基于时频域特征融合的IR-UWB穿墙雷达人体行为识别方法

冲激脉冲(impulse radio,IR)超宽带(ultra-wideband,UWB)穿墙雷达因其良好的穿透性和距离分辨率在穿墙人体行为识别领域具有重要作用,但是常规识别方法仅采用单域特征对行为模式进行描述,识别准确率不高。针对这一问题,提出基于时频域特征融合的IR-UWB穿墙雷达人体行为识别算法。首先,通过杂波抑制及距离补偿方法获取高信噪比的人体行为距离像。其次,基于距离像提取目标时域特征,与频域特征进行融合,构建数据集。最后,基于支持向量机(support vector machine,SVM)算法对人体行为进行识别。实验结果表明,所提算法对于IR-UWB穿墙雷达人体行为识别能够达到95%的准确率。

引入时距信息的IR-UWB雷达多域特征融合呼吸模式识别方法

人体呼吸系统相关疾病常常伴随着呼吸深度和节律的异常,因此呼吸信号监测和呼吸模式识别在医疗健康领域中尤其是对于睡眠监测、疾病预断具有重要意义。其中,非接触式的脉冲式超宽带雷达(Impulse Radio Ultra-Wideband,IR-UWB)因具有良好的距离分辨率和穿透能力以及全天候全天时、安全无创的检测优势,正逐步成为睡眠健康监护领域中最关键的感知技术之一。然而受睡眠监测特定的室内场景影响,复杂的测量环境给呼吸模式特征的准确提取带来了限制和挑战,传统的雷达呼吸模式识别算法主要关注一维呼吸时、频域特征,而IR-UWB雷达目标回波信息分散在多个距离门内,使用一维特征识别准确率较低。为此,本文针对IR-UWB雷达中人体呼吸在时间上慢速起伏运动、在距离上是扩展目标的信号模型特点,提出了一种引入时距信息的IR-UWB雷达多域特征融合呼吸模式识别方法。算法在提取一维呼吸信号波形时、频域特征的基础上更进一步挖掘雷达二维时距图像中潜在的呼吸模式形态特征,通过多域特征融合实现呼吸模式的非接触式检测和识别。在图像处理上,针对图像受呼吸异常节律影响呈现局部粘连特性导致呼吸周期提取难的问题,提出一种通过相位矩阵图像处理来检测雷达图像中的呼吸时距条带从而获取图像特征的方法。实验结果表明,利用该算法提取的多域特征对六种呼吸模式进行机器学习的分类识别,可以实现96.3%的识别准确率。

面向钻孔救援的UWB雷达探测技术研究进展

钻孔救援技术在我国已有多起成功救援的案例,但目前用于钻孔救援的探测设备不能满足穿透探测需求,无法利用终孔打偏或造成坍塌的钻孔。UWB雷达具有穿透能力强、抗干扰能力强等诸多特性,可很好地适应灾后矿井环境,实现对障碍物后方的穿透探测。为此,通过文献调研,从UWB雷达定位技术和UWB雷达成像技术两方面总结梳理了基于钻孔救援的UWB雷达探测技术的研究进展。总结出当前UWB雷达定位技术和成像技术在探测方式与装备、探测技术与理论以及回波信息处理技术与算法三方面存在的主要缺陷。针对性地提出了未来研究工作的重点:①研发基于钻孔救援的UWB雷达标识卡定位技术与装备;②结合距离选通技术、改进信息处理程序及CT领域算法研发、优化数据处理技术与算法;③通过雷达阵列分布、ICA算法、改进随机共振算法及融合主流技术构建生命信息识别系统。

