Research On BDS-3 Real-time Precision Single Point Positioning Technology

Real time precise single point positioning(PPP)is widely used because it only needs a single receiver to achieve high-precision positioning,and has great research value and practical value.In order to achieve high-precision positioning,the first thing to obtain is the precision track clock error,and then eliminate the errors in its transmission process one by one.In the past,the real-time precision track clock error has always depended on the SSR data stream broadcast by the IGS data center,and the channels to obtain the SSR data stream are limited.Usually,an IGS account is required,and then the real-time correction products of various institutions are connected through the NTRIP communication protocol.Beidou office published the relevant documents of Beidou service spatial signal in 2019.The correction number provided by its B2 b signal can provide real-time PPP services for China and surrounding areas and realize the autonomy of real-time PPP.PPP requires accurate carrier phase value,and carrier phase often cycle slips due to various reasons.The detection and repair of cycle slips is a necessary condition for realizing high-precision PPP.Based on the current situation,this paper studies and realizes the analysis of Beidou ppp-b2 b signal and analyzes the accuracy of its products.At the same time,aiming at the problem of cycle slip detection of single frequency precise single point positioning,a single frequency cycle slip detection method is proposed.The main research of this paper is as follows:1.Aiming at the problem that real-time precision single point positioning relies on SSR data stream broadcast by foreign IGS websites through ntrip,we collected ppp-b2 b,an independent precision single point positioning product newly released by Beidou office,evaluated the accuracy of its track clock error correction information,simulated its positioning results,and simulated the real-time PPP based on SSR correction information under the open source software rtklib as a comparative experiment.The experimental results show that the real-time PPP based on ppp-b2 b correction can converge to less than 0.3m within 30 min.2.To solve the cycle slip repair problem in single frequency precise single point positioning,a reconstructed Doppler integration method based on inter satellite difference is proposed.The small cycle slip detection experiment,gross error detection experiment and continuous cycle slip detection experiment of inter satellite differential reconstruction Doppler integration method are carried out under various conditions,and compared with Doppler integration method and phase pseudo range combination method.The experimental results show that the detection accuracy of this method is better than that of the traditional single frequency cycle slip detection method.Under the conditions of 1 second sampling rate and 30 second sampling rate,it can detect the small cycle slips and gross errors in one cycle,and can sensitively reflect the changes of continuous cycle slips.