Error Analysis And Quality Evalulation Of GPS Data

The quality of GPS data pre-processing is the key to improve GPS positioning precision in either GPS static positioning or dynamic POD. Based on the data processing theories for GPS and computer technologies, the data pre-processing theories in single station are researched mainly in this paper. The development experience of GPS data processing system and the research findings of the theories for GPS data pre-processing are absorbed. The detecting of cycle slips, gross error elimination, the estimation of multi-path effect, the azimuth and elevating angle, the information of observing statement are analyzed. The system of GPS data pre-processing is designed and developed. The main contents of the paper are following:1. The sources of measuring error of GPS were summed up. The reason and characteristic of error sources, the influence of observation data were analyzed.2. A method to detect the cycle slips in GPS observation data called TurboEdit is discussed in this paper, and put forward some advices according to some limits of this method. This method can also be used to detect gross error.3. The azimuth and elevating angle of satellites are calculated by using the observation files and navigation data. The effect to pseudorange caused by multi-path is estimated, and the result is showed in picture and table form.4. The result of data processing, including cycle slip detecting, gross error, azimuth and elevating angle of satellites, the signal to noise ratio, the effect caused by multi-path and ionosphere delay, are saved to different files in a certain form for the next analysis.5. The structure of data pre-processing system for GPS observation was analyzed. General structure and function of system and some critical technology used in the system development are studied. The system is developed in Visual Basic language.