基于周期LFM本振的同步Nyquist折叠接收机 多分量信号参数估计算法

 Nyquist折叠接收机(NYFR)为一种新型侦察接收机结构,可利用单/双片模数转换器(ADC)同时完成多Nyquist区域内的宽频段信号采集。本文对NYFR结构进行了改进,提出了多分量信号的参数估计算法。首先,引入了同步结构,对NYFR进行了改进,得到了同步NYFR(SNYFR);其次,以本振为周期性线性调频(LFM)为例,分析了多分量信号的输出结果;然后,提出了去斜函数(DF)以用于检测信号的Nyquist区域;最终,根据区域信息完成了信号的各参数估计。计算量分析与仿真表明,所提算法计算量小且在信噪比(SNR)优于-9 dB时性能已接近克拉美-罗(CRLB)下限。     

基于UIO的航空发动机执行机构故障诊断

为了提高航空发动机诊断过程中对噪声干扰和模型参数变化的鲁棒性,应用UIO(Unknown Input Ob-server)理论估计发动机动态系统的工作状态,通过干扰正交投影弱化外界干扰对状态估计的影响,处理了航空发动机执行机构的故障诊断问题。对航空发动机执行机构设计一组UIO观测器,其中每个UIO用于监测估计对应执行机构的故障偏移量,计算系统输出理论估计值与发动机实际测量信号间的残差数据,分析残差队列的幅值特性,实现航空发动机执行机构系统的故障检测和隔离。某型涡扇发动机上的实验结果表明,与Kalman滤波算法相比,UIO诊断方法更能鲁棒地检测和隔离出执行机构故障。     

航天器电子设备焊点质量检测技术研究

航天器电子设备焊点质量靠人工目测和民用全自动光学检测（AOI）系统很难满足未来航天电子产品焊点质量检测的需求。为此,文章提出了航天器电子设备焊点质量检测的新方法,通过三维显微镜与CCD相机提取焊点的图像特征,并与焊点质量评价准则相对应,用计算机自动识别技术进行焊点质量的判别。在此基础上,对焊点质量检测平台的总体方案进行了设计。通过焊点检测技术的研究,采用三维显微镜及CCD成像技术,可以获得焊点多角度、高清晰的图像,在提取焊点特征信息的同时,还可获取印制板信息,可以确保全焊点检测,能够满足航天电子产品的焊点质量判别标准,有效提高航天电子产品的质量控制水平。设计的焊点质量检测平台定位精度小于10μm,可以检测的最大印制板尺寸为450mm×450mm。     

基于RGPO的编队ECAVs协同航迹欺骗

基于动力学模型分析了多机协同控制下的航迹欺骗技术,利用配备有电子欺骗技术的电子战飞行器(ECAVs, Electronic Combat Air Vehicles),对敌方的防空系统中的雷达网实施电子攻击行动来达到欺骗干扰效果.对搭载距离拖引干扰(RGPO, Range Gate Pull-Off)技术的ECAVs在防空雷达网中的作战运用及协同策略进行了研究,空间模型包括单架ECAV对单部雷达以及多架ECAV对雷达组网两种情形.基于ECAV、雷达和虚假航迹点三者共线关系,削减搜索空间,解决动力约束下ECAVs轨迹规划约束最优化难题,算法高效快捷,可实时完成ECAVs轨迹规划.      

舰载雷达主动反电子侦察技术

目前舰载雷达主要采用捷变频、复杂重频、宽带高增益脉冲压缩、低副瓣天线以及发射功率管控等低截获概率设计技术来提高其反电子侦察和抗干扰能力,属于“防御性”的反电子侦察技术。从电子侦察系统的特点及存在的弱点出发,提出对其进行干扰的可能性,采取主动反电子侦察的方法来掩护己方舰载雷达工作,提高舰载雷达的电子对抗能力。     

Sequential ensemble optimization based on general surrogate model prediction variance and its application on engine acceleration schedule design

