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Peng Z.,Nanjing University of Aeronautics and Astronautics | Ben D.,Key Laboratory of Radar Imaging and Microwave Photonics | Zhang G.,Key Laboratory of Radar Imaging and Microwave Photonics | Cai X.,95835 PLA Troops
Transactions of Nanjing University of Aeronautics and Astronautics | Year: 2015

The Cramer-Rao bound (CRB) for two-dimensional (2-D) direction of arrival (DOA) estimation in multiple-input multiple-output (MIMO) radar with uniform circular array (UCA) is studied. Compared with the uniform linear array (ULA), UCA can obtain the similar performance with fewer antennas and can achieve DOA estimation in the range of 360°. This paper investigates the signal model of the MIMO radar with UCA and 2-D DOA estimation with the multiple signal classification (MUSIC) method. The CRB expressions are derived for DOA estimation and the relationship between the CRB and several parameters of the MIMO radar system is discussed. The simulation results show that more antennas and larger radius of the UCA leads to lower CRB and more accurate DOA estimation performance for the monostatic MIMO radar. Also the interference during the 2-D DOA estimation will be well restrained when the number of the transmitting antennas is different from that of the receiving antennas. ©, 2015, Nanjing University of Aeronautics an Astronautics. All right reserved.


Zhou Y.,Key Laboratory of Radar Imaging and Microwave Photonics | Hong F.,Key Laboratory of Radar Imaging and Microwave Photonics | Wang C.,Key Laboratory of Radar Imaging and Microwave Photonics | Huang W.,Nanjing University of Aeronautics and Astronautics
Proceedings of the International Conference on Power Electronics and Drive Systems | Year: 2015

This paper presents a single-phase to three-phase adjustable-speed drive (ASD) system, which consists of a diode rectifier and a single-stage boost inverter without electrolytic capacitors (E-caps). The system has no shoot through issues and gains high reliability due to the shoot-through zero state regulation method. By using E-caps-less topology, the life time can be greatly increased. By properly designing the tapping position of the inductor, the system has a high boost inversion gain and can ride-through grid voltage sags. By using the proposed harmonic injection method, the system can realize high input power factor and small dc-link ripple voltage, simultaneously. Experimental results of the electrolytic capacitors-less single-stage boost inverter (E-caps-less SSBI) based single-phase to three-phase ASD system are obtained to verify the actual performances. © 2015 IEEE.


Wen F.-Q.,Nanjing University of Aeronautics and Astronautics | Wen F.-Q.,Key Laboratory of Radar Imaging and Microwave Photonics | Zhang G.,Nanjing University of Aeronautics and Astronautics | Zhang G.,Key Laboratory of Radar Imaging and Microwave Photonics
Wireless Personal Communications | Year: 2015

This paper addresses the problem of two-dimensional (2D) direction of arrival (DOA) estimation for monostatic multiple-input multiple-output (MIMO) radar equipped with arbitrary arrays manifold. A low-complexity multi-way compressive sensing (MCS) 2D DOA estimation algorithm is derived in this paper. To ease the computational burden, the received data are first arranged into a trilinear model, and then three random compression matrixes are individually applied to reduce each tensor to a much smaller tensor. Finally, the 2D DOA estimation problem then links to the low-dimensional trilinear model. The proposed algorithm has estimation performance close to that of the trilinear decomposition algorithm while it is more appealing form the perspective of storage capacity. Compared with other estimation algorithms, such as multiple signal classification, our MCS algorithm requires neither eigenvalue decomposition of the received signal covariance matrix nor spectral peak searching. It also doesn’t require array interpolation of the array geometry, therefore the proposed algorithm has much less computational load, which indicates the proposed algorithm will have wide application in the future for Massive MIMO systems. © 2015 Springer Science+Business Media New York


Feng J.,Key Laboratory of Radar Imaging and Microwave Photonics | Feng J.,Nanjing University of Aeronautics and Astronautics | Zhang G.,Key Laboratory of Radar Imaging and Microwave Photonics | Zhang G.,Nanjing University of Aeronautics and Astronautics
KSII Transactions on Internet and Information Systems | Year: 2015

In radar imaging, a target is usually consisted of a few strong scatterers which are sparsely distributed. In this paper, an improved sparse signal recovery algorithm based on smoothed (SL0) norm method is proposed to achieve high resolution ISAR imaging with limited pulse numbers. Firstly, one new smoothed function is proposed to approximate the norm to measure the sparsity. Then a single loop step is used instead of two loop layers in SL0 method which increases the searching density of variable parameter to ensure the recovery accuracy without increasing computation amount, the cost function is undated in every loop for the next loop until the termination is satisfied. Finally, the new set of solution is projected into the feasible set. Simulation results show that the proposed algorithm is superior to the several popular methods both in terms of the reconstruction performance and computation time. Real data ISAR imaging obtained by the proposed algorithm is competitive to several other methods. © 2015 KSII.


Hong F.,Key Laboratory of Radar Imaging and Microwave Photonics | Liu J.,Key Laboratory of Radar Imaging and Microwave Photonics | Ji B.,Nanjing University of Technology | Zhou Y.,Key Laboratory of Radar Imaging and Microwave Photonics | And 3 more authors.
IEEE Transactions on Industrial Electronics | Year: 2015

A new single inductor dual buck full-bridge inverter is proposed in this paper. The inverter is improved on the basis of a dual buck inverter, and it retains the advantage of a no reverse recovery of body diode. The dc voltage utilization rate can be increased by adopting the voltage commutation bridge instead of the voltage-dividing capacitors in the inverter. In addition, comparing with other dual buck inverters, the inverter has just one filter inductor, which can make the volume and weight of the system decreased observably and improve the integration. The controlling method, combining the high- and low-frequency modulation, is adopted to weaken the complexity of control and improve the reliability and stability of the system. The operating principle, characteristic analysis, simulation and experiment are provided in this paper. A 1-kW prototype is established and tested, and the results of simulation and experiment verify the correctness of the theoretical analysis. © 1982-2012 IEEE.

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