基于ADS-B报文的“北斗”便携式终端实现

针对单个广播式自动相关监视（Automatic Dependent Surveillance-Broadcast，ADS-B）发射机传输距离受限、多地面站组网复杂以及成本较高等问题，在分析ADS-B报文编码与解码算法的基础上，探讨了基于无线网络传输的ADS-B报文信息技术，并设计了基于“北斗”卫星导航（BeiDou Satellite Navigation System，BDS）/嵌入式控制器以及无线网络的便携式监视终端系统。利用实测ADS-B数据联合搭建的监视中心对算法和系统进行测试，结果表明数据传输稳定，实现了低空空域通用航空飞机ADS-B态势信息的网络传输功能，丰富了监视信息的链路传输方式，为低空通航飞行器安全飞行和全面监视提供了新的方法。     

基于软件无线电平台的1090ES扩容信号收发处理

随着空中交通的信息传输与新应用拓展需求不断增加，1090ES信号容量有限问题日益显现，对1090ES信号进行容量扩充是一种有效解决途径。针对一种基于脉内调相的1090ES信号扩容技术，给出了叠加调制的信号模型，研究了1090ES信号的解调解码算法；在GNU Radio+ USRP软件无线电平台上，实现了1090ES扩容信号的产生和接收处理，包括脉冲位置调制（Pulse Position Modulation，PPM）与8PSK叠加调制、低通滤波、报头检测、载波同步、PPM解码和相位解调等，并利用Matlab对实验的解码错误率和信号的频谱特性做了统计分析与仿真，结果表明了该扩容技术的可行性。     

Impacts of COVID-19 on aircraft usage and fuel consumption: A case study on four Chinese international airports

COVID-19 pandemic starting in early 2020 has greatly impacted human and industrial activities. Air transport in China shrank abruptly in February 2020, following a year-long gradual recovery. The airline companies reacted to this unprecedented event by dramatically reducing the flight volume and rearranging the aircraft types. As the first major economy that successfully controls the spread of COVID-19, China can provide a unique opportunity to quantify the medium-long impacts on the air transport industry. To quantify the corresponding changes and to elucidate the effects of COVID-19 in the wake of two major outbreaks centered in Wuhan and Beijing, we analyze twelve flight routes formed by four selected airports, using the Automatic Dependent Surveillance-Broadcast (ADS-B) data in 2019 and 2020. Our results show that the total flight volume in 2020 reduced to 67.8% of 2019 in China. The recovering time of flight volume was about 2–6 months, dependent on the severity. In order to unwind the severe challenge, airlines mainly relied on aircraft B738 and A321 between February and June in 2020 because the fuel consumption per seat of these two aircraft types is the lowest. Besides, fuel consumption and aircraft emissions are calculated according to the Base of Aircraft Data (BADA) and the International Civil Aviation Organization's Engine Emissions Databank (ICAO's EEDB). At the end of 2020, the ratios of daily fuel consumption and aircraft emissions of 2020 to 2019 rebounded to about 0.875, suggesting the domestic commercial flights were nearly fully recovered. Our results may provide practical guidance and meaningful expectation for commercial aircraft management for other countries.     

采用改进型AlexNet的辐射源目标个体识别方法

针对辐射源目标精确识别需求，结合以深度学习为代表的机器学习理论技术，提出将改进型AlexNet作为特征提取器，实现目标细微特征提取固化，形成智能化识别网络模型。以广播式自动相关监视（ADS-B）信号为实验对象，在机场实地采集了13个目标的ADS-B脉冲信号数据作为辐射源目标个体识别的训练和测试样本，利用AlexNet和改进的AlexNet验证了算法的有效性。结果表明，改进的AlexNet网络训练时间更快，综合识别率达到98.32%.     

基于飞机降落信息的ADS-B数据跟踪算法

在空中交通管制（ATC）领域,广域监视系统中的ADS-B接收机在飞机飞行方向改变时 ,由于其收星的数量减少导致数据率变低,并且在飞机降落过程中丢点严重。结合ADS-B数 据的特点,采用两个模型分别表示飞机的匀速运动和匀加速运动状态,利用三点速度方向预 测修正对地速度,并引入飞机降落的先验模型,实现在广域监视中对飞机的有效跟踪。 真实数据验证了该方法可有效提高数据率和改善飞机降落过程中的跟踪效果。     

Asterix Category 021协议的应用与分析

介绍了Asterix Category 021协议的数据项内容、用户应用程序框架（UAP）的结构、 报文数据块的布局,以及ADS-B系统应用该协议的方式,分析了该协议的实例应用和协议报 文 的解析,提出了处理报文的思路。研究与分析结果可为如何使用Asterix Category 021协议 生成与解析报文提供参考。     

Runway safety at airports: A systematic approach for implementing ultra-safe options

Enhancing airport runway safety is a difficult problem because runway accidents are rare events. Nonetheless, investments are being directed at improving safety for US airport ground traffic control systems. This paper shows that under these circumstances it is difficult to assess and measure the added safety offered by new replacement systems. We develop a framework for introducing and sequencing system improvements to provide greater assurances in enhancing safety. This framework shows how a new method can first be introduced as a secondary system, to test and verify its efficacy prior to its adoption as a primary system.     

无人机共享空域管制间隔研究

国内外关于无人机在有人机共享空域运行的相应规章几乎为空白，无人机运行仍处于隔离空域。通过对无人机进行使用高度层的分类，提出无人机进入有人机共享空域的关键约束条件。根据无人机相较有人机管制操纵指令延迟的实际情况，推导管制区域内，无人机与有人机的防撞管制间隔。建立无人机与有人机碰撞风险模型，对无人机管制间隔进行风险评估。为无人机与人机共享管制区域运行的防碰撞间隔提供了可行的推导与验证方法。     

一种采用ADS-B技术的通用航空防撞系统

为适应快速发展的通用航空对避撞的迫切需求，在基于广播式自动相关监视（Automatic Dependent Surveillance-Broadcast，ADS-B）的通用航空监视系统的基础上构建了通用航空防撞系统，该系统与无人机和运输航空一体化构建。结合ADS-B工作范围广和通用航空防撞复杂的特点，提出并构建了包括紧急避撞、一般避撞和提前避撞的三级避撞系统。分析了避撞系统中区域的划分，给出了避撞处理流程，讨论了每一级避撞需求及其关键算法。     

基于1090ES的机载ADS-B设备总体设计

介绍了1090ES ADS-B系统组成和信号格式,提出了一种基于1090ES一次变频的超外差中频数 字化ADS-B设 备总体实现方案,包括天线、收发分机、终端分机和机内测试电路设计,计算了关键技术参 数,并简述了其主要技术特征。 该方案目前已在工程中得到应用,效果良好。