On detection performance of MIMO radar for Rician target

By using spatial diversity, multiple-input-multiple-output (MIMO) radar can improve detection performance for fluctuating targets. In this paper, we propose a spatial fluctuation target model for MIMO radar, where targets are classified as non-fluctuating target, Rayleigh target and Rician target. Based on Stein’s lemma, we use relative entropy to study detection performance of optimum detector for Rician target. It is found that in low signal noise ratio (SNR) region, the performance improvement of MIMO ra...     

Target models and waveform design for detection in MIMO radar

In this paper,we propose a general target model for multiple-input multiple-output(MIMO)radar.Two types of targets are presented.For each type of target,we develop a corresponding optimum waveform designing method to optimize detection performance.Based on Chernof-Stein lemma,we use relative entropy as the performance measure.We show that the optimum waveform designing method can obtain better detection performance than traditional orthogonal waveform designing method.     

极化MIMO雷达隐身目标检测性能研究*

多输入多输出(MIMO)雷达使用了远距分布的阵元,它利用了信号的空间分集增益来获取更多的目标信息。极化是另一种可以提高雷达系统性能的分集方式。当应对隐身目标时,传统的极化雷达在某些观测角度会遭受到较大的目标雷达截面积(RCS)衰减,而无法获得较好的检测性能。而在一个雷达系统中同时利用这两种分集增益,可以得到一种比传统极化雷达更具优势的新雷达检测系统——极化统计MIMO雷达,它可以更好地应对隐身目标检测。给出了相应的模型,并推导出了该雷达系统的检测性能解析式。将其与传统相控阵及非极化统计MIMO雷达比较,可以看到极化统计MIMO雷达的检测性能更佳。联系到隐身目标的特性,极化MIMO雷达的检测器特性应对它时具有显著优势。最后,以上方法通过仿真得到了验证。     

基于TDM信号的反无人机MIMO雷达系统

随着无人机威胁的日益增大,对低成本三坐标雷达的需求也逐渐增长。鉴于多输入多输出(multiple input multiple output, MIMO)技术已在通信领域得到了广泛应用,有效降低了硬件成本,可将MIMO技术引入三坐标雷达领域用于对无人机目标的探测。因此,介绍了一种基于时域复用(time-division multiplexing, TDM)信号的MIMO雷达系统。时域复用方式通过对发射单元发射时间的控制实现信号优良正交性能,并有效降低了信号产生单元与发射信道的复杂度。基于TDM信号形式,进行了MIMO雷达天线设计,给出了时分信号正交解调与数字波束形成处理的流程。计算机仿真也验证了TDM信号条件下的MIMO雷达点目标成像与波束形成的能力。     

Parameter identifiability of space-time MIMO radar

In multiple-input multiple-output (MIMO) radar, the maximum number of targets which can be uniquely identified, also known as the parameter identifiability, is one of the most basic issues. In this paper, the parameter identifiability is extended from the space-only MIMO radar to the space-time MIMO radar. According to the parameter identifiability conditions derived, the maximum number of targets which can be identified by the space-time MIMO radar is presented. Comparing with space-only MIMO radar, the parameter identifiability of space-time MIMO radar is significantly enhanced by exploiting both the spatial and temporal characteristics of the transmitted waveforms. The results are validated by several numerical examples.     

非高斯杂波下分置天线MIMO雷达的动目标检测*

目前关于分置天线MIMO雷达目标检测的研究多是假定杂波是服从高斯分布的,实际中非高斯杂波往往更能精确描述现代雷达环境下杂波的统计。考虑几种在高斯杂波模型假设下设计的检测器,构造了服从Log-Nomal分布的非高斯杂波模型。分别针对高斯杂波和非高斯杂波模型,对分置天线MIMO雷达和相控阵雷达做了系统性能曲线仿真,并在非高斯杂波模型下,对不同目标速度下的各雷达系统的检测器性能进行仿真,最终通过对比得到了一些有关在非高斯杂波背景下MIMO雷达性能的结论。     

基于多核DSP的MIMO雷达信号处理的实现

针对MIMO雷达多通道回波信号处理的同步性和实时性需求,在分析MIMO雷达信号处理的特点及多核DSP硬件结构的基础上,提出了一种基于多核处理器TMS320C6678的并行实现方法,并解决了使用过程中的诸多关键技术。该方法实现了多任务并行处理和高效通信。实验结果表明,该方法在较小规模的硬件平台上实现了较低功耗且高实时性的应用。     

