共查询到17条相似文献,搜索用时 125 毫秒
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FMCW雷达快速高精度测距算法 总被引:15,自引:0,他引:15
在FMCW雷达测距系统中,单纯采用FFT方法通过峰值点确定单频信号频率时,要想提高精度就必须增加采样点数,结果使得提高测量精度和降低计算量成为矛盾,限制了FMCW雷达在高精度实时测距方面的应用,本文提出一种将FFT与Chirpz相结合提高FMCW雷达测距精度的新算法,理论计算和在Matlab下仿真表明,此算法可显著提高计算效率和精度。 相似文献
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基于FMCW雷达的非接触式心率估计方法具有舒适、便利等优势。由于噪声和呼吸谐波的干扰,现有方法的准确率仍存在一定局限。针对上述问题,提出了一种心率估计方法。在相位分析的基础上,对相位信号进行相位差分运算,以增强心跳信号,再通过改进的小波阈值去噪方法进行去噪处理,消除噪声干扰。在频率估计时,本文通过海明窗函数对心跳信号进行处理,再用多信号分类算法进行频率估计,可以解决信号截获造成的频谱泄漏问题,并提高多信号分类算法的分辨率和稳定性,从而降低呼吸谐波及噪声对心率估计的影响,获得准确的心率值。仿真结果表明,本方法提高了心率估计的准确性。 相似文献
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基于Gabor原子的雷达辐射源信号无意调制特征提取 总被引:1,自引:0,他引:1
针对雷达辐射源的个体差异,提出一种雷达辐射源信号无意调制特征提取方法。该方法在过完备Gabor原子库基础上,采用匹配追踪(matching pursuit)方法对具有相位噪声的常规雷达辐射源信号进行时频原子分解,得到表示常规雷达辐射源信号无意调制特征信息的最佳Gabor原子,将最佳Gabor原子时频参数以及重构信号和原始信号的相似度作为个体特征参数。.实验结果表明,提取的个体特征参数可以有效地表示常规雷达辐射源信号的无意调制。 相似文献
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调频连续波(FMCW)雷达在目标测量系统中有着广泛的应用,而雷达信号的处理是决定测量精确度的关键。本研究设计了一款基于DSP的线性调频连续波(LFMCW)雷达信号处理系统,采用经过三角波调制的 LFMCW雷达信号作为发射信号,来实现目标距离及速度的测量。介绍了 LFMCW雷达的基本结构,分析了实现目标测量的原理,解决了在信号处理过程中,仅采用快速傅里叶变换(FFT)算法而存在的频率分辨率与计算时间的矛盾,提高系统的测量效率。重点研究了雷达信号处理系统的处理算法———FFT 和线性调频 Z 变换(CZT)的联合算法(FFT/CZT 联合算法),同时对 FFT/CZT联合算法也进行了 MATLAB仿真分析。分析结果表明,FFT/CZT联合算法可以显著地提高雷达信号处理的效率和精度。 相似文献
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灵敏地检测和定位电缆缺陷对于电缆安全运行具有重要的作用。调频连续波(FMCW)法是一种基于频域反射法的电缆缺陷检测方法,该方法相对于宽频阻抗谱法具有更高的缺陷检测灵敏度及抗干扰能力。该文在现有FMCW方法的基础上,提出利用FMCW的相位敏感特性对电缆缺陷进行检测的方法,提高了现有FMCW方法缺陷检测的灵敏度。首先,结合FMCW相位敏感特性与电缆分布参数模型进行了电缆缺陷检测仿真;然后,在实验室的射频同轴电缆、10 kV交联聚乙烯(XLPE)电缆上模拟不同程度的缺陷并测试,观察缺陷处相位的变化情况,验证了所提方法的有效性。结果表明:相敏-FMCW方法对于射频及10 kV XLPE电缆上模拟的缺陷敏感,不同严重程度的缺陷相位变化量不同,缺陷处对应相位变化的取值区间可为180°。定义缺陷引起的相位、幅值变化量占取值区间的比例为灵敏度,相敏-FMCW方法可以提高现有FMCW方法对该文中所设缺陷检测的灵敏度:对于电缆局部异常温升造成的容性缺陷,当局部温差为37℃时,可将灵敏度由36%提升至71%;对于电阻性、电导性及铜屏蔽破损缺陷,相敏-FMCW方法的灵敏度均优于传统FMCW方法,检测灵敏度提升... 相似文献
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直接数字频率合成技术DDS,在现代雷达信号波形产生中具有重要的地位.本文主要介绍了基于DDS的宽带雷达信号产生的几项关键技术,提出了一种宽带捷变雷达信号的产生方案,并详细介绍了基于FPGA的DDS设计的基本原理、电路结构和设计优化方法.利用Altera公司Cyclone系列芯片并采用线性插值法进行设计与仿真,不仅很方便地产生了线性调频信号(LFM),并且所产生的信号具有频率分辨率高、频率转换速度快以及相位噪声低等优点.理论分析和计算机仿真结果均验证了该方案的正确性和有效性. 相似文献
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FMCW multiplexing of fiber Bragg grating sensors 总被引:2,自引:0,他引:2
Chan P.K.C. Wei Jin Suleyman Demokan M. 《IEEE journal of selected topics in quantum electronics》2000,6(5):756-763
We report on the use of frequency-modulated continuous wave (FMCW) techniques for multiplexing fiber Bragg grating (FBG) sensors. This technique is based on the modulation of light intensity from a broadband source by a linear swept-frequency RF carrier. Signals from the FBG sensors located at different positions in an array are separated in frequency domain and demodulated using a tunable optical filter. The potential and limitation of the technique are discussed. A three-sensor FMCW multiplexed FBG array of parallel topology and a six-sensor hybrid FMCW/WDM system were experimentally demonstrated with -30 dB crosstalk between sensors and 2 με resolution in terms of root mean square (RMS) strain value 相似文献
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Yi Liang Long Zhang Mengdao Xing Zheng Bao 《Frontiers of Electrical and Electronic Engineering in China》2009,4(2):127-133
The frequency modulated continuous wave (FMCW) radar has the characteristics of low probability of interception, good hidden
property and the ability to counter anti-radiation missiles. This paper proposes a new method for high-speed ground moving
target detection (GMTD) using triangular modulation FMCW. According to the characteristic of the opposite range shift induced
by the upslope and downslope modulation FMCW, the upslope and downslope are imaged, respectively. After compensation of continuous
