A Modeling Method of Ionospheric Vertical Total Electron Content Based on Ellipsoid Harmonic Theory

Abstract

The invention discloses a method for modeling the vertical total electron content of the ionosphere based on the theory of ellipsoidal harmonic functions. S2: Calculating the naturalization of the geocentric latitude; S3: Select the order of the ellipsoid harmonic function, and use the ellipsoid harmonic function to establish the vertical total electron content model of the regional ionosphere; S4: Calculate the regional ionosphere by the least square method Parameters of the vertical total electron content model, which corrects the vertical total electron content model of the regional ionosphere. Compared with the prior art, the invention more accurately describes the nonlinear vibration characteristics of the ionospheric delay information over time, better simulates the temporal and spatial variation characteristics of the regional ionosphere, and effectively improves the 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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