Data processing method for THz-grade large-bandwidth laser synthetic aperture radar imaging system

Abstract

The invention discloses a data processing method for a THz-grade large-bandwidth laser synthetic aperture radar imaging system, which is composed of a linear tuning semiconductor, a 99:1 optical fiber coupler, a 90:10 optical fiber coupler, an emission collimating lens, a polarized beam splitter, a lambda / 4 wave plate, a target displacement platform, a receiving collimating mirror, four 50:50 optical fiber couplers, two balancing detectors, a reference time delay optical fiber, a molecular wavelength reference device, an optical power meter, a data acquisition module and a data processing program module. The laser synthetic aperture radar imaging system disclosed by the invention is based on a large-range linear tuning laser pulse signal; and a target two-dimensional image is calculated according to the homodyne coherent detection technology, the balance detection technology, the synthetic aperture technology and the final special data processing procedure. The system has the advantages of short laser signal wavelength, large bandwidth, high imaging resolution, all-weather characteristic, high stability, simple structure, high detection sensitivity and long acting distance, and most of the system is based on the optical fiber device.

Description

technical field [0001] This patent relates to lidar imaging technology, and specifically refers to a data processing method for a THz-level wide-bandwidth laser imaging system for imaging. Background technique [0002] Synthetic Aperture Radar (SAR for short) is an active imaging radar that works in the microwave band and can be used all day and all weather. At present, SAR has been maturely applied. At the same time as the development of SAR, lasers are also developing rapidly, and the spatial resolution of real-aperture lidar is limited by the diffraction limit of the emission aperture. Therefore, the microwave band synthetic aperture technology is transplanted to the optical band to obtain higher resolution images, and the laser synthetic aperture radar (Synthetic Aperture Ladar, referred to as SAL) came into being. The principle is the same as that of SAR, which transmits a linear frequency modulation signal with a large time-width-bandwidth product in the range upward ...

AI Technical Summary

Problems solved by technology

Because the laser achieves frequency modulation by adjusting the wavelength, the linear change of the wavelength, the frequency (c is the speed of light), the frequency must not change linearly, so there is a large nonlinear frequency modulation error in the laser emission pulse, and the resolution obtained by only imitating the traditional microwave SAR system and the conventional pulse compression method is meter level, which is different from the theoretical value The difference is far, and high-resolution imaging under this system cannot be realized

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