GPS接收机自适应干扰抑制关键技术研究

发布时间：2018-03-02 08:15

本文关键词： 全球定位导航系统抗干扰干扰参数估计 IIR陷波器　出处：《河北师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：全球定位系统(Global Position System,GPS),是一种定时和测距的空间交会定点导航系统,用于测量运动载体的速度、三维位置和时间。导航信息通过无线电的方式进行传递,在传递过程中会遇到各种类型以及各种强度的干扰。一旦有干扰掺杂到有用信号中,则导航接收机无法解算出正确的导航信息。同时,由于卫星导航系统的广泛使用,使得对该系统的抗干扰技术的研究迫在眉睫。本文主要针对GPS接收机自适应干扰抑制的问题做出研究,主要以一定带宽的干扰、单频窄带干扰为模型,这类干扰常常被GPS接收机所接收,且干扰强度大,影响力强。文章首先叙述了GPS系统的脆弱性以及系统应用的广泛性,点明GPS接收机抗干扰的重要性。分析了国内外在抗干扰领域的研究,一方面阐述了对干扰参数估计的研究,另一方面阐述时域干扰抑制和频域干扰抑制的方法。其次,讨论了GPS导航信号模型和信号特点,并对常见干扰模型进行分析。针对频域自适应干扰抑制算法研究。首先提出自适应门限准确确定的必要性,采用对GPS导航信号加窗的手段来处理信号在变换域频谱泄漏等问题,分析了常用的五种窗函数,通过主瓣宽度、最大旁瓣幅值以及旁瓣衰减速度来选取合适的窗函数,为了优化窗函数的性能,考虑窗函数的重叠加窗,该算法对本文GPS信号截取有明显的优化效果。其次,选择最佳门限,采用对整体信号系统的特性分析,根据随机信号实用分布律来得出干扰检测门限,通过分析干扰谱线,准确估计干扰参数。使用频域置零法,对比不同类型干扰的抑制效果,本文对该算法进行仿真,得到有效的验证。针对时域自适应干扰抑制算法研究。本文提出了自适应时域陷波的算法模型。首先,分析了一阶复数型IIR陷波器和二阶直接型IIR陷波器的陷波特性,比较低阶IIR陷波器与高阶IIR陷波器的特点。随后,通过陷波器级联的特点,提出了两种陷波器级联方式,分别为陷波器串行级联和陷波器高阶级联。对两种级联方式分别进行干扰抑制以及输出信干噪比的仿真,得出两种级联方法的更优算法。此外,从输出信干噪比探讨了干扰带宽、陷波带宽和陷波器级联个数三者之间的关系,从硬件设计和节约资源的角度来选择陷波器级联的个数。采用时域陷波算法进行干扰信号抑制,通过仿真验证算法的有效性。最后,可在理论上分析出,通过将时域与频域结合起来,检测出干扰类型,对其进行抑制,达到更好地干扰抑制效果。随着近几年航天技术的发展,中国、俄罗斯等国家均在建设或完善自己的全球导航定位系统,其都是基于卫星的导航定位系统原理。因此,在相对成熟的GPS系统基础上研究其干扰和抗干扰的问题,对我国“北斗”系统的建设与完善是很有必要的。
[Abstract]:Global Position system GPS, a fixed point navigation system for timing and ranging, is used to measure the speed, three-dimensional position and time of a moving carrier. Navigation information is transmitted by radio. In the course of transmission, interference of various types and intensities is encountered. Once interference is mixed into useful signals, the navigation receiver cannot solve the correct navigation information. At the same time, due to the wide use of satellite navigation systems, It is urgent to study the anti-jamming technology of the system. This paper mainly focuses on the problem of adaptive interference suppression of GPS receiver, mainly based on the interference of a certain bandwidth and single-frequency narrowband interference. This kind of interference is often received by the GPS receiver, and the interference is strong and powerful. This paper first describes the vulnerability of the GPS system and the wide application of the system. The importance of GPS receiver anti-jamming is pointed out. The research in the field of anti-jamming at home and abroad is analyzed. On the one hand, the research of interference parameter estimation, on the other hand, the methods of time-domain interference suppression and frequency-domain interference suppression are expounded. The GPS navigation signal model and signal characteristics are discussed, and the common interference models are analyzed. The necessity of accurate determination of adaptive threshold is put forward for the study of adaptive interference suppression algorithm in frequency domain. The GPS navigation signal is windowed to deal with the signal leakage in the transform domain, and five window functions are analyzed. The proper window function is selected by the main lobe width, the maximum sidelobe amplitude and the sidelobe attenuation speed. In order to optimize the performance of the window function, the superposition window of the window function is considered. The algorithm has obvious optimization effect on the interception of the GPS signal in this paper. Secondly, the optimal threshold is selected and the characteristics of the whole signal system are analyzed. According to the practical distribution law of random signals, the threshold of interference detection is obtained, and the interference parameters are accurately estimated by analyzing the interference spectral lines. By using the frequency domain zeroing method, the suppression effect of different types of interference is compared, and the algorithm is simulated in this paper. The algorithm model of adaptive time-domain notch is proposed. Firstly, the trapping characteristics of first-order complex IIR notch and second-order direct IIR notch are analyzed. The characteristics of low order IIR notch and high order IIR notch are compared. Then, through the characteristics of notch concatenation, two kinds of notch concatenation modes are proposed. The two cascades are serially concatenated and high-order cascaded respectively. The simulation of interference suppression and output signal-to-noise ratio of the two cascades is carried out, and a better algorithm of the two cascading methods is obtained. The relationship among interference bandwidth, notch bandwidth and the number of notch cascades is discussed from the output signal-to-noise ratio. The number of notch cascades is selected from the point of view of hardware design and resource saving. The time domain notch algorithm is used to suppress the interference signal. The effectiveness of the algorithm is verified by simulation. Finally, it can be theoretically analyzed that, by combining time domain with frequency domain, the interference type can be detected and suppressed. With the development of space technology in recent years, China, Russia and other countries are building or perfecting their global navigation and positioning systems, which are all based on the principle of satellite-based navigation and positioning systems. It is necessary for the construction and perfection of Beidou system in our country to study the interference and anti-interference of GPS system.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4

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