共查询到18条相似文献,搜索用时 250 毫秒
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脉冲噪声下的时间延迟估计方法研究 总被引:2,自引:0,他引:2
针对室内脉冲噪声居多的情况,提出了一种根据噪声的分布特性,选用不同算法来实现时延估计.这里时延估计算法包括基于分数低阶和二阶统计量的方法.由于脉冲噪声服从低阶分布,采用分数低阶协方差方法.可以得到较好的时延估计精度及良好抗噪声能力和抗混响能力,比较适合室内的语音源定位. 相似文献
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以Alpha稳定分布作为噪声模型,研究了脉冲噪声环境下宽带双基地MIMO雷达系统中参数估计问题.针对在脉冲噪声环境中,基于传统的信号模型和算法效果显著退化的问题,本文提出了基于分数低阶统计量的宽带模糊函数算法.首先根据分数低阶宽带模糊函数的峰值点实现对多普勒频率尺度因子和时延的联合估计.接下来基于分数低阶宽带模糊函数构造两个子阵.通过采用改进的MUSIC算法和ESPRIT算法实现了收发角的联合估计.仿真实验表明本文算法具有很好的性能. 相似文献
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针对脉冲噪声条件下利用传统广义互相关法(Generalized Cross-Correlation,GCC)进行时延(TDOA,Time Difference of Arrival)估计性能退化问题,提出一种基于最小1-范数准则的TDOA参数估计算法.对于高斯噪声,传统GCC估计方法能够实现统计最优,但当噪声的统计分布为非高斯分布时,利用传统GCC参数估计方法的估计精度和鲁棒性急剧下降.利用最小1-范数准则,提出一种存在α-稳定分布重尾脉冲噪声环境下的TDOA估计算法.系统仿真实验与结果分析表明,与传统GCC方法和分数低阶矩(Fractional Lower Order Moments,FLOM)方法相比,该算法在鲁棒性和估计精度方面均有明显改善. 相似文献
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针对脉冲Chirp类信号的时延估计问题,理论推导了基于离散分数阶Fourier变换的脉冲Chirp信号的特性,分析了当时延参量等效的分数阶Fourier域的频率大于采样率时,脉冲Chirp信号的分数阶Fourier域谱产生混叠,造成时延估计模糊的问题,并提出基于离散分数阶Fourier变换(DFRFT)双通道互谱法进行时延估计,给出两个通道采样率选取的原则及算法的性能分析,实验结果表明,在一定的采样率下,算法能够快速精确地估计脉冲Chirp信号的时延参数. 相似文献
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该文针对稳定分布噪声模型,依据分数低阶矩理论提出一种新的非整数时延估计算法EFMML (Explicit Fractional lower order Mix Modulated Lagrange)方法。从理论上对算法的收敛条件进行了讨论,计算机仿真结果表明该方法具有良好的韧性,同时适用于高斯噪声和稳定分布脉冲噪声下的时延估计,且比另一种脉冲噪声下的非整数时延方法FSETDE(Fractional lower order Simplified Explicit Time Delay Estimation)更有效。 相似文献
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在多站时差定位系统中使用基于LMS自适应滤波的互相关法进行时延估计时,若采用固定步长因子则会在收敛速度和稳态失调之间存在较大矛盾,从而影响时延估计精度。针对这一问题,文中提出了一种基于分段变步长LMS自适应滤波和希尔伯特差值的互相关时延估计优化算法。该方法首先采用分段变步长LMS自适应滤波对信号进行滤波处理,然后将滤波后的信号作互相关运算,最后通过希尔伯特差值法锐化相关函数的峰值,进一步提高时延估计精度。在相同条件下,文中模拟分析了不同算法的时延估计精度。实验结果表明,新的优化算法时延估计精度更高。在不同信噪比下,新方法相较传统时延估计方法精度提高了2.2%以上,具有良好的抗噪声性能。 相似文献
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脉冲噪声环境下基于分数低阶循环相关的MUSIC算法 总被引:2,自引:0,他引:2
该文以稳定分布作为噪声模型,研究了脉冲噪声环境下循环平稳信号的波达方向估计问题。针对在脉冲噪声环境中基于传统2阶循环相关的算法效果显著退化的问题,该文提出了基于分数低阶循环相关的分数低阶循环MUSIC算法(FLOCC-MUSIC)。将分数低阶循环相关与MUSIC算法相结合,可以有效抑制脉冲噪声的同频带干扰。计算机仿真表明了此算法可有效完成高斯噪声和脉冲噪声条件下的波达方向估计,其性能优于传统的基于2阶循环相关的Cyclic-MUSIC。 相似文献
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Li Li Tian-shuang Qiu De-rui Song 《AEUE-International Journal of Electronics and Communications》2013,67(11):947-954
This paper takes the alpha-stable distribution as the noise model and works on the parameter estimation problem of wideband bistatic Multiple-Input Multiple-Output (MIMO) radar system in the impulsive noise environment. In many applications, it is not appropriate to approximate the wideband signal by the narrowband model. Furthermore, the echo signal may be corrupted by the non-Gaussian noise. The conventional algorithms degenerate severely in the impulsive noise environment. Thus, this paper proposes a new wideband signal model and a novel method in wideband bistatic MIMO radar system. It combines the fractional lower order statistics and fractional power spectrum, for suppressing the impulse noise