Table of Content

30 June 2009, Volume 30 Issue 6

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Paper

Research on the Method of Adjusting Main Pressure for HD4070PR Automatic Transmission

SUN Wen-tao, CHEN Hui-yan

2009, 30(6):  657-662.  doi:10.3969/j.issn.1000-1093.2009.06.001

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On the basis of describing the principle of adjusting main pressure and establishing the model of clutch engaging process for the electronic automatic transmission, the different torques transferee! by the transmission and the influence of main pressure on shifting process under different gears were ana?lyzed, and the necessary of adjusting main pressure was proposed. The principle and the method of ad?justing main pressure were obtained by analyzing the electro-hydraulic control system of HD4070PR automatic transmission. The adjusting technique of main pressure was verified by an experiment, and the improvement of shifting equality was analyzed by the experimented data.

Research on Utmost Shooting Boundary and Time Limit of Anti-craft Artillery against Hypervelocity Target

LI Yin-ya, CHEN Li, QI Guoqing,SHENG An-dong

2009, 30(6):  663-667.  doi:10.3969/j.issn.1000-1093.2009.06.002

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Taking aim at the problems and results proposed in Ref. [2], in the snooting process of anti?craft artillery against nigh or ultra high- velocity target, the problem of the change trends of utmost shooting boundary with the changes of target fly velocity and anti-craft artillery maximum tracking an?gle velocity was studied respectively, and influence of the detector maximum find distance on the effec- tiye shooting area was also discussed. Taking a certain type anti-craft for example, the change trends of utmost shooting boundary with the changes of target fly velocity and anti-craft artillery maximum tracking angle velocity, and the change trend of effective shooting area with the change of detector maximum find distance, are proposed, respectively, and the anti-craft artillery minimum shooting time was interpreted by applying the warhead fly time curve. The studied results show that the effective shooting area and shooting time limit interval can be broadened effectively via increasing the detector maximum find distance and anti-craft artillery maximum tracking angle velocity and the fight capabili?ty can be enhanced.

Research on the Discarding Characteristic of a Novel Sabot with Wing

YU Yu-bin, ZHANG Jing, WANG Ke-qin

2009, 30(6):  668-671.  doi:10.3969/j.issn.1000-1093.2009.06.003

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In order to reduce the negative mass of the sabot, a novel sabot with wing configuration was designed. The mass of the novel sabot is only 3/4 of the saddle shape sabot. The discarding character?istic of the novel sabot was analyzed, the discarding force of the sabot was calculated, the discarding process of the novel sabot was simulated. Finally an experiment of the novel sabot was carried out, and the result validates that the novel sabot with wing configuration can discard rapidly and reliably.

Observer-based Sensor Fault Reconstruction Method and Its Application

HE Jing, QIU Jing, ZHANG Chang-fan

2009, 30(6):  672-676.  doi:10.3969/j.issn.1000-1093.2009.06.004

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A sensor faults reconstruction proposal for a class of uncertain nonlinear system with un?known input disturbances was presented. The sensor fault was equated to the actuator one by a new introduced state variable; a state observer based on sliding mode variable structure theory was designed with specific equivalent control methodology, in order to eliminate the effects of unknown disturbances on the system; the faults were reconstructed by means of adaptive method ? Results of numerical simu?lations on the artillery position servo system verify the validity of the proposed approaches.

Miiltiscale Extended Fractal Analysis for Identifying Bullet Engraving

YANG Min, MOU Li

2009, 30(6):  677-681.  doi:10.3969/j.issn.1000-1093.2009.06.005

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Analysis and comparison of bullet engraving are one of the keys for unearthing the case relat?ed to the gun. A method of comparing geometric morphologies, positions and striations among the bul?let engravings is mainly used domestically and abroad at present. An extended fractal model describing bullet engraving in rifle area was established, and the muitiscale extended fractal analysis methods and their algorithms used for classifying and identifying individually were proposed, on the basis of analyz?ing forming characteristics of the engraving and describing complex surface characteristics of the natu?ral body by fractal analysis. The researched results show that the methods are feasible and effective for checking bullet engraving. A new thinking of checking bullet engraving can be provided by the meth?ods for judicial analysis and expert testimony, a researching method of judicial ballistics can be extend?ed.

