…,P);
步骤2(a),当P=1且INRP≥ψ时,通过乘幂法迭代估计x(k)的协方差矩阵的主特征向量利用与干扰导向性矢量的差异估计幅相误差 为对角矩阵。Step 2(a), when P = 1 and INR P ≥ ψ, estimate the covariance matrix of x(k) by the power method The principal eigenvector of use Interference-oriented vector The difference in the estimated amplitude and phase error is a diagonal matrix.
步骤2(b),当P>0,即存在有效干扰时,根据P、和u,v方向的零陷展宽宽度Δu,Δv构建具有零陷展宽特性的干扰子空间C,并利用步骤2(a)中计算得到的幅相误差进行修正C,得到: Step 2(b), when P>0, that is, when effective interference exists, according to P, The interference subspace C with null-sinking characteristics is constructed by using the null-sinking widths Δu and Δv in the u and v directions, and the amplitude and phase errors calculated in step 2(a) are used to By making correction C, we get:
步骤3,对进行施密特正交化处理,采用正交投影算法计算零陷深度和零陷宽度优化控制的空域零陷抗干扰权重w。Step 3, Schmidt orthogonalization is performed, and the spatial nulling anti-interference weight w of the nulling depth and nulling width optimization control is calculated using the orthogonal projection algorithm.
步骤1的具体细化处理过程为:The specific detailed processing process of step 1 is as follows:
步骤1-1,二维FFT干扰检测与角度估计;Step 1-1, two-dimensional FFT interference detection and angle estimation;
对于二维矩形栅格平面阵,(up,vp)方向的波束输出为:For a two-dimensional rectangular grid array, the beam output in the ( up , vp ) direction is:
其中,为第n个阵元的输出信号,Nx,Ny分别为x轴和y轴方向上阵元个数,dx,dy分别为x轴和y轴方向的阵元间距,λ为波长。in, is the output signal of the nth array element, Nx , Ny are the number of array elements in the x-axis and y-axis directions respectively, dx , dy are the array element spacing in the x-axis and y-axis directions respectively, and λ is the wavelength.
对x(k)进行二维FFT处理得到:Performing two-dimensional FFT processing on x(k) yields:
可以看出,x(k)的波束形成输出y(up,vp,k)与二维FFT输出F(lx,ly,k)之间存在直接对应关系,即:It can be seen that there is a direct correspondence between the beamforming output y( up , vp , k) of x(k) and the two-dimensional FFT output F( lx , ly , k), namely:
进而得到:Then we get:
对二维FFT输出进行检测判决并通过上式给出的二维FFT输出通道(lx,ly)和角度(up,vp)对应关系,得到干扰检测和角度估计结果。The two-dimensional FFT output is detected and judged, and the interference detection and angle estimation results are obtained through the corresponding relationship between the two-dimensional FFT output channel (l x , ly ) and the angle ( up ,v p ) given by the above formula.
步骤1-2,计算干扰检测门限T;Step 1-2, calculating the interference detection threshold T;
首先,计算噪声功率Pn:First, calculate the noise power P n :
其中,I为二维FFT行列点数,IP为剔除的较大峰值的个数,I0为剔除点位置集合。Among them, I is the number of two-dimensional FFT row and column points, IP is the number of large peaks to be eliminated, and I0 is the set of eliminated point positions.
