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1.
孙挺  程旭 《电子与信息学报》2022,43(5):1275-1281
波形优化可有效抑制干扰,显著改善雷达探测性能.针对全极化雷达,考虑发射波形满足能量和相似性双重约束,以最大化信杂噪比为准则,对发射波形和接收滤波器进行联合优化.该文设计了一种波形和滤波器的迭代优化算法,该方法序贯提高输出信杂噪比.算法的每一次迭代需要分别解决一个凸问题和隐凸问题,整个算法的计算量与迭代次数和接收滤波器长度分别呈线性和多项式关系.最后,通过仿真实验分析了算法的收敛性、优化波形的模糊度函数方面的性质,与其他算法进行了对比,结果表明:与现有方法相比,该文方法可实现信杂噪比的有效提升.  相似文献   

2.
通过优化发射波形,可降低各种干扰和噪声对雷达场景信息的影响,从而提高雷达性能,以极化雷达为研究对象,在给定目标特性矩阵T(θ)、杂波参数和系统噪声υ条件下,采用最大化滤波器输出信杂噪比(Signal Clutter plus Noise Ratio, SCNR)为目标函数,通过优化设计发射波形与接收滤波器?实现了一种迭代优化方法。实验表明,相比现有的Pillai方法,该算法确保了极化雷达最大化输出SCNR的单调收敛性,提高了雷达的输出信杂噪比。  相似文献   

3.
孙挺  程旭 《电子与信息学报》2021,43(5):1275-1281
波形优化可有效抑制干扰,显著改善雷达探测性能。针对全极化雷达,考虑发射波形满足能量和相似性双重约束,以最大化信杂噪比为准则,对发射波形和接收滤波器进行联合优化。该文设计了一种波形和滤波器的迭代优化算法,该方法序贯提高输出信杂噪比。算法的每一次迭代需要分别解决一个凸问题和隐凸问题,整个算法的计算量与迭代次数和接收滤波器长度分别呈线性和多项式关系。最后,通过仿真实验分析了算法的收敛性、优化波形的模糊度函数方面的性质,与其他算法进行了对比,结果表明:与现有方法相比,该文方法可实现信杂噪比的有效提升。  相似文献   

4.
针对射频频谱环境愈发拥挤问题,深入研究了通过波形设计的手段实现频谱共享的问题。为紧密贴近工程实践,提出了一种新的方法设计恒定幅度信号的问题。该算法首先针对雷达发射端,提出雷达波形满足特定的时域与频谱要求,施加约束,然后考虑雷达接收滤波器接收杂波,以优化最大信干噪比建立优化问题模型,得到了一个非凸的分式规划问题模型。最后,利用分步优化方法分解为两个优化问题,并且将非凸问题松弛为可解的凸问题再利用高斯随机化方法得到优化信号,多次循环优化。仿真结果验证了该算法的有效性,该方法设计得到的探测信号能够实现频谱共存,而且信干噪比性能能够得到保证。   相似文献   

5.
在非均匀杂波背景下,针对旁瓣杂波抑制问题,该文提出一种基于先验信息的机载多输入多输出(MIMO)雷达发射方向图设计方法.该方法利用目标和杂波在空域和多普勒域的2维先验信息,以最大化雷达空时匹配滤波后的输出信杂噪比(SCNR)为准则,建立关于发射信号相关矩阵的优化代价函数,并采用半正定规划(SDP)方法进行求解.仿真表明,在非均匀杂波背景下,采用该文方法优化设计的发射方向图可有效提高空时2维匹配滤波后的输出信杂噪比.  相似文献   

6.
传统雷达一般采用固定的发射波形,在干扰环境下很难获得最优的目标检测性能。针对这一问题,利用集中式多输入多输出(MIMO)雷达波形分集的优势,提出了一种干扰环境下的MIMO雷达波形与接收滤波联合优化算法。以最大化输出信干噪比为准则,使发射波形满足恒模条件,同时施加波形与具备较好脉压特性雷达波形之间的相似性约束,建立了有限相位发射波形与接收滤波权值的优化模型。然后,在循环迭代的算法框架下,将优化问题分解为2个子优化问题,并分别采用拉格朗日乘子法、半正定松弛技术对子优化问题求解,得到发射波形与接收滤波权值的联合优化结果。仿真结果表明,所提算法较现有方法相比有更高的输出信干噪比,使干扰信号的抑制性能得到改善,同时可兼顾发射波形的脉冲压缩特性。  相似文献   

7.
唐波  张玉  李科  高辉 《电子学报》2014,42(9):1705-1711
为提高集中式MIMO雷达在强杂波中的目标检测性能,同时兼顾雷达发射机对于恒定包络波形的需求,以系统输出信杂噪比最大为优化准则,研究了MIMO雷达恒模多波形及接收机权值的联合优化问题.基于循环优化算法将联合优化问题分解为两个子优化步骤,并提出了基于半正定松弛及高斯随机化的恒模波形设计算法.结果表明所提算法能够在迭代过程中不断增加输出信杂噪比直至算法收敛.此外,其相比于能量约束下的最优波形性能损失很小,能够实现自适应杂波抑制并改善目标检测性能.  相似文献   