The Application of Two Dimensional Space-Time Conservation Element and Solution Element Method (CE/SE) to Turbulent Two-Phase Flow in Interior Ballistics

BAI Qiao-dong, WENG Chun-sheng

2009, 30(6):  682-687.  doi:10.3969/j.issn.1000-1093.2009.06.006

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A numerical scheme for solving turbulent two-dimensional two-phase flow in interior ballis?tics was deduced according to the idea of space-time conservation element and solution element (LE/ SE) method. The ignition process of two-dimensional two-phase flow was calculated by the method of CE/SE. The calculated results show that for central ignition pattern, at the initial stage of ignition, the pressure gradient exists along radial ana axis direction in barrel chamber, when the propellant is all ignited, the pressure gradient along radial direction vanishes; uniform extent of igniting the propellant can be improved by the different vortexes formed with the gas phase under interaction of the hign ve?locity gas jetted from the ignition vent and the solid propellant near the ignition tube; the calculated re?sults by the turbulent two-phase flow model can reflect the actual rule and the physical amount varia?tion near the gun bore wall m detail and really.

Mathematical Model of Fuze Ball Rotor Rotation Around Fixed Point with Quaternion

CHEN Hui-guang, WANG Yu-shi, WEN Quan

2009, 30(6):  688-694.  doi:10.3969/j.issn.1000-1093.2009.06.007

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The ball rotor device is a typical fuze primary explosive safety device, and can realize arming delay with optimized design. In order to conquer the fantasticality of the numerical results from the mathematical model established with the Euler kinematics equations for fuze ball rotor rotation when the rotor is nearly in alignment, on the basis of dynamics of the rotor whose mass center doesn’t coin?cide with its geometric center and has an offset from spin axis of projectile, the new mathematical model of the rotor rotation around fixed point was established with quaternion method. This is nonde-generate linearity differential equations, without fantastic dot, of help to obtaining the distortionless numerical results of the rotor motion and consequently researching on the dynamic balance angle of the rotor deeply.

Study on Shielding Effectiveness of the Rectangular Enclosure with Aperture Arrays

LU Hong-min, LUO Peng, LIU Guo-qiang, YU Zhi-yong

2009, 30(6):  695-700.  doi:10.3969/j.issn.1000-1093.2009.06.008

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With the purpose of evaluating the ability for metallically rectangular enclosures against the external electromagnetic interference, the waveguide equivalent circuit model and its analytical formu?lation were proposed for the shielding effectiveness (SE) of the enclosure with an array of the apertures and a printed circuit board (PCB) in it. The effects of loading the enclosure with PCB were modeled by considering the PCB as a lossy dielectric slab, and the previous model proposed, by Parisa Dehkhoda et ai is developed. The calculated results of the SE, by way of the present aDproach, are in well agree?ment with those obtained by commercially available numerical tool CST, which demonstrates the accu?racy and validity of the approach. The results show tkat the smaller tKe diameter of aperture is, tke better the SE is; the SE is evidently improved by means of loading the enclosure with a PCB; the SE of a 90。aperture array configuration is much better than that of the staggered configuration; the reso?nance frequency of the enclosure decreases along with the increase of the PCB thickness.

Researcli on Optimal Robust Stabilization Problem for Interval Plant Family

Lü Bin, WU Qing-he

2009, 30(6):  701-708.  doi:10.3969/j.issn.1000-1093.2009.06.009

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The robust stabilization problem (RSP) for interval plant family was studied. A necessary solvability condition of RSP is that every member plant must be stabilizable, that is, it is free of unsta?ble pole-zero cancellation. It is shown that stabilizability is also a sufficient solvability condition of RSP. The numerical example was presented to illustrate the procedure of the synthesis of the optimal robust controller for the interval plant family.

Analysis of Effect of the Pad Material on Stress in the Grain During Launching Artillery Missile

SUI Xin, WEI Zhi-jun, WANG Ning-fei,BI Shi-hua

2009, 30(6):  709-713.  doi:10.3969/j.issn.1000-1093.2009.06.010

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Three-dimensional visco-elastic large deformation incremental constitutive equation was de?rived based on total Lagrangian method. The stress distribution in the grain during launching was sim?ulated numerically by finite element method under axial mghly accelerated condition for solid rocket motor. The influences of pad material, pad thickness, ana load abidance time on the stress in the grain were analyzed. The analyzed results show that the equivalent stresses in the grain decrease with the in?crease of Poisson ratio of the pad material; equivalent stresses in the grain increase slightly with the in?crease of elastic modulus when Poisson ratio is less that 0.49, and equivalent stress in the grain de?creases first, increases slightly then with the increase of elastic modulus when Poisson ratio is equal to 0.49; the maximum stress in the grain decreases with the increase of the pad thickness; influence of load abidance time on equivalent stress in the grain is not evident after reaching steady load.