接着,计算虚警概率为PF时的恒虚警检测门限因子α:Next, calculate the constant false alarm detection threshold factor α when the false alarm probability is PF :
最后,根据上面的Pn与α计算干扰检测门限T:Finally, the interference detection threshold T is calculated based on the above Pn and α:
T=αPn (7)T= αPn (7)
步骤1-3,估计干扰个数P、干扰角度以及INRp,(p=1,…,P);Step 1-3, estimate the number of interferences P and the interference angle and INR p ,(p=1,…,P);
当dx,dy大于λ/2,由于二维FFT具有周期性,存在:When d x , d y is greater than λ/2, due to the periodicity of the two-dimensional FFT, we have:
F(lx,ly,k)=F(lx±r1Nx,ly±r2Ny,k),(r1=0,1,2,…;r2=0,1,2,…) (8)F(l x ,l y ,k)=F(l x ±r 1 N x ,l y ±r 2 N y ,k), (r 1 =0,1,2,…; r 2 =0,1 ,2,…) (8)
那么,二维FFT输出通道(lx,ly)和角度(up,vp)对应关系变为:Then, the correspondence between the two-dimensional FFT output channel (l x , ly ) and the angle ( up ,v p ) becomes:
存在同一个干扰对应多个模糊角度的情况,其中,行模糊角度间隔udim和列模糊角度间隔vdim分别为:在可视区域(u2+v2≤1)内,一个干扰对应的所有可能出现的位置数量为:其中,为向下取整符号。There are cases where the same interference corresponds to multiple blur angles, where the row blur angle interval u dim and the column blur angle interval v dim are respectively: In the visible area (u 2 +v 2 ≤1), the number of all possible positions corresponding to an interference is: in, The floor symbol.
搜索二维FFT处理后数据中超过干扰检测门限T的峰值,根据峰值对应通道位置(lx,ly)估计出干扰角度并将估计结果分组,同组角度估计值之间相差整数倍模糊间距,抑制其中一个角度就会使其他模糊角度均被抑制,因此,选择每个分组中任意一个干扰估计角度,最终确定不相关的干扰个数P。Search for the peak value that exceeds the interference detection threshold T in the data after two-dimensional FFT processing, and estimate the interference angle according to the channel position (l x , ly ) corresponding to the peak value The estimation results are grouped, and the angle estimation values in the same group differ by an integer multiple of the fuzzy spacing. Suppressing one of the angles will suppress the other fuzzy angles. Therefore, any interference estimation angle in each group is selected to finally determine the number of irrelevant interferences P.
根据干扰对应的峰值位置(lx,ly),计算干扰功率:According to the peak position (l x , ly ) corresponding to the interference, calculate the interference power:
Pp=|F(lx,ly,k)|2 (10)P p =|F(l x ,l y ,k)| 2 (10)
对应的干噪比为:INRp=10log(Pp/Pn)。其中,计算Pn时,剔除点个数IP一般选取略大于最大干扰个数与其模糊角度个数的乘积。The corresponding interference-to-noise ratio is: INR p =10log(P p /P n ) wherein, when calculating P n , the number of eliminated points IP is generally selected to be slightly larger than the product of the maximum number of interferences and the number of blur angles thereof.
步骤2分为两个并行计算的子步骤,具体细化处理过程为:Step 2 is divided into two parallel computing sub-steps, and the specific detailed processing process is as follows:
首先,假设数字阵列通道第n个通道的幅度和相位误差分别为αn和βn,阵列幅相误差矩阵表示为:N为阵元个数。First, assuming that the amplitude and phase errors of the nth channel of the digital array channel are α n and β n respectively, the array amplitude and phase error matrix is expressed as: N is the number of array elements.
步骤2(a),当P=1且INRP≥ψ时,计算并更新幅相误差 Step 2(a): When P = 1 and INR P ≥ ψ, calculate and update the amplitude and phase errors.
通过乘幂法迭代估计x(k)的协方差矩阵的最大特征向量乘幂法第l次迭代的迭代公式为:Iteratively estimate the covariance matrix of x(k) by the power method The largest eigenvector of The iterative formula for the lth iteration of the power method is:
其中,是指中模最大的元素。in, means The largest element in the model.
