Models have been a hot topic for many years. Still, people are paying unprecedented attention to them because digital engineering (DE), which uses models as the “blood,” has become a symbol of the Fourth Industrial Revolution. Space and national defense have already become the pillar fields of technological innovation today. As the two major forces in the space field of the United States, NASA (the National Aeronautics and Space Administration) and USSF (the United States Space Force) have a strong interest in DE with models as the “blood,” and actively seek coordinated development under the digital engineering ecosystem (DEE). This paper focuses on summarizing the practices of NASA and USSF in the field of DE, refining the key points and methods of DE construction in terms of core ideas, fundamental base, cultural base, etc., and forming relevant enlightenment and thinking, to provide a reference for China to carry out the work-related DE.

In recent years, military equipment has been developing towards digitization, networking, and intelligence. Software, as a core component of equipment, and network systems, as the survival environment of software, their security and stability are crucial, which are related to whether equipment can fully exert combat effectiveness and operate in an orderly and stable manner. This article proposes a new intrusion graph model generation method based on the current status of equipment development. This model can make risk analysis in network systems more accurate and has important significance in reducing network security risks. At the same time, it also reduces the protection cost of network systems and provides support for equipment network security protection.

Contour tracking accuracy is the key performance index of a multi-axis motion control system. In the previous design of the contour error feedback controller, the independent design idea of the tracking controller and contour controller of each logic axis is often adopted, which is not easy to realize the optimal control of tracking accuracy and contour accuracy. The coupling increment of each controller is inevitable in motion control compensation, which impacts the control system’s stability. Here, we propose a predictive control method for contour error. At first, through the state space model of the feed system, the system dynamics are judged to predict the contour accuracy in the future finite time domain. Besides, the linear quadratic performance index function of contour error is established, and the performance of the control objective is continuously optimized during the limited time domain with the form of rolling optimization. A closed-loop solution is obtained, which is most suitable for the current motion situation and could add to the system to realize the optimal control considering the trajectory contour and the tracking stability of each servo axis in the subsequent few sampling cycles. Finally, utilizing comparative experiments on the three-axis motion control platform, it is verified that the proposed contour predictive control strategy not only effectively reduces the tracking error but also significantly improves the contour accuracy, which is suitable for application in a complex industrial environment.

随着航天产品逐步规模化研制与生产,如何保证航天产品发挥出应有的功能成为一个重大难题.解决这个难题除了抓好研制过程的质量工作外,试验鉴定也是一个重要方法与手段. 航天产品试验鉴定的目的是确定航天产品在最接近真实条件下的能力与适用性,对航天产品是否满足可接受的最低性能要求做出可靠判断,利用试验发现装备的问题缺陷、定位产品研发的最终价值.

中国航天科技集团有限公司装备任务正经历由试验向应用、科研向装备、系统向体系转型,航天型号科研生产模式面临着迫切的转型需求.传统的航天科研生产模式是以"型号任务牵引"的生产模式,造成了航天产品尤其是单机产品存在通用产品品种规格多,技术状态固化弱,质量稳定性、一致性差,型谱化和通用性不足、型号重复研制,批量保证能力薄弱、成本和研制生产周期受限等诸多问题.为了解决上述问题,适应航天装备多型号并举、研制批生产并重、高密度发射新形势的需要,笔者提出航天型谱建设新工作模式.

针对商业货架(COTS)产品在LEO(低地球轨道)卫星上的应用频率越来越高、应用范围越来越广泛的现实情况,简要剖析了航天COTS产品标准化的内涵与外延,介绍了航天COTS产品标准化的实施进展,探索提出了适用于航天COTS产品标准化发展的几点措施与建议,为我国LEO卫星星座建设部署提供一定的参考借鉴.

美国全球定位系统（GPS）历经多年的发展建设,目前已在全球得到了广泛应用,对人类社会产生了变革性的影响。GPS系统由空间段、运行控制段和用户段三部分组成,目前处于全面运行时期,其中运行控制段起到了重要作用,本文将对GPS系统运行控制段的发展与现状进行阐述,为我国“北斗”三号系统的运行管理提供参考。

随着航天装备更新换代的速度越来越快,能够显著压缩研发时间与成本的商用货架产品(COTS)在航天装备中的使用率大幅提高,因此如何对COTS开展试验鉴定以保证航天装备的性能和可靠性成为必须考虑的问题.文章从横向范围、纵向深度及存在问题3个维度全面立体地对美军航天装备COTS试验鉴定工作进行阐述分析,在此基础上提出适用于我国开展航天货架产品试验鉴定工作的建议.

1 美国天军所面临的挑战 美国天军作战部长约翰·雷蒙德表示,天军的成立就是要避免美国天基设施面临的威胁变得日益严重.为实现这一目标,天军必须寻求提升美国部队作战效能的切入点.美国陆军、海军、空军和海军陆战队都能够在联合部队指挥官的领导下,保障联合部队作战效能的同时,直接使用火力打击威胁美国国家安全的目标.如果天军仅限于扮演"扶持角色",则可能难以充分证明其价值所在.所以,针对天军发展所面临的关键挑战进行评估显得至关重要.对此,兰德公司主要从以下三方面进行分析.

介绍了信息化条件下航天装备一体化联合试验的研究背景,从试验环境、试验技术、试验方法等角度分析了美军一体化联合试验的主要做法,研究了美军一体化联合试验质量管理的相关做法,分析了一体化联合试验的质量管理趋势,给出了航天装备联合试验发展建议.

研发一项新型航天装备对各国来说都不是一件容易的事.事实上,航天工程是当今最为典型的复杂大系统工程,具有规模庞大、系统复杂、技术密集、综合性强等特点.美军航天装备试验鉴定体系源于基础的系统工程,其包括了对硬件和软件的建模与仿真、试验与分析、飞行与作战的测试评价.试验鉴定工作从笼统意义上可分为2个部分,即 "试验"是指对硬件和软件测试中的可量化和可测量数据的实际采集,"鉴定" 是指对测量和处理的数据信息进行分析和评定.

众所周知,航天工作的典型特点是覆盖范围大,应用种类广.产品化作为航天工作中的一环,对于构建种类齐全、结构合理、性能先进的通用航天产品体系有着重要作用,航天产品化已在军工院所中逐步走向成熟.但是,目前市场规模迅猛增长的商业航天公司还尚未形成普遍的航天产品化做法,甚至尚无产品化意识. 鉴于商业航天业务发展特点和小卫星研制成本低、研发周期短的独特优势,商业航天公司所研制的卫星较多为质量低于500kg的小卫星.可以预见的是,航天产品化工作对航天装备研产模式转型升级、质量状态准确把控具有积极的推动作用,商用小卫星亟需开展相关产品化工作.