A Method of Measuring Ionospheric Tec Value Using SAR Satellite

Abstract

The invention discloses a method for measuring a TEC value of an ionized layer by utilizing an SAR satellite. After satellite-borne SAR transmission pulse signals penetrate through the ionized layer, the phase of the satellite-borne SAR transmission pulse signals contains complete TEC information of the ionized layer on the propagation path. By means of the method, multiple sub-bands are selected from the SAR signals with a certain band width, so that a freedom degree needed by phase ambiguity resolution is provided. Through the optimized design of parameters of the sub-bands and other technical means, the influence on phase position ambiguity resolution processing from an electromagnetic wave propagation distance phase is eliminated while the estimation accuracy of the TEC value is considered. Finally, a phase ambiguity resolution equation is built, and high-accuracy estimation of the TEC value of the ionized layer is achieved. The estimated TEC value of the ionized layer is utilized to supplement a satellite-borne SAR echo phase, and the satellite-borne SAR imaging quality and interferometry accuracy can be effectively improved.

Description

technical field [0001] The invention relates to a method for measuring the TEC value of the ionosphere, in particular to a method for realizing high-precision measurement of the TEC value of the ionosphere by using a SAR satellite, and belongs to the field of geosynchronous orbit SAR system development. Background technique [0002] After the space-borne SAR transmits and receives electromagnetic waves through the ionosphere, propagation effects such as group delay, phase drift, dispersion, and Faraday polarization rotation will occur, which will affect the imaging quality of low-frequency SAR. For geosynchronous orbit SAR (GEOSAR ) due to its long synthetic aperture time, the spatiotemporal changes of the ionosphere have a more serious impact on GEOSAR imaging. At present, many research institutions at home and abroad (such as NASAJPL in the United States, Cranfield University in the United Kingdom, China Academy of Space Technology, Institute of Electronics of the Chinese ...

AI Technical Summary

Problems solved by technology

However, the pulse signal transmitted and received by SAR is constantly changing with time and space. It is difficult to ensure that the measurement of the ionosphere is the same as the path and time of the signal transmitted and received by SAR. Therefore, there is a certain deviation in the measured TEC value, which cannot be accurate. Effect of Compensating Ionosphere on SAR Imaging Quality

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