A Research On High-precise Positioning Algorithm Of The Beidou Satellite Navigation System

Nowadays,Beidou Satellite Navigation System(COMPASS)has broad applicationprospects as a national strategic emerging industry.It is important to realize the precise positioning for promoting COMPASS to precision navigation,engineering survey and geographic information collection etc.This thesis focuses on the COMPASS high-precision positioning algorithm,separately discusses several hot topics in carrier phase precision positioning,which included in cycleslip detecting and repairing,and the integer ambiguity resolution.Firstly,this thesis based on COMPASS observation data,verifies the detection and repair ability of the classical algorithm at different sampling rates,probes that at low sampling rates,the increasing in the ionospheric delay error will cause this conventional method not able to detect the cycleslip accurately.Secondly,in order to detect the cycleslip,a triple-frequency geometry-free and ionosphere-free carrier phase combination is proposed,and combines with a second-order time-difference phase ionospheric residual combination(STPIR)to detect the cycleslip epoch.Meanwhile,the STPIR cannot eliminate the effect of ionospheric delay completely,so a sliding window method is presented to obtain the detection threshold in order to reduce the possibility of misjudgement.Thirdly,to repair the cycleslip,a geometry-free combination with the ionospheredelay error is proposed,then combines with two ionosphere-free code-phase combinations to repair the cycle-slips.By experiment with COMPASS triple-frequency data,this method can still detect different types of cycleslip,even in 30s sampling interval,comparing to the common algorithm,the new method has better adaptability.Finally,this thesis discusses several common integer ambiguity resolution algorithm,the LAMBDA algorithm is introduced in detail.Then it describes the importance of decorrelation for increasing the rate of ambiguity resolution,and discusses the LLL lattice reduction algorithm and inverse integer LDL~Talgorithm.By simulation,this thesis compares the performance of these algorithms.