融合全局与局部特征的UWB雷达人体动作识别算法

为了消除雷达信号中杂波和噪声对人体动作识别的干扰,提高小样本数据下动作识别的精度,在去除杂波及噪声干扰的基础上,提出一种融合全局与局部特征的超宽带(ultra-wideband,UWB)雷达人体动作识别算法。用动目标指示(moving target indication,MTI)结合自适应中值滤波对雷达原始回波信号进行预处理,再对人体动作的雷达二维特征图像利用主成分分析(principal component analysis,PCA)提取主要分量作为全局特征表征,并用二维离散小波变换(2D discrete wavelet transform,2D-DWT)结合奇异值分解(singular value decomposition,SVD)获取特征图像在不同方向与尺度划分下动作的局部特征表征,并将全局与局部特征进行串联融合;根据融合特征,在网格搜索算法(grid search,GS)优化的支持向量机(support vector machines,SVM)模型中实现人体动作的识别分类。实验结果表明,该算法能有效获取雷达信号中的人体动作信息,平均识别准确率为95.63%,具有良好的识别性能。

Adaptive waveform design based on Morlet wavelet for ultra-wideband MIMO radar

For the issue of deterioration in detection performance caused by dynamically changing environment in ultra-wideband（UWB） multiple input multiple output（MIMO） radar, this paper proposes a novel adaptive waveform design which is aimed to improve the ability of discriminating target and clutter from the radar scene. Firstly, a sequence of Morlet wavelet pulses with frequency hopping and pulse position modulation by Welch-Costas array is designed. Then a waveform optimization solution is proposed which is achieved by applying the minimization mutual-information（MI） strategy. After that, with subsequent iterations of the algorithm, simulation results demonstrate that the optimal waveform design method brings an improvement in the target detection ability in the presence of noise and clutter.

SVD-TLS extending Prony algorithm for extracting UWB radar target feature

A new method, SVD-TLS extending Prony algorithm, is introduced for extracting UWB radar target features. The method is a modified classical Prony method based on singular value decomposition and total least squares that can improve robust for spectrum estimation. Simulation results show that poles and residuum of target echo can be extracted effectively using this method, and at the same time, random noises can be restrained to some degree. It is applicable for target feature extraction such as UWB radar or other high resolution range radars.

Dataset of human motion status using IR-UWB through-wall radar

Ultra-wideband(UWB)through-wall radar has a wide range of applications in non-contact human information detection and monitoring.With the integration of machine learning technology,its potential prospects include the physiological monitoring of patients in the hospital environment and the daily monitoring at home.Although many target detection methods of UWB through-wall radar based on machine learning have been proposed,there is a lack of an opensource dataset to evaluate the performance of the algorithm.This published dataset is measured by impulse radio UWB(IR-UWB)through-wall radar system.Three test subjects are measured in different environments and several defined motion status.Using the presented dataset,we propose a human-motion-status recognition method using a convolutional neural network(CNN),and the detailed dataset partition method and the recognition process flow are given.On the well-trained network,the recognition accuracy of testing data for three kinds of motion status is higher than 99.7%.The dataset presented in this paper considers a simple environment.Therefore,we call on all organizations in the UWB radar field to cooperate to build opensource datasets to further promote the development of UWB through-wall radar.

Human Respiration Rate Estimation Using Ultra-wideband Distributed Cognitive Radar System

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.

Algorithm for Gesture Recognition Using an IR-UWB Radar Sensor

This paper introduces a human gesture recognition algorithm using an impulse radio ultra-wide- band (IR-UWB) radar sensor. Human gesture recognition has been one of the hottest research topics for quite a long time. Many gesture recognition algorithms or systems using other sensors have been proposed such as using cameras, RFID tags and so on. Among which gesture recognition systems using cameras have been extensively studied in past years and widely used in practical. While it might show some deficiencies in some cases. For example, the users might not like to be filmed by cameras considering their privacies. Besides, it might not work well in very dark environments. While RFID tags could be inconvenient to many people and are likely to be lost. Our gesture recognition algorithm uses IR-UWB radar sensor which has pretty high resolution in ranging and adjustable gesture recognition range, meanwhile, does not have problems in privacy issues or darkness. In this paper, the gesture recognition algorithm is based on the moving direction and distance change of the human hand and the change of the frontal surface area of hand towards radar sensor. By combining these changes while doing gestures, the algorithm may recognize basically 6 kinds of hand gestures. The experimental results show that these gestures are of quite good performance. The performance analysis from experiments is also given.

