基于反馈线性化的靶弹弹道跟踪制导律设计

针对导弹靶弹的弹道跟踪精度问题,基于反馈线性化和最优控制理论设计了一种弹道跟踪制导律。首先,通过对靶弹进行受力分析,建立靶弹纵向运动非线性方程组;其次,根据反馈线性化理论的定义和充要条件,详细推导得出靶弹的精确线性化运动方程;最后,通过最优控制理论设计弹道跟踪制导指令,并在阵风干扰和不同机动飞行弹道下,与基于小扰动法和固化系数法设计的跟踪制导律进行比较。结果表明:基于反馈线性化法设计的弹道跟踪制导律具有较高的弹道跟踪精度和较低的需用过载。     

基于预测控制的寻的导弹末制导律研究

为提高寻的导弹末制导性能,解决传统比例导引律在目标大机动的情况下,制导性能较差的问题,文中通过对一个简化了的二维导弹目标遭遇模型的研究,基于连续时间预测控制理论的输出跟踪方法,给出了一种寻的导弹最优末制导规律,并对其稳定性进行了分析。该预测制导规律不但解决了反馈线性化制导律在使用条件上的限制问题,而且通过数字仿真表明,所设计的预测制导规律比传统的比例导引规律具有更好的制导性能。特别是在得出的加速度指令方面,具有很大优势。     

导弹过渡段弹道优化设计与制导

针对滑翔段到巡航段的过渡段弹道优化与制导问题,在考虑过程约束和巡航段初始约束的条件下,运用Gauss伪谱法将最优控制问题转换为非线性规划问题,利用SNOPT求解了导弹过渡段的最优弹道。然后,将运动方程关于标准弹道线性化,利用LQR最优控制设计弹道跟踪器,给定弹道偏差的条件下,运用MATLAB进行了仿真校验,结果表明LQR跟踪器能够很好的跟踪Gauss伪谱法设计出的优化弹道。     

基于反馈线性化RLV再入控制律设计

针对可重复使用运载器(RLV)再入模型的非线性模型控制问题,设计了基于控制角与控制力矩间全反馈(非时标分离)条件下的反馈线性化控制器,实现RLV六自由度非线性模型线性化,应用经典的PID控制理论实现了控制律设计,完成了全弹道仿真.仿真结果验证了控制方法的可行性,实现了制导指令的精确跟踪.     

攻击地面机动目标的一种击顶制导策略

针对三维空间导弹和地面机动目标相对运动的非线性模型，将目标运动速度和机动加速度视为有界扰动，设计了一种击顶制导律策略。制导策略分为2部分：第1部分基于弹目视线倾角角速度和偏角角速度反馈，利用非线性系统输入输出线性化方法设计了接近制导律，保证导弹朝向目标运动；第2部分基于弹目视线倾角反馈，利用非线性系统输入输出线性化方法设计了击顶制导律。该制导律在保证弹目视线角速度趋零的同时还可保证视线倾角趋于- 90°，从而实现对目标的垂直打击即击顶。从理论上分析了制导系统的稳定性和精度。数值仿真结果证实该制导律有效。     

便携式反坦克导弹弹道成型制导律设计

针对飞行速度快速时变的便携式反坦克导弹制导控制问题,应用最优控制原理,提出了一种考虑导弹速度快速变化的改进弹道成型制导律。采用超前滞后环节进行时变过载自动驾驶仪设计; 基于最优控制理论推导了广义弹道成型制导律和扩展弹道成型制导律,针对便携式导弹速度快速时变的特性,设计了包含时变速度信息的弹道成型制导律,并结合工程实际讨论了参数选择方法; 最后进行了仿真对比和验证。仿真结果表明,该文提出的包含时变速度信息的弹道成型制导律能够满足武器系统的近距击顶作战需求,同时能够满足导弹系统的着角、攻角、框架角、过载等约束。     

再入机动弹头速度方向制导律设计及仿真

建立了再入机动弹道模型,设计了基于非线性系统精确线性化理论的再入机动弹头速度方向的时变最优制导律,实现了机动弹头速度方向的控制,通过三自由度机动弹道仿真证明该制导律是可行的。     

导弹中末制导弹道交接律研究

针对中远程导弹中末制导交班过程中的弹道交接问题,基于交接过渡段制导的思想设计了一种新的中末制导交接律。首先给出了满足导弹弹道一阶和二阶平滑的条件,然后分别采用三角函数和多项式函数形式的交接律平滑算子作为加权系数,求解出满足弹道平滑条件的平滑算子具体表达式。仿真结果表明:所设计的中末制导交接律算法简单,适用于导弹攻击过程中不同阶段制导律的弹道交接及实现中末制导交接过程中的弹道一阶和二阶平滑交接。     

精确对地攻击姿态约束最优末制导设计

针对远程精确对地攻击姿态约束末制导问题，提出按照命中点姿态角需求设计基准弹道，并建立了围绕基准弹道的线性时变弹目运动方程。以弹道跟踪误差和控制能量最小为优化指标，取弹道跟踪误差加权阵与剩余飞行时间的平方成反比，求得了一种新的精确对地攻击姿态约束末制导律。制导指令由基准弹道补偿项和弹道跟踪误差项两部分组成。与文献[1]制导律的仿真对照表明，本文给出的制导律具有较小的需用过载，命中点姿态角控制精度高、脱靶量小、适用性好。研究结果对远程对地攻击导弹或制导炸弹末制导系统设计具有参考价值。     

大空域变轨的变结构制导律设计

为了对抗敌方远程舰空导弹的拦截,提高突防能力,反舰导弹的飞行弹道应采用大空域变轨弹道。基于虚拟目标的概念,建立了导弹-虚拟目标的空间追逃模型,设计了一种考虑末端落角约束的变结构制导律。先设置不同的空间虚拟目标,然后,利用所设计的制导律引导反舰导弹去追踪虚拟目标,反舰导弹实现了各种各样的大空域变轨弹道。只要虚拟目标的参数设置合适,在飞行中导弹的各项性能指标都能满足要求。弹道仿真表明,所设计的制导律是很有效的。     

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.     

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 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.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

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.