高强度光纤光栅与碳纤维的复合及应变传感特性研究

针对光纤光栅工程化应用性能不佳的问题,提出将高强度光纤光栅与碳纤维材料复合,介绍了复合样品的结构形式,分析了应变传递过程,然后对其应变传感特性和疲劳性能进行了实验研究。结果表明:复合样品能够达到较高的应变传递效率,具有良好的应变传感特性;疲劳实验中复合样品保持正常工作,波长变化曲线的幅度稳定;疲劳实验前后复合样品的应变传感特性基本不变,应变灵敏度系数分别为1.12和1.17pm/με,应变响应曲线的线性度均高于0.999,重复性分别为0.623%和0.397%。     

Maritime cognitive radio spectrum sensing based on multi-antenna cyclostationary feature detection

ABSTRACT

With the development of the maritime transportation industry, the number of ships is increasing and the ships are becoming more intelligent. Due to the rapid development of maritime communication, the demand for communication spectrum is increasing. Therefore, the maritime cognitive radio (CR) system is an effective solution. Because of the multipath fading caused by sea surface and atmosphere has a more serious influence on communication signals, which increases the instability of the signal reception, the spectrum sensing technology in maritime cognitive radio is more challenging than the spectrum sensing on land. In order to solve this problem, a cyclostationary detection algorithm for multiple antennas in fading model is proposed. A maximum ratio combining algorithm based on optimal weight correlation value (OWCV-MRC) is proposed for the diversity gain and system performance degradation caused by diversity technology on multipath fading channels. The algorithm uses the correlation values of the attenuation gains on the two different branches as the weighting coefficients of each branch, thus improving the coefficient matrix in the maximum ratio combining (MRC) algorithm. The simulation results show that the proposed algorithm can effectively detect the target signal in the fading channel with ultra-low signal to noise ratio (SNR).     

基于光谱加权低秩矩阵分解的高光谱影像去噪方法

高光谱遥感影像在获取和传输过程中会受到各种类型噪声的污染,不仅降低影像质量,也限制了其后续应用的精度。高光谱影像噪声类型复杂多样,且噪声在不同波段上的强度也并不相同。通过引入光谱域上的权重矩阵,文中提出了一种基于光谱加权低秩矩阵分解的高光谱遥感影像混合噪声去除方法,利用光谱权重矩阵均衡不同波段的噪声强度差异性。为进一步将噪声与纯净影像分离,利用加权核范数最小化来约束纯净高光谱影像的局部低秩结构,并利用交替方向乘子法对所提出的模型进行优化求解。通过对模拟与真实高光谱遥感数据的实验,验证了所提方法的有效性与优越性。     

一种多传感器融合的多维数据互联算法

多传感器融合的数据关联问题一直是目标跟踪领域的核心与难点之一.文中提出了一种多传感器融合的多维数据互联算法.首先进行多目标跟踪模式的判断,根据跟踪模式选取不同维数的数据互联算法,对现有的多维数据互联算法存在问题进行了分析和改进,给出了算法实现的伪代码.仿真与实验结果表明,该算法对弹道目标跟踪具有较好的效果,对复杂环境下的多目标也能进行稳定地跟踪.     

Enhanced spectrum sensing using a combination of energy detector,matched filter and cyclic prefix

In this paper, we propose a sensing scheme based on energy detection, matched filter and cyclic prefix. Both Equal Gain Combining (EGC) and optimal combination of the aforementioned detectors are investigated in cooperative and non-cooperative spectrum sensing scenarios. In packet transmission systems such as OFDM (Orthogonal Frequency Division Multiple access) systems, the proposed scheme takes advantage of utilizing more samples than individual detectors, i.e., cyclic prefix, training or pilot samples, and data payload samples. The proposed combine-sensing scheme offers higher detection probability and lower false alarm probability, as compared with the performance of individual detectors over the same frame duration. Simulation results are congruent with the theoretical curves and confirm the validity of our derivations.     

光纤传感技术在安防领域的应用

在简要介绍光纤传感技术及其应用的基础上,重点阐述了光纤传感技术在安防领域的应用,并对基于光纤传感技术的光纤围栏报警系统的实用化进程提出建议及展望.     

基于波分复用的光纤多防区周界传感系统

提出了一种新的光纤多防区周界传感系统,采用波分复用技术实现了监控防区和通道的扩展。该系统对传统采用单根传感光纤和反射镜的结构作了改进,并扩展了传感光纤的数量,将多根传感光纤分别置于监控领域内的不同防区,每个防区分别用不同中心波长的光纤布拉格光栅作为反射装置,使每根传感光纤工作在不同的波长。利用波分复用器件与技术,多根传感光纤共用一套干涉系统,实现了多个干涉子系统同时、独立的监测。实验结果表明,该系统可以实现多个分散防区同时、独立的入侵检测和定位,信号响应时间小于1ms,不同防区间信号的串扰小于-20dB。     

基于改进PSO的WMSNs覆盖增强算法

对无线多媒体传感器网络(WMSNs)的覆盖增强问题进行了研究.在WMSNs网络中,视频、图像节点的视角范围有限,只能监控周围的部分区域.由于节点数量众多、部署方式受限等原因,网络中往往存在大量的监测重叠与监控盲区,需要对各节点的感知方向进行优化,以提高网络的监控质量.文中基于有向感知模型,提出了一种覆盖增强算法MCE.MCE对各节点的感知方向进行调整,并使用了改进的PSO算法来计算求解.仿真实验表明,MCE算法能够有效地提高网络的覆盖率.     

多变量自回归信号信息融合辨识方法

近年来,为了提高系统模型和状态估计的精度,多传感器数据融合引起了广泛关注。对于带白色公共干扰噪声和有色观测噪声的多传感器多变量自回归（AR）模型,当AR模型参数和噪声方差未知时,提出了一种信息融合多段辨识方法,其中采用多维递推辅助变量（MRIV）方法得到AR模型参数的局部和融合估值器,再用相关方法得到局部和融合噪声方差估值器。这些估值器具有一致性,通过一个信号仿真例子验证了其有效性。