首先,随机初始化迭代向量设置迭代计数l=1;接着,分别计算令如果V(l)小于为选定的阈值终止迭代,否则设置l=l+1,继续迭代;最后,通过L次迭代,得到主特征值对应主特征向量为 First, randomly initialize the iteration vector Set the iteration count l = 1; then calculate make If V (l) is less than the selected threshold Terminate the iteration, otherwise set l = l + 1 and continue iterating; finally, after L iterations, the main eigenvalue is obtained The corresponding principal eigenvector is
干扰导向性矢量为:其中,xn,yn为阵元位置,n=1,2,…,N, The interference directivity vector is: Where x n , y n are array element positions, n = 1, 2, ..., N,
与的关系为:即: and The relationship is: Right now:
其中,计算得到其他阵元除以参考阵元(第一个阵元)归一化后的幅相误差估计值:in, The normalized amplitude and phase error estimates of other array elements divided by the reference array element (the first array element) are calculated as follows:
步骤2(b),当P>0时,计算补偿幅相误差的干扰子空间 Step 2(b): when P>0, calculate the interference subspace that compensates for the amplitude and phase errors
根据P、以及u,v方向的零陷展宽宽度Δu,Δv构建具有零陷展宽特性的干扰子空间C=[C1,C2,…,CP],其中:According to P. And the null-stretch widths Δu and Δv in the u and v directions are used to construct an interference subspace C = [C 1 ,C 2 ,…,C P ] with null-stretch characteristics, where:
利用步骤2(a)计算得到的幅相误差进行修正C,得到: The amplitude and phase errors calculated using step 2(a) are By making correction C, we get:
进一步的,步骤3具体为:Furthermore, step 3 is specifically as follows:
对的列向量εi进行施密特正交化处理,得到其中,各列向量γi(i=1,2,…,5P)的计算方式如下:right The column vector ε i of the Schmidt orthogonalization is obtained in, The calculation method of each column vector γ i (i=1,2,…,5P) is as follows:
此时,干扰正交子空间投影矩阵Z⊥为:at this time, The interference orthogonal subspace projection matrix Z ⊥ is:
采用正交投影算法计算零陷深度和宽度优化控制的空域零陷抗干扰权重:The orthogonal projection algorithm is used to calculate the spatial nulling anti-interference weights of the nulling depth and width optimization control:
其中,w0为无零陷的静态权重,比如波束指向方向(u0,v0)的导向性矢量a(u0,v0)或者幅度加权的低旁瓣权重。Wherein, w 0 is a static weight without nulling, such as the steering vector a(u 0 ,v 0 ) of the beam pointing direction (u 0 ,v 0 ) or an amplitude-weighted low sidelobe weight.
根据上述描述,并结合图1本发明的算法实现流程图,总结本发明的实现方法主要包括如下两个部分:According to the above description, and in combination with the algorithm implementation flow chart of the present invention in FIG1 , the implementation method of the present invention mainly includes the following two parts:
1、干扰检测和估计:1. Interference detection and estimation:
对阵列接收数据矢量x(k)进行二维FFT处理,根据二维FFT输出与波束形成输出的关系以及计算得到的干扰检测门限,进行快速干扰检测,估计出干扰个数P、干扰角度以及INRp,(p=1,…,P);Perform two-dimensional FFT processing on the array received data vector x(k), perform fast interference detection based on the relationship between the two-dimensional FFT output and the beamforming output and the calculated interference detection threshold, and estimate the number of interferences P and the interference angle and INR p ,(p=1,…,P);
2、抗干扰权重计算:2. Anti-interference weight calculation:
当P=1且INRP≥ψ时,通过乘幂法计算x(k)的协方差矩阵的主特征向量利用与干扰导向性矢量的差异估计幅相误差 When P = 1 and INR P ≥ ψ, the covariance matrix of x(k) is calculated by the power method The principal eigenvector of use Interference-oriented vector The difference in the estimated amplitude and phase error
当P>0,即存在有效干扰时,根据P、和u,v方向的零陷展宽宽度Δu,Δv构建具有零陷展宽特性的干扰子空间C,并利用步骤2(a)中计算得到的幅相误差进行修正C,得到 When P>0, that is, there is effective interference, according to P, The interference subspace C with null-sinking characteristics is constructed by using the null-sinking widths Δu and Δv in the u and v directions, and the amplitude and phase errors calculated in step 2(a) are used to By making correction C, we get
对进行施密特正交化处理,采用正交投影算法计算零陷深度和零陷宽度优化控制的空域零陷抗干扰权重w。right Schmidt orthogonalization is performed, and the spatial nulling anti-interference weight w of the nulling depth and nulling width optimization control is calculated using the orthogonal projection algorithm.