8.
针对发射导向矢量存在未知误差的问题,该文提出了一种MIMO雷达稳健的发射波束形成算法(Robust Transmitting Beamforming,RTB).该算法在稳健的接收波束形成算法的基础上,以最大化最差情况输出信干噪比为优化准则,对发射导向矢量误差做稳健的发射波束形成.RTB算法属于对角加载方法.仿真结果表明,相比于已有算法,RTB算法的稳健性更好、计算复杂度更低、收敛速度更快.  相似文献   

9.
李涛 《电讯技术》2016,56(8):894-899
针对传统相控阵雷达与集中式多输入多输出( MIMO)雷达的干扰抑制性能优劣问题,对集中式MIMO雷达与相控阵雷达的信干噪比和改善因子进行了对比分析,从理论上研究了两种体制雷达的干扰抑制能力并进行了数字仿真。仿真结果表明,与传统相控阵雷达相比,集中式MIMO雷达通过提升信干噪比输出增强了干扰抑制能力。  相似文献   

10.
与相控阵雷达相比,集中MIMO雷达发射在采用正交波形时,虽然能够得到波形分集增益,但同时也损失了相干处理增益。针对这一问题,本文提出了发射子阵波束合成的思想。首先对集中式MIMO雷达的发射端进行非相干子阵划分,然后利用子阵内波形的相关性和子阵间波形的正交性来同时获取相干处理增益和波形分集增益,并推导出了子阵划分MIMO雷达波束方向图和输出SINR的数学表达式。与相控阵雷达和常规集中式MIMO雷达相比,采用该方法的雷达能够实现较低的空域副瓣和较大的输出信干噪比。仿真实验证明了该算法的有效性。  相似文献   

11.
The linearly constrained least squares constant modulus algorithm (LSCMA) may suffer significant performance degradation and lack robustness in the presence of the slight mismatches between the actual and assumed signal steering vectors, which can cause the serious problem of desired signal cancellation. To account for the mismatches, we propose a doubly constrained robust LSCMA based on explicit modeling of uncertainty in the desired signal array response and data covariance matrix, which provides robustness against pointing errors and random perturbations in detector parameters. Our algorithm optimizes the worst-case performance by minimizing the output SINR while maintaining a distortionless response for the worst-case signal steering vector. The weight vector can be optimized by the partial Taylor-series expansion and Lagrange multiplier method, and the optimal value of the Lagrange multiplier is iteratively derived based on the known level of uncertainty in the signal DOA. The proposed implementation based on iterative minimization eliminates the covariance matrix inversion estimation at a comparable cost with that of the existing LSCMA. We present a theoretical analysis of our proposed algorithm in terms of convergence, SINR performance, array beampattern gain, and complexity cost in the presence of random steering vector mismatches. In contrast to the linearly constrained LSCMA, the proposed algorithm provides excellent robustness against the signal steering vector mismatches, yields improved signal capture performance, has superior performance on SINR improvement, and enhances the array system performance under random perturbations in sensor parameters. The on-line implementation and significant SINR enhancement support the practicability of the proposed algorithm. The numerical experiments have been carried out to demonstrate the superiority of the proposed algorithm on beampattern control and output SINR enhancement compared with linearly constrained LSCMA.  相似文献   

12.
Using Time-Varying AR (TVAR) model and adaptive notch filter is a new method for the non-stationary jammer suppression in Direct Sequence Spread Spectrum (DSSS). The performance of TVAR model for Instantaneous Frequency (IF) estimation will be affected by some factors such as basis functions. Focusing on this problem, the optimal basis function of TVAR model for the IF estimation of the LFM signal is obtained in this paper. Besides the depth and width of notching, the phase properties of notch filter affect the Signal-to-Interference plus-Noise Ratio (SINR) of correlation output to the narrowband jammer suppression in DSSS, in response to the problem the closed solution of correlation output SINR improvement has been derived when a single frequency jammer passes through direct IIR notch filter, and its performance has been compared with those of five coefficient FIR filters. Later, a novel method for LFM jammer suppression based on Fourier basis TVAR model and direct IIR notch filter is proposed. The simulation results show the effectiveness of the proposed method.  相似文献   

13.
基于可变对角载入的鲁棒自适应波束形成算法   总被引:1,自引:0,他引:1  
针对传统算法对方向向量偏差敏感的缺点,提出了一种基于可变对角载入的鲁棒自适应波束形成算法.为了提高算法的鲁棒性,采用非线性约束条件下的最优化阵列输出功率对信号方向向量进行优化求解,且优化解中的参量能够准确求出.为了减少计算量,采用递推算法求逆矩阵并利用泰勒级数展开,推导出基于可变对角载入的权重向量公式.该算法可有效地抑制方向向量偏差所带来的影响,降低了计算量易于实时实现,提高了系统的鲁棒性,改善了阵列输出的信干噪比,使其更接近最优值.仿真结果表明,该算法相对传统算法可以获得更好的性能.  相似文献   

