电磁轨道炮速度测量方法研究

电磁轨道炮武器系统进行发射试验时,速度是评价武器性能的一个重要参数.结合实际工程,利用平均速度测量原理,设计了基于网靶、光幕靶和阴影照相3种速度测量系统.通过在电磁轨道炮发射试验中使用3种速度测量方法,分析速度相对误差及其影响因素,比较每种测速方法的优缺点及主要适用范围.结果表明,网靶测速造价简单,比较实用;靶道阴影照相测速比较直观,能再现高速发射过程;光幕靶测速具有精度高、测量重复性好等优点.试验研究结果对评估电磁轨道炮发射性能具有指导意义.     

基于可编程片上系统的激光遮断法测速系统

针对以往测速系统采用单片机和CPLD分离结构在强电磁场环境下稳定性差,不能实时显示测量结果的缺点,设计一种基于激光遮断法原理测量弹丸飞行速度的智能测速系统,利用可编程逻辑器件的高集成度在单片FPGA中完成脉冲识别、处理,并在FPGA中嵌入32位Nios Ⅱ软核处理器实现对被测信号采集、处理和结果显示等功能,采用该结构使测速系统结构简单,抗干扰能力强,能直接显示弹丸飞行速度.因系统集成度高,使测量装置本身引起的测量误差达到最小化,通过误差分析,系统测量误差小于1%,测速范围可达400～4 000 m/s.在实际测试中利用该系统成功测量了电磁轨道炮发射的弹丸速度.     

基于虚拟仪器的子弹撞击实验系统

为评定子弹撞击火炸药的感度,针对火炸药易损性子弹撞击响应试验的要求,设计了由可编程逻辑控制器(PLC)、固态继电器、电磁铁及击发装置组成的发射时序控制器,基于Labview编写了上位机程序,控制3支12.7 mm弹道枪的顺序发射,实现了子弹的稳定发射以及发射时序的控制.设计了基于虚拟仪器的光电测频、测速系统,能对连发弹丸的射频及速度进行实时测量,为子弹撞击试验提供了试验手段和测试平台.     

基于双激光幕的弹丸初速测量系统研究

弹丸初速的标称值与实际值存在着差异,此误差影响火炮的射击精度,因此有必要对弹丸的实际初速进行测定。基于双激光幕区截原理的弹丸初速测量系统,采用激光测距机和光栅尺进行距离的测量和标定,选用ARM和CPLD对测速过程进行全过程记录采集,通过平均测速法计算得到弹丸初速,对系统的测量误差进行了分析,系统样机经过实弹射击试验得到某口径弹丸的试验数据。对系统的误差分析及实弹射击证明,双激光幕测速系统在弹丸初速测量的精度和可靠性等方面有了显著的提高,可较好地进行初速的校准测量。     

基于数字摄影测量的靶场高速摄影测速方法

针对靶场静爆试验中破片测速难题,提出了基于摄影测量技术的破片测速方法。以某枪弹为例,开展了测速试验,建立了测试系统,解决了测试现场高速相机布置及参数设定问题; 研究了关键技术,通过解析高速相机捕捉的弹丸运动图像序列,还原了弹丸的运动轨迹方程,求解得到弹丸的飞行速度; 并将试验结果与铝箔靶测得速度进行对比,相对速度误差小于1%。实例表明,该方法能够准确测量破片的运动速度,测试结果可靠,测量精度能够满足靶场试验要求。     

基于快速互相关的跨声速弹丸测速方法研究

针对室内千米靶道内镜头式光幕测速系统无法对跨声速弹丸速度进行有效测量的问题,采用外弹道学理论与MATLAB仿真技术计算跨声速测速点弹丸飞行速度理论值,使用快速互相关算法处理镜头式光幕测速系统在测速点的弹丸过幕信号,得到该测速点的实测速度值集合,以理论速度值为参考,从速度值集合中选取接近理论值的速度并进行误差分析。采用5.8 mm步枪弹进行实弹验证,实验所得的接近理论速度值的实测速度与理论值之间的相对误差小于0.3%。该方法解决了由于弹丸激波作用测速光幕产生干扰信号带来的影响,为跨声速弹丸速度的准确测量提供一种新思路。     

炮口初速测量校准与修正方法

弹丸炮口初速与实际炮口初速存在差异,此误差影响火炮的射击精度,因此有必要对弹丸的炮口初速进行测量校准并修正。对影响多功能炮口装置测速精度的因素进行了研究,得出自动机后坐速度对初速测量引入误差较大,据此提出一种炮口初速测量校准与修正系统方案来对多功能炮口测速装置进行测量校准与修正。最后,对实验数据进行分析,证明了该方法的正确性和可行性。     

TP—801单板计算机在枪弹测速试验中的应用

枪弹测速试验是用来检验产品的主要依据。是科研、生产及验收所必不可少的环节。在枪弹测速试验中,用单板机自动进行测量,数据处理并立即打印出所测速度值。从而大大简化了过去仪器测时,人工换算,人工记录的繁琐过程。提高了测量精度和可靠性,并使实验人员从大量重复的数据处理劳动中解脱出来,提高了工作效率。本文通过系统框图,程序流程图及部分接口电路介绍了单板机进行自动测量,数据处理及打印的设计思想和工作原理。     

嵌入式多通道测速系统设计

针对多管阵列武器多通道测速中存在拖线布线繁杂,各管道信号相互干扰,不便于安装和灵活应用的问题,设计一种可应用于多管阵列高射频火炮的嵌入式测速装置.单管测速单元以2组相隔一定距离的串接线圈靶作为测速传感器,具有体积小,布线拖线少,便于多节点分布的特点,通过在每个炮管上嵌入此测速单元即可以实现多管阵列高射频火炮的多管测速,各组测量信息通过无线方式发送到接收主机并通过上位机显示各个通道的速度信息,并进行3个测速单元的模拟测速试验.试验结果表明:该系统能够避免长距离传输中噪声对原始信号的干扰,具有较高的稳定性和速度测量精度,具有较好的扩展灵活性和应用前景.     

