高速机动目标检测算法研究

研究机载雷达高速机动目标检测问题,指出目标的高机动性带来回波包络走动以及多普勒频率展宽,导致传统相参积累效果下降、检测概率降低.为了解决上述问题,提出了一种随机Hough变换的检测方法,将多脉冲观测时长内的高速机动目标回波能量积累问题转化为图像域的直线与曲线检测问题,使得未知速度、加速度的目标包络走动及弯曲得到积累,实现了匀速和匀加速度运动目标的有效检测,并获得速度与加速度的估计值.仿真结果证明了该方法的有效性.     

非均匀环境下机载雷达STAP方法

空时自适应处理(STAP)是机载雷达信号处理中的一项关键技术,但其应用的实际杂波环境通常是非均匀的.本文对非均匀环境下各STAP方法进行了科学分类,并详细分析了各方法的内在机理及相互间的内在联系,同时总结评述了各方法的优缺点,最后指出了机载雷达非均匀STAP方法中有待于进一步研究和完善的相关问题.     

基于非均匀检测的机载雷达空时自适应处理方法

提出了一种新的非均匀杂波环境下的数据样本选取方法－－关联维数（ＣＤ）非均匀检测器,研究了非均匀杂波环境中改进干扰协方差矩阵的估计和自适应权的形成问题。仿真结果表明,非均匀检测器与空时自适应处理（ＳＴＡＰ）方法相结合,可显著地改进机载雷达的检测性能。     

一种有效的直接数据域地面动目标检测方法

直接数据域(Direct data domain, DDD)方法利用子孔径平滑来从单个距离门中获得足够样本,但空域、时域孔径损失严重,使得空时自适应处理的地面动目标检测性能下降严重.针对该问题提出了一种不需要协方差矩阵估计和求逆的DDD方法,该方法将多级维纳滤波器引入到DDD的最优权求解过程中,在低的空时孔径损失下仍然能够获得好的性能.某机载实测雷达数据的实验结果验证了该方法的有效性.     

机载MIMO STAP收发天线联合设计研究

针对机载多输入多输出雷达进行动目标检测时,天线稀疏出现栅瓣导致盲速、天线密布导致冗余及布阵需考虑平台尺寸等问题,对天线结构进行研究.首先基于相位中心等效原理,讨论一定收发阵元数目下如何实现最大自由度和最大孔径;然后根据机载平台结构,设计更合理的收发天线布阵结构;最后结合多相编码进行空时自适应处理,实现动目标检测和杂波抑制.仿真实验表明,与其他天线结构相比,本文方法可获得更好的动目标检测性能.     

低信噪比下基于Keystone变换的高速多目标检测

微弱多目标检测中,高速运动目标的跨距离单元走动会影响长时间相参积累的效果,论文提出了在低信噪比情况下通过Keystone变换校正多目标的跨距离单元走动,对所有脉冲相参积累达到提高信噪比的目的,仿真实验结果验证了该方法的有效性。     

一种基于子孔径SAR的地面运动目标检测方法

针对UHF波段运动目标检测中信号弱、杂波展宽严重等问题,提出一种基于子孔径SAR技术的杂波抑制方法。首先通过SAR成像实现运动目标的粗聚焦,再通过距离-方位拓展局部STAP实现杂波抑制,避免了运动目标越距离单元和方位散焦带来的信号损失。最后,通过仿真结果验证了算法的有效性。     

基于TS201的STAP并行处理系统实现

空时自适应处理(STAP)是新一代机载信号处理机的关键技术之一,它对系统的实时性有严格的要求.在分析实时STAP性能需求的基础上,利用基于TS201的高性能数字信号处理板,实现了一个STAP并行处理系统.结合STAP处理特点和系统体系结构,提出了一个局部串行全局并行的系统算法模型,并在模型实现中采用了高效的通信与同步方法.该模型有效的增强了系统的负载平衡特性.实测结果表明,系统满足STAP处理实时要求,并且有很好的可扩展特性.     

基于方差检测的自适应机动目标跟踪算法

首先建立了机动目标跟踪的系统动态模型和观测模型,在此基础上提出并分析了基于方差检测的状态自适应调整滤波器,针对不加自适应修正的Kalman滤波在机动目标跟踪中的不足,通过仿真验证了基于方差检测的状态自适应调整滤波器的正确性和可行性.     

A novel STAP method for the detection of fast air moving targets from high speed platform

Space-time adaptive processing (STAP) is an effective method for detecting moving target in airborne/spaceborne radar.However,the detection of fast air moving targets from high speed platform is challenged by the range walk of both the clutter and moving targets.It is well known that keystone formatting can be used to compensate for the range walk of multiple moving targets simultaneously without using the knowledge of the motion parameters.However,in the presence of serious Doppler ambiguity of fast air moving targets,distribution of the clutter will be affected by the keystone formatting matched to the ambiguity number of targets,and as a result the STAP performance will degrade.In this paper,a novel STAP method is proposed for the detection of fast air moving targets from high speed platform,which can deal with the range walk of both clutter and targets.Effectiveness of the new method is verified via simulation examples.     

