Study On The Techniques Of Data Processing In GPS Receiver

Recently, the global positioning system (GPS) receiver has played an importantrole in many fields, such as navigation, positioning, timing, etc. This dissertation mainlyfocuses on the techniques of data processing in GPS receivers. The techniques includethe cycle-slip detection of carries phase observations, the modeling and predictionmethod of the series of receiver clock bias (RCB), the GPS positioning method underbad conditions, the auxiliary receiver autonomous integrity monitoring (RAIM) with theaid of the RCB prediction model, etc. The main contributions of the dissertation can besummarized in the following.(1) Research on the method for detecting cycle-slip of carrier phase observations.The time series method and the Hilbert-Huang transform (HHT) method are used fordetecting cycle-slip of carrier phase observations. On the basis of the theory of timeseries analysis, the first method establishes a weighted model for predicting the carrierphase observations, and then uses the prediction model to calculate the detectionstatistics for detecting cycle-slip. While in the second method, the cycle-slip is regardedas the fault of carrier phase observations, and then how to detect it is considered to bethe problem of fault feature extraction. Experimental results show that the two methodscan detect the cycle-slip of carrier phase observations correctly.(2) Research on the RCB prediction model. The RCB series is regarded as a greysystem, and then the grey theory is utilized to predict it. Meanwhile, the stabilization ofthe model is diagnosed on the basis of the matrix condition number. Theoreticalanalyses show that the RCB grey prediction model is stable and the morbidity problemdoes not exist in the model. In addition, the prediction precision of the grey model ishigher than that of the polynomial model, and it is more suitable for the short-termprediction of the RCB series.(3) Research on the GPS positioning method under two satellites. For GPS staticpositioning, the measurement equation can be expended by three observations under thecondition where there are two satellites. When the equation can be solved properly, thefunction of positioning calculation can be implemented, and the three-dimensional coordinates of GPS receiver can be obtained. Experimental results show that the methodcan provide the positioning information and can improve the positioning continuity ofGPS receiver for the case where there are two satellites.(4) Research on the auxiliary RAIM method with the aid of the RCB greyprediction model. The RCB series is regarded as one satellite, and the RCB greyprediction model is used for aiding the RAIM method so as to improve the efficiency ofdetecting and identifying faulty satellite. Experimental results show that the auxiliaryRAIM method can reduce the dependence of the traditional RAIM method on thenumbers of GPS satellites. The auxiliary RAIM method can detect the faulty satelliteunder four satellites. When there are five satellites, the faulty satellite can be identifiedand the information about it can be excluded from the measurement equation, so that thepositioning precision of GPS receiver can be ensured. In addition, the auxiliary RAIMmethod with the aid of the RCB grey prediction model can improve the efficiency ofdetecting and identifying faulty satellite and the positioning precision, compared withthe polynomial method.