我国空间站安全与任务保证工作若干问题探讨

从我国空间站运营阶段对安全性、可靠性、维修性及质量保证(SRMQA)工作的需求出发,在系统分析国外载人航天安全与任务保证(SMA)工作体系的基础上,总结国际空间站安全性可靠性工作的先进经验,并针对我国空间站对航天员安全、寿命与可靠性要求更高的需求,从管理和技术应用两个方面,系统论述了我国空间站安全与任务保证应重点开展的安全性、寿命与可靠性等工作。     

大型客机电传飞控系统余度配置研究

大型客机电传飞控系统采用余度配置是提高飞机安全性与任务可靠性的重要方法之一。大型客机通过余度配置降低系统部件发生故障后对飞行性能和整个系统飞机安全性的影响,从而提高了飞控系统的安全可靠性。本文通过对波音和空客飞机电传飞控系统余度配置等主要设计环节的对比分析,阐述了大型客机电传飞控系统在余度设计与配置方面的关键技术点和方法,为大型客机电传飞控系统的余度设计提供技术支持。     

长航时无人机飞行器管理计算机设计研究

高高空长航时无人驾驶飞机对其任务可靠性和安全性提出了极高的要求,而飞行器管理计算机是保证飞机安全和任务执行的核心部件.飞行器管理计算机采用合适的冗余配置可以有效地提高可靠性和安全性.探讨了一种基于三模冗余(TMR)结构的相似余度容错计算机,描述了计算机的硬件组成以及为满足可靠性要求所采取的任务调度和余度管理算法.在计算机综合化小型化以及调试测试方法方面所进行的创新使计算机具有良好的测试性和维修性并能够适应未来航空电子发展的需求.     

伊尔型飞机的飞行可靠性与安全性保证系统简介

伊尔─８６是首次采用了可靠性、安全性和维修工艺性定量指标的伊尔型飞机。系统的综合可靠性工程贯穿于伊尔飞机的设计、生产和使用各个阶段。在设计伊尔─８６飞机时，通过制定并实施《飞机设计、制造和使用各阶段可靠性保证、检测和验证制度》及《设计、批生产和使用阶段可靠性、安全性和维修工艺性保证综合大纲》来实现系统的综合解决办法。与这种飞机的其他机型比较，伊尔─８６飞机可靠性有了很大提高。     

测控中心实时应用软件系统采用线程机制的探讨

为了提高测控系统中心计算机应用软件在实时任务中的安全性和可靠性,实现在不同操作系统下的应用软件移植,以开发出在异型操作系统下的实时应用软件。主要分析了中心机实时应用程序采用线程机制的优势,讨论了几种线程间通信方式,并简要介绍了应用软件设计思想。     

空间站高压锂电采集电路的安全性设计与应用研究

由于空间站有锂离子蓄电池组在轨更换的需求,为保障航天员在进行电池更换操作时的人身安全,电池组内设计有分断开关,但分断开关的动作会引起浪涌电流及反向过电压,影响基于AD7280芯片的锂电采集电路及下位机系统的安全。研究了在分断开关工况下浪涌电流及反向过电压的产生原理,提出了一种基于AD7280芯片的锂电采集电路的优化设计方案,通过采取反压隔离、浪涌抑制及高低压隔离等保护措施以进一步提高系统的安全性和可靠性,并通过Cadence仿真及试验进行验证,结果表明该设计方案安全、可靠、满足系统要求。     

飞机滚转运动的控制余度与重构效能

论证了独立操纵的左右平尾使飞机滚动运动具有较大的控制余度,它增加了飞机正常飞行时的滚转力矩,在飞行中副翼出故障时可进行补偿重构,从而提高了滚动通道的余度等级和飞行的安全性,为减少滚转通道的余度配置提供了依据,通过针对操纵面失效和卡死两类故障的重构设计和仿真也证实了上述结论,同时,初步比较说明了自修复飞控系统在上述故障下的任务可靠性和基本可靠性均高于传统控制系统。     

基于SCA的综合通信导航识别系统任务可靠性研究

针对传统任务可靠性模型不能适应基于SCA架构的综合通信导航识别系统(SCA-ICNI系统)多任务通道任务可靠性分析的问题,本文首先研究了多任务通道模块的任务可靠性,简化了其可靠性模型,在此基础上,建立了一种以任务通道为基本单位的系统任务可靠性框图和数学模型,并对影响其任务可靠性的关键因素进行分析。其后,分析了在系统任务独立运行、优先级以及故障条件下的任务可靠性。最后以具体数据分析了典型波形任务在不同条件下系统的任务可靠性,比传统的CNI系统的任务可靠性有显著提升。     

