Research On The Algorithms Of Cycle Slip Detection And Correction For Beidou Observations

With the launch and continuous improvement of BDS(BeiDou navigation satellite system),its range of applications has become expanded.Cycle detection and correction is a prerequisite for high precision positioning using carrier phase observations.However,the existing cycle slip detection and correction methods are mostly based on GPS observations.In addition,BDS has its own characteristics which is different from GPS.Therefore,it is necessary to study the characteristics of Beidou observation and the features of cycle slip.Based on the algorithms of GPS cycle slip detection and correction,we can develop the methods of cycle slip detection and correction which are applicable to Beidou observations.Based on the above,the main researches of the paper focus on the following aspects:1.Based on triple-band observations of BDS,two geometry-free and ionosphere-free combinations are first proposed in this thesis.Then based on the combinations,the observation noise and multipath of the real Beidou observations have been assessed.Finally,the stochastic model is established for Beidou observations;2.For cycle slip detection and correction of single satellite one time with triple-band Beidou observations,the geometry-free phase combination,pseudorange/phase combination and the joint use of the two combinations have been tested and analyzed for cycle slip detection and correction.Taking into account the use of a combination of observations may increase the effects of the ionospheric delay,noise and multipath,a non-combination method has been proposed in this thesis.With the integer solution obtained by LAMBDA method for cycle slip,the method without use of combination of Beidou observations has been implemented;3.For cycle slip detection and correction of multi-satellite at the same time,time-relative method for cycle slip detection and correction is adopted from the time-relative positioning.By testing with Beidou observations,the characteristics of this method has been analyzed and summarized;4.By analyzing and summarizing the commonly used testing quantity for cycle slip detection and correction,the problem about how to select the optimal testing quantity has been dicussed.Then a hypothesis testing approach to evaluate the reliability of cycle slip detection and correction is proposed.Finally,the approach is verified with Beidou observations.