信号失真度数字化测试算法研究

目前失真测试所采用的传统测试方法已不能适应数字技术发展的要求.本文介绍了基于LabVIEW平台和PXI总线所研究的失真度数字化测试算法,给出了失真度数字化测试的的一种解决方案.     

隐身等离子体的几个相关问题研究

在目标的雷达隐身方面,等离子体具有巨大的应用潜力。对隐身应用时产生等离子体的气压、放电气体种类以及放电方式进行了论述。指出在大气压下,适宜利用惰性气体放电来产生等离子体。而目前许多文献中所报道的隐身等离子体的产生方法离工程应用还有一定距离,还有许多问题亟待解决。     

大规模卫星星群域管控策略设计

针对大规模卫星星群单节点管控带来的系统通联性差、地面资源依赖度高等问题,提出了分层管理、域内自治、动态维护的卫星星群分布式域管控策略。首先,设计了衡量卫星节点管控能力的静态指数及动态指数,并提出了多因素加权的星群簇首选择方法。其次,提出了通过逐层择优的方式进行域结构初始化的算法流程。最后,根据星群变化情形,提出了基于事件触发的动态时间片域管控方法,保证了大规模星群在全任务周期内能维持相对稳定的管控构型。仿真结果表明,所提出的域管控策略能够有效完成对目标星群的簇首选择、域初始化及动态维护过程,并保持域结构的稳定。实现了目标星群在空间中的域结构划分管理,使地面直接参与管理的卫星节点数目降至原管理模式的14%,有效解决了星群管控严重依赖地面资源的相关问题。     

西飞国际采用CAXA数字化制造解决方案

通过CAXA管理平台的产品结构树的管理,将西飞国际数控中心的所有产品的文档以"产品-零部件-零件"的结构分别挂接在不同的节点下,西飞国际以往的图纸可以通过系统的批量导入功能直接导入到系统中.     

An improved approach to model ionospheric delays for single-frequency Precise Point Positioning

PPP with low-cost, single-frequency receivers has been receiving increasing interest in recent years because of its large amount of possible users. One crucial issue in single-frequency PPP is the mitigation of ionospheric delays which cannot be removed by combining observations on different frequencies. For this purpose, several approaches have been developed, such as, the approach using ionospheric model corrections with proper weight, the GRAPHIC (Group and Phase Ionosphere Calibration) approach, and the method to model ionospheric delays over a station with a low polynomial or stochastic process. From our investigation on the stochastic characteristics of the ionospheric delay over a station, it cannot be precisely represented by either a deterministic model in the form of a low-order polynomial or a stochastic process for each satellite, because of its strong irregular spatial and temporal variations. Therefore, a novel approach is developed accordingly in which the deterministic representation is further refined by a stochastic process for each satellite with an empirical model for its power density. Furthermore, ionospheric delay corrections from a constructed model using GNSS data are also included as pseudo-observations for a better solution. A large data set collected from about 200 IGS stations over one month in 2010 is processed with the new approach and several commonly adopted approaches for validation. The results show its significant improvements in terms of positioning accuracy and convergence time with a negligible extra processing time, which is also demonstrated by data collected with a low-cost, handheld, single-frequency receiver.     

主轴伸长量补偿在高速数控机床上的应用

文章设计并实现了高速数控机床主轴伸长量的实时补偿;分析了补偿的原理,提出了补偿的具体措施和实现方法,给出了补偿的PLC控制程序,并用一系列的试验数据证明了补偿的有效性。这种方法在实际机床应用中提高了机床的加工精度,具有广泛的推广价值。     

刀具管理系统Tool Expert

如果能通过一个数据平台,把制造相关的各种信息统一起来,数据能够无缝地进行交换,数控设备的利用率能够提高到70%～80%.     

立足客户创新发展——本刊总编辑刘柱与ESI中国公司总裁张苏先生对话

2006年法国ESI集团与ATE公司的携手,曾引起了CAE界的轰动.经过这些年的发展,ESI集团已成为样机和虚拟制造方案的先驱和世界领先企业.最近,ESI集团推出了新的公司标识和口号,这标志着ESI集团进入了公司发展历史上的又一个新阶段.近日,本刊总编辑刘柱专访了ESI中国公司总裁张苏先生,就公司的发展做了深入的交流.     

航空工业系统发展环保产业的战略目标与构想

本文针对航空工业系统贯彻“军转民”方针的形势,研究了国内外环保产业市场和航空工业的优势,为使环保机械产品作为本系统的一大支柱民品,提出发展战略目标和构想。