Repairation Of Cycle Slip For Beidou By Wavelet Transform

Beidou satellite navigation system is an independent system researched,developed,operated by China ourselves,and it can provide navigation services for users worldwide after built completely.Beidou is a mature navigation system after GPS of the US and Russia's GLONASS.The system has been successfully applied in many fields,and has brought great benefits to the development of the society.The application of carrier phase observations has been widely concerned in positioning.The cycle slip is a unique problem in the application of carrier phase,and the existence of the cycle slip affects the accuracy of the positioning of Beidou.It is significant to ensure the observations "CLEAN",so the cycle slip detection and repair is a very important work in the use of carrier phase observations.Firstly,this paper introduces the current development situation of Beidou navigation system,and introduces the problem of the cycle slip in carrier observation.Also,the signal characteristics of the Beidou navigation system,the basic observation and its linear combination,the errors in positioning and handling methods are discussed.This paper describes the basic theory of cycle slips,such as the definition and the causes,the influence on the positioning accuracy.We describe the construction principle of the cycle slip detection and several commonly used cycle slip detection,summarize their advantages and disadvantages,and select the double difference detection volume as the cycle slip detection quantity.Secondly,based on the method of GPS cycle slip detection and repair,this paper analyzes the application of wavelet transform in the detection of cycle slip.Wavelet transform is often used in cycle slip detection rather than repair,this paper has done further study on wavelet transform.A method is proposed using wavelet transform to detect cycle slip,then repair cycle slip directly.The basic principle is to use the wavelet transform to detect the sequence of multi-scale decomposition,the detection will be smooth without cycle slip,if there are singular values in high-frequency coefficients,indicating the existence of cycle slips.The singular value is replaced by interpolations,and then the high frequency coefficients and low frequency coefficients are combined to reconstruct signal,make a difference with the original signal to repair cycle slip.After the repair of the sequence to detect again,if singular values still exist in the high frequency coefficient,repeat the above steps until the singular is no longer exist in high frequency coefficient,that is,the end of the cycle slip repair.At the same time,there is a geostationary orbit satellite in the Beidou system,which is not in the GPS system,and it has a great influence on the observation results.Therefore,the unique characteristic is considered seriously.Finally,examples are given to verify the effectiveness of the proposed method.The wavelet transform can be used to repair the cycle slip.At the same time,the shortcomings of the repair process are found,that is,the repair process is completed.This paper summarizes the work done in this paper and the results obtained,which lays the foundation for the following research.