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Beijing, China

Zheng Z.-D.,Electronic Engineering Institute | Zhang J.-Y.,Electronic Engineering Institute | Qu J.-Y.,Unit 91635 of PLA | Lin X.-Q.,Electronic Engineering Institute
Tongxin Xuebao/Journal on Communications | Year: 2012

The extended signal subspace was constructed to reduce the computation load of former data processing of bistatic MIMO radar. According to the characteristic of this signal subspace, the polynomial rooting-spatial filtering algorithm was proposed to estimate the direction of arrivals (DOA) and direction of departure (DOD). It avoided the conventional two-dimensional spectrum searching and the estimated parameters were paired automatically without extra pairing operation. Furthermore, Cramer-Rao bounds (CRB) for DOA and DOD estimation were derived under multi-target and single target in bistatic MIMO radar. The results illustrate that when spatial sector is filtered, the higher order of the Taylor series expansion, the better angular accuracy of targets can be derived. The proposed algorithm can get good estimation performance even when the DODs of targets are close to each other. And the polynomial rooting-spatial filtering algorithm can perform better than ESPRIT algorithm in resolution in low SNR, and both of them are close to the CRB in the high SNR.

Mu A.,Naval Academy of Armament | Zhang L.,Unit 91635 of PLA
Proceedings of 2013 IEEE 11th International Conference on Electronic Measurement and Instruments, ICEMI 2013 | Year: 2013

The current weak signal measuring equipment is too large, expensive and lack of low-frequency measuring ability in the metrology support of hydro-acoustic detection. A low-cost, applicable, self-research and development weak signal detector is designed and realized through a 24-bit dynamic signal acquisition card. The software based on NI LabWindows/CVI adopts DAQmx, digital locked-in and cascade low pass filtering methods to ensure orthogonal precise measurements of frequency and amplitude for AC signals, which are partially or completely buried in noise. The functions of reference signal mathematical generation, algorithm simulation and signal analysis through software break the puzzle of the traditional design method depended on ultra-low noise amplifier and super-steady reference source. The test results show this device can extractly measure the micro-volt signal between 10 ∼ 1000Hz. © 2013 IEEE.

Tian B.,Wuhan Naval University of Engineering | Cha H.,Wuhan Naval University of Engineering | Zhou M.,Wuhan Naval University of Engineering | Song W.,Wuhan Naval University of Engineering | Zhang N.,Unit 91635 of PLA
Binggong Xuebao/Acta Armamentarii | Year: 2010

The basic principle of the analytical MGB evaporation duct model proposed by French scholars is described in this paper. The effects of air temperature, sea temperature, relative humidity, wind speed and air pressure on the evaporation duct's height of the model is analyzed through numerical simulation. Then, the duct height is taken as a criterion, and the applicability of the analytical MGB model in experimental sea areas is studied by using the measured duct height data and meteorological information at the reference altitude during recent years. The results show that the model can predict the duct height exactly in near-neutral conditions.

Ning Z.,Unit 91635 of PLA | Nan L.,Unit 91635 of PLA | Bin T.,Wuhan Naval University of Engineering | Hao C.,Wuhan Naval University of Engineering | Mo Z.,Wuhan Naval University of Engineering
2010 6th International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2010 | Year: 2010

Over the ocean, there is mutual effect between air and sea. This effect would affect atmospheric refractivity, or modified atmospheric refractivity, and a lot of kinds of the profiles of atmospheric refractivity and modified atmospheric refractivity will happen. One kind of refractivity profiles is evaporation duct, the trace of electromagnetic wave could be changed within it, and the range of wireless detection would enlarge. In this paper, one kind of LKB-based evaporation duct models called NPS model is introduced, and we use actual evaporation duct height data gathered during recent years to study the applicability of this evaporation duct model. The conclusion could offer some help for understanding NPS model. © 2010 IEEE.

Tong C.-K.,Unit 91635 of PLA | Mu L.,PLA University of Science and Technology | Li C.-J.,Unit 91635 of PLA
Proceedings of 2015 4th International Conference on Computer Science and Network Technology, ICCSNT 2015 | Year: 2015

HFDL working in the short wave band is interfered by the multipath effect, and Turbo equalizer could achieve excellent performance when dealing with the Inter symbol interference (ISI) which is caused by the multipath effect. According to the signal characteristics of HFDL, this article designs Turbo equalizer, which was based on MMSE equalization algorithm, and proposes the solutions to the problems we often encounter, including channel impulse response estimating, mutual mapping between symbol information and bit information, the Probe's Soft information setting. Meanwhile, according to HFDL signal frame structure features, the article designs the low-complexity approximate minimum mean square error (LC app MMSE) algorithm based on the Probe's cycle time. The algorithm overcomes the shortcomings of the traditional LC app MMSE when dealing with the varying channel, and has high practical application value. Finally, the simulation was completed for verifying the solution and the algorithm. The results show that the performance of Turbo equalizer is far superior to DFE. © 2015 IEEE.

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