飞机通信寻址与报告系统消息安全研究及仿真

ACARS消息安全( AMS)以一种独立于底层通信机制的应用方式,通过安全机制及支持该机制的加密算法,提供数据机密性、消息认证和完整性的安全服务。介绍了AMS消息结构和处理过程,建议采用一种综合对称和非对称加密系统优势的航空通信方案,分析了安全会话过程,仿真试验证明, AMS在面对安全威胁时能保证ACARS消息的安全传输。     

一种基于条件概率的飞机安全性分析模型

飞机的安全性不等同于飞机的可靠性,除与可靠性相关外,它还与安全监控系统、事故反应时间等相关.在分析飞机安全性与可靠性关系的基础上,从条件概率的角度,建立了一种新的飞机安全性分析模型.最后通过案例分析表明,建立的模型是有效的.     

用于量子保密通信系统的偏振控制算法研究

量子保密通信是近年来逐渐发展成熟的一种新型保密通信机制,其安全性建立在量子力学基本原理上,被证明具有信息论条件下的绝对安全性。偏振编码光纤量子保密通信系统使用光子的偏振态进行信息编码。当环境变化时,光纤传输特性的改变将导致光子偏振态变化。因此,光子偏振态的补偿控制是光纤量子保密通信系统的一项关键技术,能否快速、准确的对偏振态进行补偿将直接影响系统的通信性能。本文提出一种基于光纤偏振控制器和扫描控制算法的偏振补偿方案。该方案通过控制光纤偏振控制器的电压大小,将量子误码率最小化,实现偏振光的补偿控制,满足量子通信系统自动控制的要求。     

航天飞机系统两体分离问题的探讨

本文简要地叙述了美国研究轨道器与外挂贮油箱,轨道器与载机分离问题的概况。对垂直起飞两级入轨的并联两机的分离问题,提出了研究模型并作了具体分析,着重提出了实现两机安全分离需要解决的技术难点。 二级航天飞机的两机分离问题,是未来航天高技术领域的关键技术之一,本文阐述了解决两体并联分离问题我国现有的技术水平,并提出了解决该问题的技术方案。     

Access control system with hand geometry verification and smartcards

An access control system that joins the uniqueness of biometric verification, as well as the storage security and processing capabilities of smart cards, is defined here. The biometric technique chosen has been hand geometry, which is considered to provide low/medium security (there are other much more secure, as fingerprint, iris or retina), to be easy to use, to achieve high acceptance by users, and which performance is given throughout fast processing and medium cost. Also, the small template size needed for each user is positive for storage and processing capabilities required in the system. But the innovation in the system proposed is that the smart card not only stores the user's template, but also performs the verification process with the features set by the terminal to the card. With this improvement, the security of the system has risen because the template is never extracted from the card, avoiding duplication of such sensible data. The specifications for the enrolment process will be presented as well as the applications where this new system is recommended     

面向安全的内存管理子系统研究

以开发具有自主知识产权的军用安全OS为背景,基于最新版本Linux内核,分析并设计安全内存管理子系统.依据可信计算机系统评估标准,将安全OS的功能需求依次映射到内存管理子系统,初步提出安全内存管理子系统的四个功能:进程隔离、防止内存信息泄露、内存访问控制,虚拟内存保护;在分析Linux内存管理机制的基础上,采用安全增强法,从安全相关和硬件相关出发分解核心程序,提出安全增强型内存管理子系统的设计方案,并对各部分进行了分析和实现.     

Digital Text Watermarking: Secure Content Delivery and Data Hiding in Digital Documents

Secure communication of data over public channels is one of the most important challenges. Both the activities to secure contents and to break security are very hot. In order to reduce the chances of attack, security needs to be made invisible. The needs to preserve originality, ownership information, and integrity of text documents in a way that cannot be identified by everyone is being felt badly. Watermarking of the documents is a step toward achieving these objectives. However, to watermark a plain text document (ASCII) in a way that the original text will not change (and it would be very difficult to break it), is a great challenge. We have developed a novel encoding scheme which can be used to insert information in plain text without changing the text. A system has been developed based upon this encoding scheme. This paper describes the system and demonstrates its workings     

