Ultra-low signal-to-noise ratio medium and high orbit satellite target ISAR imaging method

A technology of ultra-low signal-to-noise ratio, imaging method, applied in the direction of reflection/re-radiation of radio waves, utilization of re-radiation, measurement devices, etc.

Active Publication Date: 2018-10-09
XIAN INSTITUE OF SPACE RADIO TECH
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Problems solved by technology

Compared with low-orbit SAR satellites, medium-high-orbit SAR satellites have unique advantages such as fast revisit, high time resolution, large imaging obser

Method used

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  • Ultra-low signal-to-noise ratio medium and high orbit satellite target ISAR imaging method
  • Ultra-low signal-to-noise ratio medium and high orbit satellite target ISAR imaging method
  • Ultra-low signal-to-noise ratio medium and high orbit satellite target ISAR imaging method

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Embodiment

[0071] In this embodiment, the L-band mid-orbit satellite target ISAR data collected in December 2016 is used. The selected satellite target is the Explorer scientific satellite of the United States, and the orbital altitude is about 6000km. The phase center position of the ground radar antenna used in data processing is obtained by high-precision differential GPS measurement, the satellite target position vector is obtained by the Shanghai Astronomical Observatory, and the ionospheric data is obtained by the ionospheric measuring instrument. The pulse repetition frequency (PRF) of the test data is 160Hz, the total number of data pulses is 5000, that is, the pulse echo data of 31.25s, the transmission pulse bandwidth of the ground radar is 50MHz, the receiving pulse sampling frequency is 100MHz, and the number of sampling units of each pulse is 50000.

[0072] Such as figure 1 As shown, in the first step, according to the measured ground radar antenna phase center position ve...

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Abstract

The invention relates to an ultra-low signal-to-noise ratio medium and high orbit satellite target ISAR imaging method, and mainly relates to the technical field of inverse synthetic aperture radar imaging. The method provided by the invention comprises the steps that the slant range course between a ground radar and a target satellite is calculated by using a target satellite orbit and the phasecenter position of a radar antenna, and pulse compression is carried out on original echo data received by the radar; according to the slant range course and radar imaging geometric parameters, the curvature walk of a target envelope is corrected; the delay phase of an ionized layer is compensated along azimuth, and a linear model is used to correct an envelope alignment error caused by a radar geometric parameter measurement error and a satellite orbit measurement error; the translation phase of the target is compensated, and fast Fourier transform (FFT) along azimuth is carried out to acquire an initial ISAR image; and finally, the quadratic translation phase error of the target is estimated and compensated according to the initial ISAR image, so as to acquire a final medium and high orbit satellite target ISAR image.

Description

technical field [0001] The invention relates to an ISAR imaging method for an ultra-low signal-to-noise ratio medium and high-orbit satellite target, and mainly relates to the field of inverse synthetic aperture radar imaging technology. The above-mentioned medium-orbit satellite refers to a satellite whose orbital height is not lower than 2,000 kilometers, and the above-mentioned high-orbit satellite refers to a satellite whose orbital height is not lower than 20,000 kilometers. Background technique [0002] Medium and high orbit SAR is a new type of microwave remote sensing radar operating in medium orbit or geosynchronous orbit. It is of great significance to build my country's aerospace remote sensing system, ensure long-term and stable aerospace microwave remote sensing data sources, and accelerate the construction of high-precision remote sensing databases. It can be widely used It is used in three-dimensional surveying and mapping data acquisition, disaster early warni...

Claims

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Application Information

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IPC IPC(8): G01S13/90
CPCG01S13/90G01S13/9064
Inventor 李锦伟李财品左伟华张升
Owner XIAN INSTITUE OF SPACE RADIO TECH
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