MIMO雷达目标数量估计

给出MIMO雷达在距离-多普勒2维分辨单元处理和距离1维分辨单元处理情况下的信号模型。根据这两个信号模型各自的特点,分别构造信号的相关矩阵,将信息论准则和盖式圆准则应用于MIMO目标数量估计之中。仿真结果表明在白噪声情况下,信息论和盖式圆准则均可有效估计目标数量;在色噪声情况下,盖式圆准则可有效估计目标数量。     

MIMO雷达正交多相编码信号优化

为获得较好的波形分集增益与避免波形间串扰,MIMO（Multi-Input Multi-Output）雷达一般要求发射正交信号。已有的正交相位编码信号对多普勒偏移敏感,制约了其在MIMO雷达中的应用。提出一种具有较好多普勒容限的正交多相编码信号优化设计方法,联合考虑目标静止、匀速运动和匀加速运动场景下MIMO雷达脉压输出,并将其转化为一个多目标优化问题,基于自适应克隆选择算法进行求解。最后,进行仿真实验。结果表明,相比典型的Deng编码和Khan编码,设计的多相编码信号具有更好的正交性能、更大的速度、加速度容限,更适合MIMO雷达系统应用。     

Detection performance analysis for MIMO radar with distributed apertures in Gaussian colored noise

This paper establishes the classic linear model of signal of the MIMO radar system with distributed apertures. Based on this model,the design principle and detection performance of MIMO radar detector is investigated under conditions of Gaussian colored noise and partially correlated observation channels. First,the research on design principle of detector shows that the clutter suppression and matched filtering can be independently implemented at each receiving aperture,which greatly reduces the difficulty ...     

Multiple target localization & data association for frequency-only widely separated MIMO radar

The multiple target localization using only Doppler frequencies in Multiple-Input Multiple-Output (MIMO) radar is a problem of great interest. The Doppler frequencies include all relevant information about the location, velocity and direction of the targets. Hence, these frequencies can be used efficiently for data association and target localization. The MIMO configuration and the frequency diversity of the system enable us to easily determine the number of moving targets using only the Doppler frequencies. Then, the data association is achieved for the known number of targets by using the estimated target velocities, directions and positions which can be utilized together or separately for data association. Using these parameters, three data association methods are proposed, namely “Position & Velocity Based”, “Direction Based” and “Position, Velocity & Direction Based” Data Associations. Moreover, when probability of detection is less than unity, data association can still be achieved with some modifications. Besides that, another algorithm, referred to as “Frequency Reduction & Association”, is proposed to eliminate spurious frequencies when they appear in the spectrum. These are the first data association methods for Doppler-only systems and they can be used efficiently when Doppler frequencies are only available information in the MIMO radar context. After received frequencies are associated with the correct targets, multiple target localization can be performed using the associated Doppler frequencies.     

MIMO雷达长时间积累下的参数优选算法研究*

长时间积累是MIMO(多输入多输出)雷达最常用的工作模式,而包络走动会严重影响积累效果.针对上述问题,推导出基于MIMO雷达运动目标回波模型的积累输出与目标速度、信号带宽等关键因素的表达式,定量说明了包络走动与其影响因子之间的关系.该表达式可用于确定需要进行包络补偿的目标速度范围,并通过发射带宽等参数的优选,使包络走动...     

Transmitter polarization optimization with polarimetric MIMO radar for mainlobe interference suppression

Polarization diverse design of the transmit waveforms based on the property of the target scattering matrix provides better performance than transmitting waveforms with fixed polarizations, especially for mainlobe interference suppression applications. In this work, we propose a radar system combines the advantages of multiple-input–multiple-output (MIMO) systems with the advantages offered by optimally choosing the transmitter polarizations, in order to achieve a better mainlobe interference suppression performance. The polarization diversity is employed in the transmit array, while the receive array adopts 2-D vector sensors to measure the horizontal and vertical components of the received signal. The optimal transmitter polarizations can be obtained by maximizing the output signal-to-interference-plus-noise ratio (SINR) in each coherent processing interval (CPI). In addition, the discrimination method for the target and the interference is studied in this paper, along with the target scattering matrix estimation method. Simulation results demonstrate that interference can be effectively discriminated and suppressed with the radar configuration, and better interference suppression performance is achieved with the optimal transmitter polarizations.     