HUID:DBN-Based Fingerprint Localization and Tracking System with Hybrid UWB and IMU

High-precision localization technology is attracting widespread attention in harsh indoor environments.In this paper,we present a fingerprint localization and tracking system to estimate the locations of the tag based on a deep belief network(DBN).In this system,we propose using coefficients as fingerprints to combine the ultra-wideband(UWB)and inertial measurement unit(IMU)estimation linearly,termed as a HUID system.In particular,the fingerprints are trained by a DBN and estimated by a radial basis function(RBF).However,UWB-based estimation via a trilateral method is severely affected by the non-line-of-sight(NLoS)problem,which limits the localization precision.To tackle this problem,we adopt the random forest classifier to identify line-of-sight(LoS)and NLoS conditions.Then,we adopt the random forest regressor to mitigate ranging errors based on the identification results for improving UWB localization precision.The experimental results show that the mean square error(MSE)of the localization error for the proposed HUID system reduces by 12.96%,50.16%,and 64.92%compared with that of the existing extended Kalman filter(EKF),single UWB,and single IMU estimation methods,respectively.

UWB radar target recognition based on time-domain bispectrum

Complex targets are irradiated by UWB radar, not only the mirror scattering echoes but also the multiscattering interacting echoes are included in target echoes. These two echoes can not be distinguished by classical frequency spectrum and power spectrurm. Time-domain bispectrum features of UWB radar signals that mingled with noise are analyzed, then processing this kind of signal using the method of time-domain bispectrum is experimented. At last, some UW-B radar returns with different signal noise ratio are simulated using the method of time-domain bispectrum Theoretical analysis and the results of simulation show that the method of extraction partial features of UWB radar targets based on time-domain bispectrum is good, and target classification and recognition can be implemented using those features.

UWB雷达在矿山钻孔救援中的应用研究

超宽带(UWB)雷达探测技术可实现面向钻孔救援的矿井人体目标探测,但UWB电磁波易受灾变矿井复杂环境影响,UWB雷达回波信号易受到灾变矿井背景杂波、环境噪声影响,导致难以实现灾变矿井人体目标精准探测。针对上述问题,介绍了基于UWB雷达的井下目标探测场景及人体目标探测原理,分析了UWB电磁波特性研究现状和UWB回波噪声滤除方法研究现状。总结了存在的问题:①UWB电磁波在灾变矿井复杂环境中的传播特性需深入研究。②背景杂波产生原因尚未明晰,灾变矿井背景杂波与环境噪声滤除技术研究较少。③面向钻孔救援的UWB雷达人体目标探测技术仍需改进。针对现有技术的不足,展望了面向钻孔救援的UWB雷达井下人体目标探测技术的发展趋势:①深入研究UWB电磁波穿透传输关键表征参数对井下复杂环境特征的敏感程度。②构建适用于灾变矿井的背景杂波与环境噪声滤除方法。③深入优化面向钻孔救援的UWB雷达人体目标探测技术。

Optimization of the UWB Radar System in Medical Imaging

During the last decades, we have witnessed a widespread deployment of the ultra wide band (UWB) radar systems. Considering a medical field, an algorithm optimizing these systems is pointed out in this contribution. Beginning with the description of the UWB radar system, this algorithm has proved to be not only able to take a medical image of the human body but also capable of diverting the human tissue. Moreover, we insist on the fact that this algorithm can easily optimize different radar parameters. So, the human body layer width, the incident angle and the frequency maximizing reflection coefficient are estimated in this paper.

