自动相关监视系统的研究与开发

介绍了自动相关监视系统的基本概念，构成原理和与实施相关的研究与开发工作，特别是重点介绍了以ＰＣ机为基础的ＡＤＳ信息处理系统的成果，最后还介绍了ＡＤＳ运行情况。     

ESA’s process for the identification and assessment of high-risk conjunction events

ESA’s Space Debris Office provides an operational service for the assessment of collision risks of ESA satellites. Currently, the ENVISAT and ERS-2 missions in low Earth orbits are covered by this service. If an upcoming high-risk conjunction event is predicted based on analysis of Two-Line Element (TLE) data from the US Space Surveillance Network, then independent tracking data of the potential high-risk conjunction object are acquired to improve the knowledge of its orbit. This improved knowledge and the associated small error covariances derived from the orbit determination process scale down the position error ellipsoid at the conjunction epoch. Hence, for the same miss-distance, in most cases an avoidance manoeuvre can be suppressed with an acceptable residual risk.     

贝叶斯权重修正模型在机场场面监视方案选择中的应用

提高机场在各种环境下的安全性措施之一是加强对机场运动目标的监视和控制,因此选用何种机场场面监视技术变得尤为重要。以浦东机场为例,采用贝叶斯权重修正模型,选取最有代表性的三项衡量指标,利用最小二乘法得出精确解并进行比较,最后结合浦东机场的数据验证结果的正确性。     

共信道干扰环境下星基ADS-B系统监视性能

星基广播式自动相关监视系统（星基ADS-B）是实现广域范围内航空器监视的主要技术手段。为揭示星基ADS-B系统共信道干扰对系统监视性能的影响，提出了星基ADS-B系统监视容量的计算方法。首先给出了星基ADS-B系统模型，随后理论分析给出消息正确接收概率、位置消息更新间隔及位置报告更新间隔的计算公式，以此为基础给出了星基ADS-B系统监视容量的计算公式，最后基于SNS软件构建了星基ADS-B仿真系统，仿真验证了理论结果的正确性。研究表明：星基ADS-B系统的监视容量由ADS-B应用子系统所要求的航空器位置报告更新间隔、航空器-卫星链路的误码率、星-地面站链路的误码率及卫星数目联合确定。     

The X-TRACK/ALES multi-mission processing system: New advances in altimetry towards the coast

In the context of the ESA Climate Change Initiative project, a new coastal sea level altimetry product has been developed in order to support advances in coastal sea level variability studies. Measurements from Jason-1,2&3 missions have been retracked with the Adaptive Leading Edge Subwaveform (ALES) Retracker and then ingested in the X-TRACK software with the best possible set of altimetry corrections. These two coastal altimetry processing approaches, previously successfully validated and applied to coastal sea level research, are combined here for the first time in order to derive a 16-year-long (June 2002 to May 2018), high-resolution (20-Hz), along-track sea level dataset in six regions: Northeast Atlantic, Mediterranean Sea, West Africa, North Indian Ocean, Southeast Asia and Australia. The study demonstrates that this new coastal sea level product called X-TRACK/ALES is able to extend the spatial coverage of sea level altimetry data ~3.5 km in the land direction, when compared to the X-TRACK 1-Hz dataset. We also observe a large improvement in coastal sea level data availability from Jason-1 to Jason-3, with data at 3.6 km, 1.9 km and 0.9 km to the coast on average, for Jason-1, Jason-2 and Jason-3, respectively. When combining measurements from Jason-1 to Jason-3, we reach a distance of 1.2–4 km to the coast. When compared to tide gauge data, the accuracy of the new altimetry near-shore sea level estimations also improves. In terms of correlations with a large set of independent tide gauge observations selected in the six regions, we obtain an average value of 0.77. We also show that it is now possible to derive from the X-TRACK/ALES product an estimation of the ocean current variability up to 5 km to the coast. This new altimetry dataset, freely available, will provide a valuable contribution of altimetry in coastal marine research community.     

