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Ai M.-S.,PLA Second Artillery Engineering University | Ai M.-S.,National Information Control Laboratory | Ma H.-G.,PLA Second Artillery Engineering University | Liu G.,National Information Control Laboratory
Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology | Year: 2010

For a special signal environment, where all of the sources have identical nonzero mean values, taking advantages of the Vandermonde structured steering vector of the uniform linear antenna array, an analytical solution of null-subspace is educed in this paper. Based on the solution, both of one-dimensional signal Direction of Arrival (DOA) estimation algorithm with uniform linear array and two-dimensional signal DOA estimation algorithm with sparse planar array are proposed. The algorithm does not involve the covariance matrix calculation and any matrix decomposition, so it is much computational saved than the conventional super-resolution DOA estimation algorithms. Beside that, the novel method works well either the signal sources are coherence or not. The simulation shows that the novel algorithm possesses the same performance with Root-MUSIC algorithm as the whole when the mean value of the noise is zero and the number of snapshots is enough, and it performs better than Root-Music when the Signal Noise Ratio (SNR) is lower.

Tang X.,Tsinghua University | Tang J.,Tsinghua University | Tang B.,Electronic Engineering Institute | Gao Z.,National Information Control Laboratory | And 2 more authors.
Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011 | Year: 2011

MIMO (multiple-input multiple-output) radar has been recently introduced as an important new radar system which emits orthogonal waveforms to cover a wide surveillance space. Therefore, the electronic reconnaissance technology for MIMO radar is of great significance in the future war. In this paper, a new electronic reconnaissance mode and identification algorithm for MIMO radar is proposed. In detail, a single reconnaissance aircraft is used to fly along a circumference of suspicious radar, collecting radiated signals on multiple positions. Furthermore, the collected data is analyzed and the number of orthogonal waveforms is estimated to detect and discriminate whether it's a MIMO radar. Studies show that the wider angle range the reconnaissance aircraft flies by, the better the estimation results will be. Accurate estimates can be achieved when the flying angle exceeds a certain threshold. In addition, the reconnaissance aircraft requires a longer flight when MIMO radar uses more orthogonal waveforms or the signal-to-noise ratio (SNR) is relatively low. © 2011 IEEE.

Wu B.,Wuhan Radar Institute | Chen H.,Wuhan Radar Institute | Chen H.,National Information Control Laboratory | Hu X.-Q.,Wuhan Radar Institute
Tongxin Xuebao/Journal on Communications | Year: 2010

A computationally efficient algorithm (SAY, self-calibration algorithm for Y-shaped array) was herein proposed for the direction of arrival estimation (DOA) of uncorrelated sources and for self-calibration of mutual couplings among sensors, with every sensor uniformly spaced. Calibration sources at known locations were not required. Based on the banded symmetric Toeplitz matrix model for the mutual couplings of uniform linear array (ULA), the proposed algorithm provided a favorable DOA and mutual coupling matrix (MCM) without the knowledge of the sensor mutual couplings. In addition, the parameter identifiably condition was also provided. Simulation results illustrate that the new algorithm possesses high resolution, low computational complexity and better accuracy of self-calibration.

Hu X.Q.,Wuhan Early Warning Academy | Hu X.Q.,National Information Control Laboratory | Chen H.,Key Laboratory of Wuhan Early Warning Academy | Chen H.,National Information Control Laboratory | Jiao X.L.,Wuhan Early Warning Academy
Advanced Materials Research | Year: 2013

The calibration algorithm for circular array in the presence of amplitude and phase error is researched deep exploiting the assistant sensors. In order to calibrate the amplitude and phase error for the circular array, in this paper, two setting methods of assitant elements are presented, i.e., assitant elements are setted on the coordinate axis and on circle. Simulation experiments results show that the two proposed setting methods are effective in the presence of amplitude and phase error for circular array, and has low computational burden and high estimation precision of angle and amplitude and phase error. © (2013) Trans Tech Publications, Switzerland.

Duan J.,National Information Control Laboratory | He Z.,University of Electronic Science and Technology of China
Journal of Systems Engineering and Electronics | Year: 2010

The proposed Doppler measurement technique shows that the Doppler measurements can be accomplished by a single pulse with multiple frequency components through optical fibre delay lines. Range and velocity ambiguity can be removed, and the velocity resolution can be improved dramatically by using long optical fibre delay lines. Furthermore, the velocity resolution can be modified by adjusting the length of optical fibre delay lines. In addition, the proposed radar can achieve high range resolution by using a single wideband pulse. As a result, the new approach can improve radar performance significantly.

