北斗导航接收机空时自适应干扰抑制算法研究

发布时间：2018-08-20 10:35

【摘要】：北斗卫星导航系统是我国自主研制、独立运行的全球卫星导航系统。随着北斗卫星导航系统越来越多地广泛应用,人们对导航系统的精确性和可靠性有了更高的要求,尤其是在北斗导航系统最为广泛应用的战场环境中,各种各样的干扰变幻莫测。为了使得北斗导航接收机在复杂的干扰环境下仍能正常高效工作,必须提高导航接收系统的干扰抑制性能。由于目前采用的空域抗干扰方案有自由度受限于阵元个数的缺陷,不能对大量宽带干扰进行有效抑制,论文对空时联合干扰抑制算法进行了相关研究。该算法在空域滤波的基础上,在每个阵元上增加相同数目的时间抽头,从而增加可处理的干扰数目,提高抗干扰性能。论文首先对卫星导航接收机的常见干扰信号进行了分析;接着对典型的抗干扰算法进行了研究,主要包括:时域、频域、空域干扰抑制算法,针对这些算法抗干扰性能的局限性,着重研究了空时联合干扰抑制算法;随后论文介绍了空时自适应的几种典型算法,在对比分析之后,论文选择采用最小均方误差(LMS)算法进行研究;由于传统LMS算法的步长因子固定,影响算法的收敛速度和稳态误差,针对这一缺陷,通过归一化LMS算法来处理步长因子,经过仿真比较,归一化LMS算法性能较优;最后将归一化LMS算法应用于空时自适应干扰抑制算法的实现。论文基于Matlab仿真,构建了空时自适应干扰抑制算法的仿真模型,设置仿真参数,把采集到的卫星信号和干扰机产生的干扰共同作为输入信号,经过各个模块的处理后,得到输出信号。通过对比输入和输出信号并计算相消比,得出空时自适应干扰抑制算法能够更有效地抑制宽带干扰的结论。最后对实验中抗干扰性能的影响因素进行了仿真分析。
[Abstract]:Beidou satellite navigation system is a global satellite navigation system independently developed and operated by our country. With the more and more extensive application of Beidou satellite navigation system, people have higher requirements for the accuracy and reliability of the navigation system, especially in the battlefield environment where Beidou navigation system is most widely used. All kinds of interference are unpredictable. In order to make the Beidou navigation receiver work normally and efficiently in complex jamming environment, the interference suppression performance of the navigation receiver must be improved. Due to the limitation of degree of freedom to the number of array elements, the existing spatial anti-jamming scheme can not effectively suppress a large number of wideband interference. In this paper, the space-time joint interference suppression algorithm is studied. On the basis of spatial filtering, the algorithm adds the same number of time taps to each array element, thus increasing the number of interferences that can be processed and improving the performance of anti-jamming. Firstly, the common interference signals of satellite navigation receiver are analyzed, and then the typical anti-jamming algorithms are studied, including: time domain, frequency domain, spatial domain interference suppression algorithm. In view of the limitation of anti-jamming performance of these algorithms, the joint space-time interference suppression algorithm is studied emphatically, and then several typical space-time adaptive algorithms are introduced. In this paper, the minimum mean square error (LMS) algorithm is chosen to study. Because of the fixed step size factor of the traditional LMS algorithm, the convergence speed and steady-state error of the algorithm are affected. Aiming at this defect, the normalized LMS algorithm is used to deal with the step factor. The performance of normalized LMS algorithm is better than that of other algorithms. Finally, the normalized LMS algorithm is applied to the implementation of space-time adaptive interference suppression algorithm. Based on Matlab simulation, the simulation model of space-time adaptive interference suppression algorithm is constructed, and the simulation parameters are set up. The acquired satellite signal and the jamming generated by the jammer are taken as input signals, and processed by each module. Get the output signal. By comparing the input and output signals and calculating the cancellation ratio, it is concluded that the space-time adaptive interference suppression algorithm can suppress wideband interference more effectively. Finally, the influence factors of anti-interference performance in the experiment are simulated and analyzed.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN965.5

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