A 3D modeling method for GNSS ionospheric delays applicable to global regions

Abstract

The invention discloses a GNSS ionosphere delayed three-dimensional modeling method suitable for a global area. The GNSS ionosphere delayed three-dimensional modeling method comprises the steps of acquiring an empirical orthogonal function which is used for representing vertical distribution of ionosphere electrons, establishing an ionosphere model based on a spheric harmonics function and the empirical orthogonal function by means of an ionosphere TEC observation amount which has been accurately estimated, and constructing an accurate three-dimensional modeling method which is suitable for ionosphere delay of the global area. Compared with an existing method, the GNSS ionosphere delayed three-dimensional modeling method is advantageous in that the empirical orthogonal function is used for representing vertical density distribution of the ionosphere electrons; not only is limitation of an ionosphere delay two-dimensional model overcome, but also change information of ionosphere large-scale structure (such as equator abnormity, midlatitude trough and different ionosphere disturbance) can be effectively monitored; and furthermore the GNSS ionosphere delayed three-dimensional modeling method has important scientific meaning and application value in monitoring and researching different scale inhomogeneities, ionosphere environment, ionosphere temporal and spatial variation and monitoring the ionosphere in a global range.

Description

technical field [0001] The invention belongs to the fields of satellite navigation, radio wave propagation and space ionosphere, and in particular relates to a three-dimensional modeling method for GNSS ionosphere delay applicable to global regions. Background technique [0002] After more than 20 years of development, GNSS (Global Navigation Satellite System) is not only used in the military field, but also widely used in the civilian field. With the advantages of precision, timing, and no geographical restrictions, it has become a general navigation tool in land transportation, navigation, and aviation. It has omnipotent, global, all-weather, continuous, and real-time navigation, positioning, and timing functions. Provide users with precise three-dimensional coordinates, speed and time. GNSS has not been a single constellation system since its inception, and currently includes GPS in the United States, GLONASS in Russia, BDS in China, and Galileo in the European Union. ...

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Problems solved by technology

The above model is very helpful to describe the whole-layer change of ionospheric electron density, and is very effective for analyzing the influence of GNSS signals passing through the entire ionosphere by the ionosphere, which greatly simplifies the process of data processing. In the latitude region, the above hypothesis is basically established; however, for the equatorial region with intense ionospheric activity or the edge region of the "equatorial anomaly" double-peak structure, the ionospheric TEC gradient on the north and south sides of the intersection point has a Larger differences, if a simple projection function is used to describe the relationship between the line of sight and the ionospheric TEC in the vertical direction, it will bring a larger error

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