基于航迹关联的抗角闪烁跟踪算法研究

角闪烁背景下，高分辨雷达在近距离跟踪阶段存在不能精确跟踪的问题。针对此问题，分析了基于距离高分辨的单脉冲测角方法，并在此基础上，结合距离向强散射点的幅度特征，提出了一种基于航迹关联的抗角闪烁跟踪算法。算法首先对和通道、方位差通道、俯仰差通道的回波信号分别进行脉压和相参积累；然后在和通道的高分辨一维距离向上实现目标强散射点的检测，依据幅度进行排序并输出各点的距离信息和角度信息；最后利用联合集成概率数据互联算法作为目标跟踪滤波算法进行跟踪。本文通过对ku波段实测数据中入射余角为60°~69°的近距离跟踪部分进行分析，将所提算法与卡尔曼滤波跟踪算法进行了对比，仿真结果表明，本文算法使多目标跟踪的精度得到了提高，具有更好的角闪烁抑制性能。     

毫米波通信定位一体化自组网资源分配技术

毫米波通信链路具有低延迟、高速率和高定向性的特点,能够实现高速率自组网通信和高精度节点定位。在通信定位一体化背景下,研究了毫米波自组网中的多用户资源分配问题。系统采用基于正交频分多址(OFDMA)的多用户通信定位一体化框架,推导了基于位置估计误差界(PEB)和方位估计误差界(OEB)的多用户定位性能准则和基于数据速率的通信准则,建立了时域和频域的资源分配优化问题模型,在保障链路通信速率的前提下,最优化用户的定位性能指标。为了求解上述混合整数非线性规划问题,引入广义Benders分解算法,将优化问题分解为主问题和子问题进行迭代求解,得到有效的资源分配结果,最后通过仿真验证了资源分配对定位与通信性能的影响以及算法的有效性。     

边缘网络下多无人机协同计算和资源分配联合优化策略

针对边缘网络环境下多人机之间存在计算负载不均，造成卸载任务失败的问题，提出了一种多无人机间协作的智能任务卸载方案。通过联合考虑多无人机任务分配、计算资源分配和无人机飞行轨迹，引入公平性指数建立了无人机公平负载最大化和能量消耗最小化问题。基于多智能体深度强化学习框架，提出了融合轨迹规划和任务卸载的分布式算法。仿真结果表明，所提出的多无人机协作方案可以显著提高任务完成率和负载公平度，并且有效适用于大规模用户设备场景。     

Close relative motion on distant retrograde orbits

Distant Retrograde Orbits (DROs) in the Earth-Moon system have great potential to support varieties of missions due to the favorable stability and orbital positions. Thus, the close relative motion on DROs should be analyzed to design formations to assist or extend the DRO missions. However, as the reference DROs are obtained through numerical methods, the close relative motions on DROs are non-analytical, which severely limits the design of relative trajectories. In this paper, a novel approach is proposed to construct the analytical solution of bounded close relative motion on DROs. The linear dynamics of relative motion on DRO is established at first. The preliminary forms of the general solutions are obtained based on the Floquet theory. And the general solutions are classified as different modes depending on their periodic components. A new parameterization is applied to each mode, which allows us to explore the geometries of quasi-periodic modes in detail. In each mode, the solutions are integrated as a uniform expression and their periodic components are expanded as truncated Fourier series. In this way, the analytical bounded relative motion on DRO is obtained. Based on the analytical expression, the characteristics of different modes are comprehensively analyzed. The natural periodic mode is always located on the single side of the target spacecraft on DRO and is appropriate to be the parking orbits of the rendezvous and docking. On the basis of quasi-periodic modes, quasi-elliptical fly-around relative trajectories are designed with the assistance of only two impulses per period. The fly-around formation can support observations to targets on DRO from multiple viewing angles. And the fly-around formation is validated in a more practical ephemeris model.     

