Method for estimating direction of coherent source based on central symmetry of uniform circular array

A uniform circular array and direction estimation technology, which is applied to the orientation device, measuring device, instrument, etc. of the direction determination, can solve the problems of not making full use of the symmetry of the uniform circular array, difficult determination of smoothing times, low signal-to-noise ratio threshold, etc. Achieve the effects of high DOA estimation accuracy, strong decoherence capability, and low signal-to-noise ratio threshold

Active Publication Date: 2018-11-16
HARBIN ENG UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

On this basis, someone applied the spatial smoothing decoherence technology to UCA, and proposed Mode Spatial Smoothing (MODESS) and Mode Forward-Backward Spatial Smoothing (MODEFBSS); but such algorithms There are problems of large amount of calculation and difficult determination of smoothing times
Later, someone proposed a mode space Toeplitz matrix reconstruction algorithm without smoothing (Mode Toeplitz, MODETOEP), which realized the diagonalization of the signal covariance matrix and had a lower SNR threshold; but MODETOEP did not make full use of the uniform Symmetry of a circular array

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  • Method for estimating direction of coherent source based on central symmetry of uniform circular array
  • Method for estimating direction of coherent source based on central symmetry of uniform circular array
  • Method for estimating direction of coherent source based on central symmetry of uniform circular array

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specific Embodiment approach 1

[0024] The coherent source direction estimation method based on the central symmetry of the uniform circular array in this embodiment, the estimation method is realized by the following steps,

[0025] Step 1. For the data X(t) received by the UCA, seek the pattern space transformation matrix T, and multiply the data X(t) by the transformation matrix T to obtain the pattern space data Y(t);

[0026] Step 2, calculating the data Z(t) after the conjugate average;

[0027] Step 3. Obtain the reconstructed Hermitian Toeplitz matrix R Toe ;

[0028] Step 4, for R Toe Carry out eigendecomposition, and use the Root-MUSIC algorithm to output the estimation result of coherent source DOA;

[0029] Among them, UCA is the abbreviation of Uniform Circular Array, which refers to an array structure widely used in high-resolution array direction finding systems; Hermitian Toeplitz matrix refers to the covariance matrix of independent signal sources. value, and the elements in the matrix s...

specific Embodiment approach 2

[0030] The difference from the first embodiment is that in the method for estimating the direction of coherent sources based on the central symmetry of the uniform circular array in this embodiment, the process of obtaining the mode space transformation matrix T described in step 1 is the array flow matrix A of the UCA ( θ) does not have a Vandermonde structure, so it is necessary to convert UCA to a virtual uniform linear array VULA first, specifically: using the formula T=J -1 F / M seeks the pattern space transformation matrix T,

[0031] in: figure 2 Represents the array model of VULA, K is the maximum number of modes that UCA can excite, And satisfy 2K Indicates rounding down;

[0032] F=[w -K ,...,w K ] H ,

[0033] w k =[1,exp(-j2πk / M),...,exp(-j2πk(M-1) / M)] T , k=-K,...,K,

[0034]

[0035] J k ( ) represents the Bessel function of the first kind whose order is k;

[0036] And get the virtual array manifold and pattern space data correlation matrix,

[0...

specific Embodiment approach 3

[0054] The difference from the second specific embodiment is that in the coherent source direction estimation method based on the central symmetry of the uniform circular array in this embodiment, the process of obtaining the data Z(t) after the conjugate average described in the second step is as follows: [R Y ] p,q Representation pattern space data correlation matrix R Y The element in row p and column q in Indicates the power of the i-th signal source, assuming that the signal source is an independent signal under ideal conditions, the following formula holds:

[0055]

[0056]

[0057]

[0058] r Y (k) is the correlation function between the received data of different array elements, and the pattern space data correlation matrix is ​​r Y (k) is expressed as:

[0059]

[0060] Among them, the elements on any diagonal of the covariance matrix of independent signal sources take the same value, and the elements in the matrix satisfy the complex conjugate symme...

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Abstract

The invention provides a method for estimating the direction of a coherent source based on the central symmetry of a uniform circular array. The method comprises the following steps: 1, calculating amode space conversion matrix T for the data X(t) received by a UCA, and multiplying the data X(t) by a transformation matrix T to obtain the mode space data Y(t); 2, solving the data Z(t) after conjugate averaging; 3, solving a reconstructed Hermitian Toeplitz matrix RToe; 4, performing characteristic decomposition of RToe, and outputting an estimation result of the DOA of the coherent source through employing a Root-MUSIC algorithm. The method is simple in implementation, and is small in the calculation burden. The method has the advantages of strong decoherence capability, high DOA estimation precision and low signal to noise ratio threshold. A simulation result shows that the method can correctly estimate the DOA of the coherent source, and is higher in resolution than MODEFBSS and MODETOEP. The method has stronger decoherence and higher DOA estimation accuracy at low SNR and small number of snapshots.

Description

technical field [0001] The invention relates to a coherent source direction estimation method. Background technique [0002] Array processing technology has a wide range of applications in mobile communications, radar, sonar and other fields. In the actual underwater acoustic environment, there are a large number of coherent signal sources, such as a large number of multi-channel signals such as seabed and sea surface reflections, sonar echoes of multiple targets in active detection, and artificial interference signals such as acoustic jammers and acoustic decoys. Since the incomplete orthogonality between the coherent signal subspace and the noise subspace will seriously degrade the performance of classic signal subspace algorithms such as MUSIC and ESPRIT, coherent source DOA estimation has always been a hot issue in the field of array signal processing. [0003] Compared with the uniform linear array (ULA), the uniform circular array (UCA) can provide 360° unambiguous az...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S3/00
CPCG01S3/00
Inventor 邹男付进田蕴琦梁国龙
Owner HARBIN ENG UNIV
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