小波分析在GPS数据处理中的应用研究

发布时间：2018-10-31 20:12

【摘要】：在采集、获取信号的过程中，由于外界多种因素的影响，造成信号中含有一些噪声。噪声成了影响信号质量的一个最主要的因素，对我们提取信号中的有用信息造成一种影响。因此，消除噪声带来的不利影响成为学者和专家最关注的话题之一。小波分析理论具有的分时分频精细表达和多尺度多分辨率分析等独特优势，，已经逐渐发展成为动态测量信号处理领域中的重要技术手段，在实际工程应用中越来越广泛，尤其在信号处理方面，比如：信号去噪、信号压缩等。本文将小波分析应用到GPS信号处理中，剔除信号中的噪声。 GPS在实际生产测量过程中，外界环境的影响，造成GPS接收到的信号发生变化，即在信号中含有一些噪声，影响测量的精度。为了消除GPS信号中的噪声，文中采用小波分析去噪方法中的阈值去噪法对信号进行去噪，小波阈值去噪法在最小均方误差意义下可达近似最优。通过对国内外研究现状、小波函数的特点、选取的原则等进行一定的研究，设计文章研究的思路与方法，利用实验结果证明研究方法的可行性。本文利用matlab编程将实际应用中采集的一组数据进行提取，提取GPS信号中的两颗卫星载波相位L1上的C/A码，分别通过不同历元间求出单差以及双差，再分别选取一定的小波基函数和选取特定的阈值对其进行小波分析去噪，通过信噪比、均方根误差作为小波函数和阈值选取的标准及去噪效果的评价标准，将获取的不同小波去噪结果进行对比，根据对比的结果确定选择哪种小波，选取何种阈值，确定小波函数和阈值以后，最后通过最新的一种评价指标——平滑度来确定最终去噪的效果。实验结果表明：选用demy小波函数和Penalize low确定的阈值达到了GPS单差和双差数据去噪的理想效果。为完善小波分析去噪理论，减少GPS数据处理的中产生的一些误差奠定了一定的理论及实践基础。
[Abstract]:In the process of signal acquisition and acquisition, there are some noises in the signal due to the influence of many external factors. Noise is one of the most important factors affecting the quality of signal, which has an effect on the extraction of useful information from the signal. Therefore, eliminating the adverse effects of noise has become one of the topics most concerned by scholars and experts. Wavelet analysis theory has the unique advantages of time-sharing and frequency-sharing fine expression and multi-scale multi-resolution analysis, which has gradually developed into an important technical means in the field of dynamic measurement signal processing, and has been more and more widely used in practical engineering. Especially in signal processing, such as: signal denoising, signal compression and so on. In this paper, wavelet analysis is applied to GPS signal processing to eliminate the noise in the signal. In the process of actual production and measurement of GPS, the influence of external environment causes the signal received by GPS to change, that is, there is some noise in the signal, which affects the accuracy of measurement. In order to eliminate the noise in GPS signal, the threshold de-noising method of wavelet analysis is used to Denoise the signal. The wavelet threshold de-noising method is approximately optimal in the sense of minimum mean square error. The present situation of the research at home and abroad, the characteristics of wavelet function and the principle of selection are studied to design the ideas and methods of this paper, and the feasibility of the research method is proved by the experimental results. In this paper, a set of data collected in practical application is extracted by matlab programming, and the C / A codes on the carrier phase L1 of two satellites in GPS signal are extracted, and the single difference and double difference are obtained from different epoch, respectively. Then select a certain wavelet basis function and select a specific threshold to Denoise by wavelet analysis. The signal-to-noise ratio (SNR) and root mean square error (RMS) are used as the criteria of wavelet function and threshold selection and the evaluation standard of denoising effect. The different wavelet denoising results obtained are compared. According to the comparison results, which wavelet is selected, what kind of threshold is selected, after determining the wavelet function and threshold, Finally, the final denoising effect is determined by the latest evaluation index-smoothness. The experimental results show that the demy wavelet function and the threshold determined by Penalize low can achieve the ideal effect of GPS single difference and double difference data denoising. It lays a theoretical and practical foundation for perfecting the denoising theory of wavelet analysis and reducing some errors in GPS data processing.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P228.4

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