共查询到18条相似文献,搜索用时 468 毫秒
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从理论上对LFM-CW雷达进行信号分析,并对LFM-CW雷达的信号处理方法进行简单研究,最后通过仿真程序验证了该信号处理方法(距离/多普勒处理)在计算运动目标距离和速度时的正确性,为LFM-CW雷达信号处理提供了理论依据. 相似文献
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DDS技术在线性调频连续波雷达中的应用 总被引:5,自引:1,他引:5
直接数字式频率合成(DDS)作为一种新的频率合成技术,它可以实现从信号参数到信号波形的转换。在传统的线性调频连续波雷达测距系统中,通过三角波发生器对压控振荡源(VCO)进行调制,输出线性调频连续波雷达(LFM-CW)信号,但是压控振荡源的扫频非线性以及很低的频率分辨率对LFM-CW雷达的测距精度产生很大的影响。文中将直接数字式频率合成技术引入LFM-CW雷达,代替压控振荡源,很好的解决了该问题。FFT频谱分析用DSP实现,系统控制用单片机完成,终端采用液晶显示。 相似文献
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一种超分辨距离多普勒成象方法 总被引:1,自引:2,他引:1
众所周知,距离多普勒成象雷达的距离分辨力和横向分辨力分别取决于发射信号的有效带宽和目标相对于雷达视线在相干处理区间内的转角,本文的研究工作旨在突破普通的FFT距离多普勒处理的限制,大大提高距离多普勒成象雷达的分辨能力,我们采用的方法是在进行付里叶重建之前用线性预测进行数据外推,用微波暗室试验数据进行转台成象的初步结果表明,这是一种改善距离多普勒成象雷达分辨能力的颇有前途的方法。 相似文献
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基于核函数的雷达一维距离像目标识别 总被引:6,自引:0,他引:6
该文分析了基于核函数的三大模式识别方法(支持向量机、非线性主分量分析、非线性判别分析)的分类机理,并将其应用于雷达一维距离像目标识别中。用3种飞机实测雷达距离像数据样本进行识别研究,结果表明对于雷达目标距离像识别,支持向量机方法较其它两种方法更为有效,并对实验结果给出了合理的解释。 相似文献
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根据雷达高分辨距离像具有非最小相位和小波特征的信号性质,采用Z变换方法给出和研究了高分辨距离像的微分复倒谱的性质,提出用微分复倒谱方法实现雷达距离像幅度归一化和实现距离像方位对齐的原理及其算法,数值计算和实测雷达数据的计算机仿真结果表明,理论分析是正确的,提出的算法是可行的;该方法适用于雷达目标识别。 相似文献
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为解决常规线性调频雷达存在的距离速度耦合和近距离盲区等问题,提出一种采用大占空比双线性间断调频脉冲信号的准连续波体制雷达。该雷达在一个脉冲重复周期内分时交替发射频谱互不重叠的两个线性调频脉冲信号,接收机通过发射信号分离、Stretch处理、时域互相关、FFT、运动补偿等过程可以在一个脉冲重复周期内获得运动目标的速度估计值和距离估计值。本文首先给出了该雷达的信号模型和距离速度去耦合原理,分析了系统性能,最后讨论了尚需解决的关键问题。 相似文献
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This paper presents the system design and experimental results of a 35GHz coherent LFM-CW radar for use in near range two-dimensional imaging. Special techniques, including FM sweep linearization, range-segment processing, system background voltage suppression and dynamic range compression are also presented. 相似文献
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线性调频连续波雷达的等效正交双通道性能 总被引:6,自引:0,他引:6
本文通过理论分析和实验研究,证明了线性调频连续波雷达可以用单通道获得等效的正交双通道性能,为简化相干线性调频连续波雷达的通道结构提供理论依据。 相似文献
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宋景唯 《电子科学学刊(英文版)》1995,12(1):66-72
A technique for measuring the linearity of a linearly frequency-modulated continuous wave (LFM-CW) signal is presented. It uses a delay-line and a mixer to sense the slope of the output of a sweep oscillator, so that the original form of frequency function deviated from idealized linear slope is retrieved by means of spectrum analysis. Consequently,the linearity of the LFM signal is determined. The formulation is performed based on the principle that an angle-modulated signal can be approximated by an amplitude-modulated signal if the modulation coefficient is sufficiently small. To examine the validity of the procedure and to study the effect of each parameter on the accuracy of measurement, a number of computer simulations has been made. The results of simulation show that the error of the measurement is less than 2%. 相似文献
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Radar interferometry opens a very wide field of new applications to synthetic aperture radar data. Although some of them could be satisfied with relative calibration of the phase signal over a short range, many of the applications linked to geophysics would require a global calibration of the signal. This calibration should ideally be valid over several hundred kilometers. Among the potential artefacts to be taken into account to fulfil this requirement are atmospheric thickness variation, improper orbit modeling, spacecraft vibrations. In order to eliminate such artefacts, the orbits must be properly tuned. This can be done by taking advantage of the limited number of the parameters which govern orbital positions. In this paper, the authors show evidence that the internal clock aboard the ERS-1 satellite can cause phase artefacts. The evidence is obtained through the analysis of a very long segment of ERS-1 data, in which the fringe patterns show features which can be caused only by a drift of the internal dock. A linear drift with time is sufficient to explain the phenomenon: the total frequency change over a five minutes orbital segment is of the order, of 5000 Hz. The drift is characterized and its consequences are detailed, in particular on the image geometry. Some new specifications are given which should avoid such an artefact in future SAR systems: with the features of ERS-1, the clock should stay within 200 Hz of its nominal value during the largest interferometric segment envisaged for the mission 相似文献