其中,辅助步骤为幅相自校准门限计算模块:通过分析期望零陷深度与通道幅相误差、通道幅相误差与校准源INR的关系,确定幅相误差自校准的INR门限ψ。Among them, the auxiliary step is the amplitude and phase self-calibration threshold calculation module: by analyzing the relationship between the expected null depth and the channel amplitude and phase error, and the channel amplitude and phase error and the calibration source INR, the INR threshold ψ of the amplitude and phase error self-calibration is determined.
下面结合具体实施例对本发明做详细说明。The present invention is described in detail below with reference to specific embodiments.
实施例Example
本发明提出了一种根据期望的方向图零陷深度和宽度,利用满足自校准门限的强干扰源动态校准通道幅相误差,进而有效控制方向图零陷深度和宽度的方法。方法流程图参见图1。The present invention proposes a method for dynamically calibrating channel amplitude and phase errors according to the desired null depth and width of the directional pattern by using a strong interference source that meets the self-calibration threshold, thereby effectively controlling the null depth and width of the directional pattern. See Figure 1 for a flowchart of the method.
本示例采用N=64阵元矩阵栅格平面阵,单元天线为各向同性的全向天线,不考虑阵元间互耦,图2给出了所用的矩形栅格阵列模型。波束指向干扰来自INR为10dB,噪声为加性高斯白噪声向量,噪声与信号互不相干。通道间存在幅相误差,幅度误差αn和相位误差βn均服从均匀分布,αn=1+rn,βn=sn,其中即αn和βn的均方根分别为选用-35dB的切比雪夫幅度加权进行低旁瓣处理。本示例期望实现的零陷深度为-45dB,零陷展宽需求Δu,Δv均为0.0348,即零陷展宽约为±2°。并且分别进行不同阵元间距时的二维FFT角度模糊问题的分析验证,包括:(1)阵元间距等于波长,即x轴和y轴方向的阵元间距分别为dx=λ,dy=λ;(2)阵元间距等于半波长,即x轴和y轴方向的阵元间距分别为dx=0.5λ,dy=0.5λ。This example uses a matrix grid array with N=64 elements. The unit antennas are isotropic omnidirectional antennas. The mutual coupling between elements is not considered. Figure 2 shows the rectangular grid array model used. Beam pointing Interference from The INR is 10dB, the noise is an additive white Gaussian noise vector, and the noise is unrelated to the signal. There are amplitude and phase errors between channels, and the amplitude error α n and the phase error β n both obey uniform distribution, α n =1+r n ,β n =s n , where That is, the RMS values of α n and β n are A -35dB Chebyshev amplitude weighting is used for low sidelobe processing. The expected null depth in this example is -45dB, and the null width requirements Δu and Δv are both 0.0348, that is, the null width is about ±2°. The two-dimensional FFT angle ambiguity problem is analyzed and verified at different array element spacings, including: (1) the array element spacing is equal to the wavelength, that is, the array element spacing in the x-axis and y-axis directions is dx = λ, dy = λ respectively; (2) the array element spacing is equal to half the wavelength, that is, the array element spacing in the x-axis and y-axis directions is dx = 0.5λ, dy = 0.5λ respectively.
针对两种阵元间距的64阵元的矩阵栅格平面阵列,基于通道幅相误差动态补偿的数字阵列方向图零陷优化控制方法的实现包括如下处理步骤:For a 64-element matrix grid planar array with two array element spacings, the implementation of a digital array pattern nulling optimization control method based on dynamic compensation of channel amplitude and phase errors includes the following processing steps:
首先,通过辅助步骤,仿真通道幅相误差与INR的关系以及零陷深度与幅相误差的关系,确定满足期望零陷深度为-45dB时的幅相自校准INR门限为:ψ=5dB。,确定门限的仿真结果如图3所示。First, through the auxiliary steps, the relationship between the channel amplitude and phase error and INR, as well as the relationship between the null depth and the amplitude and phase error are simulated, and the amplitude and phase self-calibration INR threshold that meets the expected null depth of -45dB is determined to be: ψ = 5dB. The simulation results of the determined threshold are shown in Figure 3.