Performances of Micropower UWB Radar Using Orthogonal Waveforms

Radars and their applications were, for a long time, reserved to national defense, air security or weather service domains. For a few years, with the emergence of new technologies, radar applications have been developed and have become known in the civil domain. In particular, the arrival of UWB—Ultra-Wideband technology allows the design of compact and low-cost radars with multiple fields of application. In this paper, we focus on road applications, such as driving assistance with the objective of increasing safety and reducing accidents. In classical UWB radar systems, Gaussian and monocycle pulses are commonly used. In previous works, original waveforms based on orthogonal functions (Hermite and Gegenbauer) were proposed. These provide a good spatial resolution, suitable for radar detection. Another advantage of these waveforms is their multiple access capability, due to their orthogonality. The aim of the study presented in this article is to compare simulation and experimental results obtained, especially for short-range anticollision radar application, using these waveforms in one part and Gaussian and monocycle pulses in the other part. The originality of this paper relies on the new approach. Indeed, this comparison study using these waveforms has never been done before. Finally, some examples of real experiments in a real road environment with different waveforms are presented and analysed.

面向钻孔救援的UWB雷达回波信息处理关键问题研究进展

钻孔救援技术作为一种生命通道快速构建的新型救援技术已得到广泛应用。UWB雷达可基于钻孔实现非视条件下的人员生命信息探测,但UWB雷达回波易受井下环境噪声、背景杂波和探测目标运动状态影响,难以从中获得有效的被困人员生命信息。对基于钻孔救援的UWB雷达回波信息处理研究现状进行归纳总结:从杂波滤除方法、算法和模型3个方面对杂波的滤除现状进行梳理总结;从时域/频域分析方法、时频分析方法、数字处理技术和其他处理方式4个方面对有效特征提取的研究现状进行归纳;得出当前在钻孔救援中UWB雷达回波信息处理存在的主要问题:杂波滤除技术和滤除种类比较单一且缺乏滤波后信息验证、缺乏多类型的微多普勒特征提取、矿井灾害环境下UWB雷达回波信息处理研究较少、现有信息处理设备不能满足矿山钻孔救援需求。提出UWB雷达回波信息处理在钻孔救援中的发展趋势:(1)结合时频分析方法和多域处理进行杂波滤除研究;(2)利用神经网络模型研究基于钻孔救援的UWB雷达回波成分,并与地面环境对比;(3)运用ICA算法提取多种微多普勒特征,利用同步挤压短时傅里叶变换提取运动特征,基于互相关的联合多距离门信号的体征提取算法加强心跳信号提取;(4)研发融合多领域技术设备满足钻孔救援需求,扩充井下回波数据训练集,建立深度自学习的有效特征数据库。

Zero-Index Metamaterial Superstrates UWB Antenna for Microwave Imaging Detection

Metamaterials(MTM)can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice.Note that the antenna is the element for realizing a microwave imaging(MWI)system since it is where signal transmission and absorption occur.Ultra-Wideband(UWB)antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna.The lack of conventional head imaging techniques,for instance,Magnetic Resonance Imaging(MRI)and Computerized Tomography(CT)-scan,has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems.Furthermore,the importance ofMWIhas been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis.Other than that,MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reasonings.This paper proposes the novel design of a Zeroindex Split RingResonator(SRR)MTMelement superstrate with a UWB antenna implemented in MWI systems for detecting tumor.The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB.Besides that,the MTM imitates the conduct of the zeroreflection phase on the resonance frequency,which does not exist.An antenna with an MTM unit is of a 7×4 and 10×5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna.Apart from that,Rogers(RT5880)substrate material is employed to fabricate the designed MTM unit cell,with the following characteristics:0.51mm thickness,the loss tangent of 0.02,as well as the relative permittivity of 2.2,with Computer Simulation Technology(CST)performing the simulation and design.Both MTM unit cells of 7×4 and 10×5 attained 0°with respect to the reflection phase at the 2.70 GHz frequency band.The first design,MTM Antenna Design 1,consists of a 7×4 MTM unit cell that observed a rise of 5.70 dB with a return loss(S11)−20.007 dB at 2.70 GHz frequency.The second design,MTM Antenna Design 2,consists of 10×5 MTM unit cells that recorded a gain of 5.66 dB,having the return loss(S11)−19.734 dB at 2.70 GHz frequency.Comparing these two MTM elements superstrates with the antenna,one can notice that the 7×4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10×5 MTM element in realizing MTM element superstrates antenna for MWI.

