| With the development and upgrading of many domestic industries since the beginning of 21st century, satellite navigation has more development and widely application to us and it has been paid more and more attention from the country and citizens. An independent complete controllable satellite navigation system will has a great positive role on the development of economy and society, it has great promote to the development of related industry, improve the national economy and provide guarantee for national security. In addition, Beidou satellite navigation plays a great role in promoting industrial informatization, industrial convergence, improving the productive forces and changing people’s lifestyle. However, the slip in the carrier phase is the technical difficulty of satellite navigation system which will affect the high accurate orientation, attitude determination and speed determination of Beidou satellite navigation. Therefore, it is very important and significant to the detection and repair of the cycle slip exist in Beidou satellite navigation in time.Cycle slip occurs only in the carrier phase, and the detection and repair of the essence includes three processes of identifying, locating and repairing. Among them, recognition and positioning of the epoch that cycle ship occur is the key to solving the problem of cycle ship, but also the precondition of cycle slip repair. The pseudo range combined with phase to construct the detectable quantity of cycle slip, the detectable quantity is regarded as a time-varying signal, cycle slip is a singular point of signal, according to the signal singularity detection theory, put forward several kinds of cycle slip detection method, and combined with the least square support vector machine and its advantages in the time series prediction, combination prediction model is constructed, which not only can solve the large cycle slip detection and repair problems for cycle slip also realizes the accurate detection and repair.Tlie main contents of this paper are as follows:(1)The application of local mean decomposition method in signal processing is studied, and the method of detecting the cycle slip based on improved LDM is proposed. This method can effectively solve the phenomenon of obvious shif caused by using the sliding average method within LMD, avoiding the inaccuracy of the locating of cycle ship caused by the early or delayed phase of the cycle. The LMD decomposition is a series of product function components, and sensitive evaluation algorithm is used to select the sensitive component of the cycle slip information. Then the prediction value of the sensitive component is reconstructed, and the final prediction value is obtained. The calculated value and the predicted value are different, and the cycle slip is calculated.(2)Singular value decomposition has certain advantages in the detection of the abrupt signal, the time of the occurrence of the mutation, the high signal to noise ratio. The singular point of the cycle of the carrier phase is considered, and the method of the cycle slip detection based on the SVD envelope spectrum is proposed. The method using Hankel matrix attractor trajectory matrix is constructed. Then the SVD processing, singular value can reflect the mutation information is obtained. Finally, using SVD inverse operation and counter space transform to reconstruct signal components, and the Hilbert transform envelope spectrum is obtained. Based on the amplitude maxima point position, detect cycle slips of epoch.(3)Aiming to the improved LMD and SVD has omission of one cycle in the process of the detection of cycle ship, the method to detect cycle ship is proposed based on dual tree complex wavelet. The method can effectively detect the existence of small cycle slips in time series by using the observed data. Then the prediction value is reconstructed by the sensitivity evaluation algorithm. The LS-SVM is used to calculate the cycle slip. The carrier phase observation value is obtained by the cycle ship. |
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