植被散射实验数据的特性分析

本文根据电波所获取的各种樾 射实测数据，分析了它们对不同极化波的响应特性。     

智能结构系统中的光纤传感技术

智能结构系统具有类似人体运动控制功能，埋置在工程结构或材料中便能获得顺应环境变化的自判断性、自适应性、自诊断性、自修复性等诸多性能。这一神奇的科学技术具有重大科学意义和广阔的应用前景。利用特性优良的光纤传感器可以构成一种特殊的光纤智能结构系统。本文较深入介绍适合智能结构系统的光纤多点式和分布式传感技术的原理、结构和实施方法。     

压缩感知理论及其在成像技术中的应用

在传统的Shannon/Nyquist采样定理指导下,信号处理往往面临两大难题:A/D转换器技术的限制和海量采样数据的处理压力.压缩感知(CS)理论表明当信号具有稀疏性或可压缩性时,可以通过全局非自适应线性投影的方式,用远低于Shannon/Nyquist采样定理要求的频率获取信号的全部信息.以CS理论为基础的压缩成像(CI)技术在近年来得到了快速的发展.在概述CS理论的基础上,着重介绍了CI技术的原理及其发展状况,并从稀疏分解、观测矩阵的构造和重建算法3个方面对其关键问题进行了分析.CI系统可以显著节省感光器件的数量,避免了传统成像技术"先采样再压缩"方式带来的资源浪费.     

Waveform design and high-resolution imaging of cognitive radar based on compressive sensing

We introduce the compressive sensing(CS) theory for waveform design of cognitive radar,and then propose an algorithm for the high-resolution radar signal waveform and its corresponding imaging method based on the sparse orthogonal frequency division multiplexing-linear frequency modulation(OFDM-LFM) signal.We first present the principle of spectrum synthesis and high-resolution imaging based on OFDM-LFM signals.Then,we propose the spectrum-sparse waveform design criterion and the reconstruction algorithm for a highresolution range profile(HRRP) based on CS.Based on this,we analyze in detail the relationship between the scattering characteristics of the target and the parameters of the designed signal,and we construct the feedback of the target characteristics on the waveforms.Therefore,the "cognitive" function of radar can be achieved by adaptively adjusting the waveform with the target characteristics.Simulations are given to validate the effectiveness of the proposed algorithm.     

Compressive sensing SAR range compression with chirp scaling principle

Compressive sensing(CS) techniques offer a framework for the detection and allocation of sparse signal with a reduced number of measurements.This paper proposes a novel SAR range compression,namely compressive sensing with chirp scaling(CS-CS),achieving the same range resolution as conventional SAR approach,while using fewer range samplings.In order to realize accurate range cell migration correction(RCMC),chirp scaling principle is used to construct reference matrix for compressive sensing recovery.Additionally,error diagrams are designed for measurement of the performance of CS-CS,and some experiments of using real data are performed to deal with the errors caused by three conditions:SNR,sparsity and sampling.     

Multi-channel SAR imaging based on distributed compressive sensing

The rapid development of compressive sensing(CS)shows that it is possible to recover a sparse signal from very limited measurements.Synthetic aperture radar(SAR)imaging based on CS can reconstruct the target scene with a reduced number of collected samples by solving an optimization problem.For multi-channel SAR imaging based on CS,each channel requires sufficient samples for separate imaging and the total number of samples could still be large.We propose an imaging algorithm based on distributed compressive sensing(DCS)that reconstructs scenes jointly under multiple channels.Multi-channel SAR imaging based on DCS not only exploits the sparsity of the target scene,but also exploits the correlation among channels.It requires significantly fewer samples than multi-channel SAR imaging based on CS.If multiple channels offer different sampling rates,DCS joint processing can reconstruct target scenes with a much more flexible allocation of the number of measurements offered by each channel than that used in separate CS processing.     

浅谈新疆空管系统中的GIS与RS技术应用

新疆空管运行管理系统是基于三维地理信息平台,研究遥感技术和地理信息系统在现代民用航空中的应用,将三维空间遥感数据、民航各专业数据、管理信息、业务流程等多业务平台、多管理系统结合起来,提供直观的操作控制界面,实现民航空管运行集中监控、运行保障、特殊事件及影响分析、突发事件处理及预案生成等功能。     

物联网热点问题研究

从物联网的定义出发,引出了物联网感知层研究中亟待解决的若干问题。"物联网"的"物"体现在对物体信息的感知,这可由无线传感网和RFID技术实现,属于感知层研究的内容。对于无线传感网来说,目前需要解决的问题包括能量的获取与控制,这可以从增加能量供应和控制能量消耗两方面进行研究,其热点研究方向有超级电容、无线供电、功耗控制等;无线传感器的自动组网技术包括Ad hoc网络和ZigBee协议研究两个热点方向,分别对应不同的应用场景。对于RFID来说,亟待解决的问题包括天线设计、声表面波技术、碰撞算法等,此外,文中还在感知层研究中研究了一些共性的问题,如电磁波传播特性、节点定位、超宽带技术、网络安全等。