A time-varying tec measurement method for the ionosphere based on fully polarized high-orbit SAR
A measurement method, ionospheric technology, applied in the field of signal processing, can solve problems such as loss of absolute phase error, dwell time, short synthetic aperture time, etc., and achieve high measurement accuracy and high measurement accuracy
Active Publication Date: 2020-08-04
BEIHANG UNIV
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However, since all the existing studies involved are spaceborne fully polarized SAR systems in low and medium orbits, the satellites fly faster and the synthetic aperture time is shorter, so they can only focus on the ionospheric TEC distribution (i.e., space-variable TEC) for detection, but it is impossible to achieve accurate detection of time-varying TEC in a fixed area
[0004] At the same time, the current research on high-orbit SAR only stays on the imaging error compensation caused by the ionosphere, and most of them use the phase gradient self-focusing processing method to estimate the error phase caused by the time-varying TEC in the ionosphere.
However, since this method does not use a fixed error model in the processing process, it only estimates the error phase based on the phase gradient change between pixels, thus completely losing the absolute phase error caused by the ionospheric time-varying TEC, so it is impossible to achieve accurate detection of time-varying TEC
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[0101] The present invention will be further described in detail with reference to the accompanying drawings and embodiments.
[0102] This embodiment provides a time-varying TEC measurement method for the ionosphere based on full-polarization high-orbit SAR. Since the existing space-borne SAR system does not directly acquire full-polarization high-orbit SAR data, the embodiment uses simulation to obtain full-polarization high-orbit SAR data, and adds ionospheric time-varying TEC ( Such as figure 2 Shown) caused by the Faraday rotation angle, the parameters involved in the process are shown in Table 1:
[0103] Table 1 embodiment parameter
[0104]
[0105]
[0106] This embodiment specifically includes the following steps:
[0107] Step 1: Calculate the number of synthetic aperture points in the azimuth direction;
[0108] According to the radar system parameters, the number of azimuth synthetic aperture points is calculated as 7768 according to ...
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The invention discloses an ionospheric time-varying TEC measurement method based on full-polarization high-orbit SAR, which includes step 1: calculating the number of synthetic aperture points in the azimuth direction; step 2: filling zero in the azimuth direction data; Transformation; Step 4: Decompress the azimuth signal to obtain the equivalent azimuth echo spectrum signal; Step 5: Inverse Fourier transform of the azimuth; Step 6: Estimation of the Faraday rotation angle; Step 7: Obtain the time within the synthetic aperture Variable TEC; After the above seven steps, the precise measurement of the time-varying TEC within the synthetic aperture time is completed by using the full-polarization high-orbit SAR signal. The invention has the characteristics of high measurement precision of the time-varying TEC, and has higher measurement precision compared with the traditional measurement method due to the adoption of the Faraday rotation angle model and the TEC inversion model.
Description
technical field [0001] The invention relates to an ionospheric time-varying total electron quantity (TEC) measurement method based on a fully polarized high-orbit synthetic aperture radar (SAR), and belongs to the technical field of signal processing. Background technique [0002] In recent years, with the development of science and technology and social progress, satellite communication, satellite navigation and space-based radar systems have been widely used in various aspects of military and civilian use, and have become an indispensable tool for human life, which makes the world including the ionosphere Space environment monitoring and technical support are becoming more and more important and urgent. At the same time, BIOMASS, NISAR and other satellite programs will detect the global atmospheric environment including the ionosphere, and the detection data will provide important help for geospatial weather science and meteorological support for space information systems,...
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IPC IPC(8): G01S13/90
Inventor 陈杰郭威曾虹程王鹏波杨威
Owner BEIHANG UNIV