Application of multi-layer structures of wafer-type made of composite materials for creating microwave antenna radomes

A new type of microwave antenna radome structure for aircrafts is suggested, which is a wafer radomes that possess improved characteristics if compared to traditional structures. Design peculiarities of such radome walls, wafer structures and their load-bearing elements made of dielectric composite materials are considered. A calculation model for such structures is justified and a methodology of selecting reasonable layer parameters according to radome’s level of radiolucency. A comparison of radio engineering characteristics of wafer and traditional three-layer structures of radome’s walls in a wide range of electromagnetic waves’ incidence angles in presence of mass limitations is conducted.     

线性调频信号基于FPGAIP核的脉冲压缩设计

为实现线性调频信号的数字脉冲压缩,设计一个FPGA硬件平台,并着重提出一种基于FPGAIP核的脉冲压缩设计方法。针对脉冲压缩进行了理论分析和Matlab仿真,设计完成后对系统软、硬件进行了全面测试,并根据实测数据对脉冲压缩结果进行了分析。结果表明,该系统可实现1024点的脉冲压缩功能,主副瓣比、主瓣宽度等指标与理论仿真结果一致。该方法的参数设置灵活,可以简化软件设计,缩短研发周期。     

基于子图灰度比较的匹配模板选取算法

为降低图像匹配模板选取算法的时间复杂度,提出一种基于子图灰度比较编码的图像匹配模板选取算法.首先将子图等分为2×2子块,以子图及邻近区域的4×4子块的灰度比较关系为子图赋予一个编码;其次在所有子图编码中选取重复次数最少的编码对应的一个子图或若干个子图中图像方差最大者作为匹配模板.算法复杂度分析和仿真实验结果表明,该匹配...     

无线电脉冲引信距离特性分析

防空导弹脉冲引信属于近距工作雷达,除了要有足够的探测威力外,一般要具有锐截止特性,由于脉冲发射的"遮挡效应",又不可避免的存在"盲区"。因此,作用距离、"盲区"、截止距离是防空导弹脉冲引信的基本距离特性。文章对影响引信距离特性的主要因素进行了分析和仿真,给出了引信距离特性设计的初步参数选择。     

Taking into account the impact of coupling elements on the resonance phenomena in biconical resonators

Investigations of the impact of dimensions of the coupling holes in open and closed biconical resonators on their field structure and resonance properties were performed. A number of concrete results were obtained that specified the extent of rise of the transfer ratio and the distortion of electromagnetic field structure and also the reduction of the resonance frequency and loaded Q-factor under conditions of the increasing size of the coupling holes in biconical resonators. The conditions under which the values of resonance frequency and loaded Q-factor of the open biconical resonator would be only slightly different from values of the same parameters of closed resonator were also obtained.     

基于欠采样的载频与二维到达角联合估计方法

针对阵列参数估计中传统奈奎斯特采样定理给采样和存储设备带来的巨大压力,提出了一种基于随机解调(RD)阵列结构的信号载频与二维到达角(2D-DOA)联合估计方法。利用不同天线阵列之间的互相关矩阵构造协方差矩阵,基于旋转不变子空间(ESPRIT)方法求解载频和2D-DOA参数,同时克服了载频和2D-DOA之间的配对问题。仿真实验结果证明了该方法能较好地从较少的欠奈奎斯特样本中估计目标信号的载波频率和2D-DOA,并恢复原信号的时域波形。     

故障自治系统的构想

本文提出了一种故障自治系统的基本构想:即根据系统先验信息和某些状态或参数的观 测,计算滤波残差和故障特征矩阵,构造能分离故障的投影算子(DPO).由故障探测分离逻 辑判断系统运行是否正常,分离确立故障发生的P位,补偿由故障所造成的影响,使系统具有 启动诊断治理故障的能力. 本文给出了DPO算子产生的方法,论证了存在的充要条件.为了减少计算量和保持滤 波器在系统运行正常时的最佳性和在有故障时对不期望变化的灵敏性,本文提出了一种故障 开关滤波器.数字计算结果显示了这些方法的有效性.     

一种机械被动式无热补偿方法

军用光学仪器大都工作在一定的环境温度范围内,温度变化将导致光学系统的像面离焦,成像质量明显下降,必须采取有效的温度补偿措施.介绍了多种无热补偿方式,如机电被动、光学被动和机械被动三种无热补偿方法,并且给出设计实例.提出一种新的补偿方法,利用热双金属进行机械被动补偿,使成像质量明显提高.计算和仿真结果表明,采取该方案补偿后的光学系统,在温度变化时像面与壳体依然保持相对稳定,即可以自动消除环境温度变化造成的像面离焦.这对红外光学系统的无热化设计具有重要的意义.     

Aircraft reinforcement learning multi-mode control in orbit

In order to improve the long-term in orbit flight reliability of the aircraft control system, a multi-mode control scheme is proposed based on reinforcement learning. This system includes a sensor module, a control module and an execution module. The sensor module is used to input the sensitive flight data of the aircraft to the control module in real time. This data is divided into multidimensional structured floating point data with historical relevance that can be directly used for aircraft control and the unique physical representation quantity of a particular sensor. The control module is divided into an input layer, a feature extraction layer and a full connection layer. The execution module is used to receive the driving data from the control module in real time, which includes the optimal state value for decision-making and the action output value for evaluation. The system decides which specific execution modules to use based on the optimal return value for decision making, with the output value of a selected specific execution module depending on the output value of the action used for evaluation. The system enables the aircraft to complete a long-term orbit operation in the multi-mode input and output state with 15ms fast response and 5.23GOP/s/W Performance per Watt.