图3中的图(a)仿真了四种通道幅相误差的均方根(σα,σβ)分别为(0.25dB,2.5°),(0.5dB,5°),(0.75dB,7.5°),(1.0dB,10°)情况下的残留幅相误差值与INR的关系。图3中的图(b)给出了零陷深度与残留幅相误差的关系。图(b)标注了零陷深度优于-45dB情况下的幅相校准残差的范围,对于仿真所采用的阵列,残留幅度误差的均方根不能超过0.18dB,残留相位误差的均方根不能超过8°。同时,结合图(a)的仿真结果,得到通道残留幅相误差满足上述要求的情况下,自校准INR门限ψ=5dB。Figure (a) in Figure 3 simulates the relationship between the residual amplitude and phase error value and INR when the root mean square of the four channel amplitude and phase errors (σ α ,σ β ) are (0.25dB, 2.5°), (0.5dB, 5°), (0.75dB, 7.5°), and (1.0dB, 10°). Figure (b) in Figure 3 shows the relationship between the null depth and the residual amplitude and phase error. Figure (b) marks the range of the amplitude and phase calibration residual when the null depth is better than -45dB. For the array used in the simulation, the root mean square of the residual amplitude error cannot exceed 0.18dB, and the root mean square of the residual phase error cannot exceed 8°. At the same time, combined with the simulation results of Figure (a), it is obtained that when the channel residual amplitude and phase error meets the above requirements, the self-calibration INR threshold ψ=5dB.
步骤1:设定干扰检测的虚警概率为PF=10-4,二维FFT行列点数I均为128,使用式(6)计算得到门限因子α=9.21。根据二维FFT干扰检测与角度估计算法,分别计算两种阵元间距情况下的干扰角度估计模糊角度数量。Step 1: Set the false alarm probability of interference detection to PF = 10-4 , the number of two-dimensional FFT row and column points I to 128, and use equation (6) to calculate the threshold factor α = 9.21. According to the two-dimensional FFT interference detection and angle estimation algorithm, calculate the number of interference angle estimation ambiguity angles under two array element spacing conditions.
(1)大阵元间距情况下,计算可视区域(u2+v2≤1)内模糊角度个数因此一个干扰会在可视区域内的两个角度被检测出来,间隔分别为:udim=λ/dx=1,vdim=λ/dy=1,经过角度模糊判别,可以确定仅存在一个干扰,P=1。(1) In the case of large array element spacing, calculate the number of blur angles in the visible area (u 2 +v 2 ≤1) Therefore, one interference will be detected at two angles in the visible area, with intervals of u dim = λ/d x = 1, v dim = λ/d y = 1. After angle ambiguity discrimination, it can be determined that there is only one interference, P = 1.
(2)小阵元间距情况下,计算可视区域内模糊角度个数为0,因此不存在角度模糊问题,P=1。(2) When the array element spacing is small, the number of blurred angles in the visible area is calculated to be 0, so there is no angle blur problem, and P = 1.
图4中的图(a)、图(b)分别仿真了大阵元间距和正常阵元间距情况下的二维FFT干扰检测与角度估计结果,红色虚线所围区域为可视区域。仿真结果表明,第一种情况阵元间距大于λ/2,可视区域内出现角度模糊,选择该组模糊角度中任意一个角度,比如即使用式(10)计算干扰功率并得到干噪比INRP≈10dB;第二种情况,阵元间距等于λ/2,可视区域内不存在角度模糊,干扰估计结果即INRP≈10dB。Figure 4 (a) and (b) simulate the two-dimensional FFT interference detection and angle estimation results under large array element spacing and normal array element spacing, respectively. The area surrounded by the red dotted line is the visible area. The simulation results show that in the first case, when the array element spacing is greater than λ/2, angle blur occurs in the visible area. Select any angle in the group of blurred angles, such as Right now The interference power is calculated using equation (10) and the interference-to-noise ratio INR P ≈10 dB. In the second case, the array element spacing is equal to λ/2, and there is no angle ambiguity in the visible area. The interference estimation result is Right now INR P ≈10dB.
