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题名	子空间相交目标方位估计算法的研究
作者	庞金城
学位类别	博士
答辩日期	2008-05-23
授予单位	中国科学院声学研究所
授予地点	声学研究所
关键词	阵列信号处理 子空间 MUSIC DOA估计
学位专业	信号与信息处理
中文摘要	目标方位估计是阵列信号处理的基本问题之一。许多目标方位估计方法是基于平面波假设的，但在一些情况下比如浅海环境中，这个假设往往是不准确的。因为在浅海环境中，声源可以激发出多个模态的简正波，各号简正波相迭加，平面波假设便不再成立。此时若仍利用基于平面波假设的目标方位估计算法，容易出现较大的偏差。 本文首先介绍了两种信号模型，即传统的基于平面波假设的阵列信号模型和引入了简正波理论后的阵列信号模型。 然后本文回顾了由S. Lakshmipathi 和 G. V. Anand提出一种叫子空间相交的(Subspace Intersection)方法，这种方法一方面与基于平面波假设的方法相比计算量没有增加，同时估计精度要高，另一方面与匹配场方法相比则只需要知道各号简正波的波数而不需要知道太多环境参数。但由于SI方法选取了QR作为数学工具来构造目标方位函数，而QR分解在某些情况下是不稳定的，因而SI方法在一些情形下是不稳定的。 基于以前的工作，本文对基于最小二乘法的子空间相交法CLS-SI进行了介绍，并讨论了CLS-SI与MUSIC的关系，即CLS-SI可以被视为MUSIC在多途环境下的扩展。通过数学分析, 实验数据以及仿真得出，CLS-SI与SI相比更稳定，其具体表现在，在阵列端射方向，CLS-SI有更高的分辨率，在阵列正前方向，CLS-SI出现伪峰的概率要比SI小好多。
英文摘要	Direction of arrival (DOA) estimation is a fundamental problem in array signal processing. Many direction-of-arrival (DOA) estimation methods are under an assumption that signals propagate as plane-wave form in medium. However, this assumption is not always accurate in the ocean especially in shallow ocean since sound can stimulate multiple normal modes when it propagates in shallow ocean. For this reason, plane-wave DOA estimation techniques always yield biased bearing estimation in the ocean. The array signal processing model based on plane-wave form assumption and introduced by Normal Mode theory are reviewed and compared first. Recently, a method named subspace intersection (SI) based on array signal processing and Normal Mode theory was proposed by S. Lakshmipathi and G. V. Anand for bearing estimation. The SI method reduces the estimation bias without increasing computation comparing to plane-wave methods and it needs only the wavenumbers of the normal modes instead of exact environmental parameters which is necessary for Matched Field Processing methods. But since SI uses QR decomposition, it is not very stable. Least square approach is applied in subspace intersection (SI) method for the problem of bearing estimation in shallow water. Based on that, a method called constrained least square subspace intersection method (CLS-SI) is proposed. The mathematic expressions of CLS-SI are given. In addition, the relationship between CLS-SI and MUSIC is discussed. We prove that CLS-SI is an extension of MUSIC to multipath environments. Experimental data and simulations based on real environmental parameters show that the performance of the new method proposed is better than that of the original SI method. Firstly, it increases the resolution near the endfire direction of the array. Secondly, it enhances the ability in eliminating the spurious peak around the right front direction of the array.
语种	中文
公开日期	2011-05-07
页码	59
内容类型	学位论文
源URL	[http://159.226.59.140/handle/311008/424]
专题	声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文
推荐引用方式 GB/T 7714	庞金城. 子空间相交目标方位估计算法的研究[D]. 声学研究所. 中国科学院声学研究所. 2008.

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