14.
This paper presents a beamforming technique for the reception of frequency hopping (FH) modulated signals, which takes advantage of their inherent frequency diversity. This technique, based on a code reference beamformer, requires neither temporal nor spatial a priori reference and allows continuous self-calibration of the array. The proposed framework is composed of two different stages. The first stage employs the inverse of the noise plus interference covariance matrix obtained by an anticipative processor. The second stage makes use of the steering vector of the signal of interest which is adaptively obtained by maximizing the output signal to interference plus noise ratio (SINR). Using this information, the first stage is in turn readjusted and, as a result, the scheme is able to track non-stationary scenarios following the channel variations with no previous references other than knowledge of the frequency hopping sequence. The two-stage code reference beamformer provides the convergence rate necessary to avoid the SINR reduction associated with frequency hops in existing methods.  相似文献   

15.
In this letter, we address the problem of waveform optimization for multi-input multi-output (MIMO) space-time adaptive processing (STAP) in the presence of colored Gaussian disturbance. A novel diagonal loading (DL) based method is proposed to optimize the waveform covariance matrix (WCM) for maximizing the output signal-interference-noise ratio (SINR) of MIMO-STAP such that the detection performance can be maximized. The resultant nonlinear optimization problem is reformulated as a semidefinite programming (SDP) one, which can be solved very efficiently. Simulation results show that the output SINR of MIMO-STAP can be improved considerably by the proposed method, as compared to that of uncorrelated waveforms.  相似文献   

16.
该文针对单基站功率约束的多点协同联合发送多输入单输出干扰下行链路系统,利用拉格朗日对偶理论研究了下行链路最大化最小信干噪优化问题与虚拟上行链路最小化最大信干噪比优化问题间的对偶关系。基于对偶关系和次梯度理论,提出了一种求解虚拟上行链路最小化最大信干噪比优化问题的内外层交替迭代优化波束成形算法;同时,给出了所提算法的收敛性证明;利用实数浮点运算理论分析了所提算法的复杂度;数值仿真验证了所提算法的有效性。  相似文献   

17.
陆必应  梁甸农 《信号处理》2007,23(2):169-173
本文将导向矢量失配时的稳健波束形成问题归结为二次锥规划问题,利用高效的内点法求解。该波束形成器成功地应用于存在阵元位置误差的柔性稀疏阵,相对于经典的对角线加载法、特征空间法,在不同的输入信噪比下获得了更好的输出信号干扰加噪声比。仿真结果表明对超稀疏分布的柔性阵,阵元位置误差对输出SINR起决定性影响,而阵列稀疏程度对其影响不大。  相似文献   

18.
针对波束形成中目标方位失配以及噪声加干扰的协方差矩阵非精确重构造成的波束形成方法性能下降的问题,提出一种基于嵌套阵列的稀疏表示稳健波束形成方法。在该方法中,计算嵌套阵的采样协方差矩阵,通过差合作阵处理得到一孔径扩展的虚拟均匀线列阵;基于稀疏表示的方法来估计目标以及干扰的准确方位信息;进一步利用得到的方位信息构造导向矢量,通过最小二乘方法计算干扰信号的精确功率值;最后重构干扰加噪声协方差矩阵,通过波束形成实现干扰抑制。数值仿真表明,所提方法有效提升了干扰加噪声协方差矩阵重构精确度,在不同信噪比和快拍数条件下,输出信噪比都能逼近最优信干噪比,验证了该算法的有效性。  相似文献   

19.
The principle to suppress multiple access interference (MAI) using double chip waveforms (DCW) in asynchronous DS-CDMA systems is analyzed in the paper. Based on the principle, a new method adopting optimized combinations of chip waveforms (CCW) to reduce MAI is proposed. The energy spectrum extension factor (ESEF) of equivalent chip waveform is introduced to optimally select CCW to reduce MAI, improve the signal to interference plus noise ratio (SINR) and bite error rate (BER) performance of asynchronous DS-CDMA users. The general closed form expression of SINR for asynchronous DS-CDMA users with CCW is obtained. The BER is also derived by improved Gaussian approximation (IGA). The theoretical analysis and numerical simulation results show that the optimized CCW using ESEF can effectively suppress MAI better, achieve higher SINR and BER performance compared with DCW. Moreover, the overlap between the simulation and IGA BER curves verifies the theoretical derivation.  相似文献   

20.
Separating highly correlated users can reduce the loss caused by spatial correlation (SC) in multiuser multiple‐input multiple‐output (MU‐MIMO) systems. However, few accurate analyses of the loss caused by SC have been conducted. In this study, we define signal‐to‐interference‐plus‐noise ratio (SINR) loss to characterize it in multiuser multiple‐input single‐output (MU‐MISO) systems, and use coefficient of correlation (CoC) to describe the SC between users. A formula is deduced to show the accurate relation between SINR loss and CoC. Based on this relation, we propose a user selection method that utilizes CoC to minimize the average SINR loss of users in massive MU‐MISO systems. Simulation results verify the correctness of the relation and show that the proposed user selection method is very effective at reducing the loss caused by SC in massive MU‐MISO systems.  相似文献   

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