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Method of moving-target relocation and velocity ambiguity resolution based on velocity synthetic aperture radar (VSAR) system

A moving target and defuzzification technology, applied in the field of signal processing, which can solve the problems of false spectral peaks, low estimation accuracy, and large amount of calculation of the maximization likelihood function.

Active Publication Date: 2012-07-11
XIDIAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] 1.B.Friedlander and B.Porat published "VSAR: a high resolution radar system for detection of moving targets" on IEEE Proc.Inst.Electr.Eng.Radar, Sonar Navigate in 1997, and proposed to use FFT transformation to realize moving targets Poor detection, velocity estimation performance
[0006] 2. "Application of Berg Spectrum Estimation Method in VSAR" published by Shao Juan et al. in the Journal of Beijing Institute of Technology in 2000, in view of the low accuracy of velocity estimation in VSAR, the Berg method was used to process phase information and extract speed Information, but the cost of the Berg method is to sacrifice the effective aperture of the array, false spectral peaks may appear, and the estimation accuracy is not high
[0007] 3. Xu Jia et al. published "Parametric Velocity Synthetic Aperture Radar: Signal Modeling and Optimal Methods" on IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTESENSING in 2008, using the maximum likelihood method (ML: Maximum likelihood) to effectively improve the accuracy of velocity estimation. However, the amount of calculation required to maximize the likelihood function is huge
[0011] The project team of this invention has searched domestic and foreign patent documents and published journal papers, and has not found any reports or documents closely related to the present invention.

Method used

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  • Method of moving-target relocation and velocity ambiguity resolution based on velocity synthetic aperture radar (VSAR) system
  • Method of moving-target relocation and velocity ambiguity resolution based on velocity synthetic aperture radar (VSAR) system
  • Method of moving-target relocation and velocity ambiguity resolution based on velocity synthetic aperture radar (VSAR) system

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Embodiment 1

[0071] Refer below figure 1 The present invention is described in detail:

[0072] The invention is a moving target relocation and velocity defuzzification method based on the VSAR system, which defuzzifies the speed ambiguity of the fast target during the radar detection process of the ground moving target, and needs to improve the detection of the weak slow target for the slow target ability to achieve reorientation of objectives, see figure 1 , including the following steps:

[0073] Step 1: Perform range pulse pressure, range migration correction, and azimuth focusing on the received data of M array elements of the uniform linear array, that is, the received data of each array element is imaged by the range Doppler algorithm to obtain a two-dimensional focused SAR image , the moving target signal is expressed as:

[0074] s ( m , t , t m ...

Embodiment 2

[0118] The moving target relocation and velocity defuzzification method based on the VSAR system is the same as that in Embodiment 1, and the effect of the present invention can be further illustrated by the following simulation experiments.

[0119] 2.1 Experimental conditions

[0120] The schematic diagram of the observation geometry of the VSAR system is as follows: figure 2 As shown, the X-axis represents the azimuth direction, the Y-axis represents the distance direction, and the Z-axis represents the altitude direction. s Fly along the X-axis at a speed of =200m / s. 16 array elements are evenly placed along the flight track, the array element spacing is d=1.5m, at slow time t m = 0, array element 0 is located at (0, 0, H), only array element 0 emits electromagnetic waves, and all array elements receive target echoes. Suppose the target P is located at (x 0 , R 0 )=(0, 6000m), the speed of the slow target P is (v a , v r )=(0,0.5m / s), the speed of fast target (v a...

Embodiment 3

[0128] The method of moving target relocation and velocity defuzzification based on the VSAR system is the same as in Embodiment 1-2, and the calculation of the azimuth offset in step 2 of the present invention includes the following steps:

[0129] Step1: According to the phase information of the moving target signal, the Doppler frequency of the target is:

[0130] f ( t m ) = - 2 λ × dR dt m ≈ - 2 v r λ - ( 2 x 0 - md ) v...

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Abstract

The invention discloses a method of moving-target relocation and velocity ambiguity resolution based on a velocity synthetic aperture radar (VSAR) system, which mainly solves the problems that the velocity estimation accuracy of a moving target is low and the velocity of a fast moving target is ambiguous in the radar detection system. According to the method of moving-target relocation and velocity ambiguity resolution based on the VSAR system, the process includes perform range-doppler algorithm imaging to received data of each of array elements of the VSAR system; detecting the moving target and recording the corresponding position of the moving target after image registration, clutter suppression and cell average constant false alarm detection processing; using subspace fitting algorithm to estimate normalized velocity frequency after phase compensation so that the velocity estimation accuracy is effectively improved; extracting speed channel of the target, using multi-look differential frequency method to estimate doppler ambiguity number; calculating radial velocity of non-ambiguity according to the ambiguity numbers and estimate value of the velocity frequency and achieving an accurate location of the target. According to the method of moving-target relocation and velocity ambiguity resolution based on the velocity synthetic aperture radar (VSAR) system, the estimation accuracy and the detection performance are improved. Due to the fact that the ambiguity resolution processing is merely required for 2-3 iterations, the calculation is reduced, the accurate probability of understanding doppler ambiguity is improved and the effectiveness of the method is proved in a simulation experiment.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and mainly relates to the problem of detection, positioning and parameter estimation of moving targets under the background of clutter, and in particular to the direction of detection of ground moving targets by airborne radar in the environment of strong ground clutter interference. Specifically, it is a moving target relocation and velocity defuzzification method based on VSAR system. The invention is mainly used to realize the problem of airborne radar moving target detection, can effectively improve target detection probability and positioning accuracy, realize fast target velocity defuzzification processing, and realize correct target positioning. Background technique [0002] The high-speed motion platform SAR-GMTI technology has important use value and broad application prospects in military and civilian applications, and is a hot field of radar technology research in all countri...

Claims

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Application Information

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IPC IPC(8): G01S13/06G01S7/02
Inventor 廖桂生朱圣棋李蕾陶海红李军曾操杨志伟徐青
Owner XIDIAN UNIV
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