Optimization and efficient detection of primary synchronization signal for multi‐beam satellite‐LTE systems

A new design of primary synchronization signal (PSS) sequences and an efficient detection algorithm for multi‐beam satellite long‐term evolution (LTE) systems are investigated in this paper. First, a transmit‐timing adjustment method is proposed to reduce the large time difference of arrival of received signals from different satellites. Then, using the particular subcarrier mapping scheme of LTE, original Zadoff–Chu sequences are generalized to obtain more candidate sequences with good correlation properties. Later on, choosing an optimal subset from these candidate sequences, new PSS sequences for seamless global coverage multi‐beam satellite‐LTE systems are obtained. Subsequently, an efficient synchronization and low complexity PSS detection algorithm using interference cancellation method is presented. Finally, simulation results verify the effectiveness of the proposed scheme. Copyright © 2015 John Wiley & Sons, Ltd.     

异面交会在弹道测量中的应用

综合利用两台光电经纬仪（EOMS）、GPS引导系统、全站仪（TPS110）等现有设备,设计了安全、可靠的弹道跟踪、测量方案,利用异面交会算法,对测量的弹道数据进行处理,取得了预期的结果。     

一种主瓣干扰环境下的雷达目标参数"同维"稀疏估计方法

主瓣干扰对抗一直以来是雷达领域的难题之一，给雷达的探测、跟踪和识别带来了严重威胁.对此，本文提出了一种主瓣干扰环境下的雷达目标参数"同维"稀疏估计方法，可有效抑制主瓣干扰并估计目标距离、角度参数.所提方法首先对接收信号进行阻塞矩阵预处理，可在抑制主瓣干扰的同时保持目标回波在各阵元之间的相位关系，即保留了目标的角度信息；然后对预处理后的数据进行空域波束合成并脉压，可估计目标的距离参数信息；最后，根据得到的目标距离估计，截取预处理数据中目标附近的数据，并对其进行稀疏恢复估计目标角度参数.所提方法即可应用于面阵，也可应用于线阵，其优势在于可以在空域任何一维上抑制主瓣干扰，并同时估计目标在空域两维上的角度.尤其是当目标与干扰的某一维空域角度相同时，所提方法仍然可以同时估计目标的方位、俯仰角.     

基于USB的波分复用光传飞行控制系统的开发

针对飞行控制系统的特点,开发了一套基于USB的多路数字信号进行波分复用的光纤传输系统,以提高光传系统的传输速率.着重构建了光发射器、光接收器及光波分复用器的物理系统.在直升机显模型跟踪电传飞行控制系统(MFCS)的基础上,开发了直升机贴地飞行波分复用光传系统实时半物理仿真验证平台.通过光传与电传性能对比,验证了所开发系统的可行性,具有工程实用意义.     

结合房间声学特点的子带自适应滤波声学回音抵消算法

子带自适应滤波算法是处理长阶声学回声抵消问题的重要方法之一。结合房间声学的特点,对各子带采用不同长度的FIR滤波器进行滤波,将有限的资源进行更合理的分配,节省了资源和计算量,并在一定程度上提高了收敛速度。     

实现经济型CNC系统C刀补建立与撤消的算法研究

为在经济型CNC系统中全面实现C功能刀补,提出一种简单有效的刀补建立和撤消方法,并对现行C刀补建立和撤消过程中的刀具中心轨迹加以修正,以解决刀具与工件轮廓之间的干涉问题.     

A Robust Step-Size Control Technique Based on Prop ortionate Constraints on Filter Up date for Acoustic Echo Cancellation

One of the m ain di?culties in Acoustic echo cancellation (AEC) is that the filter adaptation needs to vary according to different situations such as near-end interferences and echo path changes. In this paper, we pro-pose a robust step-size control algorithm in frequency do-main. The proposed method is based on the optimization of the square of the bin-wise a posteriori error. Constraint on the filter update is applied, which contributes to ro-bustness to near-end interferences of the algorithm. The learning rate formula is derived first and then the relation-ship between the proposed algorithm and a robust statis-tics based approach is revealed. The method is extended to the Multidelay block frequency domain adaptive filter (MDF) so as to meet the demand of low delay in prac-tical application. Moreover, the values of the constraints are designed to be updated proportionately to improve the convergence property. Simulation results demonstrate the superiority of the proposed algorithm.     

嵌入式飞行控制系统软件平台的设计及验证

为满足微型飞行器飞控系统开发的需要,设计开发了一种基于嵌入式Linux的飞控系统软件平台。介绍了宿主机嵌入式开发环境的搭建过程,进行了机载飞控系统软件平台的搭建,主要包括制作启动引导程序,编译内核,制作根文件系统和设计外围设备驱动;最后进行驱动程序的测试及软件平台的验证。通过对不同接口类型传感器的驱动程序进行测试,验证了软件平台的性能,满足微型飞行器上层飞控软件开发和测试的需要,且具有通用、易维护和易扩展的特点。     

一种基于串行干扰抵消的OFDM UWB多址方案

研究了高峰值传输速率时UWB系统的多址性能,对一种干扰抑制的OFDM传输方案进行了调整,提出了一种基于串行干扰抵消的两用户OFDM UWB多址方案.仿真结果显示所提出的方案可适度改善无纠错编码的OFDM UWB系统的误符号性能.     

西安脉冲堆热柱孔道中子束流参数测量

采用飞行时间法测量了西安脉冲堆热柱孔道热中子束流中子能谱分布,能谱测量结果较Thermal Maxwellian理论谱偏软,中子谱平均能量为0.042±0.01eV.采用金箔活化法测得热柱孔道出口前端热中子注量率为1.18×105 cm-2·s-1,热中子注量率测量的不确定度为3%.