motion of the platform and time difference between upslope and downslope signals for imaging, the moving target can be detected
through displaced phase center antenna (DPCA) technology. When the moving target is detected, the moving target image is extracted,
and correlation processing is used to obtain the range shift, which can be used to estimate the target radial velocity, and
further to find the real position of the target. The effectiveness of this method is verified by the result of computer simulation.
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Translated from Journal of Xidian University, 2008, 35(4): 586–591 [译自: 西安电子科技大学学报(自然科学版)] 相似文献
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为缓解新冠疫情下医护人员短缺的现象,实现对住院患者的智能监护,本文基于调频连续波(FMCW)雷达提出了一种
新的基于时空域增强微多普勒谱图的行为识别方法。 首先,该方法对雷达获取的人体行为数据构造微多普勒谱图;然后利用一
种新的直方图均衡化和同态滤波相结合的时空域增强算法用于谱图信息的增强;最后采用一种改进的卷积长短时记忆网络
(ConvLSTM)提取谱图的时空域特征,并有效辨识喝水、跌倒等 7 种住院患者常见行为。 实验结果表明,基于本文方法对 7 种动
作的识别准确率能达到 94%,可以有效的监护患者的行为。 相似文献
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Anton Glushchenko Vladislav Petrov Konstantin Lastochkin 《International Journal of Adaptive Control and Signal Processing》2021,35(6):1120-1137
The scope of this research is a problem of parameters identification of a linear time-invariant plant, which (1) input signal is not frequency-rich, (2) is subjected to initial conditions and external disturbances. The memory regressor extension (MRE) scheme, in which a specially derived differential equation is used as a filter, is applied to solve the above-stated problem. Such a filter allows us to obtain a bounded regressor value, for which a condition of the initial excitation (IE) is met. Using the MRE scheme, the recursive least-squares method with the forgetting factor is used to derive an adaptation law. The following properties have been proved for the proposed approach. If the IE condition is met, then: (1) the parameter error of identification is bounded and converges to zero exponentially (if there are no external disturbances) or to a set (in the case of them) with an adjustable rate, (2) the parameters adaptation rate is a finite value. The above-mentioned properties are mathematically proved and demonstrated via simulation experiments. 相似文献
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"自控变频同步电机"系统中的交流电机是箝位电动机 总被引:4,自引:0,他引:4
针对直流电动机中电枢磁动势的轴线位置由电刷决定的特征,提出了箝位概念,指出自控变频乃是箝位效应的直接后果。对作为电机类型名称的"同步"一词之含义作了明确地阐述,同步电动机是无箝位电动机,稳定运行的同步电动机内频率与本机转速之间的因果关系是以恒定的频率为因。直流电动机是箝位电动机,箝位效应使直流电动机中频率与转速的因果关系颠倒成以易变的转速为因,直流电动机具有优良的控制性能以及无振荡的特性都与箝位的存在密切相关。"自控变频同步电机"系统中的电动机应是交流箝位电动机,而不是同步电动机。 相似文献
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This paper proposes a contactless method to measure a surge voltage waveform on an overhead transmission line and on a cable sheath enclosed in a corrosion‐proof layer. To measure surge voltage and current waveforms on the overhead line, the method is based on electromagnetic coupling between the overhead line and a surge sensor, composed of a closed loop which is a distributed parameter line. The surge waveform is estimated from the induced voltage to the closed loop and from a Z‐parameter theory. To measure the cable sheath voltage waveform, the method is based on electrostatic coupling between the sheath and a detecting electrode, which is portable and detachable, and is composed of quite simple components, and its potential dividing ratio is adjustable using a lumped capacitor. The proposed method is inexpensive, is easy to measure surge waveforms with reasonable accuracy, and also is applicable to surge measurement on a live line because of its contactless nature. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 9–15, 2001 相似文献