Research on “Eclipse” Problem of Quasi-CW Phase-coded Radar and Solutions

SU Feng, GAO Mei-guo, TIAN Li-yu

2009, 30(6):  714-719.  doi:10.3969/j.issn.1000-1093.2009.06.011

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The eclipse problem of quasi-CW phase-coded radar was analyzed, and solving methods were proposed by waveform and code designs. As for waveform design, a method based on in-pulse combi?nation of long code with short code was put forward, which can solve the severe eclipse problem of short range target, and simultaneously detect the whole range. As for code design, a range sidelobe suppression method based on interpulse code agility was proposed. Ineoretical analysis and simulated results show that, the code agility method can work well even when the target echo is eclipsed, so meet the demand of low pulse repetition frequency long code quasi-CW radar.

Research on 3D Terminal Guidance Laws Based on Actively Self-homing Spiral Variable Trajectory

ZHANG Ru-chuan, GU Wen-jin, ZHAO Hong-chao

2009, 30(6):  720-726.  doi:10.3969/j.issn.1000-1093.2009.06.012

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Design scheme of 3D guidance laws (GLs) based on actively self-homing spiral variable tra?jectory for the supersonic antiship missile was proposed to solve that the friendly missile can either e- vade the enemy interceptor or nit the sea maneuver target. Geometric relation models of relative mo?tions among the missile, the interceptor and the ship were established; spiral variable trajectory of the missile during the course of pursuit was realized by making angular rate of line-of-sight-angle (LOSA) track the given spiral variable trajectory command signal based on the adaptive sliding mode variable structure control idea to evade the enemy interceptor; angular rate of LOSA during the course of flying was approached to zero by selecting the reasonable parameters to ensure that the friendly missile can hit the sea maneuver ship. The simulated results show that the GLs can either make the antiship missile perform actively spiral variable trajectory, 1.e. make the miss amount of the enemy interceptor reach the minimum of 209? 233 m at the time of 4.41 s, or hit the sea maneuver ship at the precision indicat?ed by the miss amount of 0.932 m.

Cloud Neural Network Based Fault Detection and Diagnosis of Space Propulsion System

XU Zong-ben, FAN Zhong-ze

2009, 30(6):  727-732.  doi:10.3969/j.issn.1000-1093.2009.06.013

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An approach of cloud neural network was proposed and used for fault detection and diagnosis of the space propulsion system. A physical propulsion system of space vehicle was used to validate the approach. The simulated result demonstrates that the new approach can provide a real-time description for work state of the propulsion system with higher identify precision and makes fault defection deci?sion in time.

Multi-stage Reliability-Growth Bayes Analysis for Exponential Product Based on New Dirichlet Prior Distribution

MING Zhi-mao, ZHANG Yun-an, TAO Jun-yong,CHEN Xun

2009, 30(6):  733-739.  doi:10.3969/j.issn.1000-1093.2009.06.014

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A new method for the application of Bayes theory to the reliability-growth for exponential distribution was developed. Lismg some history and expert information during the development of a product, a Bayes reliability-growth model was presented based on new Dirichlet distribution. Bayes point estimation and lower confidence limits on product reliability at current stage were calculated by comprehensively making use of prior information and field test information at every stage. The method for determining prior distribution parameters was given by optimization which is easy to confirm the parameters of prior distribution, and to solve the problem of how to verify the hyper parameters of the new Dirichlet prior distribution because of these parameters having no specific physical meaning. The Oribbs sampling algorithm was used to solve the problem that interference on parameters of Bayes poster higher dimensions can’t be calculated directly, and numerical simulations were performed by the mod?el. The analyzed result of practical cases proves the observability and validity of the model.

The Study of Equipment Degradation State Recognition Method Based on KPCA-HSMM

ZENG Qing-hu, QIU Jing, LIU Guan-jun, et al.

