Ionosphere vertical-total-electron content modeling method based on ellipsoidal-harmonic-function theory

Abstract

The invention discloses an ionosphere vertical-total-electron content modeling method based on ellipsoidal-harmonic-function theory. The method comprises the following steps: S1, acquiring geographiclongitude of a puncture point of region observation points, geographic latitude of the puncture point and an electron content of a vertical direction of the puncture point; S2, carrying out reductioncalculation on geocentric latitude; S3, selecting the order of an ellipsoidal harmonic function, and adopting the ellipsoidal harmonic function to establish a region ionosphere vertical-total-electroncontent model; and S4, calculating parameters of the region ionosphere vertical-total-electron content model through a least square method, and correcting the region ionosphere vertical-total-electron content model. Compared with the prior art, the method more accurately describes nonlinear vibration characteristics of ionosphere delay information over time, better simulates spatiotemporal variation features of a region ionosphere, and effectively improves model accuracy.

Description

technical field [0001] The invention relates to a modeling method for the vertical total electron content of the ionosphere based on the ellipsoid harmonic function theory. Background technique [0002] In the related research and application of GNSS ionospheric modeling, the more commonly used ionospheric correction models are generally divided into two categories: one is the empirical model, including the Klobuchar model, IRI model, Bent model, etc. used in GPS. , because the establishment of empirical models is based on long-term data collection, some models have complex structures and poor applicability, and usually cannot meet the requirements when ionospheric model modeling and GNSS positioning accuracy are high; One is a fitted ionospheric model based on high-precision GNSS dual-frequency observation data. Generally, the commonly used ionospheric models include the following three types: polynomial model (POLY), spherical harmonic function model (SHF), and trigonometr...

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Problems solved by technology

Compared with the empirical model, the accuracy of the fitting model has improved to a certain extent, but the absolute accuracy of the fitting model is still not very high. The spherical harmonic function model (SHF) is a fitting model that is widely used and studied at present, and it can Describe the ionosphere to a certain extent, but as we all know, the surface of the earth is closer to a spheroid than a sphere. Using spherical harmonics to establish an ionospheric delay model will produce a certain deviation, and the flattening of the earth will affect high-precision positioning. It will have adverse effects. The spherical harmonic function model can no longer meet the current requirements of relatively high-precision positioning and navigation applications due to ignoring the flatness level error. services to meet the needs of higher precision measurement

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