Three dimensional simulation of electromagnetic railgun's exterior ballistics

In order to evaluate the electromagnetic railgun＇ s practical combat capability as well as its tactic application prospects, a three dimensional simulation model of electromagnetic railgun＇ s exterior ballistics is presented. On the hypothesis of the Earth＇ s being round and ignoring the influ- ence of rotation, the railgun＇ s atmospheric environment and its motion equations are established by the Simulink Module of Matlab. And the railgun＇ s characteristics of exterior ballistic under different muzzle energy and emission inclinations are discussed. Results show that its incomparable superiori- ty in improving range and lethality to conventional artillery under the same launch condition based on railgun＇ s range and variation of velocities. It is useful for the efficacy evaluation of railgun＇ s combat capability and its practical applications in fields such as ground war, missile interception and so on.

Control of exterior ballistic properties of spin-stabilized bullet by optimizing internal mass distribution

This paper introduces a novel approach for controlling the exterior ballistic properties of spin-stabilized bullets by optimizing their internal mass distributions. Specifically, the properties of interest are the bullets’ stability characteristics that are examined through dynamic and gyroscopic stability parameters.New analytical expressions for aerodynamic quantities are also derived to address the compressibility of air. These expressions are utilized in a bullet model that enables efficient computation of the stability parameters for a given mass distribution. The bullet model is used in the formulation of nonlinear optimization problems that provide optimal mass distributions with respect to given goals, i.e., desired stability characteristics. The bullet types investigated in this paper are a long range bullet and a limited range training bullet. In the optimization of the mass distribution of the long range bullet, the goal is that the bullet stays stable for as long as possible. The mass distribution of the training bullet is optimized such that the bullet is stable at launch but becomes unstable shortly afterwards. The global optimal solutions obtained with the new approach fulfill the desired stability characteristics better than currently used uniformly filled bullets. Overall, the optimization approach reveals a new goal focused philosophy for bullet design compared to current trial and error design practices.

Parameters of Exterior Ballistic Feature Points Extraction in Radar Measurement Data by EMD

The problem of measuring exterior ballistic feature points is always difficult to solve and it is essentiale on exterior ballistic measurement.By analysis of radar reflection characteristics and non-stationary echo signals of exterior ballistic feature points,the echo data of exterior ballistic feature points is measured by using the continuous wave radar.The parameters of feature points are extracted by the empirical mode decomposition method(EMD)of Hilbert-Huang transform(HHT)spectrum analysis technique.The radar echo signal model and EMD extraction model are established to analyze the exterior ballistic mutation point detection and EMD extraction method of aliasing echo signal.Typical feature point parameters of exterior ballistic in rocket flight tests are carried out and the effectiveness of the method is verified.A new method of measuring the parameters of exterior ballistic feature point is therefore presented.

拓展高原环境的航空炸弹弹道快速解算方法

为快速、精确地求解高原环境下的航空炸弹弹道,在经典弹道模型的基础上,面向高原环境提出一种基于改进Runge-Kutta的航空无控炸弹弹道解算(improved Runge-Kutta based uncontrolled bombs trajectory calculation,IRK-UBTC)方法。首先,针对炸弹下落过程中时刻变化的环境参数,提出了基于起飞点的空气比重函数估算方法。然后,引入战斗机所处环境的温度、湿度、纬度、科尔奥利力等信息对经典炸弹质心运动微分方程组进行重构。最后,在三阶Runge-Kutta算法的基础上,提出了带误差控制机制的微分方程组实时解算方法。实验结果表明,该方法在1.4 GHz主频的嵌入式计算机中的解算周期小于5 ms,且最大射程误差小于0.2%,能够被有效应用于高原地区航弹弹道的实时解算。

Improved theory of generalized meteo-ballistic weighting factor functions and their use

It follows from the analysis of artillery fire errors that approximately two-thirds of the inaccuracy of indirect artillery fire is caused by inaccuracies in the determination of the meteo parameters included in fire error budget model.Trajectories calculated under non-standard conditions are considered to be perturbed.The tools utilized for the analysis of perturbed trajectories are weighting factor functions(WFFs)which are a special kind of sensitivity functions.WFFs are used for calculation of meteo ballistic elements B(ballistic wind w B,densityρB,virtual temperatureτB,pressure p B)as well.We have found that the existing theory of WFF calculation has several significant shortcomings.The aim of the article is to present a new,improved theory of generalized WFFs that eliminates the deficiencies found.Using this theory will improve methods for designing firing tables,fire control systems algorithms,and meteo message generation algorithms.

Problem of the reference height of the projectile trajectory as a reduced meteo-ballistic weighting factor

This paper deals with the issue of preparation of the aiming angles with the use of tabular firing tables and needed determination of the ballistic elements μ_B(ballistic wind w_B,w_(xB),w_(ZB),ballistic(virtual) temperature τ_B.ballistic density p_B) from the standardized met messages.The weighting factors are used for the calculation of ballistic elements μ_B that are incorporated into the trajectory calculations characteristics of weapon and ammunition.Two different methodologies practically used in the praxis are analysed and compared.For the comparison of the two methodologies the reference height of trajectory determined from the weighting factor functions is employed.On the basis of the analyses conducted,the potential for further increase in accuracy of these aiming angles preparation methods is pointed out.

Improved theory of projectile trajectory reference heights as characteristics of meteo-ballistic sensitivity functions

Projectile trajectories calculated under non-standard conditions are considered to be perturbed. The tools utilized for the analysis of perturbed trajectories are weighting factor functions(WFFs) which are a special kind of sensitivity functions. WFFs are used for calculation of meteo ballistic elements mB(ballistic wind wB, virtual temperature tB, pressure pB, density rB, speed of sound a) as well. An effect of weapon system parameters can be incorporated into calculations through the reference height of trajectory-RHT.RHT are also calculated from WFFs. Methods based on RHT are far more effective than traditional methods that use weighting factors q.We have found that the existing theory of RHT has several shortcomings due to we created an improved theory of generalized RHT which represent a special sensitivity parameters of dynamical systems. Using this theory will improve methods for designing firing tables, fire control systems algorithms, and meteo message generation algorithms.

基于射表的外弹道仿真模型的设计与实现

针对实弹射击训练场地条件限制大、训练耗费较高、安全保障困难以及训练内容无法适时弹性变更的问题,提出了仿真系统基于射表的外弹道仿真方法,以射表数据为输入、系统设定外界环境为修正的抛物线拟合弹丸质心方程组,通过方程组拟合获得较为切合实际外弹道的曲线模型;以C++作为开发语言对外弹道进行拟合运算,实时显示弹丸运动轨迹,由此获得室内训练场环境的模拟模型,并将误差控制在一定范围内;使用Unity3D为虚拟引擎,将驱动坦克与炮弹引入三维可视化实体模型,并搭建相应地形场景与命中效果;应用3D Studio Max软件建立坦克与炮弹实体模型,体现战场环境多变性与射击系统过程的仿真模拟,为外弹道及射击仿真训练系统提供了研究基础。

双N型六光幕阵列弹丸斜入射速度测量方法研究

针对炮管仰角射击、枪弹扫射、弹丸末端弹道飞行等斜入射情况下的弹丸速度测量需求,提出一种双N型六光幕天幕靶弹丸斜入射速度测量方案,系统主探测器,两台三光幕天幕靶通过“N”型狭缝光阑和光学镜头在预定弹道空间形成六个探测光幕,弹丸以一定角度入射并依次穿越六个探测光幕时,六个探测光幕对应的六套信号处理电路依次输出六路弹丸信号,通过数据采集仪对六路弹丸信号进行采集和处理,得到弹丸穿过六个探测光幕的时刻值,再进一步结合系统光幕结构参数,计算出弹丸的飞行速度和飞行方向,并对系统速度测量误差进行了分析和仿真,最后通过实弹试验的方法验证了系统的速度测量精度≤1.1‰。

基于刚体外弹道学仿真的中大口径旋转炮弹引信力学环境

为了得到中大口径旋转炮弹引信及其零部件在外弹道上所受力学环境变化规律,以76 mm舰炮和155 mm加榴炮榴弹为例,通过解算弹丸刚体外弹道模型即六自由度外弹道微分方程组,得到中大口径火炮旋转弹丸外弹道运动规律,在此基础上进一步得到引信及其零部件在外弹道上受力分析所需的弹丸外弹道欧拉角运动即章动、自转和进动规律。弹丸以45°以下射角射击时,最大章动角在全弹道上逐渐衰减;而以45°以上射角射击时,最大章动角总体上也是在全弹道上逐渐衰减,但在弹道顶点附近会略有增大。由弹丸刚体外弹道模型解算得出的弹丸外弹道自转角速度衰减规律,与幂函数经验公式估算结果以及落点测试结果较为接近。

舰载防空制导炮弹杀伤空域建模

针对新型舰炮武器与先进制导弹药的技术特点,提出了融合普通弹药与防空导弹优点的制导炮弹拦截空中目标的思路,构建了防空制导炮弹的杀伤空域数学模型。根据防空制导炮弹外弹道的特点进行外弹道建模;基于外弹道模型,分析杀伤区、发射区的影响因素,建立杀伤区、发射区的数学模型;构建了零航路捷径的垂直杀伤区数值模型,设计了一种快速生成不同航路捷径上垂直杀伤区数值模型算法;并针对具体实例进行了数值化仿真分析。仿真实例分析表明,随着目标航路捷径的增大,炮弹的垂直杀伤区范围逐渐减小,构建的防空制导炮弹杀伤空域模型合理有效,对防空制导炮弹的作战使用具有较大的应用价值。

大口径机枪枪管内膛损伤的试验研究

针对大口径机枪枪管寿命显著低于国外同类型枪械的问题,开展了枪管综合寿命试验。以某12.7 mm大口径机枪枪管为研究对象,对各支枪管在寿终前各寿命阶段的初速、精度、内膛直径和内膛表面形貌等进行了测量或内窥。通过对枪管综合寿命试验的结果进行深入分析,获得了大口径机枪枪管内膛损伤的主要形式,验证了各支枪管在相同制造工艺下寿命极限和内膛损伤形式的一致性。可以得出以下结论:枪管内膛损伤形式分为均匀磨损和局部损伤2类;按损伤规律的不同沿枪管轴向可以分为4个区域,各区域轴向长短不一,内膛损伤在这4个区域之间表现出较大的差异性。研究结果可以为建立准确的损伤枪管弹/枪相互作用模型提供依据。

一种高精度弹道导弹落点预测方法

为高精度预测弹道导弹落点,提出了高精度落点预测算法,即首先基于椭圆弹道粗估计所划定的落点范围搜索可能目标,然后基于4D外弹道模型应用遗传算法对弹道导弹弹道进行精细预测.该算法可快速划定目标搜索范围并精确生成弹道导弹轨迹;以导弹必定攻击我方军事目标的基本假定改变了以往算法仅依靠弹道特性的局限,并支持多弹头弹道导弹的落点预测.仿真实验表明该算法的运行时间平均在2s以内,精度在100m范围,可以满足弹道导弹预警的时间和精度要求,也可为多弹头同时预测落点.

弹道修正弹在脉冲力矩作用下的飞行稳定性条件

弹道修正是近年来为提高弹药设计精度而出现的一种新技术。该文对弹道修正技术中常采用的脉冲力矩修正作用 ,对弹丸飞行稳定性状况的影响等进行了讨论 ,给出了脉冲力矩作用下飞行稳定性条件。这对目前开展的修正弹道技术研究 ,特别是对弹道修正设计方案的选取 ,有一定的参考意义。

高速旋转飞行弹丸外弹道表面温度场研究

为了获得弹丸表面在高速旋转飞行状态下的温度特性,基于其六自由度(6-DOF)刚体弹道模型,应用节点热网络法,建立了热流平衡方程组。在气动加热的计算中,利用绕流圆柱换热理论考虑了弹丸旋转产生的影响,通过与弹道模型联立求解,得到了受弹道诸元和气流物性所控制的表面温度场分布。分析了弹丸的发射速度、初始转速、发射角以及气流温度对其平均温度场的影响规律。结果表明:弹丸表面温度随发射速度增加而非线性增加;温度梯度与距弹头的距离呈反比;初始转速越高,峰值温度和温度变化率越大;来流气温越高、发射角越小,平均温度越高。

高弹道测量数据电波折射误差快速修正算法

飞行器制导精度评估 ,特别是航天器的姿态与定点控制、落点预报等 ,都离不开高精度的外弹道测量数据。在影响测量数据精度因素中 ,折射误差是主要误差源之一。目前折射误差修正方法中 ,一类精度很高 ,但计算速度太慢 ,无法应用于实时计算 ;一类速度很快 ,但因为使用的是简化模型 ,因而精度较差 ,难以满足未来高精度测控的需要。如何在确保实时计算速度基础上 ,又能提高其处理精度 ,正是文章构造出的快速折射修正二步方法所解决的课题。经仿真计算证明 。

弹道一致性检验准则应用中的问题分析和建议

根据数理统计的知识和射击理论,针对现行弹道一致性检验、判据的假设条件及模型来源和实际应用遇到的问题,分析了该判据的一些不足.从允许误差、判据稳健性、统一性以及多参数综合评判分析等方面提出了相关建议,对今后的弹道一致性检验判据的完善和改进有一定的参考价值.

弹道修正中弹道诸元探测时间间隔的确定

弹道修正技术是减小弹道散布的一种新措施 .修正过程中首先要采用某种测试手段在飞行弹道上逐点进行诸元测量 .测点过密信息处理量大 ,测点过疏又引入较大误差 .为确定合理的测点密度进行了计算分析 ,并给出了确定最大测点间隔的界限判据 。

单翼末敏弹扫描运动研究

稳态扫描技术是末敏弹系统研制过程中的关键技术之一。本文在分析末敏弹现有稳态扫描技术优缺点的基础上提出了一种新的技术 ,即用端部配重的单侧翼 ,也即用人为的子弹质量和空气动力的强非对称实现稳态扫描。分析了此种末敏弹系统的受力情况 ,建立了系统的二体运动模型 ,并详细讨论了此模型中约束力及约束力矩的消元化简方法 ,推导出了适于上机编程的标准形式的方程组 ,并用其编制了诸元计算程序。程序算例表明这种结构可以实现稳态扫描并用作稳态扫描装置 。

末敏弹减速运动和稳态扫描段运动特性的研究

对末敏弹这一全新反坦克武器在减速运动和稳态扫描段的运动特性进行了仔细的研究。恰当地引入了降落伞的附加质量和附加惯性矩，完整地分析了伞体和弹体所受的外力和外力矩，建立了由伞体和弹体组成的末敏弹系统二体运动模型。编制了完整的计算程序。给出了末敏弹扫描角速度、扫描角和扫描曲线随时间的变化，以及扫描覆盖区随高度的变化。计算结果与试验结果有很好的一致性。该模型可进一步用于末敏弹系统的弹道修正、参数优化和弹道模拟。