Study On GPS Data Processing Theory Based On Wavelet Analysis

Based on the introduction of errors from different sources in GPS measurements and wavelet analysis theory, this paper introduce wavelet into GPS cycles slip detection and data denoising. Combined with actual measurements, this paper verifies the effect of this method. At the end,"Data Pre-process system for GPS"based on wavelet analysis is designed. The main contents of the paper are following:①Summarize sources of measuring error of GPS, the reason and characteristic of error sources, the influence on observation data.②Introduce the basic theory of wavelet analysis. Conclude basic conception, multi-resolution analysis and Mallat algorithm, common-used wavelet functions and so on.③The article introduce theory of wavelets into the cycle slip detection. Based on characters of wavelet, we take advantage of the multi-resolution analysis of the DWT(Discrete Wavelet Transformation) to decompose carrier phases sequence, then special frequency components will be picked up and the epoch on which the cycle slip occurred is located. The different wavelets have different characters and different abilities in cycle slip detecting and repairing. After the popular wavelets are compared through the instances, this article not only gains good results but also demonstrates the best wavelets used for cycle slip detecting and repairing in the terms of the theory and the practice. This job is meaningful for the further research in this field.④Pick-up the raw carrier phase from GPS data, and form the single differenced and double differenced observation. Then apply three-level decomposition with bior3.1 wavelet function on these observations and research denoising effects using different observations. The investigation demonstrated that wavelet analysis has great theoretical significance and practical value to decompose and reconstruct GPS data. It can be easily seen that wavelet analysis is a very important mathematical tool to GPS data processing.⑤The wavelet was applied to GPS baseline processing. The original observation of a baseline was analyzed. Three kinds of methods were used to denoise, which are different decomposition level, different threshold selection and rescale methods, and different wavelet functions. An optimal denoising method was found based on the comparative study. The results show that an appropriate denoising method can effectively improve the precision of the baseline. ⑥The structure of"Data Pre-processing System for GPS"was designed. General structure and function of system were studied.