面向林火持续侦察的多无人机分布式控制方法

为解决目前面向林火持续侦察多无人机（UAV）协同控制实用性与自主性不足的问题，基于蔓延速度诱导元胞自动机（SVICA）林火蔓延算法、无人机与传感器建模，构建了较为真实的三维多无人机火场侦察仿真环境与侦察效能指标，提出了一种面向林火持续侦察的多无人机双层分布式控制架构，在行动层基于强化学习训练的人工神经网络（ANN），实现了有风条件下无人机自主火场环绕与地形跟随功能，在策略层设计通过时域均匀分布算法进行各无人机空速的离散自主调节，最终达到多无人机林火持续侦察时域分布的均匀性与即时性目的。通过一系列数值仿真实验，验证了所提出的无人机分布控制策略在无人机损失和补充突发情况下的自适应性。基于无人机数量与侦察效能指标关系的实验与研究，定义了无人机出动阈值并验证了无人机长时间出动回收策略。最终实验结果表明，针对林火持续侦察任务，所提出的多无人机分布式控制方法具备一定的有效性与实用性。     

A novel signal processing approach for LEO space debris based on a fence-type space surveillance radar system

The increase in space debris can seriously threaten regular activities in the Low Earth Orbit (LEO) environment. Therefore, it is necessary to develop robust, efficient and reliable techniques to understand the potential motions of the LEO debris. In this paper, we propose a novel signal processing approach to detect and estimate the motions of LEO space debris that is based on a fence-type space surveillance radar system. Because of the sparse distribution of the orbiting debris through the fence in our observations, we formulate the signal detection and the motion parameter estimation as a sparse signal reconstruction problem with respect to an over-complete dictionary. Moreover, we propose a new scheme to reduce the size of the original over-complete dictionary without the loss of the important information. This new scheme is based on a careful analysis of the relations between the acceleration and the directions of arrival for the corresponding LEO space debris. Our simulation results show that the proposed approach can achieve extremely good performance in terms of the accuracy for detection and estimation. Furthermore, our simulation results demonstrate the robustness of the approach in scenarios with a low Signal-to-Noise Ratio (SNR) and the super-resolution properties. We hope our signal processing approach can stimulate further work on monitoring LEO space debris.     

自由飞行下基于IPS算法的碰撞风险研究

自由飞行是解决空域拥挤问题的一种有效飞行模式。随着通信、导航、监视（ CNS ）技术的不断进步和自由飞行理论的不断完善,自由飞行将会使飞机由被动指挥向自选最优路径转变,能够明显提高空域的容量和飞行的效率。在评估自由飞行环境下飞机运行的安全性时,需要行之有效的碰撞风险评估方法。首先考虑通信、导航、监视（CNS）性能对飞机定位误差的影响,在执行飞行冲突解脱命令过程中引入相互作用粒子系统（IPS）,提出一种自由飞行下飞机碰撞风险评估算法,最后结合目标安全水平寻找最优最小安全间距。算例表明,算法能够快速有效计算自由飞行下飞机间碰撞风险,具有可行性。     

旋翼试验塔监视报警技术的实现

监视报警系统作为旋翼试验塔测试系统的重要组成部分,不仅为试验的全过程提供实时、直观、准确的数据显示,同时对超过设定值的参数发出声光报警,为试验提供直接的判断。本文较为全面地论述了监视报警技术在实际测试工作中的特点、难点及其减少误报率所采取抗干扰技术的新方法。     

基于PEV准则的不确定随机多目标规划问题求解

为解决独立变量的不确定随机多目标规划问题在传统求解中存在分析不全面等问题,在期望值-方差准则下提出了一种新的求解方法。基于机会理论,引入不确定随机变量,在此基础上提出了不确定随机多目标规划问题;引入不确定随机变量的序关系,利用变量间的序关系把不确定随机多目标规划问题转化成不确定随机单目标规划问题,并通过期望值-方差准则把不确定随机单目标规划问题转化成确定的单目标规划问题进行求解;通过理论推导证明,在新准则下转化后的问题得到的最优解是原不确定随机多目标规划问题的有效解;最后,通过对无人机情报侦察监视任务分配问题的求解,利用改进的萤火虫算法求得有效飞行序列,验证了所提方法的可行性和有效性。