Research On BDS/GPS Relative Positioning Algorithm And Its Application In Landslide Monitoring

Beidou satellite navigation system is China's independent construction and development of the global satellite navigation system,following the GPS,GLONASS,GALILEO after the fourth largest global satellite navigation system.It is of practical significance to study the BDS location algorithm,which can provide better service for users.With the completion or modernization of GPS,GLONASS,GALILEO,BDS system,multi system combination positioning highlights a significant advantage,which has become a hot topic of navigation and positioning.In the GNSS high-precision positioning technique,many errors of the two stations which are synchronously observed can be eliminated or greatly weakened by differential method in relative positioning,thus obtaining high-precision positioning results,and have become the main operation mode of precise positioning.Based on the research of BDS/GPS relative positioning theory,this paper focuses on the BDS short baseline relative positioning algorithm and BDS/GPS system combination positioning method,and the relative positioning technology of the single BDS system and BDS/GPS combination system was applied to Jingyang landslide monitoring.The main contents and conclusions of this paper are as follows:(1)Aiming at the problem of cycle slip detection in BDS carrier phase relative positioning,the MW combination method and the method of detecting the cycle slip by the ionospheric residual method are analyzed in depth,and the measured data of BDS are used to validate the method.The results show that both of the two methods are insensitive to certain cycle slip.Therefore,it is necessary to combine the two methods to detect the cycle slip.(2)The theory of ambiguity parameter estimation and LAMBDA ambiguity resolution in relative positioning algorithm are introduced in detail,and the method of changing the ambiguity parameter when the method is superimposed by sequential least squares adjustment is deduced.The relative positioning solution is carried out by BDS measured data.The results show that the relative positioning precision plane of BDS is better than 1.1 cm,and the elevation is higher than 3.5cm,which can reach centimeter level positioning accuracy.(3)Aiming at the key problems of BDS/GPS combination positioning,the difference of frequency,time system,coordinate system between BDS and GPS is analyzed.In this paper,the relative positioning function model of BDS/GPS in the coordinate domain,the normal equation domain and the observation equation domain is derived.From the theoretical analysis,it is concluded that the combination of the normal equation domain and the observation equation domain is equivalent.The method of estimating the BDS/GPS based on the height angle and the Helmert posterior variance component estimation method are studied.Finally,analysis the angle prior right posterior variance estimation combined with Helmert weighting method and using only the prior rights angle positioning accuracy,using the measured data of BDS/GPS integrated system the results show that the positioning accuracy of the former than the latter in E,N,U direction were improved.(4)GNSS relative positioning technique applied to the South Jingyang plateau Miaodian landslide,and compared with the total station deformation monitoring results.The result shows that the monitoring result of GNSS is consistent with that of total station.The positioning accuracy of the combined system is better than that of the single system in the horizontal and elevation directions,and the positioning accuracy of the BDS/GPS single system is basically the same.Under short baseline condition,BDS relative positioning technique can be applied to landslide deformation monitoring with high reliability.