Study The Algorithms And Software Of The Single-frequency RTK Based On The Combination Of BDS And GPS

With the development of satellite navigation systems from every country,multisatellites navigation system will be the mainstream product in the future.Aiming at the limitation in the matter of positioning accuracy,this article studied on the singlefrequency RTK algorithms witch are used in BDS/GPS integrated navigation system.The main research contents are as follows.(1)this article introduced the transmission mode,including the TCP/IP based on networks and transmission based on Ntrip protocol,and transfering data through the serial port based on physical medium,Meanwhile,introduced the definition of RTCM data format and decoding process of RTCM data.(2)this article gave parameter estimation algorithm in GNSS positioning,analyzed elevating angle model and relative merits of SNR model,at the same time,described the error sources in GNSS positioning and methods for diminishing errors,in the meantime figured out the disadvantages of the parameter estimation method which is used for eliminating tropospheric error,last but not least,gave the further researches.(3)Considering the existent shortcoming of quality control on single-frequency and real-time GNSS data and making a comparative analysis on polynomial fitting method and Kalman filtering algorithm,this paper proposes a method which is based on Kalman filtering to smooth pseudo-range to improve the effect of combination between grey model and pseudo-range phase method.Effectiveness of the proposed algorithm has been proved by measured data.Then basic flow of probing clock jump in real time is introduced in brief.(4)referring to the design ideas of the softwares,including GOGPS and RTKLIB,the author developed an application program named BDS/GPS-RTK positioning system,which has been tested using measurement data,and the results showed that this program is stable and reliable.