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针对调频连续波合成孔径雷达(FMCW SAR)用于单基机载平台时无法实现发射和接收隔离的难题,提出了基于中断连续波(FMICW)的单基机载SAR成像研究。基于FMICW的信号特点,详细讨论了FMICW用于SAR成像时门控脉冲宽度、门控脉冲重复频率、门控脉冲周期数、扫频频率等参数的制约关系,给出了FMICW SAR的系统结构,并有针对性地分析了信号处理模块。最后结合距离多普勒(RD)算法对FMICW SAR进行成像仿真试验,对模型进行了验证。结果表明机载FMICW SAR不但可以有效解决收发隔离,并且可以实现对目标的精确成像。 相似文献
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为了解决单脉冲雷达体制中距离分辨率与实际探测距离之间的矛盾,现有雷达一般采用(线性)调频中断连续波(FMICW)体制。根据模糊函数定义推导出(线性)调频中断连续波信号的模糊函数,并对重复周期FMICW信号的距离和多普勒分辨性能进行了分析与研究。分析结果表明,FMICW信号的距离分辨率仅与其发射波形带宽有关,而多普勒分辨率仅与其相干积累时间有关,这对进一步研究雷达新体制有一定的帮助。 相似文献
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针对传统的线性调频连续波(FMCW)雷达在多目标检测中存在距离速度耦合的缺陷,[JP]提出了一种FMCW+CW的改进方法,利用CW回波多普勒频率估算出的速度来剔除雷达多目标检测中存在的虚假目标,有效地解决了从多目标中检测真实目标的问题,并能估算出目标的速度和距离信息。计算机模拟仿真的结果证明了理论分析的正确性和新方法的有效性。 相似文献
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根据线性调频中断连续波(FMICW)的原理,结合OSMAR2000雷达总体设计要求,在满足无距离混迭、无Doppler频谱混迭的前提下,兼顾其它性能指标,本文重点介绍了波形参数的设计过程。 相似文献
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线性调频连续波雷达的一种信号处理方法 总被引:1,自引:1,他引:0
线性调频连续波(LFMCw)雷达具有距离和多普勒频率分辨率高,结构简单,体积小,重量轻和良好的低截获概率特性,得到了广泛的应用。对线性调频连续波雷达的目标回波信号进行分析,使用差拍一频谱分析-MTD的方法进行仿真,从回波信号中提取目标的相位信息,从而获取目标的距离和速度信息,该方法可有效地抑制固定杂波,方便动目标检测。 相似文献
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Detection and discrimination of radar targets 总被引:1,自引:0,他引:1
A new method for detection and discrimination of radar targets is described. The basis for this method is that the gross structure of a radar target can be identified from scattered fields of the target at harmonic radar frequencies located just in the low resonance region. This is in sharp contrast to many target signature schemes that operate at much higher frequencies and observe many of the details of the target in lieu of its gross features. Multiple frequency radar scattering data and the complex natural resonant frequencies of radar targets are integrated into a predictor-correlator processor. The method is illustrated using as target models both classical shapes and thin-wire configurations of simple geometry. Integral equation programs are utilized to calculate multiple frequency backscatter data for the wire geometries and to deduce the complex natural resonant frequencies of the wire structures. Discrete multiple frequency radar scattering data spanning a particular spectral range are shown to be desirable for optimum capability but discrimination and detection can be achieved using just two near-conventional radars, even if the radars are located at different sites and hence view the target from different aspects. 相似文献
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多载频MIMO雷达的一种新的信号处理方法 总被引:2,自引:2,他引:0
多载频MIMO雷达(Multi-Carrier MIMO radar)是指利用频率分集和空间分集的方法来实现发射信号正交的具有多个发射和多个接收天线的雷达系统,该文研究了该体制雷达基于Dechirp处理实现距离高分辨的方法,分析了IFFT相参合成法以及伪峰产生原因,提出了一种新的处理方法空域合成带宽法,它将空域分散发射的多载频LFM信号,先做Dechirp处理,然后再将通道分离后的各路信号顺序时移拼接合成一个大带宽的LFM信号,最后再对合成后的信号做IFFT处理以获得高分辨距离信息。它实现简单,能够在不增加运算量的条件下有效的抑制伪峰,并受目标运动影响小,计算机仿真验证了这些结论。 相似文献
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Anil Kumar Vuppala K. Sreenivasa Rao Saswat Chakrabarti 《AEUE-International Journal of Electronics and Communications》2012,66(8):697-700
