ISAR image lateral calibration method based on IAA spectrum estimation technology

A spectral estimation and horizontal technology, applied in the field of ISAR image horizontal calibration based on IAA spectral estimation technology, can solve the problems of inaccurate target speed, target recognition, inconvenient three-dimensional reconstruction, low accuracy of ISAR horizontal calibration, etc., to achieve horizontal The effect of improving the calibration results, saving the amount of calculation, and improving the accuracy of horizontal calibration

Active Publication Date: 2018-07-24
HARBIN INST OF TECH
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  • Summary
  • Abstract
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  • Claims
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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that the target rotational speed estimated by the existing method is inaccurate, which leads to the low accuracy of ISAR lateral calibration and brings inconvenience to the subsequent target recognition and three-dimensional reconstruction, and proposes an ISAR based on IAA spectrum estimation technology Image Horizontal Scaling Method

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  • ISAR image lateral calibration method based on IAA spectrum estimation technology
  • ISAR image lateral calibration method based on IAA spectrum estimation technology
  • ISAR image lateral calibration method based on IAA spectrum estimation technology

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specific Embodiment approach 1

[0028] Specific implementation mode one: combine figure 1 , figure 2 To illustrate this embodiment, the specific process of the ISAR image horizontal calibration method based on IAA spectrum estimation technology in this embodiment is:

[0029] Step 1. Perform distance dimension compression and motion compensation on the ISAR imaging data acquired by the radar. After motion compensation, the ISAR observation target can be treated as a turntable target, and the ISAR imaging echo after motion compensation is approximately equivalent to the turntable target. Wave, that is, to obtain the ISAR imaging echo data of the turntable target, calculate the normalized amplitude variance of J range gate echoes, sort from small to large, and select M range gate echo signals with the smallest variance;

[0030] The ISAR is an inverse synthetic aperture radar; J is the number of range gates;

[0031] Step 2. Record the maximum longitudinal distance corresponding to the M range gate echo si...

specific Embodiment approach 2

[0036] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that in the step 1, the ISAR imaging data obtained by the radar is compressed and motion compensated. After motion compensation, the actual observation target can be equivalent to a turntable target. After processing, the motion-compensated ISAR imaging echo is approximately equivalent to the echo of the turntable target, that is, the ISAR imaging echo data of the turntable target is obtained, and the normalized amplitude variance of J range gate echoes is calculated, from small to large Sorting, selecting M range gate echo signals with the smallest variance; the specific process is:

[0037] Assuming that the radar emits LFM signals, the ISAR imaging data acquired by the radar is compressed in the range dimension and motion compensated, and the ISAR imaging echo after motion compensation is approximately equivalent to the echo of the turntable target, that is, the ISAR imaging ech...

specific Embodiment approach 3

[0059] Embodiment 3: This embodiment is different from Embodiment 1 or Embodiment 2 in that: the M is 8-10.

[0060] In the case that many range gates include scattering points, M can be set to 8-10.

[0061] Other steps and parameters are the same as those in Embodiment 1 or Embodiment 2.

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Abstract

The invention relates to an ISAR image lateral calibration method based on IAA spectrum estimation technology. The invention relates to a lateral calibration method for the image of inverse syntheticaperture radar (ISAR) imaging. The invention aims to solve the problems of inconvenient subsequent target recognition and three-dimensional reconstruction brought by low ISAR lateral calibration precision caused by inaccurate target rotation speed estimated by an existing method. The method comprises the steps of (1) obtaining ISAR imaging echo data of a turntable target, calculating a normalizedamplitude variance of all J distance gate echoes and selecting M distance gate echo signals with a smallest variance, (2) obtain the length of spectrum windowing, wherein the window type is a rectangular window, (3) obtaining M preprocessed distance gate echo signals, (4) obtaining an angular frequency estimation value of M de-skew signals, (5) calculating an estimation value of a rotation angularvelocity of an equivalent turntable target, and (6) calculating the lateral scale of an ISAR image and redrawing the ISAR image according to the lateral scale to complete the lateral scaling of the ISAR image. The method is used in the field of radar imaging.

Description

technical field [0001] The invention relates to a lateral calibration method for inverse synthetic aperture radar imaging. Background technique [0002] ISAR imaging technology can obtain high-resolution two-dimensional images of ships, aircraft, satellites and other targets. The high resolution in the range direction is obtained by the large bandwidth of the transmitted signal, which is a known quantity without changing the bandwidth of the transmitted signal; while its azimuth (lateral) resolution is obtained through Doppler analysis, so the lateral unit scale is determined by the Doppler The resolution of the Le frequency domain is determined, and it changes with the target speed and accumulation time. Therefore, the two-dimensional ISAR image can only reflect the relative position of the scattering point in the azimuth direction. For subsequent processing such as target recognition and 3D reconstruction, it is necessary to perform horizontal calibration on the 2D image...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S13/90
CPCG01S13/904G01S13/9041G01S13/9064
Inventor 王勇黄鑫谢俊好李绍滨李高鹏
Owner HARBIN INST OF TECH
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