Research On GPS/GLONASS Combined Kinematic Precise Point Position

As the rapid development of technology,the application of navigation position technique has expanded its width and depth.Compared with the traditional technique of RTK,the kinematic precise point position has many advantages,which does not depend on other reference station and has high precision.The kinematic precise point position can achieve a decimeter to centimeter level outcome.However,in the complex external environment,the receiver always achieves a poor outcome for the lack of satellites,which makes the significance of researching of GPS/GLONASS combined kinematic precise point position.This thesis has studied on GPS/GLONASS combined kinematic precise point position in depth and analyzed the outcome using dilution of precision.The main research contents and conclusions are as follows:(1)In this thesis,we have studied the time reference system and coordinate reference system,the positioning model and the combination model which used in kinematic GPS/GLONASS combined precise point position.The existed errors in kinematic precise point position have been analyzed,including the satellite related error,propagation related error and receiver and station related error.Besides,the detailed solution of every error sources has been discussed in this thesis.(2)This thesis describes the data preprocessing method in kinematic precise point position,the position model of GPS kinematic PPP and GPS/GLONASS combined kinematic PPP,and the parameter estimating method.The related software has been completed independent.(3)In this thesis,we using dilution of precision to evaluate the precision of the kinematic simulation experiment and real kinematic experiment in theory.Analyzing the parameter dilution of precision which is calculated in kinematic simulation experiment,we find that the dilution of precision in horizontal is not sensitive to satellite geometric distribution.However,the dilution of precision in the vertical,clock error,and the zenith wet troposphere are very sensitive to satellite geometric distribution.Besides,the dilution of precision in vertical is strong correlation with the dilution of precision in clock error,and the zenith wet troposphere.When the cut off angle is 10°in kinematic simulation experiment,the GPS/GLONASS combined kinematic PPP would be improve by 41.5%,26.1%,36.8%,40.0%,43.4%in the N,E,U,clock error and the zenith wet troposphere compared to the GPS kinematic PPP.Compared with kinematic simulation experiment,dilution of precision of each parameter in real kinematic experiment is worse.(4)Three simulated experiments data is analyzed,including the single system kinematic precise point position of GPS,the GPS/GLONASS combined kinematic precise point position and the simulated GPS/GLONASS combined kinematic precise point position with the elevation of 25 degree in poor circumstance.The research result shows that the GPS/GLONASS combined kinematic PPP,on the whole,is better than the GPS kinematic PPP in the N,E,U direction with better than 10cm accuracy,which indicates the software in this thesis can reach a precision of cm level,when the satellite elevation is 10°.In the simulated poor experiment,the accuracy of GPS/GLONASS combined kinematic PPP can be improved by 36%,70.2%,44.8%compared to the GPS kinematic PPP in N,E,U direction.Comparing with the simulated poor experiment and the ordinary simulated experiment,the condition of poor environment has a great impact on GPS kinematic position in N,E,U direction.However,as to GPS/GLONASS combined kinematic PPP,there is no great impact would make in N and E direction except a great impact in vertical.In the kinematic experiment,for the change of external environment,the receiver clock loss of lock,continuous cycle slip and data loss phenomenon occur,which leads to the final result is not ideal.The precision and the convergence rate of GPS kinematic PPP and the combined PPP have poor performance.