基于载荷质量调节的同步电磁线圈发射器速度相似性分析

电磁线圈发射器相似性关系是开展缩比试验研究的基础,通过分析同步电磁线圈发射器的发射机理和物理过程,推导了基于速度、应力和温度相等条件下的发射器系统参数比例关系,针对系统中电阻和质量的不相容性问题,提出了通过调整载荷质量实现发射出口速度相等的电磁线圈发射相似关系模型,并通过仿真计算验证了相似模型中速度具有相似性,磁力和温升关系相对缓和。系统参数相似关系和调整载荷质量实现发射出口速度相等的方法对电磁线圈发射器缩比试验研究具有一定的指导作用。     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Design and Analysis of Test Schemes of Static Postponing Time on Shrapnels Used to Riot Control

The test scheme of static postponing time given in our actual national military test standard on shrapnels used to control riot is a nine-point test scheme on the combined action of three kinds of temperatures and three kinds of pressures,the consumed ammunitions are more excessive. Statistic analysis and tentative checkout about a lot of test data are done,feasibility gists are put forward for optimizing of the test design scheme. The optimizing design and data analysis of test scheme of the item are done by managing uniformity design theory, two scientific and reasonable six-point test schemes are confirmed. The feasibility and reliability of the optimizing design schemes put forward above are proved ulteriorly by test validating. The gained schemes not only have good design uniformity and little ammunition wastage and meet the test demand, but also have better forecast ability for the result data of other points using the mathematic models from the actual test points.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.     

Design of Non-fragile Satisfactory Estimator for Linear Continuous Perturbed Stochastic Systems

The design problem of non-fragile estimator is addressed for a class of perturbed linear continuous systems. The perturbations occur on the plant and estimator parameters. The estimator designed should force the error system to achieve the desired decay rate and force the steady error variance less than the specified upper bound irrdevancy of the admissible plant perturbations and estimator perturbations. Consistency problem of the decay rate with the variance upper bound is first considered via linear matrix inequality （LMI） approach. The solution of the estimator parameter under specifications to be consistent is then discussed. The consistency condition of specifications and estimator parameter solution are transformed to feasible or minimum problems subject to a set of LMI respectively. The method is illustrated by a numerical example.     

An Improved Scene-based Nonuniformity Correction Algorithm for Infrared Focal Plane Arrays Using Neural Networks

The improved scene-based adaptive nonuniformity correction （NUC） algorithms using a neural network （NNT） approach for infrared image sequences are presented and analyzed. The retlna-like neural networks using steepest descent model was the first proposed infrared focal plane arrays （IRFPA） nonuniformity compensation method, which can perform parameter estimation of the sensors over time on a frame by frame basis. To increase the strength and the robustness of the NNT algorithm and to avoid the presence of ghosting artifacts, some optimization techniques, including momentum term, regularization factor and adaptive learning rate, were executed in the parameter learning process. In this paper, the local median filtering result of Xij （ n ） is proposed as an alternative value of desired network output of neuron Xij （ n ）, denoted as Tij （ n ）, which is the local spatial average of Xij （ n ） in traditional NNT methods. Noticeably, the NUC algorithm is inter-frame adaptive in nature and does not rely on any statistical assumptions on the scene data in the image sequence. Applications of this algorithm to the simulated video sequences and real infrared data taken with PV320 show that the correction results of image sequence are better than that of using original NNT approach, especially for the short-time image sequences （several hundred frames） subjected to the dense impulse noises with a number of dead or saturated pixels.     

Piecewise Filter of Infrared Image Based on Moment Theory

The disadvantages of IR images mostly include high noise, blurry edge and so on. The characteristics make the existent smoothing methods ineffective in preserving edge, To solve this problem, a piecewise moment filter （PMF） is put forward. By using moment and piecewise linear theory, the filter can preserve edge. Based on the statistical model of random noise, a related-coefficient method is presented to estimate the variance of noise. The edge region and model are then detected by the estimated variance. The expectation of first-order derivatives is used in getting the reliable offset of edge. At last, a fast moment filter of double-stair edge model is used to gain the piecewise smoothing results and reduce the calculation. The experimental result shows that the new method has a better capability than other methods in suppressing noise and preserving edge.     

Bistatic Sonar Localization Based on Best Linear Unbiased Estimation

A best linear unbiased estimation （BLUE） algorithm for bistatic sonar localization is proposed. The Cramer-Rao bound for bistatic Sonar and the geometrical dilution of precision （GDOP） in different conditions are given. The simulation results show that the location accuracy of BLUE algorithm is higher than the weighted least square method.     

Research on Gear-broken Fault Diagnosis in a Tank Gearbox

A fault diagnosis method of working position gear in a tank gearbox is put forward based on simulating the fault of working position gear in an actual tank, extracting the envelope of vibration signal by Hilbert transformation amplitude demodulation method, and zooming the low-frequency band to envelope signal.