and estimating parameters of the target. Firstly, a new signal array model is proposed under the alpha-stable distribution noise model. Secondly, Doppler stretch and time delay are jointly estimated by peak searching of the FLOS-FPSD. Furthermore, two modified algorithms are proposed for the estimation of the direction-of-departure and direction-of-arrival, including the fractional power spectrum density based on MUSIC algorithm (FLOS-FPSD-MUSIC) and the fractional lower-order ambiguity function based on ESPRIT algorithm (FLOS-FPSD-ESPRIT). Simulation results are presented to verity the effectiveness of the proposed method. 相似文献
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This paper presents a robust time delay estimation algorithm for the α-stable noise based on correntropy. Many time delay estimation algorithms derived for impulsive stable noise are based on
the theory of Fractional Lower Order Statistics (FLOS). Unlike previously introduced FLOS-type algorithms, the new algorithm
is proposed to estimate the time delay by maximizing the generalized correlation function of two observed signals needing
neither prior information nor estimation of the numerical value of the stable noise’s characteristic exponent. An interval
for kernel selection is found for a wide range of characteristic exponent values of α-stable distribution. Simulations show the proposed algorithm offers superior performance over the existing covariation time
delay estimation, least mean p-norm time delay estimation and achieves slightly improved performance than fractional lower
order covariance time delay estimation at lower signal to noise ratio when the noise is highly impulsive 相似文献
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A method based on the scaled ambiguity function for parameter estimation of LFM signals under noncooperative conditions is presented. In the proposed algorithm, the scaling principle is employed to remove the linear frequency migration brought by the coupling between the time variable and the lag variable. Afterward, the Fourier transform is performed for feature extraction of LFM signals on the centroid frequency versus chirp rate plane. The method avoids centroid frequency information loss, which is almost inevitable in the Radon-ambiguity transform. Furthermore, fractional lower-order statistics and the scaled ambiguity transform are combined to improve the performance in practical impulsive noise environments. Simulation results show that the fractional lower-order scaled ambiguity transform is robust for both Gaussian and impulsive noise, and it achieves significant performance improvement in a heavy noise environment. 相似文献
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针对大瞬时宽带线性调频信号的时差/尺度差在低信噪比下估计精度下降和算法运算量大的问题。本文利用时频轴旋转、魏格纳分布和模糊函数的关系推导出分数阶傅里叶四阶中心矩和尺度差的关系式,通过寻找两路信号的分数阶傅里叶四阶中心矩在角度域的位置,即可获得尺度差的估计值。将估计的尺度差对一路信号进行伸缩,并计算伸缩后信号与另一接收信号的时域相关,根据相关峰的位置估计出时差,并对本文算法抗噪性进行定性推导。仿真结果表明,相比于分数阶傅里叶尺度变换时差/尺度差估计算法,本文算法提高了在低信噪比下时差/尺度差估计精度,并对算法抗噪性定量分析得出本文算法抗噪性更好。 相似文献
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