A new target tracking filter based on deep learning

At present, current filters can basically solve the filtering problem in target tracking, but there are still many problems such as too many filtering variants, too many filtering forms, loosely coupled with the target motion model, and so on. To solve the above problems, we carry out crossapplication research of artificial intelligence theory and methods in the field of tracking filters. We firstly analyze the computation graphs of typical a-β and Kalman. Through analysis, it is concluded that ...     

Multiframe weak target track-before-detect based on pseudo-spectrum in mixed coordinates

Traditional multiframe Track-Before-Detect(TBD) may incur adverse integration loss resulting from model mismatch in sensor coordinates. Its suboptimal integration strategy may cause target envelope degradation. To address these issues, a pseudo-spectrum-based multiframe TBD in mixed coordinates is proposed firstly. The data search for energy integration is conducted based on an accurate model in the x-y plane while target energy is integrated based on pseudo-spectrum in sensor coordinates. The a...     

Advances in fabrication of ceramic corundum abrasives based on sol–gel process

Corundum abrasives with good chemical stability can be fabricated into various free abrasives and bonded abrasive tools that are widely used in the precision machining of various parts. However, these abrasives cannot satisfy the machining requirements of difficult-to-machine materials with high hardness, high strength, and strong wearing resistance. Although superhard abrasives can machine the above-mentioned materials, their dressing and manufacturing costs are high. By contrast, ceramic corundum abrasives fabricated by sol–gel method is a cost-effective product between conventional and superhard abrasives. Ceramic corundum abrasives exhibit self-sharpening and high toughness. In this review, the optimization methods of ceramic corundum abrasive properties are introduced from three aspects: precursor synthesis, particle shaping, and sintering. Firstly, the functional mechanism of seeds and additives on the microstructural and mechanical properties of abrasives is analyzed. Specifically, seeds can reduce the phase transition temperature and improve fracture toughness. The grain size and uniformly dense structure can be controlled by applying an appropriate amount of multicomponent additives. Then, the urgent need of engineering application and machinability of special shape ceramic corundum abrasives is reviewed, and three methods of abrasive shaping are summarized. The micromold replication technique is highly advanced and can be used to prepare functional abrasives. Additionally, the influence of a new sintering method, namely, two-step sintering technique, on the microstructural and mechanical performance of ceramic corundum abrasives is summarized. Finally, the challenge and developmental trend of the optimization of ceramic corundum abrasives are prospected.     

A Poisson multi-Bernoulli mixture filter with spawning based on Kullback–Leibler divergence minimization

In the classical form, the Poisson Multi-Bernoulli Mixture (PMBM) filter uses a PMBM density to describe target birth, surviving, and death, which does not model the appearance of spawned targets. Although such a model can handle target birth, surviving, and death well, its performance may degrade when target spawning arises. The reason for this is that the original PMBM filter treats the spawned targets as birth targets, ignoring the surviving targets’ information. In this paper, we propose a Kullback–Leibler Divergence (KLD) minimization based derivation for the PMBM prediction step, including target spawning, in which the spawned targets are modeled using a Poisson Point Process (PPP). Furthermore, to improve the computational efficiency, three approximations are used to implement the proposed algorithm, such as the Variational Multi-Bernoulli (VMB) filter, the Measurement-Oriented marginal MeMBer/Poisson (MOMB/P) filter, and the Track-Oriented marginal MeMBer/Poisson (TOMB/P) filter. Finally, simulation results demonstrate the validity of the proposed filter by using the spawning model in these three approximations.     

相控阵雷达的“P”与“A”

<正>不久前,一张新型歼11的照片出现在网络上,有人从其雷达罩的涂装分析该机可能搭载了相控阵雷达,而且很可能是AESA(主动相控阵)雷达。这令广大军迷振奋不已,因为果真如此的话,那么就意味着我国在战斗机机载雷达领域已迈入国际先进行列。但是,在机载雷达方面,有的国家直接研制AESA雷达,而有的国家则既有AESA雷达也有PESA(被动相控阵)雷达。这P与A的一字之差究竟有何分别?     