2009, 30(6):  740-745.  doi:10.3969/j.issn.1000-1093.2009.06.015

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In order to reduce redundancy among Multi-channel observations by sensors and compress high dimensional fault features, a new equipment degradation state recognition method based on kernel principal component analysis-hidden semi-Markov model ( KPCA-HSMM) was proposed. The single channel vibration signal was processed by the way of wavelet transform correlation filter and wavelet correlation feature scale entropy vector of single channel vibration signal was constructed; the wavelet correlation feature scale entropy vectors of multi-channel were fused by KPCA to obtain the fused eigenvector and eliminate redundancy; the fused eigenvector of multi-channel was inputted to the HSMM for training, and running states classification model of equipment based on HSMM was con?structed. to recognize the equipment degradation states. The experimental results show that the pro?posed method is very effective for equipment degradation state recognition and opens up a new way for recognizing equipment degradation state by multi-channel feature information fusion.

A Dynamic Model for the Mass Transfer with Chemical Reaction of Hazardous Liquid in Coating andIts Analytical Solution

HUANG Shun-xiang, HAO Rong-zhang, LIU Feng, CHENG Zhen-xing, CHEN Hai-ping，HU Fei

2009, 30(6):  746-752.  doi:10.3969/j.issn.1000-1093.2009.06.016

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A one-dimension model of mass transfer, coupled with chemical reaction, was solved analyt?ically using Laplace transform to describe absorption of the hazardous liquid in the coating. The exact solution for diffusion coeflicient D, when degradation rate constant k=0，was obtained after defining two standard functions, 1.e.，err(x) and aer(x). Its theoretical error is 0，and experimental stan?dard deviation when applied in the transportation of sulfur mustara (HD)，α=1 ? 95 X 10 -10 cm2/ s, is much less than the result in other literatures. On basis of that, the equations for absorption amount and flux of hazardous liquid in coating were obtained, then, their dispersion characters in time and space were described, and the influences of degradation rate constant k on them were also analyzed. A described rule of the absorption of hazardous liquid in coating is exact and systematic. The calculating method for diffusion coefficient is more simple and exact. The results can provide theoretical basis for decontamination, risk assessment and protective measures of hazardous materials.

Study on the Microwave Absorbing Properties of Surface Modified Si02 Composites

LI Li-guang, TAN Ye-fa, CAI Wen-li, et al.

2009, 30(6):  753-758.  doi:10.3969/j.issn.1000-1093.2009.06.017

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The technology of liquid phase hydrogen reduction under high pressure was employed to modify the Si〇2 powder in oraer to prepare light mass and wide frequency band absorbing coatings.The surface modified Si〇2 coatings were prepared. The SEM and XRD analysis results show that the nickel particles on the surface of Si〇2 particles were homogeneously crystallized and the cladding was complete gradually with the increase of nickel plating. The absorbing properties of the surface modified Si〇2 coatings at the frequency ranges from 8 to 18 GHz were measured. The influences of mass frac-tions of nickel, particle content and thickness on the absorbing properties of the Si〇2 coatings were studied. The researched results show that the surface modified Si〇2 coating with 75% nickel plating, 65 % particles ana 2 mm in thickness exhibits better microwave absoromg property; the minimum re?flectivity of the absorbing coating is — 14.6 dB at the frequency of 17.15 GHz and the bandwidth is 7 GHz when the reflectivity is less than 一 10 dB.

Experimental Techniques and Analysis

Noise Testing and Analysis of Automotive Engine Timing Chain

WANG Shu-kun，MENG Fan-zhong, LI Qi-hai,SUN Shu-hong

2009, 30(6):  759-763.  doi:10.3969/j.issn.1000-1093.2009.06.018

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Noises of the different type automotive engine roller chains were tested and analyzed at dif?ferent rotational speeds by a test bench of testing noise of high speed chain transmission developed in?dependently with the initiative in their own hands and a two channel noise analyzer in real time of type AWA 6290A. Frequency spectrum rule of transmission noise of the high speed roller chain was ana?lyzed by tested results and kinematic characteristic of the chain transmission, to draw the conclusions that periodic variation appears in the chain transmission noise and low frequency noise increases with increase of the sprocket speed. The proposed conclusions has practically instructive significance for con?trolling automobile chain noise.

