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利用非线性最小二乘方法的最优性质,本文提出了双基地雷达的两种最优化算法:LMF(Leenberg-Marquardt-Fletcher)定位算法和拟牛顿定位算法。仿真结果表明,与目前的定位优化算法相比,这两种新的定位算法不但具有更好的定位精度,而且在不增加观测量的条件下避免了定位模糊问题。 相似文献
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对多被动浮标的目标定位问题进行了研究,在给定各枚浮标与目标之间距离的差值的条件下,给出一种基于最小平方意义下的被动目标定位算法,即在保证定位误差平方最小的条件下,实现目标定位的方法。在对算法定位原理及定位误差研究分析的基础上,针对近场目标和远场目标两种情况,采用Monte-Carlo方法对该算法的定位性能进行了仿真;在一定假设条件下,仿真分析了不同距离差值量测噪声对目标位置误差、位置均方根误差及方位误差的影响,并且对近场目标和远场目标两种情况下目标定位的性能进行了分析比较。 相似文献
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提出两种在WLAN环境下利用RSSI值与距离之间关系进行定位的匹配算法。分别对两种算法的原理进行理论分析,建立算法实现的模型,使之在不同情况下都能够精确地计算匹配结果。提出实现算法的基本流程,并对算法本身的特点进行了理论分析。分析表明通过该方法的修正可以明显改善定位的精度。 相似文献
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以矢量水听器的三元纯方位被动定位和测时差被动定位两种方法为基础,针对算法特点和声纳浮标的使用特点,分别设计了两种方法所采用的水下换能器基阵结构。两种基阵结构相似,部分重合,可根据实际工作条件任意选择算法,也可两种算法相互间自行切换。此种相互补偿的设计可以提高水下目标被动定位的精度和可靠性。 相似文献
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在对定位算法中的测距和非测距算法研究的基础上,本文提出了在改进阅读器排布的定位空间中,将最近邻居算法与Chan算法结合,进行协同定位的方法。在设定的两种小范围仿真空间中,通过均方误差(RMSE)和误差累计分布曲线(CDF)两个定位精度评价指标对改进前后的算法进行比较,在噪声较小且误差均匀分布的环境下,改进算法的定位误差可90%控制在0.4m以内。 相似文献
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Guan Gui Abolfazl Mehbodniya Fumiyuki Adachi 《Wireless Communications and Mobile Computing》2015,15(12):1649-1658
Standard least mean square/fourth (LMS/F) is a classical adaptive algorithm that combined the advantages of both least mean square (LMS) and least mean fourth (LMF). The advantage of LMS is fast convergence speed while its shortcoming is suboptimal solution in low signal‐to‐noise ratio (SNR) environment. On the contrary, the advantage of LMF algorithm is robust in low SNR while its drawback is slow convergence speed in high SNR case. Many finite impulse response systems are modeled as sparse rather than traditionally dense. To take advantage of system sparsity, different sparse LMS algorithms with lp‐LMS and l0‐LMS have been proposed to improve adaptive identification performance. However, sparse LMS algorithms have the same drawback as standard LMS. Different from LMS filter, standard LMS/F filter can achieve better performance. Hence, the aim of this paper is to introduce sparse penalties to the LMS/F algorithm so that it can further improve identification performance. We propose two sparse LMS/F algorithms using two sparse constraints to improve adaptive identification performance. Two experiments are performed to show the effectiveness of the proposed algorithms by computer simulation. In the first experiment, the number of nonzero coefficients is changing, and the proposed algorithms can achieve better mean square deviation performance than sparse LMS algorithms. In the second experiment, the number of nonzero coefficient is fixed, and mean square deviation performance of sparse LMS/F algorithms is still better than that of sparse LMS algorithms. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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文中介绍了自适应滤波算法的原理和干扰抵消器工作原理,并将LMS算法、NLMS算法和变步长LMS算法分别应用在了干扰抵消器中进行了仿真。仿真的结果表明,三种自适应算法运用到了干扰抵消器中,都可以很好地滤除干扰,提取有用信号。其中运用了变步长LMS算法的干扰抵消器无论在收敛速度和滤波性能上,都要强于其他两种算法。 相似文献
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The article gives a general analysis of the LMS-based adaptive filters when used for tracking a class of time varying plants. The algorithms covered are the conventional LMS, the transform-domain normalized LMS, and the LMS/Newton algorithm. An important fact that we observe is that in comparing these algorithms, better initial convergence does not necessarily mean better tracking. A few special cases are presented that show the contrary 相似文献
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Fast convergence and simplicity of the real-time implementation of the adaptive filter algorithm are desirable in several applications. In this paper, a fast modified least mean square (LMS) algorithm is presented and analysed. The performance of the LMS and the modified LMS algorithm is compared with the help of both simulation and experimental results. Once the algorithms reach the track period (i.e. steady-state conditions), their performance is found to be essentially the same. The tracking performance of the modified algorithm is better as it operates twice as fast as the LMS algorithm. 相似文献
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根据时分多址(TDMA)系统的同步特征,利用TDMA运动目标准周期性信号的到达时间,提出了3种在三站时差定位系统中实现目标定位的算法.采用目标运动分析的方法,对TDMA目标位置的可观测性进行分析,提出了目标运动分析时差定位算法,利用目标航迹上多个位置的时差实现目标的定位.运用目标运动分析测距算法,提出了测距与传统时差定... 相似文献
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Sparse least mean fourth algorithm for adaptive channel estimation in low signal‐to‐noise ratio region 下载免费PDF全文
Both least mean square (LMS) and least mean fourth (LMF) are popular adaptive algorithms with application to adaptive channel estimation. Because the wireless channel vector is often sparse, sparse LMS‐based approaches have been proposed with different sparse penalties, for example, zero‐attracting LMS and Lp‐norm LMS. However, these proposed methods lead to suboptimal solutions in low signal‐to‐noise ratio (SNR) region, and the suboptimal solutions are caused by LMS‐based algorithms that are sensitive to the scaling of input signal and strong noise. Comparatively, LMF can achieve better solution in low SNR region. However, LMF cannot exploit the sparse information because the algorithm depends only on its adaptive updating error but neglects the inherent sparse channel structure. In this paper, we propose several sparse LMF algorithms with different sparse penalties to achieve better solution in low SNR region and take the advantage of channel sparsity at the same time. The contribution of this paper is briefly summarized as follows: (1) construct the cost functions of the LMF algorithm with different sparse penalties; (2) derive their lower bounds; and (3) provide experiment results to show the performance advantage of the propose method in low SNR region. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Recently, several noise‐robust adaptive multichannel LMS algorithms have been proposed based on the spectral flatness of the estimated channel coefficients in the presence of additive noise. In this work, we propose a general form for the algorithms that integrates the existing algorithms into a common framework. Computer simulation results are presented and demonstrate that a new proposed algorithm gives better performance compared to existing algorithms in noisy environments. 相似文献
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传统的最小均方误差(LMS)算法难以同时获取较快的收敛速度和较小的稳态误差,而变步长LMS算法可获得二者之间的平衡。对已有的一些变步长LMS算法进行了分析,在变系数步长(VFSS)算法的基础上,引入输入信号因子,并建立步长因子与误差信号之间新的非线性函数关系,提出一种改进的变步长LMS算法,该算法不仅继承了VFSS算法在低信噪比环境下抗噪声性能好的特点,而且能够快速跟踪系统的变化,仿真结果表明改进算法的性能优于现有算法。 相似文献