未知源数的波达方向估计算法研究

发布时间：2018-08-06 09:50

【摘要】：随着信源定位技术的发展,信号波达方向(DOA)估计的限制条件越来越多,估计的准确性也有待进一步提高。所以尽可能的提高自适应阵列天线DOA估计的精确度和分辨率是一个十分重要的研究工作。多重信号分类(MUSIC)和最小方差无失真响应(MVDR)这两个经典的算法在接收端为均匀线性阵列(ULA)的时候,对于已知信源个数的DOA估计具有较高的分辨率。随后出现了MUSIC-like算法,这种算法在接收端阵元数较少的时候,对于未知信源个数的相邻信源能够做到较精确的DOA估计检测。在接收端为十字阵列(PA)的情况下,上述算法可以进一步精确DOA的估计,使得谱估计的效果更为明显,但是该算法在谱估计的时候,伪峰值的出现相比MUSIC算法而言更为严重。对DOA的估计效果有着决定性影响的主要是信号接收端阵元的排列形式以及估计算法本身的不同。本文主要采用了将单一阵列接收信号的方式改为两种阵列相组合的方式。组合阵的原理是波达方向峰值因叠加增强,非波达方向峰值因叠加而削弱。信号通过组合列列接收处理后,DOA估计的准确性与分辨率均会有所提高。算法的主要思想有两点,第一是对同一个算法而言,随着接收端阵元个数的增加,信号彼此之间的扰动会增大,谱函数的伪峰值也会随之增多。特别是对MUSIC-like这一类的算法而言,当采用对数形式的谱函数进行DOA估计时,真正的波达方向会因组合阵叠加的原理使得信号的输出功率增大,非波达方向的伪峰值会因为组合阵叠加的原理被削弱,即达到抑制或判定伪峰值。第二是因为估计相邻信源的时候,对同一个算法而言,PA阵列相比ULA阵列的分辨率要更高一些。采用阵列组合叠加之后,由于峰值叠加相乘的倍数远大于非峰值处的值,所以组合阵列在估计相邻信源DOA的时候其谱峰值估计效果也更为明显。本文最后对宽带调频信号的MUSIC-like算法也做了简单的研究,对其进行了如窄带信号的快速MUSIC-like算法改进处理,改进后依旧使用MUSIC-like算法思想,则宽带调频信号DOA估计的计算量可减少。
[Abstract]:With the development of source location technology, there are more and more restrictions on the DOA (DOA) estimation, and the accuracy of the estimation needs to be further improved. Therefore, it is very important to improve the accuracy and resolution of adaptive array antenna DOA estimation. The classical algorithms of multiplex signal classification (MUSIC) and minimum variance distortion free response (MVDR) have high resolution for the DOA estimation of the number of known sources when the receiver is a uniform linear array (ULA). Then the MUSIC-like algorithm appears. When the number of received elements is small, the algorithm can detect the DOA estimation for the adjacent sources with unknown number of sources. When the receiver is a cross array (PA), the proposed algorithm can further accurately estimate the DOA, which makes the spectral estimation more effective. However, the pseudo-peak value is more serious than that of the MUSIC algorithm in the case of spectrum estimation. The main factors that have a decisive effect on the estimation effect of DOA are the arrangement form of the signal receiving end array and the difference of the estimation algorithm itself. In this paper, the method of single array receiving signal is changed into two kinds of array combination. The principle of combination matrix is that the peak of DOA is enhanced by superposition, and the peak of non-DOA is weakened by superposition. The accuracy and resolution of DOA estimation will be improved. The main idea of the algorithm has two points. The first is that for the same algorithm the disturbance between signals will increase and the pseudo-peak value of spectral function will increase with the increase of the number of received terminal elements. Especially for the MUSIC-like algorithm, when the logarithmic spectral function is used to estimate the DOA, the real DOA will increase the output power of the signal due to the principle of the superposition of the combined array. The non-DOA pseudo-peak is weakened because of the superposition of the composite array, that is, to suppress or determine the pseudo-peak. The second reason is that the resolution of the PA array is higher than that of the ULA array for the same algorithm when estimating the adjacent sources. Because the multiple of peak stacking multiplying is much larger than the value of non-peak value, the spectral peak value estimation effect of the combined array is more obvious when estimating the DOA of adjacent sources. In the end, the MUSIC-like algorithm of wideband FM signal is studied simply, such as the fast MUSIC-like algorithm of narrow band signal is improved, and the MUSIC-like algorithm is still used after the improvement, so the computation of DOA estimation of broadband FM signal can be reduced.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.23

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