点阵结构工艺参数对透波平板电磁波谱的影响

文摘为研究点阵结构工艺参数对透波平板电磁波谱的影响,基于体心立方结构(BCC)点阵基本构型,建立透波平板仿真模型,运用CST仿真软件分别从孔隙率、蒙皮厚度、胞元尺寸、入射角度4方面探究不同结构工艺参数对透波平板共振频率及透射率的影响。并运用选区激光烧结(SLS)制备点阵透波平板结构,用于2～18 GHz透射率对比测试。结果表明,仿真数据与实验结果高度一致;透波平板共振频率随孔隙率增大,第一频率点向低频偏移,第二频率点向高频偏移;随着蒙皮厚度的增加,透射率降低;胞元尺寸与蒙皮厚度决定透射谱的通带共振频率,孔隙率影响较小;入射角增大时,水平极化入射波透射率均大于75%,影响较小;竖直极化入射波透射率在高频处逐渐降低。     

自适应盲均衡信道的设计与实现

针对星地高速遥感传输信道中客观存在的码间串扰、信道不确定性等情况，提出采用双模式自适应盲均衡方法，综合了CMA（Constant Modulus Agorithm，恒模算法）均衡器的高稳健性以及LMS（Least Mean Square，最小均方算法）均衡器的高精度等优势。方法在均衡初期，利用CMA均衡器实现快速收敛；在MSE（Mean Square Error，均方误差）较小时切换为LMS均衡器，完成高精度收敛，实现了星地高速传输信道失真信号的快速高精度校正。     

CPU-GPU协同高性能卫星数传预处理方法

空间数据系统咨询委员会(CCSDS)协议的分层特征对数传预处理的完全并行提出挑战，虚拟信道、应用过程的多路复用为并行处理提供契机。本文面向高性能数传预处理需求，在分析处理性能瓶颈的基础上，提出一种层间流程中央处理器(CPU)控制、层内瓶颈步骤GPU加速的协同处理新方法。以高级在轨系统(AOS)帧循环冗余校验(CRC)、工程参数提取与物理量转换算法为研究对象，对图形处理器(GPU)线程分配、CPU-GPU协同任务划分进行设计。实验结果表明:方法可实现CRC校验11.449 6 GB.s^-1、工程参数提取与物理量转换0.902 4 GB.s^-1的处理速率，性能较传统CPU架构提升显著。     

基于无线网络的机载数字视频遥测传输技术

针对目前飞行试验视频遥测传输中遇到的遥测频带资源有限、传输视频路数少、数据保密性差等技术问题进行了分析,提出利用单向无线网络进行数字视频遥测传输的技术优势,分析飞行试验单向无线网络数据传输中网络通信协议,主张采用H.264视频压缩技术进行飞行试验图像数据遥测传输的优势技术,对在无线环境下视频传输需要解决的压缩数据编码问题,采用分级编码技术和误码掩盖技术;结合飞行试验对研究结果进行了技术验证,对试验方法和结果进行了说明。     

民用飞机航电数据网络带宽资源分配优化设计

民用飞机航电数据网络在设计过程中,通过对带宽资源的合理分配,来满足网络成员系统的数据传输需求.而在设计过程中,存在因网络带宽需求分布的非均匀性等因素造成的局部带宽资源不足的问题,因此需要在初步带宽资源分配结果上进行局部优化设计.提出一种通过网络带宽资源使用率最高的链路和端系统进行识别,以及进行针对性物理链路连接关系调整...     

一种低数据传输的多机器人实时视觉SLAM

针对多机器人视觉SLAM在实际应用中带宽受限的问题,设计了一种低数据传输的多机器人实时视觉SLAM系统.系统中引入了NetVLAD神经网络模型,通过改进NetVLAD降低了多机器人回环检测的计算资源占用,提高了回环检测的实时性.提出了一种针对描述子缺失情况下的特征匹配算法,提高了回环检测与相对量测的鲁棒性,并提出了一种增量式多机器人位姿图共享和优化方法.最后,通过在KITTI数据集进行测试,验证了该SLAM系统能有效减少多机器人通信过程中的数据传输,具有与单机器人SLAM相当的定位精度和实时性.     