An attack-immune trusted architecture for supervisory aircraft hardware

With the wide application of electronic hardware in aircraft such as air-to-ground communication, satellite communication, positioning system and so on, aircraft hardware is facing great secure pressure. Focusing on the secure problem of aircraft hardware, this paper proposes a supervisory control architecture based on secure System-on-a-Chip (SoC) system. The proposed architecture is attack-immune and trustworthy, which can support trusted escrow application and Dynamic Integrity Measurement (DIM) without interference. This architecture is characterized by a Trusted Monitoring System (TMS) hardware isolated from the Main Processor System (MPS), a secure access channel from TMS to the running memory of the MPS, and the channel is unidirectional. Based on this architecture, the DIM program running on TMS is used to measure and call the Lightweight Measurement Agent (LMA) program running on MPS. By this method, the Operating System (OS) kernel, key software and data of the MPS can be dynamically measured without disturbance, which makes it difficult for adversaries to attack through software. Besides, this architecture has been fully verified on FPGA prototype system. Compared with the existing systems, our architecture achieves higher security and is more efficient on DIM, which can fully supervise the running of application and aircraft hardware OS.     

Is information security an oxymoron?

Although weaknesses have been demonstrated in some security techniques (encryption, protocols, mobile code such as Java, etc.), current security technology is quite strong in many areas. Despite this, information security has proved difficult to achieve in large modern software systems. Many problems have been reported in which supposedly secure systems have been penetrated and, in some cases, significant damage done. One problem considered is a buffer-overrun attack. The idea called a 〈wrapper〉 which is a layer of software that logically surrounds a software artifact and enhances the functionality of the artifact in some way, is then discussed. Most proposals for the use of wrappers assume that their presence is transparent to the artifact being wrapped. In other words, the artifact sees its operating environment as unchanged and the artifact does not have to be modified in i order to permit it to be wrapped. Wrappers have been proposed as an approach to dealing with deficiencies in existing systems, deficiencies in security for example. The use of shells as a feasible solution to the problem of security is also considered     

Multiple target detection using modified high order correlations

This work is concerned with the problem of multiple target track detection in heavy clutter. Using the “modified high order correlation” (HOC) process and a track scoring mechanism a new method is developed to perform data association and track identification in the presence of heavy clutter. Using this new scheme any number of very close, crossing or splitting target tracks can be resolved without increasing the computational complexity of the algorithm. The applicability of the method for continuous detection of target tracks that can originate and terminate at any scan is also demonstrated, In addition, the operating characteristics as a function of the clutter density are also provided. Simulation results on all the cases are presented     

Simulative technology for auxiliary fuel tank separation in a wind tunnel

In this paper,we propose a simulative experimental system in wind tunnel conditions for the separation of auxiliary fuel tanks from an aircraft.The experimental system consists of a simulative release mechanism,a scaled model and a pose measuring system.A new release mechanism was designed to ensure stability of the separation.Scaled models of the auxiliary fuel tank were designed and their moment of inertia was adjusted by installing counterweights inside the model.Pose parameters of the scaled model were measured and calculated by a binocular vision system.Additionally,in order to achieve high brightness and high signal-to-noise ratio of the images in the dark enclosed wind tunnel,a new high-speed image acquisition method based on miniature self-emitting units was presented.Accuracy of the pose measurement system and repeatability of the separation mechanism were verified in the laboratory.Results show that the position precision of the pose measurement system can reach 0.1 mm,the precision of the pitch and yaw angles is less than 0.1° and that of the roll angle can be up to 0.3°.Besides,repeatability errors of models' velocity and angular velocity controlled by the release mechanism remain small,satisfying the measurement requirements.Finally,experiments for the separation of auxiliary fuel tanks were conducted in the laboratory.     

飞机性能参数预测的不确定性处理

 利用飞机的性能参数对飞机进行故障预报和状态监控是非常重要的。飞机的性能参数不仅具有非线性而且往往包含噪声,使得故障预测结果具有不确定性。针对这些问题,研究了利用非线性支持向量机处理飞机性能参数的预测问题,通过增加线性约束的方式解决了噪声带来的不确定性问题。此种方法不仅提高了预测的精度,而且模型可以利用适用于处理大规模二次规划的序列最小最优化算法进行求解,使得其可以解决大数据量的预测问题。利用仿真数据以及实际飞机性能参数对该方法进行了实验分析,实验结果表明此方法在精度上较不考虑噪声影响的模型有所提高,对于进一步提高飞机故障预测的精度,从而提高飞机的安全性具有重要意义。