Modeling GPS multipath effect based on spherical cap harmonic analysis

Most GPS positioning errors can be eliminated or removed by the differential technique or the modeling method, but the multipath effect is a special kind of system or gross error, so it is difficult to be simulated or eliminated. In order to improve the accuracy of GPS positioning, the single-epoch pseudorange multipath effects at GPS station were calculated, and firstly modeled based on the spherical cap harmonic (SCH), which is the function of satellite longitude and latitude with the robust method. The accuracy of the kinematic point positioning technique was improved by correcting pseudorange observations with the multipath effect calculated by the SCH model, especially in the elevation direction. The spherical cap harmonic can be used to model the pseudorange multipath effect.