超光谱成像仪成像电路的设计与实现

超光谱成像仪是环境减灾-1A卫星的主载荷之一,也是我国第一台采用静态干涉型光谱成像技术的星载遥感相机。成像电路是超光谱成像仪的核心组件之一,文章介绍了超光谱成像仪成像电路的系统组成,以及各功能模块的结构、功能和设计原理。     

新型Σ-Δ多通道动态测试分析系统研究与实现

 动态测试与分析系统需要动态范围（DRN）大、信噪比（SNR）高,传统方法实现复杂且成本高。本文分析了Σ-Δ调制的动态特性,提出基于Σ-Δ ADC(模-数转换器)ADS1271,Σ-Δ DAC（数-模转换器）AIC23及浮点数字信号处理器（DSP）芯片TMS320C6713的新型高精度动态测试与分析系统,实现了多通道实时动态测试与分析,系统具有24位采集精度,8通道可级联基本模块,实时频率细化FFT（Zoom-FFT）、功率谱密度（PSD）等分析功能, 正弦、瞬态扫频、随机和冲击响应谱等信号源功能以及高速USB2.0数据传输功能。系统用于振动、冲击、噪声工程等测试与分析系统,可取代国外最新产品。     

基于稀疏阵列和码分信号的机载预警雷达STAP研究

基于稀疏阵列和码分正交信号,研究了机载雷达的空时自适应处理（STAP）技术,用于空中预警背景下的地面杂波抑制和运动目标探测。提出了稀疏阵列码分多相位中心孔径综合方法,采用正交编码信号实现多发多收,使综合后不同编码信号的相位中心在数量和分布情况上和满阵天线的相同,从而避免了稀疏阵列天线旁瓣较高的问题;在孔径综合的基础上,利用空时自适应处理方法完成杂波抑制,实现运动目标检测。仿真结果表明了本文方法的有效性。     

指数型单元混联系统可靠性综合的信息论方法

研究了一种求解具有多层指数型数据混联系统可靠性近似限的信息论方法。根据单元试验信息提供的信息量与系统折合试验应提供的信息量相等的原理,导出了单元试验信息等效折合的基本公式,给出了指数型单元混联系统可靠性综合的基本模型和方法步骤,建立了系统可靠性近似限的基本模型,并以实例形式说明了方法的具体应用。      

基于ADF4153的频率合成器设计

设计实现一种基于ADF4153的频率合成器,介绍该频率合成器的构成原理。结合测试结果对本频率合成器进行相位噪声性能分析和杂散分析,并提出相应的改善措施。利用软件仿真对环路的稳定性进行分析。测试及分析结果表明,本频率合成器相位噪声水平可达-96.59dBc@10kHz,杂散抑制大于45dBc,频率合成器环路工作稳定。     

7一种双S形进气道流场特性殛控制的试验研究

In order to provide the line of-sight blockage of the engine face for an advanced Uninhabited Combat Air Vehicle(UCAV), a highly curved serpentine inlet is proposed and experimentally studied. Based on the static pressure distribut ion measurement along the wall, the flow separation is found at the top wall of the second S duct for the baseline inlet design, which yields a high flow distortion at the exit plane. To improve the flow uniformity, a single array of vortex generators (VGs) is employed within the inlet. In this experimental study, the effects of mass flow ratio, free stream Mach number, angle of attack and yaw on the performance of a serpentine inlet instrumented with VGs are obtained. Results indicate: (1) Compared with the baseline serpentine design without flow control the application of the VGs promotes the mixing of core flow and the low momentum flow in the boundary layer and thus prevents the flow separation. Under the design condition, the exit flow distortion (

) decreases from 11. 7% to 2.3% by using the VGs. (2) With the descent of the free stream Mach number the total pressure loss decreases. How ever, the circular total pressure distortion increases. When the angle of attack rises from - 4° to 8°, the total pressure recovery and the circular total pressure distortion both go down. In addition, with the increase of yaw the total pressure recovery is fairly constant, while the circular total pressure distortion ascends gradually. (3) When Ma₀=0.6-0.8, α= −4°-8° and β= 0°-6°, the total pressure recovery varies between 0.936 and 0.961, the circular total pressure distortion coefficient varies between 1.4% and 5.4% and the synthesis distortion coefficient has a ranges from 3.8% to 7.0%. The experimental results confirm the excellent performance of the newly designed serpentine inlet incorporating VGs.     

航天发射特征事件综合和弹道融合策略优化研究与应用

特征事件综合和弹道融合是航天发射过程中最为重要的一项工作,通过特征事件发生时间和火箭飞行弹道可直观地反映出运载火箭的飞行状态。因此,为了进一步提高特征事件综合和弹道融合效果,基于遥、外测量信息,分别对参与特征事件综合和弹道融合的信息源进行分类及其影响因素进行分析,并提出了相应的信息融合策略。通过采用优化的融合策略,可进一步提高特征事件时间解算的准确性和实效性,提升弹道融合的效果,满足航天发射飞行态势显示和安全控制的任务需求。     

Nonlinear aeroelastic analysis of the folding fin with freeplay under thermal environment

The nonlinear aeroelastic behavior of a folding fin in supersonic flow is investigated in this paper. The finite element model of the fin is established and the deployable hinges are represented by three torsion springs with the freeplay nonlinearity. The aerodynamic grid point is assumed to be at the center of each aerodynamic box for simplicity. The aerodynamic governing equation is given by using the infinite plate spline method and the modified linear piston theory. An improved fixed-interface modal synthesis method, which can reduce the rigid connections at the interface, is developed to save the problem size and computation time. The uniform temperature field is applied to create the thermal environment. For the linear flutter analyses, the flutter speed increases first and then decreases with the rise of the hinge stiffness due to the change of the flutter coupling mechanism. For the nonlinear analyses, a larger freeplay angle results in a higher vibration divergent speed. Two different types of limit cycle oscillations and a multiperiodic motion are observed in the wide range of airspeed under the linear flutter boundary. The linear flutter speed shows a slight descend in the thermal environment, but the effect of the temperature on the vibration divergent speed is different under different hinge stiffnesses when there exists freeplay.     

语音合成遥控指令回报系统

本文介绍了用于无人机的语音合成回报系统,代替传统的信号盘灯光显示,向地面指挥监测人员回报遥控指令接收情况。语音合成系统由基于LPC原理制成的单片语音合成处理器TMS5220组成,用Z-80 CPU实现控制。系统结构简单,通用性强,合成语音清晰、自然可懂。     

一种四连杆机构位置综合的迭代方法

本文提出了一种四连杆机构位置综合的迭代方法,解决了一般解析法对初始点要求过高的问题。该方法对初始点要求很低,而且在计算机上也不易出现“溢出”。