Liu C.-J.,Harbin Engineering University | Liu C.-J.,National Information Control Laboratory | Liu F.,National Information Control Laboratory | Zhang S.,Harbin Engineering University
Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics | Year: 2010

A novel direction of arrival (DOA) estimation algorithm for wideband sources is proposed. This technique estimates DOAs according to a new covariance matrix which is constructed by summing up the covariance matrices of various frequency bins. The new idea originates from the focusing transformation and its validity is proved theoretically. Afterwards, the optimal reference frequency is discussed in detail. The analysis of computational cost shows that the new algorithm has less computational burden compared with the conventional wideband DOA algorithms. Simulation results show that the new algorithm performs better than others and the criterion of choosing optimal reference frequency is also validated by simulations.

Wang W.,University of Electronic Science and Technology of China | Wang W.,National Information Control Laboratory | Li L.,University of Electronic Science and Technology of China | Liu C.,National Information Control Laboratory | Liu F.,National Information Control Laboratory
Journal of Systems Engineering and Electronics | Year: 2011

A minimum geometric power distortionless response beamforming approach against impulsive noise (including all α-stable noise) of unknown statistics is proposed. Due to that definite logarithmic moments require no priori knowledge of impulsive noise, this new beamformer substitutes the logarithmic moments for the second-order moments and iteratively minimizes the "geometric power" of the beamformer's output snapshots, subjected to a linear constraint. Therefore, the proposed beamformer can provide significantly higher output geometric signal-to-noise-andinterference ratio. Moreover, the optimum weight vector is obtained by using a new iteration process. The simulation results prove that the new method is effective.

Ren C.,National Information Control Laboratory
International Journal of Heat and Mass Transfer | Year: 2011

The capillary-driven flow with conductive, convective and evaporative heat transfer occurs in the capillary wick of a loop heat pipe, so-called the inverted meniscus evaporator. An axisymmetric two-dimensional mathematical model is developed to investigate the effects of heat flux and porous structure parameters on wick's working states and performances. The full effects of the interaction between the flowfield and the liquid-vapor interface are adequately considered in this model, as well as the capillary effect of evaporation and the combined effect of conductive, convective and evaporative heat transfer. Wick's performances are introduced and discussed while parametric effects are discussed in detail. Wick's working states are classified into three operating modes while all operating modes are discussed in detail. Furthermore, the phase-diagrams on the q-k t,l plane and the q-K plane are also obtained and discussed. © 2011 Elsevier Ltd. All rights reserved.

Geng Z.,Zhejiang University | Shi Z.,Zhejiang University | Yan X.-L.,Zhejiang University | Luo K.-S.,National Information Control Laboratory | Pan W.-W.,Zhejiang University
Journal of Computer Science and Technology | Year: 2015

Inverse lithography technology (ILT) is one of the promising resolution enhancement techniques (RETs), as the advanced integrated circuits (IC) technology nodes still use the 193 nm light source. Among all the algorithms for ILT, the level-set-based ILT (LSB-ILT) is a feasible choice with good production result in practice. However, existing ILT algorithms optimize masks at nominal process condition without giving sufficient attention to the process variations, and thus the optimized masks show poor performance with focus and dose variations. In this paper, we put forward a new LSB-ILT algorithm for process robustness improvement with fast convergence. In order to account for the process variations in the optimization, we adopt a new form of the cost function by adding the objective function of process variation band (PV band) to the nominal cost. We also adopt the hybrid conjugate gradient (CG) method to reduce the runtime of the algorithm. We perform experiments on ICCAD 2013 benchmarks and the results show that our algorithm outperforms the top two winners of the ICCAD 2013 contest by 6.5%. We also adopt the attenuated phase shift mask (att-PSM) in the experiment with test cases from industry. The results show that our new algorithm has a fast convergence speed and reduces the process manufacturability index (PMI) by 38.77% compared with the LSB-ILT algorithm without the consideration of PV band. © 2015, Springer Science+Business Media New York.

Liu C.,Harbin Engineering University | Liu C.,National Information Control Laboratory | Liu F.,National Information Control Laboratory | Zhang S.,Harbin Engineering University
Signal, Image and Video Processing | Year: 2012

A simple and novel direction-of-arrival (DOA) estimation method for wideband signals is proposed. The proposed method estimates DOAs according to a covariance matrix which is constructed by summing up the covariance matrices of various frequency bins. It provides a lower computation complexity and a better performance compared to the traditional wideband DOA methods. This new idea is inspired by the concept of focusing transformation, and its validity is theoretically proved. A technique to determine an optimal focusing frequency is also introduced. Finally, simulation results demonstrate the effectiveness of the method. © 2010 Springer-Verlag London Limited.

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