步骤2(a):P=1,INRP≥5dB,计算幅相误差 Step 2(a): P = 1, INR P ≥ 5dB, calculate the amplitude and phase errors
快拍数设为256,计算x(k)的协方差矩阵选定乘幂法终止迭代的阈值估计出的主特征向量 和干扰导向性矢量的关系为: The number of snapshots is set to 256, and the covariance matrix of x(k) is calculated. Select the threshold for terminating the iteration of the power method Estimated The principal eigenvector of and interference-oriented vector The relationship is:
仿真设置初始幅相误差σα=1dB,σβ=10°,INR=10dB,根据式(13)估计得到幅相误差矩阵表1给出了设置的通道真实幅相误差与算法估计出的幅相误差对比。The simulation sets the initial amplitude and phase error σα=1dB, σβ=10°, INR=10dB, and estimates the amplitude and phase error matrix according to formula (13): Table 1 shows the comparison between the actual amplitude and phase errors of the set channels and the amplitude and phase errors estimated by the algorithm.
表1通道真实幅相误差与估计幅相误差对比Table 1 Comparison between the actual channel amplitude and phase error and the estimated amplitude and phase error
从表1中数据分析可知,利用幅相校准算法估计得到幅相误差基本接近于真实的幅相误差。From the data analysis in Table 1, it can be seen that the amplitude and phase errors estimated by the amplitude and phase calibration algorithm are basically close to the actual amplitude and phase errors.
步骤2(b),P>0时,计算补偿幅相误差的干扰子空间 Step 2(b), when P>0, calculate the interference subspace that compensates for the amplitude and phase errors
阵元间距设置为λ/2,使用式(14)构建具有零陷展宽特性的干扰子空间C,由步骤一得到,二维FFT角度估计结果P=1。零陷展宽宽度Δu,Δv均为0.0348,则式(14)中的C1表示为:The array element spacing is set to λ/2, and the interference subspace C with null-stretching characteristics is constructed using equation (14). The two-dimensional FFT angle estimation result is obtained from step 1. P = 1. The null expansion widths Δu and Δv are both 0.0348, so C 1 in equation (14) is expressed as:
C1=[a(0.5625,0),a(0.5625,0-0.0348),a(0.5625,0+0.0348),a(0.5625+0.0348,0),a(0.5625-0.0348,0)]C 1 =[a(0.5625,0),a(0.5625,0-0.0348),a(0.5625,0+0.0348),a(0.5625+0.0348,0),a(0.5625-0.0348,0)]
利用进行修正C1,得到: use After modifying C 1 , we get:
步骤3:使用式(15)对进行施密特正交化处理得到干扰正交子空间投影矩阵为:采用正交投影算法计算零陷深度和宽度优化控制的空域零陷抗干扰权重:Step 3: Use formula (15) to After Schmidt orthogonalization, we get The interference orthogonal subspace projection matrix is: The orthogonal projection algorithm is used to calculate the spatial nulling anti-interference weights of the nulling depth and width optimization control:
其中,w0为-35dB的切比雪夫幅度加权的低旁瓣权重。表2给出了w的具体值。Wherein, w0 is the low sidelobe weight of -35dB Chebyshev amplitude weighting. Table 2 gives the specific value of w.
表2空域零陷抗干扰权重w系数Table 2 Spatial null anti-interference weight w coefficient
图5中的,图(a)、图(b)仿真了是否幅相补偿的干扰零陷方向图对比和输出信干噪比随快拍数目的变化情况对比。可以看出,补偿幅相误差后的方向图零陷深度优于-45dB,干扰附近形成±2°左右的展宽零陷,且输出信干噪比大于未进行幅相补偿的情况。Figure 5 (a) and (b) simulate the interference null pattern comparison with and without amplitude and phase compensation and the output signal to noise ratio change with the number of snapshots. It can be seen that the null depth of the directional pattern after compensating for the amplitude and phase errors is better than -45dB, a widened null of about ±2° is formed near the interference, and the output signal to noise ratio is greater than the case without amplitude and phase compensation.
需要说明的是,在本文中,诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来,而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且,术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含,从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素,而且还包括没有明确列出的其他要素,或者是还包括为这种过程、方法、物品或者设备所固有的要素。It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
尽管已经示出和描述了本发明的实施例,对于本领域的普通技术人员而言,可以理解在不脱离本发明的原理和精神的情况下可以对这些实施例进行多种变化、修改、替换和变型,本发明的范围由所附权利要求及其等同物限定。Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
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