杂波环境下目标无源跟踪算法

针对杂波（虚假量测）环境下的目标无源跟踪问题进行了研究,并给出了只测角情况下相应的跟踪算法。该算法在利用修正增益扩展卡尔曼滤波(modified gain extended Kalman filter, MGEKF)对目标进行无源纯方位跟踪的同时,通过建立波门对不同时刻的测量数据进行选择,然后利用角度测量数据计算落入波门内的有效测量数据的概率（包括波门内所有有效量测均为虚假量测的概率和第i个有效回波是正确的概率）,并以这些概率值作为权值对目标状态进行加权融合,实现杂波环境下对目标的实时纯方位无源跟踪。同时,仿真分析对文中所提算法的可行性和有效性进行了验证。     

基于频域处理的机载雷达自适应杂波抑制方法

传统的机载雷达自适应杂波抑制多是从时域角度来考虑的,提出了一种基于频域的杂波抑制方法——FFT频域处理法。该方法将输入数据首先经过FFT运算变换到频域上,然后利用质量中心法来估计杂波谱的中心多普勒频率和带宽,最后将杂波分布区内的FFT通道输出置零(即滤除杂波)。实验仿真结果表明,与传统的基于谱估计的自适应MTI方法相比,该方法具有良好的改善因子和较小的信噪比损失,对于慢速目标检测十分有利,并能有效地防止目标白化,其运算简单,适于工程实现。     

无源北斗/高度组合导航自适应滤波算法

为了减小用户机动对无源北斗双星组合导航系统定位精度的影响,论文研究了自适应滤波定位算法.首先,在分析组合导航算法Singer模型的基础上,提出了模糊逻辑自适应滤波方案.然后,通过仿真获取系统知识,建立模糊逻辑系统,实时调整滤波器驱动噪声方差,实现滤波定位算法模型对用户机动的适应性.最后,通过仿真验证,设计的模糊逻辑自适应滤波算法能根据用户机动情况实时调整卡尔曼滤波器的驱动噪声方差参数,并能有效提高组合导航系统机动时的定位精度.     

基于两步空域滤波的GSM辐射源雷达干扰抑制

在基于全球移动通信（global system for mobile communication,GSM）信号的外辐射源雷达中,不仅有能量很强的基站直达波和强多径干扰,同时还存在大量的弱干扰,单独利用自适应波束形成和低副瓣技术很难完全有效抑制所有的干扰信号。提出一种基于两步空域滤波的GSM辐射源雷达干扰抑制方法,首先利用低副瓣技术对弱干扰进行抑制,然后利用一种稳健的自适应波束形成方法对残留的强干扰信号作进一步抑制,计算机仿真结果验证了本文方法的有效性。     

基于两步空域滤波的GSM辐射源雷达干扰抑制

在基于全球移动通信(global system for mobile communication,GSM)信号的外辐射源雷达中,不仅有能量很强的基站直达波和强多径干扰,同时还存在大量的弱干扰,单独利用自适应波束形成和低副瓣技术很难完全有效抑制所有的干扰信号.提出一种基于两步空域滤波的GSM辐射源雷达干扰抑制方法,首先利用低副瓣技术对弱干扰进行抑制,然后利用一种稳健的自适应波束形成方法对残留的强干扰信号作进一步抑制,计算机仿真结果验证了本文方法的有效性.     

共形阵机载火控雷达杂波建模与杂波抑制

共形阵机载火控雷达较常规平面阵机载火控雷达有着更少的负载、更好的空气动力性能及更大的扫描范围等优点。对机头共形阵火控雷达的子阵划分、方向图特性、杂波建模和杂波抑制等问题进行了研究。首先,给出了机头共形阵天线的数学模型和几何结构,依据火控雷达动目标检测需求确定了该天线工作方式和子阵合成方式,并分析了机头共形阵的天线方向图特性;然后,结合共形阵阵面结构特点分析了机头共形阵的杂波谱分布特性;最后,利用空时自适应处理(space time adaptive processing, STAP)方法对共形阵机载火控雷达进行了杂波抑制处理,并通过仿真分析了STAP方法的杂波抑制性能。     

