Ren S.,National University of Defense Technology |
Chang W.,National University of Defense Technology |
Liu X.,PLA Navy Submarine Academy
Progress In Electromagnetics Research M | Year: 2011
In order to ensure that SAR scene matching aided navigation system can acquire the position errors and yawing errors simultaneously, we propose an image matching algorithm based on Scale Invariant Feature Transform (SIFT). However, the SIFT is proposed for optical image, and its performance degrades when used in SAR image. To enhance the adaptability of SIFT, two ways are employed. One is the application of a preprocessing on image pairs before matching. The other is the establishment of a scale and rotation restriction criteria on tie-points after SIFT matching. Compared with other matching methods, experiment results show that the proposed method is much more suitable for SAR image and successes in matching performance improvement. Furthermore, the method can meet the real-time requirement.
Xiao B.,PLA Navy Submarine Academy |
Wang J.,PLA Navy Submarine Academy
ISVRI 2011 - IEEE International Symposium on Virtual Reality Innovations 2011, Proceedings | Year: 2011
Marine noise is a complex audio signal combined by multi-sources, marine noise simulation is one of the important parts in various training and research area such as sonar and ship collision prevention. Based on signal spectrum analysis, spectrums for independent sources in various steady statuses are established, and dynamic spectrum in transiting status is reached with spectrum interpolation. With acoustic spread attenuation model and Doppler effects model, spectrum at listening position is obtained. Time series data of combined noises is generated, and listened noise simulation for multi-sources is implemented finally. © 2011 IEEE.
Hu K.,PLA Navy Submarine Academy |
Zhang X.-F.,PLA Navy Submarine Academy |
Liu C.-B.,PLA Navy Submarine Academy
Binggong Xuebao/Acta Armamentarii | Year: 2013
A kind of auto disturbance rejection controller(ADRC) based on genetic algorithm for keeping UUV depth was designed according to the characteristics of UUV maneuvering. Because of more parameters of ADRC, its parameter design was transformed to parameter optimization. The controller parameter of ADRC in a UUV depth control system was optimized by using the genetic algorithm. The depth control of UUV was simulated without disturbing and near the surface. The simulation results show that the ADRC controller has better depth keeping and anti-jamming performances. Compared with the conventional PID controller, the amplitude and the frequency of steering controlled by ADRC controller are reduced much more obviously. The control quality of ADRC is significantly improved.
Wu H.T.,University of Jinan |
Jiang Y.S.,PLA Navy Submarine Academy |
Yue Y.L.,University of Jinan
Ceramics International | Year: 2012
Trirutile-structure MgTa 2O 6 ceramics were prepared by aqueous sol-gel method and microwave dielectric properties were investigated. Highly reactive nanosized MgTa 2O 6 powders were successfully synthesized at 500°C in oxygen atmosphere with particle sizes of 20-40 nm. The evolution of phase formation was detected by DTA-TG and XRD. Sintering characteristic and microwave dielectric properties of MgTa 2O 6 ceramics were studied at different temperatures ranging from 1100 to 1300°C. With the increase of sintering temperature, density, ε r and Q·f values increased and saturated at 1200°C with excellent microwave properties of ε r ∼ 30.1, Q·f ∼ 57,300 GHz and τ f ∼ 29 ppm/°C. The sintering temperature of MgTa 2O 6 ceramics was significantly reduced by aqueous sol-gel process compared to conventional solid-state method. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Bin X.,PLA Navy Submarine Academy |
Chunsheng S.,PLA Navy Submarine Academy
Proceedings - 2011 International Conference on Virtual Reality and Visualization, ICVRV 2011 | Year: 2011
A SERIES MODELS FOR RADAR DETECTION RANGE UNDER COMPLEX ELECTROMAGNETIC ENVIRONMENT WERE ESTABLISHED, INCLUDING ANTENNA GAIN, PROPAGATION IN MULTI-PATH, ATTENUATION, CLUTTERS OF RAINFALL AND SEA SURFACE, AND ACTIVE ELECTRICAL JAMMING. RADAR RANGE SIMULATION WITH VISUALIZATION IS IMPLEMENTED AND PROVIDES DIRECT IMAGE FOR TACTICAL DECISION. © 2011 IEEE.
