Time filter

Source Type

Tang B.,Sichuan University | Tang B.,Chengdu Aeronautic Vocational and Technical College | Zheng M.,Sichuan University | Chen K.,Sichuan University | And 2 more authors.
Dianbo Kexue Xuebao/Chinese Journal of Radio Science

For the purpose of using as few elements as possible to form a desired pattern, a new method based on matrix enhancement and matrix pencil (MEMP) is proposed to solve the element position and to design the excitation. Firstly, an enhanced matrix is built using the sampling data of the desired planar array radiation pattern and the singular value decomposition (SVD) can be performed. Then the minimun number of elements can be determined. Secondly, the generalized eigen-decomposition is employed to calculate the eigenvalues and the estimating signal parameters via rotational invariance techniques (ESPRIT) is utilized to pair the eigenvalues of each column. Finally, excitations and locations are calculated according to the correct pairing of eigenvalues. Simulation results are presented to illustrate the efficiency and numerical accuracy of the approach. © 2013 by Editorial Department of Chinese Journal of Radio Science. Source

Zhang Y.,The Second Research Institute | Khalighi M.A.,Ecole Centrale Marseille | Sadough S.M.-S.,Shahid Beheshti University | Bourennane S.,Ecole Centrale Marseille
IET Communications

In amplify-and-forward wireless relay networks, channel state information is required at the destination for signal detection when coherent distributed space-time coding is performed at the relays. The authors consider in this study signal detection in the case of imperfect partial channel knowledge at the destination. For the case of maximum a posteriori signal detection, they propose a modified detector formulation that takes the variance of channel estimation errors into account, and reduces the impact of channel uncertainty on the receiver performance. They show that the proposed modification permits a significant performance improvement, while increasing only slightly the receiver's complexity. It is of special interest for non-constant modulus signal constellations of relatively large size, as well as for relatively low pilot powers. © The Institution of Engineering and Technology 2014. Source

Lu Y.,Sichuan Normal University | Lu Y.,National Communication Laboratory | Lu Y.,The Second Research Institute | Liu C.-Z.,The Second Research Institute | Liu P.-F.,The Second Research Institute
Guangdian Gongcheng/Opto-Electronic Engineering

In view of the accurate tracking for the airport surface targets, a multi-sensor trajectories fusion method based on geography guidance is proposed to process the data from Automatic Dependent Surveillance - Broadcast (ADS-B) and Multilateration (MLAT). This method deals with the relations among the different sensors using distribute filters to realize the trajectories fusion. The process of filtering is under the control of the airport surface geography information and improves the precision through a variable structural multi-model mechanism. Experimental results show that the proposed method has the advantages of both high detection precision and project application value. Source

Huang R.S.,The Second Research Institute | Yang H.M.,University of Electronic Science and Technology of China | Wu H.G.,The Second Research Institute
Applied Mechanics and Materials

The automatic dependent surveillance-broadcast (ADS-B) system is the backbone of the next-gen air traffic control (ATC) modernization plan. Unfortunately, ADS-B system suffers from serious cyber-security vulnerabilities due to the open broadcast of aircraft data, without regard to message confidentiality. However, using common encryption scheme to provide confidentiality of ADS-B data is not a good solution, because encrypting data with ordinary cryptosystem would violate the original openness intention of ADS-B system design. In this paper, based on the new format-preserving encryption (FPE), we present an efficient data encryption scheme for the ADS-B data. The security analysis demonstrates that our scheme can achieve confidentiality of ADS-B data. The performance evaluation shows that the scheme is computationally efficient for the typical avionics devices with limited resources. © (2014) Trans Tech Publications, Switzerland. Source

Lu Y.,Sichuan Normal University | Lu Y.,University of Electronic Science and Technology of China | Lu Y.,The Second Research Institute | He D.L.,The Second Research Institute | Yao H.,The Second Research Institute
Applied Mechanics and Materials

MLAT (Multilateration) is becoming one of the leading techniques in the airport surveillance. It locates the positions of aircrafts by the TDOAs (Time Difference of Arrivals) of signal from the aircraft to the different remote stations. In views of the influence from the geometric relation and the clock error among different stations, an improved simulation is proposed to estimate the measurement error for the optimal tracking. The model of simulation takes both the GDOP (Geometric Dilution of Precision) and TOA (Time of Arrival) error into consideration. Experiment results show that compared with the traditional simulation method, the improved simulation is more accurate and is able to be used in the practical application. © (2013) Trans Tech Publications, Switzerland. Source

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