Study on the Different Test Methods for Power Density of Power Batteries

ZHAO Shu-hong, WU Feng, WANG Zi-dong, ZHANG Jing-wei

2009, 30(6):  764-768.  doi:10.3969/j.issn.1000-1093.2009.06.019

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Power density of the batteries is an essential parameter for designing vehicle auxiliary system and battery pack. Influence factors of the tested results on power density of the batteries were com?pared and analyzed by the methods of JEVS and HPPC and the battery A with 8.5 Ah/12 V made in US, the battery B with 5.5 Ah/3.6 V made in Japan. The studied results show that larger difference of the calculated power density of the battery exists in the different testing methods, caused by the dif?ferent ways of determining internal resistance; the battery power capacity is characterized by the volt?age response characteristics at charge/discharge currents of 0 — 10C series based on the JEVC method, which avoids the result，s deviation caused by single current but doesn ’ t consider the variation of the capacity at the high magnification currents; the capacity is characterized by the voltage response char?acteristic at a certain current based on the HPPC method, which compromises the voltage response characteristics at the middle-low and high magnification currents but doesn’t avoid the result s devia?tion of the capacity at a certain current.

Research on Flow Field of Turbulent Boundary between Smooth and Riblet Surfaces

SONG Bao-wei, LIU Zhan-yi, HU Hai-bao,HUANG Ming-ming, HUANG Qiao-gao, MA Ji

2009, 30(6):  769-772.  doi:10.3969/j.issn.1000-1093.2009.06.020

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Measurements on velocity distributions in boundaries at the same point over smooth and ri- olet surface were carried out by means of hot-wire anemometer in low-speed wind tunnel. It was found that the riblet surface, having drag reducing effect, can increase near-wall flow velocity and decrease turbulent intensity, but have little influence on high-order moment by contrasting and analyzing the turbulence statistical average values, and have more than 10 percent drag-reduction by calculating mo?mentum loss thickness.

Comprehensive Reviews

A New Type of Hybrid- Driven Power System ： Integrated Propulsion System Based on Hydraulic Free Piston Engine

ZHAO Zhen-feng，ZHAO Chang-lu，ZHANG Fu-jun

2009, 30(6):  773-778.  doi:10.3969/j.issn.1000-1093.2009.06.021

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Hydraulic free piston engine propulsion system is a new type hybrid-driven power system, into which internal combustion engine, hydraulic pressure, electronic control technologies are integrat?ed. Owing to its small size, light weight, nighly flexible layout, and extensively adaptive fuel scope, the system is a promising hybrid vehicle transmission，which has functions such as infinitely variable speed, stepless steering and brake energy recovery. On the basis of working principle and structural characteristics of the hydraulic free piston engine (HFPE)，scheme, key technologies, applied prospect and countermeasure of the integrated propulsion system based on Ht PE were proposed.

Research Progress of Mitigation Technologies of Turbulence Effects in Atmospheric Optical Communication

CHEN Chun-yi, YANG Hua-min, JIANG Hui-lin，FENG Xin, WANG Hui

2009, 30(6):  779-791.  doi:10.3969/j.issn.1000-1093.2009.06.022

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Atmospheric turbulence causes the increases of bit-error-rate (BER) in atmospheric optical communication links. Mitigation technologies of turbulence effects can be used to improve the perfor-mance and enhance the data-rate and communication distance of optical communication. The latest mechanism researches of turbulence effects on optical communication were briefly summarized, and the various influences of turbulences on that were described, such as intensity scintillation, beam wander, angle-of-arrival fluctuation, phase fluctuation, beam spreading, etc. The development of mitigation technologies of turbulence effects was summarized. Based on different principles, various mitigation technologies were described m detail, such as large aperture receiver, diversity, partially-coherent- beam propagation, temporal-domain processing & threshold optimization, adaptive optics, etc. Focus?ing on their principles and impacts, various mitigation technologies were analyzed and discussed. Last?ly, the future research directions were given.

Research Notes

Mechanical Characteristic Analysis and Experiment Research of Hydro Pneumatic Spring

CHEN Yi-jie, YANG Zhan-hua, LEI Qiang-shun, WANG Ya-jun, NINGDan

2009, 30(6):  792-796.  doi:10.3969/j.issn.1000-1093.2009.06.023

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Taking aim at damping valve with overlapping slices the calculation method of fold slices de?flection based on the equivalent thickness rules was presented, and the expressions between aperture parameters and deformation of slice were deduced. The throttle analytic calculation of annular aperture was researched, and the flow equation of aperture under the turbulence state was deduced by using the boundary layer theory, rhe nonlinear mathematic model of Hydro-pneumatic spring with single gas chamber was established by using the Van der Waals state equation of real gas. The relations between elastic force and the total output force vs. the displacement were studied, and the correctness of model was validated through comparing with the experimental data. The influence rules of structure parame?ters of valve on the output force of hydro-pneumatic spring were studied, which offer reference to accu?rately design the damping valve.

