【作者】 李芬；

【导师】 刘爱军；

【作者基本信息】 哈尔滨工业大学 ， 信息与通信工程， 2016， 硕士

【摘要】 空间谱估计技术一直是高频地波雷达阵列信号处理中的重点研究课题。近年来由于海岸占地空间越来越小,使得高频地波雷达阵列天线孔径也在变小,因此利用信号处理技术提高波达方向(DOA)估计算法的精度也变成了研究热点。时频分析方法在处理非平稳信号中有独特的优势,而极化敏感阵列可以敏感到电磁波信号的极化信息,因此本文将以极化敏感阵列为模型,并结合时频分析方法对高频地波雷达回波信号进行波达方向估计,这样可以充分利用到回波信号的空域、时频域以及极化域信息。本文首先介绍了现代空间谱估计技术的原理,包括多重信号分类(MUSIC)算法、旋转不变子空间(ESPRIT)算法以及它们的改进算法,并对它们进行了MATLAB仿真验证,以及实测数据的验证。为提高波达方向估计的精度,引入了时频分析的方法,用时频变换得到的空间时频矩阵代替传统波达方向估计算法中的协方差矩阵可以得到时频MUSIC算法和时频ESPRIT算法。详细分析了两种算法的原理,并通过计算机仿真分析了它们的性能和各自的优缺点,在此基础上对算法进行了一些改进,最后用实测数据进行了验证。为充分利用电磁信号的极化信息,建立了双极化正交偶极子阵列,以此为基础介绍了极化MUSIC算法和极化ESPRIT算法,并通过仿真分析了其性能。然后研究了综合极化信息的时频MUSIC和ESPRIT算法,并结合两者的优缺点提出了改进算法。改进算法是首先用极化时频ESPRIT算法对来波信号确定大致的方位角,然后以每个方位角为中心确定一个小的范围,在此范围内用MUSIC算法谱峰搜索得到较准确的DOA估计值,这样可以在保证DOA估计精度的基础上节省运算时间。最后研究了极化参数对DOA估计的影响,主要包括极化参数的估计误差对波达方向估计的影响以及何种状态的极化信息会使不同信号的估计值精度更高。更多还原

【Abstract】 Spatial spectrum estimation technology has always been the focused research project in array signal processing of High Frequency Surface Wave Radar(HFSWR). In recent years, as the coastal area of space gets smaller to make HFSWR array antenna sperture get smaller too, using signal processing technology to improve the precision of the direction of arrival(DOA) estimation algorithm has also become a research hotspot. The time-frequency analysis method has unique advantages in dealing with non-stationary signals, and the polarization sensitive array is sensitive to the polarization information of electromagnetic signals. Therefore, this thesis takes the polarization sensitive array for the model, and combine with time-frequency analysis method for DOA estimation of HFSWR echo signals, which can make full use of the spatial, time-frequency and polarized domain information of signals.This paper introduces the principle of modern spatial spectrum estimation technologies, including Multiple Signal Classification(MUSIC) algorithm, Estimation of Signal Parameters Via Rotational In-variance Techniques(ESPRIT) as well as their improved algorithms. In addition, these algorithms are verified with simulation experiments and real data in MATLAB platform.In order to improve the accuracy of DOA estimated value, this paper introduces the method of time-frequency analysis. Time-frequency MUSIC algorithm and time-frequency ESPRIT algorithm can be realized when the spatial time-frequency matrix substitude the covariance matrix of traditional DOA estimation algorithms. The principles of both algorithms are analyzed in detail, and their performance as well as respective advantages and disadvantages are analyzed by computer simulation. On this basis, some improvements are made on the algorithm. Finally the improved algorithm is verified with the real data.To take full advantage of polarization information of electromagnetic signals, double polarization orthogonal dipole array is established. On this basis the polarized MUSIC algorithm and polarized ESPRIT algorithm are introduced, and their performance is analyzed through simulations. Then time-frequency MUSIC and ESPRIT algorithms of integrated polarization information are studied, and the improved algorithm is proposed based on the advantages and disadvantages of both algorithms. The improved algorithm first estimate the azimuth angles of signals roughly with the polarized time-frequency ESPRIT algorithm, and then determine a small scope centered on each azimuth. Within the scope a more accurate DOA estimated value is got by spectral peak search with MUSIC algorithm, so it can save computation time on the basis of accuracy of the DOA estimation. Finally, the polarized parameters influence on DOA estimation is studied, including the polarized parameter estimation error influence on DOA estimation and what kind of polarization state will make higher accuracy of DOA estimates for different signals.更多还原