一种基于自适应提升小波变换的GNSS多径抑制方法

在卫星导航定位系统中,多径干扰是影响定位精度的重要误差源之一。在分析研究现有多径抗干扰方法和小波理论的基础上,提出了一种基于自适应提升小波变换(Adaptive Lift Wavelet Transform,ALWT)的多径抑制方法。该方法利用小波分析在时频域将待处理信号局部放大的特性,将待分析信号通过提升小波变换进行自适应多级分解,通过最小方差准则(Least Mean Square,LMS)自适应确定分解级数,在一定的阈值条件下将多径信号排除过滤掉,从而达到多径抑制的目的。Matlab7.0仿真实验中,与窄相关技术和传统小波变换方法(Traditional Wavelet Transform,TWT)相比,该方法通过多级小波级数分解,将多径信号进行局部时频域放大,选取合适阈值判别条件过滤多径信号,再通过小波逆变换还原直接信号,实验证明使用ALWT方法多径抑制效果显著提高。

A method of GNSS Multipath Suppression based onLift Wavelet Transform

In satellite navigation and positioning system, the multipath interference is one of the important error sources that affect localization accuracy. On the analysis of the existing multipath interference study method and on the basis of wavelet theory, this paper proposes a Wavelet Transform based on Adaptive Lift of multipath suppression method. The method using wavelet analysis in frequency domain will be processed when the characteristics of local signal amplification, the signals to be analysed through lift wavelet decomposition adaptive multistage decomposition, determined by the rule of minimum variance adaptive decomposition series, under the condition of a certain threshold to exclude the multipath signal filtering, so as to achieve the purpose of inhibiting multipath. Narrow Matlab7.0 simulation experiments, and related technology compared with traditional wavelet transform method, the method by multilevel wavelet series decomposition, the multipath signal amplification of local time-frequency domain, select appropriate threshold criterion for filtering the multipath signal, the signal by wavelet inverse transform back directly, experiment proves that using multipath suppression effect is significantly improved.