Research On Carrier Phase Difference Positioning Technique Of BeiDou Navigation Satellite System

As one of the world's four major navigation systems,BeiDou Navigation Satellite System is completely independent of China's development of a new generation of satellite positioning timing system,and completely independent of the United States and other countries.BeiDou Navigation Satellite System's development will bring China,neighboring countries and the world to more reliable,more secure and more secure positioning time service,which marks the development of China's satellite navigation industry will have a bright future.Carrier phase differential positioning technology has been the hotspot and difficult point of the scholars at home and abroad,and the research on Beidou navigation carrier phase differential positioning technology is also a trend to adapt to the development of navigation in China.In this paper,we focus on several key problems of Beidou carrier phase differential positioning technology,namely accurately detecting and correcting cycle slip and correcting integer ambiguity.The main work of this paper is as follows:Firstly,it introduces the development situation of the four most widely used navigation systems and the current research on key algorithms of carrier phase differential positioning technology,and focuses on the new system of Beidou Navigation in China.The three most commonly used models of carrier phase differential positioning are introduced in detail,including three kinds of difference modes: single difference,double difference and three difference.For the Beidou tri-band characteristics,the Beidou multi-frequency combination is introduced,and several common linear combination directions are compared.The sources of errors and the methods of offset or attenuation in differential location using carrier phase are briefly introduced.Taking into account the carrier phase differential positioning may occur in the signal loss of lock and other contingencies,resulting in cycle slip,the commonly used cycle slip detection and repair method of research,the algorithm were modeling and simulation analysis.These methods have their own advantages and disadvantages,such as polynomial method has the advantage of detection and repair of large cycle jump,wavelet transform method to detect large or small weeks are good,but the cycle of the repair ability is not.Combined with the advantages and disadvantages of various methods of cycle slip detection,the existing method is improved.The combination of polynomial fitting method and wavelet transform method can better detect and fix the size cycle slip,and the localization precision can be greatly improved.Another important difficulty in differential positioning based on carrier phase lies in the determination of integer ambiguity,which means whether precise positioning can be achieved.In this paper,several commonly used ambiguity determination methods are introduced,and each method has advantages and disadvantages,among which LAMBDA method is the most effective method to solve the ambiguity of the whole cycle.In order to improve the search efficiency of integer ambiguity,the LAMBDA method is improved to reduce the search space of ambiguity by the constraint of baseline length to improve the search efficiency of ambiguity.The baseline resolution is more accurate and faster.Real-time performance of differential positioning is satisfied.