Research On GPS Tri-frequency Ionospheric Error Correction Algorithm

Due to the instability of the medium in the ionosphere,the elimination of the ionospheric delay error will face a severe test.Although on the road of this technology development,scholars have proposed ways to improve GPS positioning accuracy in ionospheric delay error correction,such as Bent model,IRI model,Klobuchar model,NeQuick model,GIM model,GNSS dual-frequency observation correction method.,no ionospheric delay combination,surface fitting model,distance weighting method,multi-face function method,but there is still no unified GPS ionospheric delay error correction method to eliminate the influence of ionosphere on GPS signal propagation.In this paper,mainly in the correction of GPS ionospheric refraction error,the dual-frequency ionospheric correction method for GPS carrier and code observation and the tri-frequency second-order correction method for GPS ionospheric refraction error are studied.Taking the GPS observation data of March 2017 as the experimental object,the research content of this paper mainly focuses on the following two aspects:(1)Based on the research of GPS carrier and code observation dual-frequency ionospheric correction method,the tri-frequency second-order correction method of GPS ionospheric refraction error is combined to construct a tri-frequency ionospheric correction method for GPS carrier and code joint observation.Effectively avoids the distance between the actual satellite and the occultation detector in the GPS ionospheric tri-frequency delay error correction,the carrier and code observation respectively solve the problem caused by the GPS ionospheric tri-frequency delay error,the receiver clock difference and the satellite The difference between the clock difference,the delay caused by the tropospheric refraction,and the solution of the ambiguity in the GPS ionospheric tri-frequency delay error correction.(2)In MATLAB,the dual-frequency ionospheric correction algorithm for GPS carrier and code observation and the tri-frequency ionospheric correction algorithm for GPS carrier and code observation are respectively constructed.Taking the GPS data of March 2017 as an example,GPS will be respectively used.The dual-frequency observation data and the GPS tri-frequency observation data are solved.From the results,the feasibility of the tri-frequency ionospheric delay error correction method for GPS carrier and code observation can be known.After the larger error value is removed,the ionosphere is solved.The delay error correction is in the range of-16 to 28 m,and the ionospheric delay error is controlled.Figuer[33]table[2]reference[83]...