MIMO系统中低复杂度的MCMC迭代检测算法

针对多输入多输出(MIMO)系统中现行的马尔科夫链蒙特卡洛(MCMC)检测算法复杂度较高的问题,提出了一种SIC-MMSE算法辅助的MCMC检测算法,信号的预估计值和软信息均作为软输入软输出(SISO)检测器的输入,提高了吉布斯采样值的可信度,进而减少采样点数。仿真结果表明,同样的信噪比情况下,达到相同误码率时,与传统MCMC算法相比,改进MCMC算法的复杂度明显降低。     

A nested-PARAFAC based approach for target localization in bistatic MIMO radar systems

Bistatic MIMO radar systems gather several advantages such as increased resilience to electronic countermeasures, unknown receiver location, higher identifiability of targets and direct application of several high resolution adaptive techniques. In this paper, we propose a tensor-based method for joint direction of departure (DoD) and direction of arrival (DoA) estimation in bistatic MIMO radar systems. By assuming that the transmit array is divided into two maximally overlapping subarrays, we initially model the cross-covariance matrix of the matched filters outputs as a Nested-PARAFAC decomposition of a fourth-order covariance tensor. Then, exploiting the structure of this decomposition, we first propose a two stage algorithm for joint DoD and DoA estimation of multiple targets based on double alternating least squares (DALS). In addition, for scenarios in which the number of receive antennas exceeds the number of targets, we propose a closed-form solution to the second stage of the proposed method based on the least squares Khatri-Rao factorization (LS-KRF) concept. Simulation results show that the proposed method offers a highly-accurate localization of multiple targets in real-world scenarios where the antenna elements at the transmit and receive arrays have positioning errors as well as less complexity compared to competing state-of-the-art tensor-based solutions.     

数字子阵级MIMO雷达设计方法

设计并实现了一种集中式数字子阵级MIMO雷达实验系统,该系统在子阵间实现正交二相相位编码信号发射,接收端实现了子阵级发射数字多波束合成与接收数字多波束合成,有效完成了对民航飞机的观测。子阵多波束与子阵正交波形发射成倍简化了系统设计复杂度,具有良好的工程应用价值,使得MIMO雷达功能可作为数字相控阵雷达的典型工作模式在数字阵中推广应用。     

一种M~2发N~2收MIMO雷达平面阵列及其三维成像方法

具有二维合成孔径的宽带雷达阵列可实现对飞行目标的单次快拍实时三维成像,然而,这需要超乎实际的天线阵元,且当发射信号频率很高时,天线阵元间隔难以满足空间采样定律,造成方位分辨率的下降.本文提出了一种M2发N2收的MIMO雷达平面阵列,它可通过MIMO技术等效成具有(MN)2个阵元的均匀矩形阵列,实现对空中目标的实时三维成像.该MIMO雷达阵列还与ISAR技术相结合,利用ISAR的时间采样来替代实际阵元的空间采样,进一步减少实际天线阵元个数,同时也能增加采样密度,使采样间隔满足采样定律.本文基于该MIMO雷达阵列的实时三维成像模型和MIMO-ISAR三维成像模型均进行了推导和论证,仿真实验也验证了其有效性.     

基于自适应脉冲压缩-Capon滤波器的MIMO阵列雷达CFAR检测器

针对强杂波背景和有限训练样本数量条件下采用脉内编码压缩波形的MIMO阵列雷达目标检测问题,借鉴自适应波束形成技术中Capon最小功率估计器的相干源信号对消思想,提出了自适应脉冲压缩—Capon滤波器(简记为APC-Capon滤波器),并基于此滤波器的输出设计了一种CFAR检测器.理论分析和数值仿真均表明,该滤波器能够在执行非迭代自适应脉冲压缩并抑制各发射波形自相关距离旁瓣和互相关干扰的同时,实现杂波信号对消,即杂波抑制功能.检测性能仿真表明,尽管相同尺寸参数(包括发射阵元数、接收阵元数、脉冲编码位数、相参脉冲个数)条件下,所设计的基于APC-Capon滤波技术的CFAR检测器的性能不如训练样本数量充足时基于匹配滤波+样本矩阵求逆(SMI)技术的AMF检测器,但是随着尺寸参数的适当增大,前者的检测性能将逐渐超过后者在较小尺寸参数时的检测性能,且不显著增加计算复杂度和训练样本数量,而后者则因大尺寸参数时对计算复杂度和训练样本数量的需求过高而在实际中难以实现.仿真还表明,APC-Capon滤波器及其相应的CFAR检测器对发射波形的相关性(包括自相关性能和互相关性能)有一定的依赖性,但随着发射波形数量的增加,这种依赖...