Terahertz SAR high-frequency vibration error compensation method

Abstract

The invention discloses a terahertz SAR high-frequency vibration error compensation method. Terahertz SAR imaging under high-frequency vibration has a pair of echo phenomena, firstly, according to a vibration geometric model of a terahertz SAR airborne platform, the influence of the platform vibration on the instantaneous slant distance of the SAR imaging is obtained, and a echo signal model underthe terahertz SAR high-frequency vibration is established; after the echo is subjected to the distance pulse pressure, the influence of the high-frequency vibration of the platform on the distance walking of the signal is analyzed, and the secondary phase position is introduced, and focusing of the pairing echo is completed by adopting the terahertz SAR high-frequency vibration imaging method based on doppler keystone transformation; and then a wavelet multi-resolution analysis is introduced to carry out platform vibration frequency estimation aiming at the relation between the phase of the imaging result and the vibration parameters of the platform, a vibration amplitude phase is estimated by combining a frequency estimation value with a parameter space projection method, and a phase compensation function is constructed to realize accurate compensation of the terahertz SAR high-frequency vibration error. According to the method, accurate compensation of the terahertz SAR high-frequency vibration error is realized, and the imaging quality of the actual terahertz SAR platform is improved.

Description

technical field [0001] The invention relates to the technical field of radar signal processing, in particular to a terahertz SAR high-frequency vibration error compensation method. Background technique [0002] Terahertz waves generally refer to electromagnetic radiation with a frequency between 0.1 THz and 10 THz, and a wavelength of 3 mm to 30 μm. In terms of frequency, terahertz waves are between millimeter waves and infrared light; in terms of energy, terahertz waves are between electrons and photons. Due to the special properties of terahertz waves, using them in synthetic aperture radar imaging can break many bottlenecks in traditional optical radar and millimeter-wave radar imaging. Compared with optical radar, Terahertz Synthetic Aperture Radar (THz-SAR) has high transmittance, can penetrate dielectric materials to detect hidden objects, and can be used in the field of security inspection and quality inspection; compared with microwave and millimeter wave radar , T...

AI Technical Summary

Problems solved by technology

[0004] Regarding the high-frequency vibration error of terahertz SAR, there is currently an optical vibration isolation platform combined with echo data self-focusing compensation method, but the optical vibration isolation platform is bulky, inconvenient to install on the airborne platform, and the price is relatively expensive

Another widely used method is parametric self-focusing, in which short-time Fourier transform (STFT) is used to estimate the vibration frequency. This method has a single resolution, low high-frequency resolution, and cannot simultaneously achieve the optimal resolution

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