Rapid Detection Method of Surface Defects of Steel Ball for Bearing

YANG Dong-lin, YU Zheng-Iin

2009, 30(6):  797-802.  doi:10.3969/j.issn.1000-1093.2009.06.024

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Taking aim at the issue occurred now in detection method of surface defects of steel ball for bearing, a rapid detection method was proposed. An expansion structure of steel ball was designed to resolve its rapid expansion and ensure the integrity of the detected surface simultaneously; specular re?flection disturbance of steel ball surface occurred in image acquisition was eliminated via the design im?provement of light source and check slot; separating steel ball from background, pits from steel ball was realized by digital image processed witk computer and pattern recognition to achieve the purpose of acquiring characteristics of the pits and making detection process automatization. In actual experience, it shows that the method is available for detecting surface defects of the steel ball, such as pits, scratches, burn marks, scuffs, cracks, etc. and used for on-line detection of surface defects of the steel ball.

Research on the Method of Low-power Consumption Design for Linear Force Motor

LI Yong, DING Fan, MAN Jun,SHAO Sen-yin

2009, 30(6):  803-807.  doi:10.3969/j.issn.1000-1093.2009.06.025

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Based on analysis of energy conversion relation of moving-iron type electromechanical con-, verter, a method of low-power consumption design for linear force motor was presented, by which a low-power consumption Di-directional linear force motor used for high hydraulic pressure was devel?oped. Based on the mathematic model, the effects of main structural parameters on the force-versus- stroke characteristics of linear force motor were simulated by the finite element method. The simulated results demonstrate that by introducing radial operating airgaps while reducing axial non-operating air- gaps, energy conversion efficiency can be improved and steady power consumption can be reduce by 36% under equal output capability. The simulated results agree well with the experimental results, which are that non-linear error of the prototype linear force motor is less than 1.5% within a stroke of 士 I mm, and its steady state power consumption is only 7 W at the maximum force output of 土 100 N.

Scale Invariant Interest Point Detectors Based on Normalized LoG

SUN Jing, XING Ying-jie, YANG Jian, WU Yu-feng

2009, 30(6):  808-812.  doi:10.3969/j.issn.1000-1093.2009.06.026

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The performance of the detector based on gray declines with scale s changing in applied fields of image matching, ooject recognition and video retrieval. To get over the denciency, a detector with scale invariance, that is iterative Harris-Laplace detector (Ite-HL-Det), was constructed. Harris corner detector was used first to extract initial points in conditions of multi-scale. Then, in the whole scale space, iterative method was applied to confirm characteristic scale of certain local structure ac?cording to the local extremum of the normalized Laplacian and finally the spatial locations of interest points by Harris measure based on the definition and property of the characteristic scale proposed com?prehensively. The experimental results show that neighborhoods of interest points extracted by Ite- HL-Det can well cover the same local image regions at varying scale and rotation.

Watermarking Algorithm for Digital Image Against RST Attacks Based on Geometric Moment

LI Jian, YE You-pei, LIU Guang-jie

2009, 30(6):  813-819.  doi:10.3969/j.issn.1000-1093.2009.06.027

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Resistance to rotation, scaling, translation vRST) attacks is a difficulty of digital water?marks. A novel watermark algorithm which is resistant to geometric attacks based on geometric mo?ment was proposed. Geometric distortions of the watermarked image were estimated accurately and its inverse transformation was corrected by geometric moments, of the original and the watermarked im?ages, used for pattern recognition, to ensure synchronization between embedding and detecting of the watermark and improve the resistance to RST attacks. The simulated results demonstrate that the al?gorithm is very robust to RST attacks.

