Real-time positioning accuracy analysis of single-frequency GPS based on predicted ionosphere grid products

Firstly,this paper introduces the common methods and accounts for the advantage of ionosphere grid products for correcting ionosphere errors with single-frequency GPS,according the analysis that ionosphere grid products can effectively ameliorate errors of single-frequency GPS navigation and positioning.In detail,this article gives the establishment,forecast and operation methods of ionosphere grid products,and introduces the method that calculates the VTEC(Vertical Total Electronic Contents)values of the geocentric latitude of the ionospheric pierce point,the VTEC values of four-point interpolation models and the single-layer mapping function.It also compares different pairs of ionosphere correction data and satellite ephemeris which use to analyze the impact of real-time positioning accuracy of single-frequency GPS.The experiments prove that the predicted ionosphere grid products can obviously improve the precision for single-frequency users,and have some practical values for singlefrequency positioning and orbit determination.