【作者】 张晓芳；

【导师】 田红心；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2009， 硕士

【摘要】 随着现代通信的发展,天线抗干扰技术已成为通信对抗领域一项重要的抗干扰技术。本文研究了平流层通信平台的抗干扰技术,通过采用阵列天线对平流层通信平台的干扰实现自适应抑制,完成的主要工作如下:1.在天线阵方面,比较了均匀线阵和均匀圆阵的特点,由于均匀圆阵可以达到360 o的全方位扫描,接收天线采用阵列间距为半波长的八阵元圆形天线。2.在DOA估计方面,采用两种算法对天线波达方向进行估计,仿真结果证明MUSIC算法具有更好的谱峰高度和分辨率;仿真了在信号方向和个数固定的情况下的LCMV算法、ESB算法以及四阵元圆形天线的功率反演算法的干扰抑制性能。3.在干扰抑制方面,提出了一种频域内归一化LMS自适应算法。该算法在LMS算法的基础上对输入信号进行频域变换和对收敛因子进行归一化,比LMS算法有着更高的收敛速度和更小的失调量。4.提出了一种平流层通信平台的自适应天线抗干扰方案。该方案适用于平流层中继系统中信号频偏动态变化较大条件,采用八阵元圆形天线、前后向平滑的虚拟线阵MUSIC算法阵列信号进行DOA估计和频域内归一化LMS自适应算法进行自适应干扰抑制,优点是收敛速度较快和失调量较小。更多还原

【Abstract】 With the development of the modern communication, interference suppression technique in antenna arrays is becoming an important research field. This paper is concentrated on the adaptive jamming suppression using antenna array in High Altitude Platform Stations (HAPS). The author’s researches involve four aspects as follows:1. On the aspect of antenna array, the characteristic of linear array and circle array is compared. The circle array antenna with eight antennas that can scan the degree from 0 to 360 degree is used in this paper.2. On the aspect of DOA estimation, two kinds of algorithms to estimate antenna arrays’ direction of arrival are adopted. MUSIC algorithm has better peak height and resolution which is proved by simulation result. LCMV algorithm, ESB algorithm and power inversion algorithm are simulated under the condition that the number and the direction of the signal are fixed.3. On the aspect of jamming suppression, frequency domain normalized LMS algorithm is presented. The transform in frequency domain increases the converge speed and normalize technology decreases the imbalance rate. This algorithm has higher convergence speed and smaller imbalance rate than LMS.4. An adaptive jamming suppression scheme using antenna array in HAPS is proposed. The signal in HAPS that has dynamic frequency partial is adopt as the expectation signal, eight element circular antennas are adapted as the receiving antenna, to process the array signal. Using forward/backward spatial smoothing virtual line array MUSIC algorithm to estimate the signal angel and adopt frequency domain normalize LMS algorithm that has fast convergence speed and small imbalance rate to track the expectation signal.更多还原