Research On Key Techniques Of Indoor And Outdoor Precision Positioning Based On BDS/GPS Systems

The development and wide application of global navigation satellite system(GNSS)are greatly changing the way of human production and life.With the development of society and the demand for high-precision positioning in various application scenarios,carrier phase scheme is the key technology to achieve high-precision positioning.Absolute positioning has the advantages of simplicity,but how to conveniently determine the ambiguity and improve the accuracy of single point positioning are also problems to be solved.At the same time,with the expansion of application field,the limitation of traditional navigation satellite system becomes more and more obvious.For example,in indoor,valley or complex environment,BDS/GPS satellite signals disappear or become weak due to occlusion,resulting in positioning failure or positioning accuracy affected to varying degrees.The introduction of pseudo satellite technology provides a new technical idea to solve the limitation of GNSS system.Although pseudo satellite adopts the same technical system as GNSS satellite,there are some difficult problems such as frequent cycle slips of receiver and ambiguity in high-precision indoor applications.Aiming at the problems of BDS/GPS satellite navigation system in indoor and outdoor high-precision positioning application environment,carrier phase technology scheme is adopted in this paper to analyze the difficulties involved in outdoor BDS/GPS system and indoor pseudo satellite system precision positioning respectively,and study the key positioning algorithm.At the same time,a verification and evaluation platform for indoor and outdoor precise positioning performance analysis is designed to test and evaluate the performance of various relevant algorithms.This topic mainly analyzes and studies the key technical issues from the following four aspects:Firstly,Research on the ambiguity algorithm based on the joint difference between pseudo-range and carrier phase.In order to solve the key technical problem of the ambiguity in the outdoor positioning algorithm of BDS/GPS satellite navigation system,an ambiguity algorithm is proposed to deal with the basic measurement values by difference operation.The pseudo-range observation equation is used to assist the carrier phase observation equation to conduct joint difference modeling,and the value of the ambiguity is obtained and applied to the subsequent positioning solution.The experimental results show that the proposed algorithm can quickly and stably determine the single epoch ambiguity.Secondly,the precise single point absolute location algorithm is researched and designed based on the multi-difference model between observations.Aiming at the problem of how to improve the absolute single point positioning accuracy in the outdoor positioning application of BDS/GPS satellite navigation system,a precise single point absolute positioning scheme is proposed in which the observation receiver can complete the system without the satellite providing high quality ephemeris information.The experimental results show that this scheme can provide better positioning accuracy.Thirdly,the design and implementation of carrier phase cycle slip detection and repair algorithm based on indoor pseudo satellite.In order to solve the problem of frequent lock-out of indoor pseudo satellite receiver and the phase cycle slip detection and repair technology involved,two solutions based on differential ambiguity reconstruction integral Doppler algorithm and improved polynomial fitting predictive integral Doppler algorithm are proposed respectively.The experimental results show that the two schemes can effectively detect and repair the phase cycle slip phenomenon,and the repaired values can be well applied to indoor positioning algorithm to achieve the desired accuracy.Fourthly,the design and construction of indoor and outdoor precision positioning verification and evaluation platform based on BDS/GPS satellite and pseudo satellite.Aiming at outdoor and indoor application scenarios,a platform for analysis,verification and evaluation of precise positioning results applied to indoor and outdoor positioning environment was designed and built according to requirements,and used for evaluation and analysis of relevant positioning algorithms.