基于钻孔救援的UWB雷达波传输衰减研究及展望

快速精准地获取井下受灾人员位置是钻孔救援前期生命信息探测的关键问题。针对在垂直钻孔救援过程中,由于探测区域巷道坍塌或终孔位置偏移,无法快速准确地获取被困人员位置,耽误救援的黄金时间,影响人员生命安全的问题,通过开展UWB雷达波传输衰减研究,为现场救援指挥人员快速制定救援方案。分析了UWB雷达波应用于矿山钻孔救援的现状和需求,并结合矿山钻孔救援背景,指出UWB雷达波传输衰减规律,从介质的各向同异性分析了介质的特性参数对雷达波传输衰减的影响;从介电常数、电导率、磁导率和时空变化4个方面分析了介质的电性参数对雷达波传输衰减的影响;从雷达频率和极化2个方面分析了雷达特征参数对雷达波传输衰减的影响。根据上述分析,指出目前对UWB雷达波同时穿透煤岩体等各向异性介质的研究和介质传播衰减机理研究较少;在井下复杂多变或模拟受灾后环境的UWB雷达波传输衰减理论与实验较少,相关规律总结较少;UWB雷达波关键参数与影响因素之间的映射关系数据库尚未完善。并给出未来需研究的关键技术:(1)对煤岩体等各向异性介质在宏观与微观上进行研究;(2)搭建灾变环境条件下雷达波传输衰减实验模拟系统;(3)增加灾变后非结构环境下UWB雷达信号传播特性的研究与信道建模数值模拟。

UWB MIMO穿墙雷达的阵列设计和成像方法

利用多发多收(MIMO)方式对超宽带(UWB)穿墙成像雷达天线阵列进行稀疏化处理不失为一种很好的选择。该文从成像模型出发,分析了UWB MIMO天线阵的等效接收阵列问题,给出了基于空间卷积理论的UWBMIMO阵列设计方法,仿真验证了方法的有效性和在穿墙成像系统中应用的可行性。此外,提出了相干系数加权稳健Capon波束形成的自适应成像方法,理论分析和实验结果表明该方法能够获得较高的分辨率和图像信噪比。

基于二维映射的LFMUWB雷达动目标速度估计

针对线性调频超宽带雷达动目标存在的距离-多普勒耦合以及多普勒色散对测速的影响,该文采用了频率-多普勒平面的2维映射方法。首先将接收的脉冲串回波,通过快-慢时间的2维傅里叶变换获得相应的频率-多普勒2维平面。然后,利用2维映射处理,将超宽带信号映射为窄带信号,实现多普勒域能量的聚焦。最后,根据映射后的窄带信号对应的多普勒频率获得目标径向速度。该方法不但有效地解决了超宽带雷达多普勒色散对测速的影响,而且规避了由于目标沿距离维的走动引起的慢时间域不能有效的能量积累。通过速度估计值,进行运动补偿后可获得目标距离像。此外,根据相关条件,进一步推导了速度适应范围。仿真实验结果验证了该方法的有效性。

VHF/UHF UWB SAR基于通道均衡的RFI抑制方法

对工作于甚高频/超高频(VHF/UHF)波段的超宽带合成孔径雷达(UWB SAR),射频干扰(RFI)会严重恶化图像质量。该文提出了一种基于通道均衡的RFI抑制方法,它能有效地抑制雷达接收信号中的RFI分量,同时保持图像质量。实际的处理结果证实了该算法的有效性。