A method and system for obtaining ionospheric delay of oblique path

Abstract

The invention discloses a method and system for obtaining inclined path ionized layer delay, and relates to the technical field of global navigation. The method includes the following steps: a serverdivides grids for a service area to obtain grid point coordinates; the server receives real-time observed values of a plurality of reference stations in the service area, an area ionized layer delay model is built according to the real-time observed values, and the area ionized layer delay model includes inclined path ionized layer delay between each reference station and each satellite and puncture point position data; the server obtains inclined path ionized layer delay between each grid point and each satellite according to the area ionized layer delay model; and the server receives a request of a user terminal, searches the grid point which is closest to the user terminal, and sends all inclined path ionized layer delay of the closest grid point to the user terminal. The method and system for obtaining inclined path ionized layer delay do not need to perform secondary transformation on TEC, avoid positioning accuracy loss brought by projection from an inclined path to a zenith direction, and reduce calculation load of the server.

Description

technical field [0001] The present invention relates to the technical field of global navigation, in particular to a method and system for acquiring ionospheric delay of oblique paths. Background technique [0002] In Global Navigation Satellite System (GNSS) positioning, the ionosphere generates a time delay for the GNSS satellite signals passing through it, and it is converted into a distance error when the user terminal measures distance through the transmission time, making the ionosphere delay become a major source of positioning error. The traditional method of ionospheric delay correction generally adopts the horizontal layered ionospheric model, that is, measures the total electron content (TEC) on the satellite signal propagation path, and projects the measured discrete oblique path ionospheric delay to the zenith direction, establish a vertical TEC spatial distribution model, and then convert it to the oblique TEC in the actual measurement and provide it to the us...

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Problems solved by technology

This method not only requires a second conversion of the TEC, but also when the projection function is not accurate enough, positioning with the ionospheric model represented by the vertical TEC will inevitably lead to a loss of positioning accuracy, such as Klobcher, which is widely used in single-frequency user positioning (Klobuchar) model and the ionospheric grid model provided by IGS, although the calculation is fast and the application is simple, they can only correct 60% of the ionospheric delay error in the best service area, and the ionospheric grid model provided by IGS is obtained through The global model with a difference of 5° and a latitude difference of 2.5° has sparse grid points, which also affects the accuracy of ionospheric delay correction

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