一种改进的OTHR自适应海杂波抑制方法

海杂波抑制严重限制天波超视距雷达(over the horizon radar, OTHR)系统对低速舰船目标检测能力的主要原因之一。针对自适应海杂波抑制方法中当杂波与目标多普勒频率接近时存在目标谱峰分裂或目标谱峰偏移的问题,提出一种采用运动目标显示（moving targetindication, MTI）与基于特征值分解的自适应杂波抑制相结合的改进的特征值分解（modified eigen value decomposition, MEVD）海杂波抑制方法。该方法通过MTI滤波器抑制目标谱峰内杂波,之后通过自适应抑制方法抑制其他杂波,具有同时抑制一阶和高阶海杂波的能力,提高了目标信杂噪比,有助于提高OTHR对舰船目标的检测性能。理论分析、仿真实验和实测数据处理结果均验证了MEVD方法的有效性。     

机动运动辐射源的单站无源定位自适应算法

利用目标到达角(DOA)和到达时间(TOA)作为测量数据,采用最优加权最小二乘估计和基于机动加速度的非零均值时间相关模型的自适应卡尔曼滤波算法,通过加速度方差对滤波增益的修正,完成机动加速度方差自适应算法,实现了对机动目标进行单站无源定位与跟踪的方法.计算机仿真验证了算法的有效性和可行性,证明该方法在无源定位系统中有一定的参考价值.     

基于改进粒子滤波的双站无源定位跟踪算法研究

在非线性非高斯状态空间下,粒子滤波器是一种有效的非线性滤波算法,它的关键问题包括粒子权重的计算、粒子重采样和状态估计等.根据粒子滤波算法思想和双站无源定位跟踪的非线性,将粒子滤波算法用于双站无源定位跟踪问题,给出了一种改进的粒子滤波算法,并对其关键问题根据双站无源定位跟踪的特殊性进行了改进.利用matlab进行了仿真实验,与最小二乘算法、扩展卡尔曼滤波算法进行了比较,结果表明所提算法定位跟踪精度优于其他方法.     

一种迭代可分离的机载面阵雷达杂波抑制方法

为了解决传统空时自适应处理方法由于独立同分布训练样本不足无法有效抑制机载面阵雷达非均匀杂波的问题,提出了一种迭代可分离的机载面阵雷达杂波抑制方法。该方法首先通过雷达系统和载机平台运动参数先验知识构造杂波表示基矩阵,然后基于协方差矩阵匹配估计准则分别估计待检测单元的杂波空域和时域功率谱,接着按照线性约束最小方差准则计算待检测单元的空域和时域部分权向量,最后再结合杂波参数化模型和得到的空域和时域部分权向量计算空时滤波权向量用于处理待检测单元回波数据。该方法不需要训练样本,不需人为设置超参数,具有全局收敛性,即使存在距离模糊也可以有效地抑制机载面阵雷达回波数据中的非均匀杂波。仿真实验说明了本文方法的有效性。     

实测数据的降秩空时自适应处理方法

针对全空时自适应处理协方差矩阵估计和计算复杂问题,介绍了在直接处理器结构上基于主分量法和互谱法的两种降秩空时自适应处理方法,这两种方法利用杂波和干扰的低秩属性,应用采样数据来构造降维转换矩阵。对Mountain Top计划进行了详细描述,对从Mountain Top计划测得的数据应用上述两种降秩方法对其进行了分析。仿真实验表明了这两种方法的可行性,减少了计算量,并提高了有效可测收敛性。     

Knowledge-based adaptive polarimetric detection in heterogeneous clutter

The detection performance and the constant false alarm rate behavior of the conventional adaptive detectors are severely degraded in heterogeneous clutter. This paper designs and analyses a knowledge-based （KB） adaptive polarimetric detector in het-erogeneous clutter. The proposed detection scheme is composed of a data selector using polarization knowledge and an adaptive polarization detector using training data. A polarization data selector based on the maximum likelihood estimation is proposed to remove outliers from the heterogeneous training data. This selector can remove outliers effectively, thus the training data is purified for estimating the clutter covariance matrix. Consequently, the performance of the adaptive detector is improved. We assess the performance of the KB adaptive polarimetric detector and the adaptive polarimetric detector without a data selector using simulated data and IPIX radar data. The results show that the KB adaptive polarization detector outperforms its non-KB counterparts.     

基于协方差拟合准则的降维空时自适应处理方法

最优空时自适应处理方法由于计算量大且需要大量的训练样本来估计杂波协方差矩阵而无法满足实际应用,针对此问题,本文提出一种基于协方差拟合准则的降维空时自适应处理方法.该方法首先对每个阵元收到的回波信号进行时域滤波,然后通过协方差拟合准则构造了在高斯信源下与最大似然估计器渐近等价的优化问题,同时我们将协方差拟合优化问题转换为...     

