The Research Of GPS Data Pre-processing Methods And Its Application

Based on the data processing theories for GPS control network and computer technologies, the data pre-processing theories were researched mainly. The development experience of GPS data processing system and the research findings of the theories for GPS data pre-processing were absorbed. The detecting and repairing of cycle slips, gross error elimination, the elimination of multi-Path effect and some measurement noises were analyzed. The system of GPS data pre-processing was designed and developed. The main contents of the paper are following:1. The sources of measuring error of GPS control network were summed up. The reason and characteristic of error sources, the influence on observation data were analyzed.2. The theory for GPS observation data pre-processing was researched. Detection and Reparation for cycle slips using dual frequency differenced carrier-phase was improved with iterative algorithm. The ambiguity of cycle skip was solved in effect.3. The error detection and correction of GPS control network was studied. Based on the accidental and the solitude of error, the methods based on unascertained filtering were brought after the unascertained filtering theory was quoted in error process. Compared with traditional methods, some good results were achieved.4. The wavelet was applied to GPS baseline processing. On the condition of poorly observation environment the multi-path effect and multifarious noises was very serious, so the signals of GPS were disturbed seriously and the precision of surveying results were reduced. The noises of high frequency signals were eliminated by using the decomposition and reconstruction of wavelet, then the multi-Path effect and some observation noises of the carrier observation data were filtered. It makes the precision of the baseline result was improved.5. The structure of data pre-processing system for GPS control network was analyzed. General structure and function of system and some critical technology used in the system development were studied. The system was developed in VC++ language.