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Method for estimating direction of arrival of narrowband signal based on expectation-maximization algorithm

A technology of direction of arrival estimation and expectation maximization, applied in the field of signal processing, it can solve the problems of degraded estimation performance, low estimation resolution, and error-prone multi-dimensional search, achieving good stability and resolution, and avoiding errors.

Active Publication Date: 2018-09-28
KUNMING UNIV OF SCI & TECH
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Problems solved by technology

[0004] The invention provides a method for estimating the direction of arrival of narrowband signals based on the expectation maximization algorithm, which mainly solves the problem that the estimation performance of subspace algorithms such as MUSIC decreases when the signal-to-noise ratio is low; the multi-dimensional search of the maximum likelihood estimation method is prone to errors, Estimated low resolution issues

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  • Method for estimating direction of arrival of narrowband signal based on expectation-maximization algorithm
  • Method for estimating direction of arrival of narrowband signal based on expectation-maximization algorithm
  • Method for estimating direction of arrival of narrowband signal based on expectation-maximization algorithm

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Embodiment 1

[0040] Embodiment 1: as figure 1 As shown, a narrowband signal direction of arrival estimation method based on expectation maximization, the specific steps are as follows:

[0041] Step 1: Use the antenna receiver to form an equidistant uniform line array.

[0042] One antenna receiver is placed at a distance d, and a total of M are placed to form a uniform line array. Each antenna receiver becomes an array element. Suppose there are P far-field narrowband signals incident on the uniform line array, and the signal is in Gaussian white noise with zero mean value is added to the propagation process, where, M≥P, λ is the wavelength of the incident signal.

[0043] Step 2: Sampling the spatial signal to obtain the received signal Y(t).

[0044] Step 3: Construct Hidden Variables It represents the output of the i-th signal on the array, then the output of P signals on the array can be expressed as

[0045] Step 4: Implicit variable y in construction i (t) The logarithmic ...

Embodiment 2

[0072] Embodiment 2: calculate according to the method in embodiment 1, wherein consider the uniform linear array that 8 omnidirectional array elements are formed, the array element spacing is 0.5, the number of sampling points is 100, and the airspace angle search range is [-90 ° 90 °].

[0073] The formula for calculating the mean square error is:

[0074] In the formula, I represents the number of Monte Carlo experiments, Indicates the direction of arrival angle of the i-th trial, θ p Indicates the true direction of arrival of the signal.

[0075] Assuming that three independent signal sources are incident on an equidistant uniform linear array composed of 8 omnidirectional array elements at angles [-30° 30° 60°], the signal-to-noise ratio of this experiment increases from -10dB to 10dB, and each signal Carry out 50 independent DOA estimation experiments under the noise ratio, utilize the method of the present invention to compare with the DOA estimates obtained by th...

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Abstract

The invention relates to a method for estimating a direction of arrival, in particular to a method for estimating a direction of arrival of a narrowband signal based on an expectation-maximization algorithm, and belongs to the technical field of signal processing. The method proposes to use the implicit variable to perform the update iteration in the direction of arrival estimation of the narrowband signal to which the expectation-maximization algorithm is applied, and construct the maximum likelihood function about the direction of arrival by using the implicit variable to solve the algorithmof the direction of arrival of the signal. Compared with the prior art, the method mainly solves the problems that the estimation performance of the subspace algorithm such as MUSIC is low at the lowsignal-to-noise ratio, and the maximum likelihood estimation method is prone to error and low estimation resolution and the like in the multi-dimensional search. The method utilizes the expectation-maximization iteration for respective calculations, thereby avoiding the error as much as possible and ensuring the excellent performance of the direction of arrival estimation under the condition of low signal-to-noise ratio and low number of snapshots, and has good stability and resolution ratio.

Description

technical field [0001] The invention relates to a method for estimating a direction of arrival, in particular to a method for estimating a direction of arrival of a narrowband signal based on an expectation maximization algorithm, which belongs to the technical field of signal processing. Background technique [0002] Direction of arrival estimation based on antenna array is an important research direction in array signal processing. Its main purpose is to use the measurement data received by the sensor array in a certain arrangement in space to estimate and extract the incoming wave of the space target signal to be measured. Parameters such as direction and number of signals have broad application prospects in military and civilian fields such as radar, passive sonar, biomedicine, radio astronomy, and seismic exploration. [0003] Multiple signal classification algorithm (MUSIC) and other subspace classification algorithms are a kind of spatial spectrum estimation method th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S3/06
CPCG01S3/06
Inventor 段慧芳赵宣植刘增力
Owner KUNMING UNIV OF SCI & TECH
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