【作者】 刘伟；

【导师】 孙克文；

【作者基本信息】 合肥工业大学 ， 通信与信息系统， 2014， 硕士

【摘要】 无论在民用或者军事应用上,GNSS接收机的导航和定位性能都是非常重要。由于GNSS信号在传播的过程中受到各种射频干扰,以至于接收机很难根据接收到GNSS信号进行准确的定位和导航。因此,剔除GNSS信号中的干扰信号就显得很重要了,这就要求GNSS接收机具备很强的干扰检测和滤波能力。接收机接收到的信号是非平稳,其统计量是时变函数。因为只了解信号在频域或时域的全局特性是远远不行的,所以需要知道信号频谱在时间上变化的情况。在本文中,提出了基于时频分析的Choi-Williams(CW或威廉姆斯)变换,以用于GNSS接收机干扰检测。为了减少传统时频分析中交叉项的影响,将核函数引入Wigner-Ville分布中得到的CW变换。在实验中,对加入射频干扰伽利略1号卫星信号进行了仿真分析,并对CW变换、短时傅里叶变换和Wigner-Ville 3分布的干扰检测方法进行比较,证明了CW变换在GNSS接收机干扰检测中的有效性和可行性。在GNSS接收机的滤波方面,为了减少滤波过程对有用GNSS信号损害,本文设计了自适应陷波器去剔除或抑制干扰信号,并通过仿真实验验证了自适应陷波器能够有效剔除或抑制干扰信号,而对有用信号几乎没有损害。本文提出的时频分析和自适应陷波器能够大大提高GNSS接收机的干扰检测和滤波能力,这样就大大的提高接收机的导航和定位的性能。更多还原

【Abstract】 Both in civilian and military applications, navigation and positioning performan--ce of GNSS receivers are very important. GNSS signals in the process of transmissi--on will be affected by a variety of continuous wave interference, so that it is difficult to offer accurate navigation and position based on GNSS receiver signal. Therefore, eliminating the interference signal of the GNSS signals is very important, which requires the GNSS receiver has the capability of strong interference detection and filtering.GNSS receiver’s signal is non-stationary, its statistic is a time-varying function. Only to understand global characteristics of signal in time or frequency domain is not enough, it need to know the signal spectrum changes over time. In this paper, a novel CWT based TF analysis algorithm has been proposed in the interference detection for GNSS receivers. The CW kernel function is introduced to the Cohen’s class in order to attenuate the cross terms of the traditional TF approaches. The proposed method is tested by simulations on Galileo El signals in radio frequency interference scenarios compared to the state of the art TF analysis interference detection techniques such as spectrogram and WVD, unproved TF localization properties and interference detecti--on sensitivity have been achieved with the developed technique, providing its effecti--veness and validity for interference detection for GNSS receivers. In terms of GNSS receiver filter, in order to reduce the damage to useful GNSS signal filtering process, the paper designs the adaptive trap to eliminate interference signals, and is verified by simulation experiment adaptive trap can effectively eliminate interference signals, and the useful signal has almost no damage.In this dissertation, the time-frequency analysis and adaptive trap can greatly improve the GNSS receiver interference detection and filtering ability, thus greatly improve the performance of the navigation and positioning receiver.更多还原