The Efficient Global Optimization (EGO) algorithm has been widely used in the numerical design optimization of engineering systems. However, the need for an uncertainty estimator limits the selection of a surrogate model. In this paper, a Sequential Ensemble Optimization (SEO) algorithm based on the ensemble model is proposed. In the proposed algorithm, there is no limitation on the selection of an individual surrogate model. Specifically, the SEO is built based on the EGO by extending the EGO algorithm so that it can be used in combination with the ensemble model. Also, a new uncertainty estimator for any surrogate model named the General Uncertainty Estimator (GUE) is proposed. The performance of the proposed SEO algorithm is verified by the simulations using ten well-known mathematical functions with varying dimensions. The results show that the proposed SEO algorithm performs better than the traditional EGO algorithm in terms of both the final optimization results and the convergence rate. Further, the proposed algorithm is applied to the global optimization control for turbo-fan engine acceleration schedule design.     

Recent advances in precision measurement & pointing control of spacecraft

There exists an increasing need for precision measurement & pointing control and extreme motion stability for current and future space systems, e.g., Ultra-Performance Spacecraft (UPS). Some notable technologies of realizing Ultra-Pointing (UP) ability have been developed particularly for Ultra-accuracy Ultra-stability Ultra-agility (3U) spacecraft over recent decades. Usually, Multilevel Compound Pointing Control Techniques (MCPCTs) are deployed in aerospace engineering, especially in astronomical observation satellites and Earth observation satellites. Modern controllers and/or algorithms, which are a key factor of MCPCTs for 3U spacecraft, especially the jitter phenomena that commonly exist in a UPS Pointing Control System (PCS), have also been effectively used in some UP spacecraft for a number of years. Micro-vibration suppression approaches, however, are often proposed to deal with low-level mechanical vibration or disturbance in the microgravity environment that is common for UPS. This latter approach potentially is one of the most practical UP techniques for 3U tasks. Some emerging advanced Disturbance-Free Payload (DFP) satellites that exploit the benefits of non-contact actuators have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of UP technologies and/or methods which have been developed, mainly over the last decade, specifically for or potentially could be used for 3U spacecraft pointing control. The problems discussed in this paper are of reference significance to UPS and millisecond optical sensors, which are involved in Gaofeng Project, deep space exploration, manned space flight, and gravitational wave detection.     

星载电子器件用空气射流散热特性

在前期设计卫星大功率电子设备地面测试用通风散热系统的基础上,对系统散热性能进行了优化设计,对不同结构参数下电子器件的空气射流强化散热开展了数值仿真.研究结果表明系统中喷嘴出口直径、喷嘴出口至换热面距离、射流倾斜角以及喷嘴出口风速等参数对散热性能均有直接影响,并给出了定量的无量纲参数优化设计结果.该结论也可应用于表面热流密度为1 kW/m2级电子器件散热的优化设计,并为星载大功率电子设备对流式热控系统设计和地面测试提供技术参考.      

涡轮动力装置闭环仿真试验器的设计与应用

针对涡轮动力装置电子控制器的控制逻辑检测和调试问题,本文提出了一种采用电子仿真试验器替代真实涡轮动力装置的方法。将电子仿真试验器与电子控制器构成闭环控制同路,从而实现对涡轮动力装置闭环运行过程的模拟。仿真试验表明,利用该电子闭环仿真试验器能较好地模拟涡轮动力装置系统的实际工况,为涡轮动力装置电子控制器的调试和检测提供了‘种简便、有效的途径,且能显著降低试验成本和危险性。     

中国商用飞机有限责任公司总经理助理 马恒儒先生访谈

2009年11月,中国商用飞机有限责任公司总经理助理马恒儒先生接受了本刊编辑部主任李华文的专访。在访谈中,马先生介绍了中国C919大型客机的研制和发展情况,分析了中国研制的客机用上中国研制的发动机的发展契机;阐述了中国商用飞机有限责任公司拟与中航商用发动机有限公司采取的合作方式,认为中国的航空发动机设计与制造机构其几十年不变的工作模式应当进行适当变革。