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Two-dimensional imaging method and system based on recursive structure beam forming

A recursive structure, two-dimensional imaging technology, used in radio wave measurement systems, radio wave reflection/re-radiation, utilization of re-radiation and other directions, can solve problems such as unsatisfactory beam bandwidth, affecting signal reception, and poor beam forming effect. Achieve improved resolution performance, extremely narrow beamwidth, and robustness

Active Publication Date: 2021-06-18
PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The beamformer structure (the structure is the same as the non-recursive filter in the time domain) used in the existing precision tracking imaging radar is to carry out weighted summation of the element signals, and according to the space-time equivalence, it is necessary to form an extremely narrow beamwidth The number of array elements is very large
Moreover, the spectrum of the non-recursive filter has sidelobe interference, and the stopband ripple will affect the signal reception. At the same time, the formed beam is not ideal in bandwidth and resolution is not high, resulting in poor beamforming effect.

Method used

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  • Two-dimensional imaging method and system based on recursive structure beam forming
  • Two-dimensional imaging method and system based on recursive structure beam forming
  • Two-dimensional imaging method and system based on recursive structure beam forming

Examples

Experimental program
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Effect test

example 1

[0140] Set up the simulation experiment as follows:

[0141] (1) Set the desired beam pattern parameters;

[0142] (2) Obtain the expected IIR parameters through space-time equivalence;

[0143] (3) The IIR filter coefficient is obtained by applying FDATOOL design;

[0144] (4) Taking the IIR coefficient as the corresponding beamforming coefficient;

[0145] (5) Calculate the beam response, analyze the two-dimensional beam pattern, and examine characteristics such as bandwidth.

[0146] Table 2 Beam pattern simulation parameters

[0147] parameter list parameter value Sampling Rate 4Hz The sampling period 0.25s Signal wavelength 0.5m Azimuth pitch (-π / 2,π / 2) Element spacing 0.25m Time Domain Filter Center 0Hz Sampling points 256，1024，32768 Weighting factor 3.0869709262274656*10e-16 feedback coefficient -0.99999999999999933

[0148] Table 3 Two-dimensional beamforming characteristic parameters

[0149]...

example 2

[0152] Two signals with very close incident angles are designed, and DBF (Digital Beam Forming) is designed to test the effect of spatial filtering. The filtering simulation parameters are shown in Table 4.

[0153] Table 4 Filter Simulation Parameters

[0154] parameter list parameter value Sampling points 512 input signal Sinusoidal signal receive signal frequency 100Hz Interfering signal frequency 300Hz direction of arrival 0° Interference direction 1 1*pi / (1e16) Interference direction 2 1*pi / (1e14)

[0155] Figure 13 are the spectrograms of the two signals S1 and S2 with very close incident angles, Figure 14 For the comparison of S1 signal waveforms before and after the direction of arrival filtering, Figure 15 Filtering (incomplete) signal comparison diagram for S2 signal in interference direction 1, Figure 16 Filtering (complete) signal comparison diagram for S2 signal in interference direction 2, Fi...

example 3

[0158] When there are phase and array element position errors, the wavelength varies between 500-100GHz, the signal bandwidth varies between 10-10000B, and the interference angle is 1.8×10 -28° The signal-to-noise ratio varies between -100-50dB, which proves the robustness of recursive structured beamforming, which can form extremely narrow beams for spatial filtering.

[0159] The present invention also provides a two-dimensional imaging system based on recursive structural beamforming, the system comprising:

[0160] The radar echo signal acquisition module is used to receive the signal emitted by each scattering point on the target to be imaged through the radar system as the radar echo signal of each scattering point;

[0161] The deflection azimuth and deflection pitch determination module is used to determine the deflection azimuth and deflection pitch of each scattering point according to the radar echo signal of each scattering point;

[0162] The spatial parameter in...

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Abstract

The invention relates to a two-dimensional imaging method based on recursive structure beam forming, which comprises the following steps of determining the deflection orientation and the deflection pitch of each scattering point according to a radar echo signal, obtaining the airspace parameter information of an expected beam, and according to the deflection orientation, the deflection pitch and the airspace parameter information of the expected beam, by using space-time equivalence, constructing a two-dimensional recursive structure beam response expression of the two-array-element first-level feedback beam former of each scattering point, obtaining a beam output signal of each scattering point through the two-dimensional recursive structure beam response expression, and according to the corresponding relation between the intensity amplitude and the gray level, determining the gray level corresponding to the beam output signal of each scattering point after matched filtering and the position of each scattering point on the azimuth pitching plane, and generating a two-dimensional image of the to-be-imaged target. High-precision imaging is realized by using a recursive structure ultra-narrow beam width beam forming technology, the ultra-narrow beam width is realized through fewer array elements, and the resolution performance is improved while the robustness is considered.

Description

technical field [0001] The present invention relates to the technical field of radar imaging, in particular to a two-dimensional imaging method and system based on recursive structured beam forming. Background technique [0002] At present, the imaging of precision tracking imaging radar adopts one-dimensional range image technology or ISAR image recognition technology, while one-dimensional range image technology and ISAR (Inverse Synthetic Aperture Radar, Inverse Synthetic Aperture Radar, Inverse Synthetic Aperture Radar) image recognition technology face main lobe interference, imaging speed, Bottleneck issues such as imaging plane stability, imaging legibility, and matching recognition accuracy. [0003] Beamforming is essentially a spatial filtering technology. It obtains the weighting coefficient of the beamformer based on certain criteria, so that the main lobe of the beam is only aligned with the desired signal direction and only receives signals in the desired direc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S13/90G01S7/292
CPCG01S7/292G01S13/9004G01S13/9064
Inventor 杨君葛鹏程李冬冯婷婷张硕
Owner PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV