飞机在有源干扰保护下的探测概率研究

研究了飞机与雷达探测系统遭遇时，雷达对飞机的探测概率随距离的变化问题，采用X^2类目标波动模型，针对飞机在有源干扰保护的情况对探测概率随距离的变化进行了研究，对不同RCS对探测概率的影响问题进行了分析，研究结果可为飞机的雷达探测敏感性评估，飞机生存力的定量化分析与权衡，以及雷达探测系统的效能评估提供量化依据。     

基于动态RCS的隐身飞机探测概率研究

动态RCS是影响战斗机突防概率的重要因素。围绕动态RCS这一关键要素,建立了空空动态RCS求解模型,得到了典型机动下战斗机的动态RCS变化规律,并分析了基于动态RCS的典型机动下的雷达探测概率。基于仿真的静态RCS数据库,耦合飞机抖动模型,研究了拉升机动、空间机动以及空空对抗下某型隐身飞机的动态RCS。通过仿真发现:战斗机的机腹、垂尾及尾喷管部位RCS较大,从而导致了较高的探测概率;对于拉升机动,保持较大的航路捷径更有利于隐蔽突防。     

从探测概率的角度评价飞机的隐身性能

采用雷达散射截面(RCS)均值来衡量飞机的隐身性能并不能给出足够充分的信息,从信号检测概率的角度来衡量飞机的可探测性可以提供更完整的信息。本文从探测概率的角度详细分析了4种典型隐身飞机RCS起伏数据与虚警概率、探测概率、探测距离、信噪比(SNR)等参数间的关系,并给出了完整的推导过程,采用此方法可以对任意飞机目标在给定雷达参数下的可探测性进行准确计算。一般在雷达性能评估中需要用到RCS起伏模型,本文对飞机目标回波信号进行检测分析时采用数值计算方法,信号的概率密度函数(PDF)直接来源于原始回波起伏信号,避免了模型拟合带来的回波特性失真,且不会产生大的计算误差。通过对比分析计算结果发现:单脉冲检测下回波信号均值中值比越大,回波取值范围越小,则信号的检测概率越小,其中均值中值比一般相差3倍以上时可以得到明显不同的检测概率;在快起伏假设下,非相参积累检测的积累脉冲数Nin即便较小,也能得到较大的信噪比增益,此增益可能大于Nin。     

不同机载电子干扰条件下的飞机敏感性模型

对典型作战场景中雷达制导导弹威胁下的飞机敏感性进行了研究,分别从导弹发射和命中2个方面,建立了远距离支援干扰(SOJ)和自卫干扰(SPJ)条件下的飞机敏感性模型。首先分析了在典型电子对抗措施(ECM)和电子抗干扰措施(ECCM)条件下的雷达探测距离;其次提出了用于评价欺骗干扰的有效时间模型,结合典型制导律,建立了不同干扰条件下导弹命中分析的仿真模型;最后对不同干扰条件下的飞机敏感性进行了仿真实验。结果表明:电子干扰一定程度上能够降低非隐身战机的敏感性,但是对于低雷达散射截面(RCS)或者采用先进抗干扰措施的武器系统而言,电子干扰对飞机敏感性降低的作用有限甚至有害。研究结果对现役飞机通过电子干扰降低敏感性以及对在研飞机的敏感性设计具有一定的参考意义。     

飞行器雷达隐身性能评估研究

考虑飞行器与雷达的对抗环境和相对位置关系,通过建立雷达的探测模型以及飞行器的雷达散射特性模型,初步构建了飞行器雷达隐身性能评估系统。该系统可以有效地计算RCS的不同而引起的发现概率及暴露距离的变化,从而可以定量地比较隐身性能的变化;还可以根据暴露距离或预警时间的要求,制定出满足该要求的RCS指标的取值,从而指导隐身飞机RCS指标的确定。对算例的计算分析表明,该系统的计算结果可信,具有一定的实用价值。     

二对一超视距空战仿真及效能分析

建立了一种战斗机超视距空战的作战方法,构建了雷达、导弹和战斗机的功能模型,以及空战各阶段的作战流程。以战斗机损失比来分析结果,采用2k因子法设计和统计了战斗机隐身性能、导弹射程、战斗机数量、信息共享等因素的影响。当战斗机的RCS较低,使得敌方雷达探测距离显著降低,导弹的发射距离显著低于其射程时,导弹射程将无法充分发挥作用,其对空战结果的影响将小于RCS;战斗机之间有信息共享相对于无信息共享情况,红/蓝损失比平均提高61%;信息共享可以增加空战优势,提高己方战斗机群的打击效率。     

针对雷达LPI波形验证的目标RCS估算

根据某型雷达低截获概率波形设计的需要,分析了雷达探测目标的高频散射机理,并运用物理光学法、等效电磁流法计算了约定目标在不同姿态下和不同电磁波频率照射下的RCS值,从而为验证雷达波形在能探测到目标情况下的LPI性能提供了支撑。实验结果表明,基于电磁场理论的目标RCS估算方法是研究雷达LPI波形的一种有效工具,方法也适合于其他领域RCS估算的需要。     

F-22飞机隐身技术分析

介绍了当前飞机的雷达波隐身和红外隐身技术，分别从低RCS外形设计特点、低RCS材料技术的应用、红外辐射技术的应用以及电子对抗技术的应用等方面，对F-22飞机的隐身技术作了简要分析。     

飞机作战生存力分析方法研究进展与挑战

军用飞机在执行作战任务过程中,常常会与武器系统遭遇,如何分析其生存能力从而进行改进设计一直是航空领域的研究难点。回顾了作战生存力研究的历史与现状,从敏感性计算和易损性计算两方面总结了生存力的定量分析方法,重点综述了基本信号探测敏感性模型、雷达对抗下的敏感性模型、红外对抗下的敏感性模型,以及部件间弹道遮挡关系确定、部件毁伤测度与判据、重叠及高维空间易损性计算、薄弱部位确定方法等方面取得的新进展。在此基础上,针对未来体系对抗与先进武器环境,提出了生存力研究需要关注和解决的问题,包括网络与信息战下的敏感性分析、敏感性对抗装置的效益代价与权衡设计、部件易损性毁伤机理与判据、先进武器及多因素耦合下的易损性分析以及大数据背景下的性能降级易损性研究等。     

基于典型任务的突防飞机概念阶段雷达隐身指标论证方法

主要研究基于对地突防任务的飞机雷达隐身指标的论证方法。通过对典型对抗态势的分析,提出成功突防的判定依据,同时,开展雷达威胁探测模型的建模和飞机雷达隐身参数表征方法的研究,并重点针对雷达连续跟踪和武器拦截飞机过程开展理论建模、仿真计算和迭代评估,最终提出较为系统的基于典型突防对抗的飞机雷达隐身指标论证方法。     

Influence of stealth aircraft dynamic RCS peak on radar detection probability

For modern stealth aircraft, it is important to analyze the influence of Radar Cross Section (RCS) peak exposure on penetration for guiding stealth design and penetration trajectory planning, which needs to reflect the RCS statistical uncertainty and the RCS difference with the change of incident angle. Based on the RCS characteristics of typical stealth aircraft, this paper established a simplified RCS dynamic fluctuation statistical model with the parameters log mean and log standard deviation. According to the detection probability algorithm in radar signal processing field, this paper built the algorithm of radar detection probability based on the RCS dynamic fluctuation statistical model. The analysis of examples concluded that the key to successful penetration is to shorten the RCS peak exposure time, which can be reduced by decreasing the RCS peak width or increasing velocity. Based on the conclusion, this paper proposed the method of turning maneuvering to reduce RCS peak exposure time dramatically.     

Numerical simulation of RCS for carrier electronic warfare airplanes

This paper studies the radar cross section(RCS) of carrier electronic warfare airplanes.Under the typical naval operations section, the mathematical model of the radar wave’s pitch angle incidence range analysis is established. Based on the CATIA software, considering dynamic deflections of duck wing leading edge flaps, flaperons, horizontal tail, and rudder, as well as aircraft with air-to-air missile, anti-radiation missile, electronic jamming pod, and other weapons, the 3D models of carrier electronic warfare airplanes Model A and Model B with weapons were established. Based on the physical optics method and the equivalent electromagnetic flow method, by the use of the RCSAnsys software, the characteristics of carrier electronic warfare airplanes’ RCS under steady and dynamic flights were simulated under the UHF, X, and S radar bands. This paper researches the detection probability of aircraft by radars under the condition of electronic warfare, and completes the mathematical statistical analysis of the simulation results. The results show that: The Model A of carrier electronic warfare airplane is better than Model B on stealth performance and on discover probability by radar detection effectively.     

关于低RCS目标外形优化中目标函数的确定

在分析了低RCS目标外形优化中现有的两种目标函数的局限性的基础上,根据雷达检测概率与目标RCS分布之间的关系,提出了一种新的目标函数,即目标在威胁区域内其RCS大于规定的临界RCS的概率。算例表明本文所提出的目标函数比现有的目标函数更为有效,适用范围更广。为低RCS目标外形优化设计以及气动与隐身一体化设计提供了一个合理而有效的目标函数。     

Probability of Detecting Aircraft Targets

The statistics of aircraft radar cross section (RCS) are estimated by fitting members of the chi-square family of distributions to empirical distributions obtained from blocks of RCS data, each block of data corresponding to a particular aircraft azimuth aspect. The parameters of the fitted distributions vary with azimuth aspect angle, type of aircraft, and radar frequency. Detection probabilities based on the estimated statistics are calculated and compared with detection probabilities based on Rayleigh statistics. This comparison indicates that the average value of radar cross section has much more effect on probability of detection than the normalized variance of RCS, and in the usual situation tends to mask the effect of the normalized variance on probability of detection.     

放宽静稳定度飞机时间延迟稳定边界

针对飞机初步设计阶段其放宽静稳定度（RSS）与电传飞控系统时间延迟边界之间的定量关系求解问题，以战斗机纵向短周期方程为基础，分析了飞控系统中的时间延迟因素，描述了放宽静稳定度与方程参数间的关系。并以等效输入延迟的形式构建了含飞控系统时间延迟的闭环系统特征方程，通过根轨迹趋势理论和数值计算方法确定了放宽静稳定度与飞控系统时间延迟边界的定量数值关系，同时探讨了舵效与动导的参数不确定性对所求时间延迟边界的影响。本文方法对飞机初步设计阶段飞控系统时间延迟指标和可放宽静稳定度边界的确定具有一定的工程实践意义。     

A New Method for Analyzing Integrated Stealth Ability of Penetration Aircraft

Taking into account the limitations of existing stealth performance analysis methods, a method termed as the integrated stealth performance analysis method is proposed for evaluating the stealth ability of the penetration aircraft. Based on various target radar cross section (RCS) scattering characters, this article integrates the relevant parameters needed for building up target circumferential RCS scattering model and proposes the RCS scattering controlling parameters to control the changing trends of the relevant model RCS scattering characters. According to the radar dynamic detecting characters during the whole penetration course, a dynamic stealth performance evaluating model is proposed accompanied by a series of stealth ability estimation rules. This new analysis method can enhance the integrality and dependability of the stealth analysis conclusions and summarize the relationship between the target RCS scattering characters and their effects on stealth performance. The rules indicated by this relationship can be used as the reference for designing new type of stealth aircraft and setting up specific penetration tactics.     

Fast coating analysis and modeling for RCS reduction of aircraft

In order to fast analyze the aircraft Radar Cross Section(RCS) and accurately reduce it with Radar Absorbing Materials(RAM), a comprehensive analysis method based on Higher-Order Method of Moments(HOMOM), termed Locally Coating Method(LCM), is proposed in this paper. There are two steps to fast analyze coatings for RCS reduction in this method: analyze the RCS of various parts before coating the aircraft; model a coating over the aircraft and analyze the wave absorbing effect of it. The aircraft RCS is calculated as a whole but analyzed in various parts by LCM, and thus the RCS contribution of different parts can be compared without disturbing the current continuity. A model expansion algorithm is also presented in LCM to model absorption coatings on specified aircraft parts for later stage RCS calculation of the coated aircraft.     

一对一遭遇时飞机生存力-探测时间解析模型

 考虑探测事件的发生时间对开火、击中以及杀伤事件的影响,分析飞机与威胁的一对一遭遇情形,推导出飞机遭遇打击的次数的概率分布以及特定打击次数下飞机的生存概率,最后得到了一对一遭遇飞机生存力 探测时间的解析求解公式。该解析模型精确考虑了威胁与飞机遭遇的全过程,包括：探测,跟踪、开火以及重新装弹、开火等。根据该模型,不仅可以计算一对一遭遇飞机生存概率,而且可以方便地绘制生存力随平均发现时间、一次打击杀伤概率等参数变化的曲线。算例和分析结果表明该模型计算简便、合理有效。