A Method of Measuring Poses of the Aircraft Model Based Computer Vision

LUO Wu-sheng, LI Pei, LI Guan-zhang, LU Hai-bao

2009, 30(6):  820-824.  doi:10.3969/j.issn.1000-1093.2009.06.028

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In order to measure the aircraft model’s poses at the spin time in the wind tunnel experi?ment, a method was proposed based on computer vision. The method depends on a set of manmade signs, which are easily identified and have high correctness rate of matching between corresponding them. To compute the poses, the signs are symmetrical about axis of model body and have known po?sition. Unstability and influence of the signs on the computed results were analyzed and solved. The experimented and analyzed results show that the method has better stability and precision.

GPS Error Modeling Based on Time Series and Research on the Accuracy of Point Positioning

LIU Di，BO Yu-ming, ZOU Wei-jun

2009, 30(6):  825-828.  doi:10.3969/j.issn.1000-1093.2009.06.029

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A data processing algorithm was proposed to improve the GPS single point positioning accu?racy. Full details were provided on how to use time series analysis in the modeling of the first order dif-ferential series for the GPS error. The AR( n) model which is adopted to describe the first order dif?ferential series for the GPS error was derived from the observed data, and model parameter values were obtained using the least square method; one step prediction for the error series was effectively achieved by conditional expectation; positioning accuracy of ordinary GPS receivers was improved remarkably through online adjustment to the observation data. The simulated results show efficiency and reliability of the proposed method.

Design Method of Flying over Guidance System of Antitank Missile with Strapdown TV Guidance

LI Zhao, ZHANG Jing, CUI Zhan-zhong

2009, 30(6):  829-833.  doi:10.3969/j.issn.1000-1093.2009.06.030

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In order to solve tne problem of antitank missile unable to damage fatally in direct impact mode, a method of flying over guidance system was brought forth. The range calculus module and the additional angular speed module were added in, based on direct impact mode guidance system. Explo?sively formed warhead with down open was ignited when the missile controlled by the guidance system was flying over the tank to attack its top armor vertically. The feasibility of the guidance method and the correctness of the math model were validated by the simulation test and analysis.

Time- frequency Identification of Weak Warship Signals in Complex Sea State Background

ZHANG Ning, LIN Chun-sheng, PANG Xue-liang,YU Li-yang

2009, 30(6):  834-838.  doi:10.3969/j.issn.1000-1093.2009.06.031

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The signal time-frequency analysis was applied to identifying the weak physical field signals of warship in complex sea state background. The cross-interference problem of Wigner-Ville distribu?tion in weak signal identification was analyzed. To restrain the cross interference and improve time-fre?quency resolution, a high-order Butterworth pre-filter was introduced into a hydraulic pressure field collecting system and an algorithm of smooth pseudo Wigner-Ville distribution (SPWD) with Black?man window was brought forward. Based on a sea experiment of warship hydraulic pressure measure, the algorithm was validated and contrasted. The results show that the algorithm can improve ability of identiiying the weak warsmp signals obviously in complex sea state.

Research on Robustness of the Layered Complex Networks

CHEN Ye, ZHAu Jin-chao, QI Huan

2009, 30(6):  839-843.  doi:10.3969/j.issn.1000-1093.2009.06.032

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Based on a nierarchical structure of the layered complex networks, relationship between the layers was expounded; definition of the load was introduced into the network; redistribution of the load and its influence on robustness of the network at countermeasures of reselecting the different paths were analyzed. The simulated results of the nary fleet combat system as the layered comolex network show that influence of logic layer on the attack effect is larger than that of physical layer, the counter?measures of reselecting path and the load can generate important influence on the attack effect of the layered complex network.

Research on the Deployment Strategy of Multistatic Sonar

LI Yi, SUN Chang-yu, YU Hua-bing, CHEN Xin-hua

2009, 30(6):  844-848.  doi:10.3969/j.issn.1000-1093.2009.06.033

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A deployment strategy of multistatic sonar based on detecting coverage was put forward. First, according to the operational range formula, the characteristics of the detecting coverage of bistatic sonar were analyzed. Ana the conclusion that the detectable field is inside Cassini curve was gained. Then the conclusion was applied to multistatic sonar. It can be seen that the detecting cover?age of multistatic spnar was relevant to the position of receivers and transmitters, and the main parts of the detecting coverage are near receivers and transmitters. At last, based on the simplified model, a deployment algorithm of multistatic sonar which replaces the detecting coverage by circles was put for?ward. Through simulation to tms algorithm, it can be seen that the algorithm is good for deployment.