Guan Z.-J.,Shanghai Radio Equipment Research Institute |
Zhou X.-L.,Shanghai JiaoTong University
International Journal of Communication Systems | Year: 2015
A kind of amplify-and-forward (AF) and decode-and-forward (DF) mixed relay communication system is proposed in this letter. The source broadcasts the signal to all the relays. Relays that can decode the signal adopt DF scheme to retransmit the signal, while the rest adopt AF scheme for retransmission. The destination employs maximum ratio combining technique tomaximize the received signal-to-noise ratio. Another situation concerned in this letter is that when the relay cannot decode the source signal, it may retransmit the interference signal with AF scheme. Closed-form expressions of outage probability are derived. Simulation results show that the analytical curves agree with the simulated ones very well, and the AF-DF mixed relay system can improve the availability of the relays. Copyright © 2013 John Wiley & Sons, Ltd.
Chao S.,Shanghai Radio Equipment Research Institute
IET Conference Publications | Year: 2013
A model of multiple-input multiple-output (MIMO) radar combining widely separated and colocated antennas is developed and the joint Cramer-Rao bounds (CRBs) for estimating the target location and the target velocity are derived for this type of MIMO radar system in order to analyze its estimation performance and the factors affecting on the performance. Simulation results are presented and illustrate that MIMO radar with more separated subarrys consisting of colocated antenna elements has better and more stable performance on the location and velocity estimation for a moving target.
Tang W.,Shanghai Radio Equipment Research Institute |
Zhou Y.,University of Sichuan
Electronics Letters | Year: 2012
A power pattern synthesis technique for a wideband array including mutual coupling (MC) is proposed. A frequency-dependent MC (FDMC) matrix is obtained accurately via the complex curve fitting technique. With the FDMC matrix the mutual coupling effect is included in the synthesis procedure automatically, resulting in an MC-compensated frequency-invariant power pattern. © 2012 The Institution of Engineering and Technology.
Jiang Y.,Harbin Engineering University |
Zhang S.,Harbin Engineering University |
Guo Q.,Harbin Engineering University |
Li M.,Shanghai Radio Equipment Research Institute
IEEE Antennas and Wireless Propagation Letters | Year: 2016
An improved integer genetic algorithm (IIGA) that overcomes the inefficient searching and the severe computational effort of genetic algorithms (GAs) has been presented. Uniformly excited concentric ring arrays with aperture sizes from the small to the medium (the array diameter is up to 50 wavelengths) are synthesized with IIGA. All the obtained arrays meet the minimum element spacing constraint of a half-wavelength. Numerical results show IIGA can search out a lower peak sidelobe level with less iterations, which provides an alternative global optimum approach to the synthesis of planar arrays with thousands of elements. © 2002-2011 IEEE.
Zhang Y.,Shanghai Radio Equipment Research Institute |
Zhang Y.,CAS Center for Space Science and Applied Research |
Zhang Y.-H.,CAS Center for Space Science and Applied Research
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2012
Space-time adaptive processing (STAP) has proven to be one of the best techniques capable of detecting weak moving targets in strong clutter environment and has been widely applied in airborne ground moving target indication (GMTI) radar. An airborne GMTI simulation system was established based on the uniform linear array (ULA). The simulation method was discussed in detail, including return signal simulation and signal processing flow. In addition, Amplitude and Phase Estimation (APES) approach was applied to STAP algorithm to improve the detecting performance. Simulations show the effectiveness of the method and the reliability of the system. © Right.
Huang F.,Shanghai Radio Equipment Research Institute |
Zhou Z.,Shanghai Radio Equipment Research Institute |
Zheng Q.,Shanghai Radio Equipment Research Institute
IET Conference Publications | Year: 2015
A novel direction of arrivals (DOAs) estimation method based on a modified spatial spectrum is proposed in this paper, which can be used for the source number and DOAs estimation of the weak signals in the presence of the strong interferences. First, the eigenvectors of the spatial covanance matrix is sorted according to the descending order of the eigenvalues. Then, the modified spatial spectrum of each eigenvector is estimated in turn based on the projection features and orthogonal features. Finally, whether there is a signal source or not is judged by the ratio of the maximum value of the spatial spectrum to the mean value of the sidelobes, and the DOA of the signal is obtained by the angle corresponding to the maximum value. The method does not require the angle information of strong interferences. Simulation results demonstrate the effectiveness and the superiority of the proposed method.