Aerial-ground collaborative routing with time constraints

The advancement of autonomous technology makes electric-powered drones an excellent choice for flexible logistics services at the last mile delivery stage. To reach a balance between green transportation and competitive edge, the collaborative routing of drones in the air and trucks on the ground is increasingly invested in the next generation of delivery, where it is particularly reasonable to consider customer time windows and time-dependent travel times as two typical time-related factors in daily services. In this paper, we propose the Vehicle Routing Problem with Drones under Time constraints (VRPD-T) and focus on the time constraints involved in realistic scenarios during the delivery. A mixed-integer linear programming model has been developed to minimize the total delivery completion time. Furthermore, to overcome the limitations of standard solvers in handling large-scale complex issues, a space-time hybrid heuristic-based algorithm has been developed to effectively identify a high-quality solution. The numerical results produced from randomly generated instances demonstrate the effectiveness of the proposed algorithm.     

Sequential dynamic resource allocation in multi-beam satellite systems:A learning-based optimization method

Multi-beam antenna and beam hopping technologies are an effective solution for scarce satellite frequency resources. One of the primary challenges accompanying with Multi-Beam Satellites(MBS) is an efficient Dynamic Resource Allocation(DRA) strategy. This paper presents a learning-based Hybrid-Action Deep Q-Network(HADQN) algorithm to address the sequential decision-making optimization problem in DRA. By using a parameterized hybrid action space,HADQN makes it possible to schedule the beam patte...     

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...     

一种基于模型预测的火星返回推力器容错控制再分配方法

针对火星返回上升器由于环境等因素造成的推力器故障导致的姿态控制系统失稳而难以安全返回的严重问题，提出基于模型预测的动态容错控制再分配方法。根据推力器动态特性建立上升器推力分配模型，对模型参数误差进行实时估计从而修正分配模型，根据模型预测自适应推力再分配方法实施容错控制。同时，将推力器输出限制作为优化求解器的约束，并将推力器故障模型作为优化求解的约束域，实现最小化分配误差和最小化燃料消耗意义下的最优推力再分配。计算机仿真表明了该方法的可行性和实用性，获得了满意的结果，它能使推力器输出推力误差降低60%以上，姿态控制系统能在故障状态下3～5 s快速镇定。     

Parameterized design of abort trajectories with a lunar flyby for a crewed mission

This article proposes an analytical preliminary design method for abort trajectory with a lunar flyby and the trajectory ergodic representation based on parameterization, as well as their application in studying the abort trajectories’ characteristics. First, by introducing two parameters, the perilune altitude and the perilune transfer time, the preliminary solution is developed parametrically using pseudostate theory to connect two special Lambert processes. The fast convergence of the improved differential correction under the high-fidelity gravity field verifies the accuracy of the proposed preliminary design method. Next, the two parameters are regarded as a set of variables to define an abort trajectory. Based on this, an ergodic representation of the abort trajectory with a certain abort time is yielded using the proposed design method, which offers a global view of the feasible abort trajectories. In addition, the influences of some factors on the performance of these abort trajectories are investigated based on the proposed design method and ergodic representation. The simulation results show that the abort time and the transfer time of the nominal trajectory significantly affect the ergodic representation and characteristics of the abort trajectory.     

动态跳波束策略中的自适应波束功率分配算法

摘要：多波束卫星发射机的成本很高，同时地面小区的通信需求和通信优先级一直处在动态变化中。通过研究一种动态波束跳跃策略，实现在卫星资源受限和较少发射机数量约束下的广域覆盖和按需服务。区别于传统的分簇波束跳变思想，为了提高卫星系统的频谱效率，考虑在整个频率带宽上应用全局波束跳变。因此考虑在共信道干扰背景下，提出一种新型服务质量指标来衡量波束跳变结果。在卫星资源有限的情况下，各波束提供的通信容量不能满足地面小区的业务请求，基于粒子群算法选择的波束跳动图案，提出了一种自适应波束功率分配算法。该算法通过优先级加权，最小化波束业务容量需求差值，进而提高服务质量水平。最后，通过仿真验证了所提算法的性能优越性。