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

A laser synthesis, aperture radar technology, applied in radio wave measurement system, radio wave reflection/re-radiation, utilization of re-radiation and other directions, can solve the large nonlinear frequency modulation error of laser emission pulse, not linear change, can not achieve high resolution rate imaging, etc.

Active Publication Date: 2013-10-23
SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI
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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

Method used

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

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Example Embodiment

[0192] The imaging process of the target by the THz-level wide-bandwidth laser synthetic aperture radar imaging system is divided into the following steps:

[0193] 1) Set the laser tuning frequency range and tuning speed, turn on laser 1, the laser adopts NewFocus semiconductor laser, the wavelength is 1550~1630nm, the maximum output power is 50mW1590nm, the line width is 30kHz (120μs delay), set the starting wavelength to 1550nm, stop The wavelength is 1560nm, the tuning rate is 20nm / s, and the laser scanning is triggered. The laser tuning pulse (approximately chirped pulse) has a duration of 0.5s, and the wavelength changes as follows. The 0.5s linear wavelength decreases, and the subsequent 0.5s is a linear decrease to 1550nm, so it is a cycle. The output of the laser is laser light with a fixed polarization direction. The laser beam S output by laser 1 0 Divided into two parts by 99:1 fiber coupler 2, a small part is marked as S 1 , and the other part is denoted as S ...

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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 ...

Claims

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Application Information

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IPC IPC(8): G01S7/41G01S13/90
Inventor 吴军张琨锋胡以华洪光烈舒嵘徐显文吴世辉于啸
Owner SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI
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