Multi-scale simulation model of air system based on cross-dimensional data transmission method

The Secondary Air System (SAS) plays an important role in the safe operation and performance of aeroengines. The traditional 1D-3D coupling method loses information when used for secondary air systems, which affects the calculation accuracy. In this paper, a Cross-dimensional Data Transmission method (CDT) from 3D to 1D is proposed by introducing flow field uniformity into the data transmission. First, a uniformity index was established to quantify the flow field parameter distribution characteristics, and a uniformity index prediction model based on the locally weighted regression method (Lowess) was established to quickly obtain the flow field information. Then, an information selection criterion in 3D to 1D data transmission was established based on the Spearman rank correlation coefficient between the uniformity index and the accuracy of coupling calculation, and the calculation method was automatically determined according to the established criterion. Finally, a modified function was obtained by fitting the ratio of the 3D mass-average parameters to the analytical solution, which are then used to modify the selected parameters at the 1D-3D interface. Taking a typical disk cavity air system as an example, the results show that the calculation accuracy of the CDT method is greatly improved by a relative 53.88% compared with the traditional 1D-3D coupling method. Furthermore, the CDT method achieves a speedup of 2 to 3 orders of magnitude compared to the 3D calculation.     

IABC: An iteratively automatic machine learning boosted hand-eye calibration method for laser displacement sensor

An on-machine measuring (OMM) system with a laser displacement sensor (LDS) is designed for measuring free-form surfaces of hypersonic aircraft’s radomes. To improve the measurement accuracy of the OMM system, a novel Iteratively Automatic machine learning Boosted hand-eye Calibration (IABC) method is proposed. Both the hand-eye relationship and LDS measurement errors can be calibrated in one calibration process without any hardware changes via IABC. Firstly, a new objective function is derived, containing analytical parameters of the hand-eye relationship and LDS errors. Then, a hybrid calibration model composed of two kernels is proposed to solve the objective function. One kernel is the analytical kernel designed for solving analytical parameters. Another kernel is the automatic machine learning (AutoML) kernel designed to model LDS errors. The two kernels are connected with stepwise iterations to find the best calibration results. Compared with traditional methods, hand-eye experiments show that IABC reduces the calibration RMSE by about 50%. Verification experiments show that IABC reduces the measurement deviations by about 25%-50% and RMSEs within 40%. Even when the training data are obviously less than the test data, IABC performs well. Experiments demonstrate that IABC is more accurate than traditional hand-eye methods.     

无人机协同测控中SC-FDMA技术设计

针对无人机协同任务测控传输的多机接入问题,提出基于分布式任务分配模型的高动态SC-FDMA技术.通过将贪婪原则、信道动态分配机制和多用户接入技术结合,利用集中映射方式设计子信道数目可调的映射规则,配置各无人机节点所占用子载波数目.仿真结果表明,与传统FDMA、CDMA、TDMA、OFDMA等相比,基于SC-FDMA设计...     

遥感卫星多路数据传输系统同频共用方法

为节省频率资源，遥感卫星通常采用扩频体制实现多路数据的同频共用传输，针对通道间容易引起相互干扰的问题进行了研究，通过改进码分多址干扰估算模型，对采用平衡Gold码序列扩频系统抗干扰容限上界进行预测。在满足国际电信联盟（ITU）对卫星辐射功率通量密度约束条件下，提出了一种基于直接序列扩频体制的两路业务数据同频共用传输方法。仿真结果表明：当载波频率2GHz左右，两路辐射源的EIRP之差不大于8～15dBw时可以实现同频共用传输；如对信号扩频带宽进行差异化处理，则其相互兼容性还可进一步提高。