Wang X.,Shanghai JiaoTong University |
Wang X.,PLA Navy Submarine Academy
Journal of Software | Year: 2013
Due to having the explicit evidential reasoning (ER) aggregation function, the analytical ER algorithm has been extensively applied to decision problems under uncertainty. However, there are some different opinions to the validity of the analytical ER algorithm. In this paper, a new method is proposed for proving the equivalence between the recursive and analytical ER algorithms, in such a way that is different from and, it is believed, mo e rigorous than that of Wang et al (2006). The new method is based directly on Dempster-Shafer's combination rule and mathematics induction principle. It allows to consider simultaneously the combination and normalization of evidence. In addition, the iterative relationship of the normalization factors between two algorithms is derived. The paper further demonstrates the validity of the analytical ER algorithm theoretically and clarifies the relationship between the recursive and analytical ER algorithms. Index Terms-Dempster-Shafer theory; combination and normalization of evidence; multiple attribute decision analysis; evidential reasoning approach. © 2013 ACADEMY PUBLISHER.
Liu B.J.,PLA Navy Submarine Academy |
Lu W.Z.,PLA Navy Submarine Academy |
Ji H.Y.,PLA Navy Submarine Academy
Applied Mechanics and Materials | Year: 2014
The paper proposed a novel neural network ensemble algrithm (NNNEA) whose individual was generated by clonal selection algorithm. NNNEA can produced individuals of ensemble with better difference than other algrithm. NNNEA was used for predicting ciruit functions and finding sneak circuit. The inputs of NNNEA are states of switches, and the outputs are states of functional components. NNNEA predicted all possible functions of circuit. The sneak circuits can be discovered by comparing the predicted with designed functions. Although there are several limitations of NNNNEA, the results revealed that NNNNEA can exactly discover sneak circuits. © (2014) Trans Tech Publications, Switzerland.
Xu Z.,PLA Navy Submarine Academy |
Han S.,PLA Navy Submarine Academy
2011 International Conference on Electronics, Communications and Control, ICECC 2011 - Proceedings | Year: 2011
The passive tracking of moving target in water based on bearings of two sonar sensors is a nonlinear state estimation issue. The filtering algorithm used in the state estimation is sensitive to the initial value of filtering, which is usually set by people, while in this paper it is acquired based on the positions of two sensors, observed values of bearings and errors of observed values, so that this is more consistent with the facts. The results of simulation based on the initial value of filtering given in this paper show that this method is simple and the precision of tracking is superior. © 2011 IEEE.
Xing S.-L.,PLA Navy Submarine Academy |
Huang X.-K.,PLA Navy Submarine Academy
Applied Mechanics and Materials | Year: 2014
A kind of tapered and spherical combined liner shaped charge warhead is researched, and the damage mechanism is analyzed. The physics modle of warhead to columniform hull target is build, numerical simulation is done. The result shows that the shaped charge jet formed by this structure can provide movement space, which is in favor of damaging target with water layer. © (2014) Trans Tech Publications, Switzerland.
Jiang N.,National University of Defense Technology |
Li Z.,PLA Navy Submarine Academy |
Yang H.,National University of Defense Technology |
Hu Y.,National University of Defense Technology
Guangxue Xuebao/Acta Optica Sinica | Year: 2012
The principle of polarization maintaining fiber (PMF) is analyzed and a three-dimensional model is established by utilizing the finite element method (FEM). The stress distribution and normalized birefringence are obtained through this model. Three pure-optical beat-length measuring systems are carried out for contrastive research and the advantages and disadvantages are described. Experimental results are in good agreement with the theoretical results. Then one simple and effective method to test the beat-length of high-birefringence photonic crystal fiber (Hi-Bi PCF) is chosen and the results indicate that its beat-length is about 1.2 mm. This research provides an effective theoretical method for the analysis of PMF and a convenient experimental system for the beat-length testing of complex structure PMF and Hi-Bi PCF.