Vowel onset point (VOP) is the instant at which the onset of vowel takes place in the speech signal. Accurate detection of VOP is useful for applications such as consonant–vowel (CV) unit recognition and speech rate modification. Existing VOP detection methods determine VOPs within 40 ms deviation, which may not be suitable for the applications mentioned above. In this paper, a two level approach using multiple sources of evidence is proposed for the accurate detection of VOP. In the proposed method, at the first level, VOPs are identified by combining the complementary evidence from excitation source, spectral peaks and modulation spectrum. At the second level, hypothesized VOPs are verified (genuine or spurious), and their positions are corrected using the uniform epoch intervals present in vowel region. Zero frequency filter method is used to determine the epoch locations in speech. Performance of the proposed method is analyzed using TIMIT database, and compared with the recent method which uses the combination of evidence from excitation source, spectral peaks and modulation spectrum. Using the proposed method about 85% of VOPs are detected within 10 ms deviation. 相似文献
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WiFi (Wireless Fidelity)信号具有覆盖范围广、带宽大等优点,利用其作为外辐射源进行探测可达到较高的距离与多普勒分辨率。该文分析了典型WiFi 信号的结构,建立了描述信号的数学模型,并针对双基地外辐射源雷达应用,探讨了典型WiFi 信号结构与其模糊函数特性的关系。同时根据模糊函数副峰出现的时频及幅度特征,结合信号构成分析了其产生机理,并提出了一种基于直达波提纯的副峰抑制方法,从而可避免副峰干扰在目标探测中带来的虚警。仿真结果表明了该信号分析与处理方法的有效性。 相似文献
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高分辨宽测绘带静态场景成像与运动目标检测与成像是星载合成孔径雷达(SAR)两个重要功能需求,也是新体制SAR的前沿和重点.现有的基于阵列接收多相位中心技术可解决方位分辨率与测绘带宽的矛盾,但其空时等效单通道数据难以实现运动目标的有效检测.现有的多通道SAR能改善杂波抑制和运动目标检测性能,但其对静态场景成像时仍存在方位分辨率与测绘带宽的矛盾.本文提出一种基于空时等效采样复用的信号处理新方法,同时改善了星载SAR在高分辨率宽测绘带静态场景成像与运动目标检测与成像两方面的性能.进而,本文深入研究目标径向速度在等效回波信号中引入的周期调制产生的目标方位像的"假峰"效应,并提出了有效的抑制"假峰"的补偿方法.最后,数值仿真试验验证了新方法的有效性. 相似文献
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Lei Wen Long Teng Han Yueqiu 《电子科学学刊(英文版)》2001,18(1):8-16
Stepped frequency signal is often used to synthesize high-resolution range profile, but redundant high-resolution range profile exists before synthesis. Two methods have been given to extract target from overlapped high-resolution range profile and analyzed to show how spurious peaks appear. This paper provides a reverse-count algorithm to resolve the problem of spurious peaks for moving target. This proposed method selects the peak with maximum amplitude as the extracted target and gets its position by using the number of samples prceding before the present sample position and the number of high-resolution range cell of the target. This proposed method is compared with the already given method and the result shows the ability of the proposed method to remove spurious peaks, it provides the foundation for high-resolution range profile. 相似文献
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雷达高距离分辨力需要大带宽发射信号,而雷达发射连续大带宽信号受硬件成本和频谱资源限制。利用多个窄带发射信号进行宽带合成时,由于窄带信号频谱不连续性和步进量的增大,会出现距离旁瓣增大、不模糊距离范围缩小的问题。为解决上述问题,并充分利用不连续或跨波段的频谱资源,提出一种用于宽带聚合的雷达稀疏频率配置方式。通过子频带之间的差分处理,获得等效的连续均匀步进虚拟频率信号,在获得高分辨力的同时避免距离旁瓣增大和距离模糊;对于频率跨度较大的子频带,提出了基于几何绕射理论(GTD)模型的目标散射特性频率一致性校正方法,并仿真分析了不同频率跨度对宽带聚合效果的影响和跨波段宽带聚合的可能性。该研究可进一步为雷达系统的后续兼容研究提供参考。 相似文献
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针对线性调频脉冲压缩雷达参数化检测高速多目标时受到距离徙动、多普勒扩散和速度模糊的影响,该文首先采用联合频域变标脉冲压缩处理与吕方法(2011)实现目标信号的相参积累,然后在其基础上采用基于多普勒频率模糊数搜索的方法完成高速多目标的参数化检测.算法所提出的频域变标脉冲压缩处理可同步完成距离维的徙动补偿与多普勒维的模糊数补偿,降低了实现目标参数化检测的计算复杂度,且由于算法采用相参积累方式,在低信噪比下可以进行精确的目标检测和运动参数估计.相参积累算法运算量分析、计算机仿真以及实测数据处理结果验证了该文所提算法的有效性. 相似文献
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