机载MIMO雷达两级降维空时自适应处理方法

针对机载多输入多输出( Multiple-input multiple-output,MIMO)雷达杂波抑制问题,提 出一种两级降维空时自适应处理 方法。首先利用多普勒滤波对杂波信号进行时域降维处理;然后将空域发射 接收二维波束 形成权矢量重构为发射权矢量和接收权矢量Kronecker积形式,并将高维权矢量转化为两个 低维权矢量进行分别求解,最后进行权矢量合成。该算法能够有效降低训练样本数需求与运 算复杂度,在小样本条件下具有良好的杂波抑制性能,因此更具有实际应用价值。仿真结果 验证了算法的有效性。     

利用先验信息的幅度-相位联合STAP样本选取方法

针对分立杂波和强目标信号等引起的机载雷达杂波非均匀特性,提出一种利用先验信息的幅度-相位联合选取样本的方法,利用杂波多普勒频率与入射角度之间的先验关系,将检测多普勒通道在特定角度的幅度最强的单元作为样本集,确保对分立杂波的对消深度,再通过相位检测方法剔除样本集中相位明显偏离相位期望的样本,克服样本集包含目标信号引起的目标自相消效应。通过某机载相控阵雷达的实测数据比较研究表明,该方法较传统样本选取方法更具优势,且计算量较小便于工程采用。     

Reduced-rank space-time adaptive detection for airborne radar

For airborne radar,there are usually insufficient independent and identically distributed(IID)training data because of geometric considerations and terrain variations.The rank reduction technique is one of the most effective approaches to circumvent this problem.In this study,we investigate four reduced-rank spacetime adaptive detectors for airborne radar,namely,the reduced-rank sample-matrix-inversion(RR-SMI),the reduced-rank adaptive matched filter(RR-AMF),the reduced-rank adaptive coherence estimator(RR-ACE),and the reduced-rank generalized likelihood ratio test(RR-GLRT).Their asymptotic analytical probabilities of detection(PD’s)and false alarm(PFA’s)are all derived.These detectors all asymptotically attain a constant false alarm rate(CFAR).It is shown that these four reduced-rank detectors exhibit detection performance which is better than or comparable to that of two existing reduced-rank detectors,proposed by Reed and Gau(RG1and RG2).Moreover,these four reduced-rank detectors are more robust to change in power of clutter and noise than RG1 and RG2.     

基于DPSS投影矩阵的单通道运动目标检测方法

为了提高机载单通道雷达在低多普勒分辨率情况下的运动目标检测性能,提出了一种基于离散长球序列(DPSS)投影矩阵的运动目标检测方法.首先根据系统参数构造DPSS投影矩阵,然后利用正交DPSS投影矩阵抑制主瓣杂波,最后在多普勒域进行运动目标检测.该方法在抑制主瓣杂波的同时能够比较好地保留目标的能量,能够明显提高目标的检测性能.仿真实验验证了上述方法的有效性.     

Detection,parameter estimation and imaging of maneuvering target in wide-band signal

The signal-to-noise ratio may be increased by the cross-range coherence integration so as to detect the moving target in low signal-to-noise ratio (SNR) condition. But, the radial velocity, acceleration and the change of acceleration due to the maneuvering motion of target may induce serious range migration and cross-range high-order phase terms leading to the unfocused cross-range image, the reduction of signal-noise ratio and the invalidation of target detection. Therefore, in order to solve these problems, this paper proposes a new method based on the adjacent correlation and scale transform methods for detection, parameters estimation and imaging of maneuvering targets in wide-band signal. This method can align the range and remove the cross-range high-order phase terms induced by the radial motion of target, enabling us to detect the target and estimate its moving parameters better. Finally, the simulated target is used to confirm that the method proposed by this paper can perfectly detect the maneuvering target in low signal-to-noise ratio condition, estimate its motion parameters and obtain an ISAR image of target. Supported by the National Natural Science Foundation of China (Grant No. 60502044), and the Program for New Century Excellent Talents in University (Grant No. NCET-06-0861)     

Ground moving target detection and location based on SAR images for distributed spaceborne SAR

In recent years, a new concept of spaceborne SAR implementation has been propos- ed[1,2], i.e., the distributed (constellation) spaceborne SAR implementation in which sev-eral formation-flying small satellites (or micro-satellites) cooperates to perform multiple missions. The coherent combination of ground echoes acquired by all small satellites can significantly improve the performance of ground moving target indication (GMTI), SAR mapping, interferometric SAR (InSAR), etc. Since the …     

机载双基地雷达STAP分析

空时自适应处理(STAP)是机载雷达信号处理中的一项关键技术,近年来机载双基地雷达STAP的研究成为热点.机载双基地雷达表现出复杂的杂波特性,即严重的杂波距离相关性,导致传统STAP方法杂波抑制性能严重下降.为此,本文首先对现有解决机载双基地雷达STAP面临的杂波距离相关性问题的典型方法的机理和特点进行了分析,然后对各...