Research On High-precision Pseudo-range Positioning In BDS

With the full completion of the Beidou-3 global satellite navigation system,China ’s Beidou navigation system officially has the ability to cover the world all-day and all-weather services.It can provide real-time high-precision navigation and positioning timing services for global users.Providing positioning service for users is one of the most basic functions of Beidou navigation system.At present,Beidou navigation and positioning technology mainly includes pseudo-range measurement positioning technology and carrier phase positioning technology.Among them,the pseudo-range measurement positioning technology has been widely studied and applied,because of its simple implementation,fast positioning speed and no integer ambiguity.However,various errors from the satellite,the environment,and the receiver itself will cause the positioning accuracy of the pseudo-range measurement to fail to meet the demand.Therefore,eliminating the influence of error and improving the positioning accuracy is an important issue to be solved in Beidou navigation pseudo-range measurement and positioning technology.In this thesis,the current situation of pseudo-range measurement and positioning technology at home and abroad and the mechanism of Beidou navigation system.On this basis,the positioning principle and error factors of pseudo-range single point positioning and pseudo-range differential positioning in Beidou pseudo-range positioning are studied in detail.Furthermore,a high-precision pseudo-range positioning method is proposed.In this method,the satellite clock error,ionospheric delay error and tropospheric delay error are eliminated by pseudo-range differential positioning.At the same time,a random error correction model is established to solve the uncertainty introduced by random error.The model can correct the accidental pulse interference and other periodic interference that cannot be completely corrected by the mathematical model.Not only that,the model also filters out the high-frequency thermal noise in the observation noise,and eliminates the receiver clock error while suppressing the expansion of the observation noise.The traditional positioning estimation model does not take into account the fact that the pseudo-range observations between the observation satellites are not related to each other and have different distributions.Therefore,an adaptive weighted estimation model is proposed to reduce the positioning error caused by the inaccurate positioning estimation model.Finally,through the simulation performance analysis,it is verified that the high-precision pseudo-range positioning error meets the requirements of Beidou navigation high-precision pseudo-range positioning.At the same time,the error of high-precision pseudo-range positioning is compared with that of pseudo-range double differential LS positioning,pseudo-rang double differential LS-KF positioning and pseudo-range double differential WLS-KF positioning.It is further verified that the high-precision pseudo-range positioning method has certain advantages.