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Open Access Issue
Orientation-dependent error calibration algorithm for polarization sensitive array
Journal of National University of Defense Technology 2024, 46(6): 174-183
Published: 28 December 2024
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In practical applications, multiple types of array errors exist simultaneously. In view of the orientation dependence of array errors in this case, an improved MUSIC (multiple signal classification) algorithm based on MST (manifold separation technique) was proposed, which can effectively solve DOA (direction of arrival) estimation problem under the influence of multiple array errors. The sampling matrix, which contains all the non-ideal characteristics of the array was obtained by using MST, so as to achieve accurate direction finding. By using two-dimensional Fourier transform, the 2D spatial spectrum was solved. Compared with existing MUSIC algorithm, the computation amount of spectrum peak searching was reduced. Theoretical analysis and simulation verify the effectiveness of the algorithm, which can provide reference for the solution of practical problems.

Open Access Issue
Multi-station fusion sorting algorithm for radar signals based on partial connection number trend
Journal of National University of Defense Technology 2024, 46(6): 159-165
Published: 28 December 2024
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Aiming at the situation that the existing sorting algorithms were more or less dependent on prior information or difficult to adapt to multi-function radar, a multi-station fusion sorting algorithm based on set pair potential of partial coefficients was presented. The partial connection number parameter was introduced from the set pair analysis in the mathematical field to establish a clustering model. On this basis, the decision level fusion of clustering results was carried out by using the arrival time difference parameter in the multi-station cooperation mode. The actual measurement data and simulation results show that the algorithm can adapt to multi-functional radar systems such as search, acquisition and tracking, and realize the accurate clustering and fusion of radar pulse signals without any prior information. The sorting success rate is more than 97% in case of the jamming pulse ratio is lower than 60%.

Open Access Issue
Radar echo characteristic analysis and parameter estimation method for rotor UAV
Journal of National University of Defense Technology 2025, 47(2): 202-211
Published: 28 April 2025
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The proliferation of “low, slow and small” UAVs (unmanned aerial vehicles) poses a serious threat to flight safety in airspace. Accurate analysis of the characteristics of UAV echo signals is of great significance for the detection of non-cooperative UAVs. Based on the time-domain integral echo model of rotor UAV target and the principle of cepstrum algorithm, the frequency-domain expression and cepstrum expression of echo signal were derived, the corresponding relationship between echo signal parameters and frequency-domain and cepstrum characteristics was analyzed, and a parameter estimation method for UAV echo signal was proposed, and the effectiveness of this method was verified by simulation and measured data. The results show that, it can estimate the bandwidth and rotation frequency of UAV echo signal more accurately and provide an important reference for target detection and recognition of UAV.

Issue
Research on DOA technique of non-ideal array based on rotating projectile
Chinese Journal of Ship Research 2024, 19(3): 337-343
Published: 04 July 2023
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Objective

This paper proposes an online calibration direction-of-arrival (DOA) estimation algorithm to solve the problem of error interference by strong clutter in the flight of a rotating missile direction-finding system.

Method

Using the prior condition of the known array-rotation angles, the maximum likelihood criterion-based method is used to estimate the conformal array errors and spatial-polarization parameters of the signal.

Results

The simulation experiment results show that the proposed algorithm can achieve online error calibration and signal parameter estimation for arrays with directione-dependent amplitude-phase inconsistency errors. Moreover, the estimation performance of the algorithm is related to the rotation times of the array platform and signal-noise ratio (SNR) ratio. When the number of rotations exceeds twenty-four, the estimation error of the spatial domain parameters is less than one degree under the condition of low SNR (10 dB).

Conclusion

The proposed algorithm uses the idea of fractal dimension alternating processing to solve the multi-parameter estimation problem, enabling it to ensure the convergence of parameters and greatly reduce computational complexity.

Issue
Joint estimation for DOA and polarization parameters of orthogonal dipole array based on compressive sensing
Chinese Journal of Ship Research 2022, 17(1): 221-226
Published: 23 February 2022
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Objectives

As the detection-of-arrival (DOA) estimation algorithm used in traditional polarization sensitive arrays has such problems as high computation complexity and poor real-time performance, this study proposes a data compression-based orthogonal dipole polarization sensitive array structure.

Methods

By applying compression sensing technology to the system design (i.e., data compression technology), the proposed structure compresses the dimensions of the receiving signal vector, controls the complexity of the system by reducing the number of front-end chains, and brings high flexibility to the array structure design. At the same time, a dimensionality reduction-based multiple signal classification (MUSIC) algorithm is also proposed. First, the DOA estimation of signals is realized through spatial spectrum searching. The Lagrange multiplier method is then used to reduce the searching dimensionality, and the signal polarization parameters are obtained by solving the optimization problem.

Results

Simulation experiments show that the proposed array structure and MUSIC algorithm can correctly estimate DOA and polarization parameters when the incident signals are completely polarized and incoherent. When the signal-noise ratio (SNR) is greater than 10 dB, the root mean square error (RMSE) of the elevation angle is less than 0.05°.

Conclusions

Compared with the non-compressed structure with an equal channel number under the same conditions, the proposed structure can provide higher estimation accuracy and lower computational complexity.

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