“长征三号乙”火箭成功发射“中星2A”卫星

北京时间2012年5月26日23时56分,中国在西昌卫星发射中心用＂长征三号乙＂运载火箭成功将＂中星2A＂卫星顺利送入预定轨道。＂中星2A＂卫星是中国卫星通信集团有限公司所属一颗通信广播卫星,承担＂中星2A＂卫星发射任务的＂长征三号乙＂运载火箭是由中国航天科技集团公司所属中国运载火箭技术研究院自主研制、     

“中国定制版”区域型A330

共同应对新挑战 随着中国航空业的持续快速发展，空客预计，到2031年，中国将超过美国成为全球第一大航空市场，中国国内航空运输周转量届时将占据全球总周转量的10．4％。中国民航“十二五”规划也显示，到2015年，中国民航年旅客运输量将从2010年的2．68亿人次增长到4．5亿人次，年均增长11％。届时，相当于全国人口总量1／3的航空旅客，无疑会给中国的经济社会发展带来巨大的机遇，但显然，它也意味着不小的挑战。     

Ariane 5: A “textbook” launch

The fourth Ariane 5 lifted off from Europe's Spaceport on 10 December 1999 at the beginning of a launch window announced two months earlier when the launch campaign resumed. This flawless countdown and flight kicked off the commercial career of Arianespace's new heavy-lift launcher.     

“A 320 HLF Fin” flight tests completed

On September 17, 1998, another Airbus-first happened - the first flight of an A320 aircraft with a hybrid laminar flow (HLF) fin. This report gives an overview of the programme as part of an overall European research activity on the technology with the highest fuel saving potential Laminar Flow.     

宝刀未老——F-86A“佩刀”战斗机

<正>画中这架北美F-86A(编号8178)原属美国空军,1958年退役,后于1974年恢复为可飞状态。该机目前在英国注册,并经常在当地的航展上亮相表演。     

A Magnificent Party For “The Night Of Piaget”

Piaget, the name brand for the world's top-class wrist watch and jewellery, showed itself at a magnificentparty--``the Night of Piaget'--held at Shanghai BundNo.3 on January 14. The charming night scenery along theHuangpu River, the special favour of the Bund No.3 and theglittering golden and silver colours on the spotjoined together to present visitors asparkling world of Piaget. It has been considered as the most magnificent partyheld for Piaget in the China mainland.The party was deco…     

“战鹰”创造历史——美国P-8A“海神”反潜巡逻机首次部署

"据外电报道,在印度洋里寻找马航失联的MH370航班客机的20支海空队伍中,美国海军的P-8A"海神"巡逻机似乎最有可能帮助解开这个现代航空界的谜团。""据媒体报道,美国海军调动高性能P-8A"海神"巡逻机,投入搜寻马航失联客机MH370,希望通过P-8A巡逻机长距离海面侦察与续航能力,加大搜索力度。据报道,这是美国海军在连续9天大规模搜索行动未有结果后,进行的一次调整。"在搜寻马航MH370的报道中,P-8A的身影屡屡出现,并且均是以一副被寄予厚望的"面孔"出现。这款飞机的出类拔萃之处究竟在哪里?它的驾驶者们应该是最有发言权的人。本期的封面故事就将为您奉上P-8A入役首个作战单位——美国海军VP-16海上巡逻中队的报道。     

优雅的空中“绿巨人” 走近空中客车A380飞机

<正>绿色,代表生命、健康和活力,它孕育了生命,承载着人类持续发展的希望。如今,绿色不仅仅是一种颜色,正逐渐成为一种发展理念,改变着人们的行为方式。作为目前世界上唯一采用     

“中国造”首架空客A320将于5月试飞

位于天津滨海新区空港加工区的空客天津总装公司厂房,第8架飞机开始组装。2009年4月21日,法国国民议会议长阿克耶一行参观考察了这条空客公司在欧洲之外唯一的总装线。空客(天津)总装公司总经理尚鲁国告诉记者,自     

X-47A“飞马”无人战斗机完成首次滑行试验

本次试验于7月19日在加利 福尼亚美国海车空战中心进 行。作为诺斯罗普·格鲁门 (UCAV—N) 顶目的一部 分,X-47A将用于验证适合 从航空母舰上进行自主飞行     

XH-59A“前行桨叶概念”(ABC)验证机

所谓的“前行桨叶”,指的是直升机旋翼旋转形成的“圆盘“中的桨叶移动方向与直升机移动方向相同的一侧,反之另一侧则称为“后行桨叶”。例如,直升机向前飞行时,旋翼“圆盘”右侧的桨叶为“前行桨叶”,向后飞行时“前行桨叶”在左侧,向左飞行时,在前侧,向右飞行时,在后侧。直升机向前飞行时,“前行     

Thales公司为“阵风”、A400M和“守望者”无人飞机研制航电设备

来自法国、英国、美国和欧洲的A400M空中运输机项目的合同似乎再次证明了Thales公司的“多国”防御市场策略的明智。