Scheme of adaptive polarization filtering based on Kalman model

1.INTRODUCTIONIn modern high technology war,the electroniccounter measures(ECM)and precise guidance tech-nology are rapidly developed and becoming the re-search hotspot of militarysciencefor all the countries.The guidance missiles are the main weapons andhigher anti-jamming ability and guidance precision arerequired for guidance radar.For the active mono-pulse guidance radar,the angle information of thetarget is obtained by usingthe angle measured methodof amplitude sum/difference or pha…     

递推最小二乘算法在新型无源探测系统中的应用

针对新型无源探测系统的要求,在原有最小二乘算法的基础上,为缩短定位时间,减少运算量,提出了递推最小二乘算法。同时引入自适应卡尔曼滤波算法对原始定位结果进行了处理。多次计算机仿真结果表明该算法有效地提高了定位的实时性、可靠性和定位精度,能够满足新型无源探测系统的技术要求。     

FM interference suppression for PRC-CW radar based on adaptive STFT and time-varying filtering

The influence of frequency modulation (FM) interference on correlation detection performance of the pseudo random code continuous wave (PRC-CW) radar is analyzed.It is found that the correlation output deteriorates greatly when the FM interference power exceeds the anti-jamming limit of the radar.According to the fact that the PRC-CW radar echo is a wideband pseudo random signal occupying the whole TF plane,while the FM interference only concentrates in a small portion,a new method is proposed based on adaptive short-time Fourier transform (STFT) and time-varying filtering for FM interference suppression.This method filters the received signal by using a binary mask to excise only the portion of the TF plane corrupted by the interference.Two types of interference,linear FM (LFM) and sinusoidal FM (SFM),under different signal-to-jamming ratio (SJR) are studied.It is shown that the proposed method can effectively suppress the FM interference and improve the performance of target detection.     

Target detection using CDMA based passive bistatic radar

Recently, the code division multiple access (CDMA) waveform exists in the large area across the world. However, when using the CDMA system as the illuminator of opportunity for the passive bistatic radar (PBR), there exists interference not only from the base station used as the illuminator of opportunity but also from other base stations with the same frequency. And because in the CDMA system, the signal transmitted by each base station is different, using the direct signal of one base station can not cancel the interference from other base stations. A CDMA-based PBR using an 8-element linear array antenna as both the reference antenna and surveillance antenna is introduced. To deal with the interference in this PBR system, an adaptive temporal cancellation algorithm is used to remove the interference from the base station used as the illuminator of opportunity firstly. And then a robust adaptive beamformer is used to suppress the interference from other base stations. Finally, the preliminary experiment results demonstrate the feasibility of using CDMA signals as a radar waveform.     

干扰条件下自适应滤波定位精度分析

在干扰条件下,单纯采用自适应滤波(adaptive Kalman filter, AKF) 或扩展卡尔曼滤波器(extensive Kalman filter, EKF) 在全球导航卫星系统/惯性测量单元(global navigation satellite systems/inertial measurement units, GNSS/IMU)组合导航的运用中都无法达到系统精度最优。为了指导组合导航系统的数据融合滤波器设计,获取AKF和EKF定位性能的经验数值是十分必要的。首先推导出EKF和一种AKF算法--新息序列自适应估计(innovation based adaptive estimation, IAE)的数学模型和计算公式。然后提出了一种实际数据结合仿真的验证方法。针对不同的干扰程度造成的精度降低的测量值,比较AKF算法跟普通EKF在GNSS/IMU组合导航数据融合中的定位精度性能。试验和仿真得到了在实验所采用的IMU精度条件下,自适应滤波在组合导航方面的定位性能的经验曲线以及IAE与EKF定位精度存在的临界点。     

Range walk and array rotation in space-time adaptive processing: effects and compensations

This paper proposes a unified clutter model incorporating the effects of range walk and array rotation for space-time adaptive processing (STAP) in airborne multi-channel early-warning radar. Based on this clutter model, STAP performance is then analyzed from the perspective of covariance matrix tapering (CMT). For STAP performance degradation due to array rotation, a determinate compensation method is proposed based on the CMT method. Numerical examples are provided to verify the analysis and the proposed compensation method.