LARES successfully launched in orbit: Satellite and mission description

On February 13th 2012, the LARES satellite of the Italian Space Agency (ASI) was launched into orbit with the qualification flight of the new VEGA launcher of the European Space Agency (ESA). The payload was released very accurately in the nominal orbit. The name LARES means LAser RElativity Satellite and summarises the objective of the mission and some characteristics of the satellite. It is, in fact, a mission designed to test Einstein's General Relativity Theory (specifically ‘frame-dragging' and Lense-Thirring effect). The satellite is passive and covered with optical retroreflectors that send back laser pulses to the emitting ground station. This allows accurate positioning of the satellite, which is important for measuring the very small deviations from Galilei–Newton's laws. In 2008, ASI selected the prime industrial contractor for the LARES system with a heavy involvement of the universities in all phases of the programme, from the design to the construction and testing of the satellite and separation system. The data exploitation phase started immediately after the launch under a new contract between ASI and those universities. Tracking of the satellite is provided by the International Laser Ranging Service. Due to its particular design, LARES is the orbiting object with the highest known mean density in the solar system. In this paper, it is shown that this peculiarity makes it the best proof particle ever manufactured. Design aspects, mission objectives and preliminary data analysis will be also presented.     

CFDP协议中延迟NAK文件传输时间分析与仿真

未来的深空通信需要一个鲁棒的、有效与可靠的文件传输协议,在研究CCSDS提出的CFDP协议基础上,针对延迟NAK模式提出了一种新的分析方法。在保证吞吐量的前提下,对ARQ定时器优化设置,导出了平均文件传输时间的理论表达式。在单跳直连链路中,对不同条件下的平均文件传输时间进行了仿真与数值分析。仿真结果表明平均文件传输时间与PDU错误概率、PDU数目及单向传播时间等有密切关系。随机仿真与理论分析具有很好的一致性。     

REMOTE SENSING IMAGE CODING METHOD COMBINING WAVELET TRANSFORM WITH CLASSIFIED VECTOR QUANTIZATION

A new remote sensing image coding scheme based on the wavelet transform and classified vector quantization (CVQ) is proposed. The original image is first decomposed into a hierarchy of 3 layers including 10 subimages by DWT. The lowest frequency subimage is compressed by scalar quantization and ADPCM. The high frequency subimages are compressed by CVQ to utilize the similarity among different resolutions while improving the edge quality and reducing computational complexity. The experimental results show that the proposed scheme has a better performance than JPEG, and a PSNR of reconstructed image is 31～33 dB with a rate of 0.2 bpp.     

易燃毒性气体检测电路设计

从TGS813气敏传感器灵敏度特性出发，给出了采用该传感器检测易燃毒性气体，消除传感器离散性、非线性影响的检测电路设计方法。     

风速对电容式湿度传感器测量值和响应时间影响的研究

研究了风速对电容式湿度传感器最终测量值和响应时间的影响,并分析了产生影响的机理;根据测量数据拟合出了电容式湿度传感器的响应时间和风速之间的函数关系。     

基于薄膜热电堆的新型高温瞬态热流密度传感器的研制

目前针对国内薄膜瞬态热流传感器一致性较差、制备工艺不成熟等问题，提出了一种基于光刻工艺和离子束溅射镀膜工艺的制备方法，200对T型金属薄膜热电偶沉积在10mm×10mm的水冷块上，测量1μm的氧化铝热阻层温差，从而得到瞬态热流密度值。对新型高温瞬态热流密度传感器进行比对法标定，一致性误差为0.211%，即工艺的一致性约为99.79%。实验表明，研制的新型高温瞬态热流密度传感器的一致性好,制备工艺具备良好重复性和可移植性，能够满足高温瞬态热流检测需要，为热流传感器的推广应用及标准化、批量化生产提供了良好的技术支撑。     

基于MPI的卫星遥感数据实时处理平台设计

针对高速率卫星遥感数据实时处理的要求,设计了一种卫星遥感数据实时处理平台。该平台采用分层设计思想,自上而下分为表现与控制层、业务处理层、基础服务层和应用支持层。结合消息传递接口(MPI)技术,构建了分布式实时并行处理平台框架。原型系统验证结果表明,该平台能处理下传码速率达450Mbit/s的双通道数据,单通道处理速率高达6Gbit/s。文章提出的平台设计应用于遥感卫星的地面检测系统,具有处理速度快、运行稳定的优点。     

互相关函数在窄槽对中上的应用研究

不等距的窄槽载正加工是机械加工的难题之一。文中采用了电涡流传感器来采集窄槽的位置信号，利用信号边沿部分对称的特点，采用了“倒序列相关”的方法 用倒序信号与原信号进行互相关分析，充分利用了信号的全过程，滤除了信号中的随机成分，精确地求得窄槽的中心位置。试验的结果与理论研究基本相符，表明此方法具有实用价值。     

光电自准直仪现状与展望

介绍了国际和国内光电自准直仪技术发展的现状，着重介绍国内外几种有代表性的光电自准直仪的情况，并对光电自准直仪今后的发展作出展望     

实线性赋范空间中算子的Fermat定理

本文给出并证明了文中的定理１，该定理是经典分析中的Ｆｅｒｍａｔ定理在现代分析学中的合理推广。据此又给出了一个中值公式在抽象分析中成立的充分条件。最后，指出了经典分析中的中值定理在抽象分析中不成立。文中各项内容相结合，较深刻地说明了中值定理在抽象分析学中不成立的原因。