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围绕工程实际中干涉仪测向技术面临着布阵平台空间有限、不能同时对多个信号分辨的问题进行研究,提出相应的解决办法.首先根据机载平台特点,给出了5元均匀椭圆阵列模型,分析了椭圆阵列孔径与波长之比对入射角度的估计性能影响,得出了在一定孔径范围内增大阵列孔径能提高测向精度的结论;接着采用四阶累积量MUSIC算法引入虚拟阵元来解决受限平台上增大孔径的问题,仿真验证了此算法在干涉仪椭圆阵列模型中的有效性. 相似文献
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波达方向估计是阵列信号处理一个重要的研究分支,广泛地应用于军事及民用领域.基于空域信号自身具备的稀疏性,压缩感知理论为窄带信号波达方向估计提供了一种新的思路.通过本文设计的仿真实验,学生可以建立远场窄带测向模型,并对基于块稀疏算法的窄带测向和相干非相干信号块稀疏混合测向仿真. 相似文献
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一种基于L阵的二维解相干测向算法 总被引:1,自引:0,他引:1
本文对高斯白噪声环境下基于L型阵列二维测向的ESPRIT算法进行了改进.该算法利用阵列结构特点通过平滑原理获得3个互相关矩阵,然后由3个矩阵构造一个特殊大矩阵并对其进行奇异值分解来估计信号子空间,最后利用2D-ESPRIT方法实现二维测向.该算法估计精度高,运算量小,能够对相干信号进行估计. 相似文献
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在海面低空飞行目标探测场景中,主要利用声学方法对目标进行测向从而为其他高精度雷达系统提供引导,这就对声学测向方法的实时性提出了较高要求。针对低空高亚音速飞行目标DOA的快速估计问题,以利用布设于有限空间内的声传感器阵实现海面高亚音速目标角度的快速估计为背景,针对其宽带声信号精确测向的难题,建立了基于均匀线性空间十字阵的宽带时域阵列信号模型,为实现海面低空飞行目标的快速声学测向,将经典宽带时域多级维纳滤波器(MSWF)的DOA估计方法拓展至时域模型,提出了相应的宽带DOA快速估计方法,该方法在保持了多重信号分类算法优势的同时,有效提升了声学DOA估计的实时性。 相似文献
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基于均匀圆形阵列,提出了一种同时估计空间非相干信号源方位角、仰角和多普勒频率的快速算法。该方法对均匀圆阵的输出信号进行模式空间转换,使得阵列流形具有类似于均匀线阵的形式,然后通过构造相应的数据矩阵得到传播算子的最小二乘(LS)估计,并由传播算子构造出一个特殊的低维矩阵,其特征值给出多普勒频率估计,特征向量舍有阵列流形的信息。结合模式空间阵列流形的性质,给出了一种DOA估计的总体最小二乘算法,在低信噪比条件下可提高测向精度。该方法不需要谱峰搜索和参数配对,具有运算量小的优点。计算机仿真验证了该方法的有效性。 相似文献
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针对基于谐波特征分析的时间调制阵列(time-modulated array, TMA)测向技术中信息利用率低的问题,提出了一种基于信号频谱特征分析的多谐波TMA测向方法.通过分析接收信号的频谱特征,构建了基于信号频谱特征多谐波测向模型,推导了基于频谱特征的来波方向最优线性无偏估计(best linear unbiased estimation, BLUE)表达式,从而提高了测向精度及稳定性.以BPSK信号为例,通过仿真实验验证了所提算法的有效性,同时搭建了工作于S频段的二单元TMA测向系统证实了所提方法的可行性. 相似文献
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Abstract--This paper presents a novel time delay estimation (TDE) method using the concept of entropy. The relative delay is estimated by minimizing the estimated joint entropy of multiple sensor output signals. When estimating the entropy, the information about the prior distribution of the source signal is not required. Instead, the Parzen window estimator is employed to estimate the density function of the source signal from multiple sensor output signals. Meanwhile, based on the Parzen window estimator, the Renyi's quadratic entropy (RQE) is incorporated to effectively and efficiently estimate the high-dimensional joint entropy of the multichannel outputs. Furthermore, a modified form of the joint entropy for embedding information about reverberation (multipath reflections) for speech signals is introduced to enhance the estimator's robustness against reverberation. 相似文献
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远近效应和多径衰落会降低WCDMA收发器的性能.快速功率控制的广泛应用就是为了减小这种不良影响,这样就需准确地估计出接收信号的信干比.文中在传统SIR估计方法的基础上,提出了一种改进SIR估计的方法.此方法考虑并消除了多径间的干扰,克服了其它现有方法在精确度、复杂度和实时性方面的不足.经仿真验证,文中提出的SIR估计方法相比传统算法更为精确. 相似文献
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Ben-Haim Z. Eldar Y.C. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2007,53(9):3145-3157
We consider the linear regression problem of estimating an unknown, deterministic parameter vector based on measurements corrupted by colored Gaussian noise. We present and analyze blind minimax estimators (BMEs), which consist of a bounded parameter set minimax estimator, whose parameter set is itself estimated from measurements. Thus, our approach does not require any prior assumption or knowledge, and the proposed estimator can be applied to any linear regression problem. We demonstrate analytically that the BMEs strictly dominate the least-squares (LS) estimator, i.e., they achieve lower mean-squared error (MSE) for any value of the parameter vector. Both Stein's estimator and its positive-part correction can be derived within the blind minimax framework. Furthermore, our approach can be readily extended to a wider class of estimation problems than Stein's estimator, which is defined only for white noise and nontransformed measurements. We show through simulations that the BMEs generally outperform previous extensions of Stein's technique. 相似文献
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Cost-Estimate Relations (CER's) are derived for launch/orbit insertion, payload/satellite(s), and the total satellite system. These CER's are expressed in terms of orbit altitude (or apogee), orbit type (circular or elliptical), and payload weight. The CER's are also presented briefly in terms of number of rings, number of satellites per ring, and satellite weight. They are applicable only to recurring (production) costs and include an 80percent "learning-curve rate." Satellite-subsystem percent weights are also discussed for single-axis and three-axis stabilized satellites, and guidance is developed for estimating total satellite weight given the required RF power. 相似文献
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Energy-Based TOA Estimation 总被引:1,自引:0,他引:1
D'Amico A.A. Mengali U. Taponecco L. 《Wireless Communications, IEEE Transactions on》2008,7(3):838-847
This paper investigates time of arrival estimation via impulse radio ultra-wideband technology. A dense multipath channel is assumed and frequency-selective propagation effects are taken into account that make the individual received pulses different in shape from the transmitted monocycles. In these conditions a conventional correlation-based estimator cannot be used and other schemes must be resorted to. Assuming only an approximate knowledge of the received pulses' duration, a TOA estimator is derived making use of least mean square techniques. The algorithm operates on energy measurements made on a folded version of the received signal. Its performance is investigated by simulation under implementation conditions of different complexity. In particular, sub-Nyquist sampling rates are considered and analog-to-digital conversion with limited resolution is explored. Comparisons are made with other available schemes. 相似文献