Lei Y.,Shanghai Radio Equipment Research Institute |
Ke D.,Shanghai Radio Equipment Research Institute |
Zhi T.,Shanghai Radio Equipment Research Institute
IET Conference Publications | Year: 2015
The dual-use synthetic aperture radar (SAR) ground moving target indication (GMTI) system should display moving targets on a well focused SAR image in real time. The clutter suppression, necessary for increasing the moving target signal to clutter ratio (SCR) and then the probability of detection, is sensitive to channel balance. Adaptive clutter suppression methods aiming at resolving the channel imbalance cost too much processing time. In this letter, a simple but effective approach is proposed to blindly calibrate the data with unknown channel imbalance and then simplify the clutter suppression. The spectral analysis (SPECAN) algorithm can 'look' a large coverage area with short processing time, however, with a poor azimuth resolution. A method mapping the detected and relocated position of moving targets from SPECAN processed image onto SAR image obtained by full azimuth compression is then discussed. The validity of the proposed fast GMTI method is demonstrated with real data collected by a tri-channel airborne experimental SAR system.
Su P.,Shanghai Radio Equipment Research Institute |
Zhao S.,Shanghai Radio Equipment Research Institute |
Tang Z.,University of Electronic Science and Technology of China
Microwave Journal | Year: 2013
A Ku-Band push-push voltage-controlled oscillator (VCO) based on a substrate integrated waveguide (SIW) resonator is presented. The push-push oscillator configuration is chosen to realize a fundamental oscillator and a frequency doubler in one circuit. A varactor-loaded SIW resonator is designed to achieve electrical tunability. In order to ensure accuracy and reliability, all the designs are simulated with a full electromagnetic (EM) wave simulator. As the experimental results show, the range of the output frequency is from 13.98 to 14.09 GHz, with a frequency tuning range of 110 MHz. The output power is -1.85 dBm, while the suppression of fundamental frequency and the third harmonic are -15.37 dBc and -23.80 dBc, respectively, and the phase noise is -101.27 dBc/Hz.
Yangg K.,Xidian University |
Jiang L.,Shanghai Radio Equipment Research Institute |
So A.M.-C.,Chinese University of Hong Kong
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2016
We consider the problem of geolocating two unknown co-channel emitters by a cluster of formation-flying satellites using both time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements. As the association between the TDOA/FDOA measurements obtained by each pair of satellites and the corresponding emitters is typically not known, the emitter-measurement association and the emitters' locations need to be jointly estimated. In this paper, we first formulate the joint estimation problem as a mixed integer nonlinear optimization problem. Then, we propose a semidefinite relaxation-based approach to tackle the problem and demonstrate its efficacy via simulations. © 2016 IEEE.
Shanghai Radio Equipment Research Institute | Date: 2011-11-11
A marine emergency position indicating system that can communicate wirelessly between beacon and search engine is provided. When someone carrying the beacon falls into the water, power supply of the beacon opens through drowning automatic switch or manual switch, therefore the beacon can emit wireless SOS signals out. Rescue boat or aircraft installed with search engine can search and receive SOS signals sent from beacons over a 5-kilometer radius along the way to accidental site. The search engine can distinguish the beacons around this area and determine the direction and approximate distance between drowning persons carrying beacons and the search engine through wireless communication technology and wireless positioning technology to help rescuers implement fixed-point rescue. Therefore, the marine emergency position indicating system can overcome the bad weather impact on marine rescue, speed up the rescue process and improve the success possibilities of fixed-point rescue.