一种确定空管监视台站选址范围的方法

为了使空管监视设备的选址更加科学高效,探讨了一种减小选址范围的分析方法。首先,结合地形遮蔽因素和设备垂直辐射特性对设备的覆盖性能进行分析,得到空间内任意一点设备可视的条件,在此基础上提出一种反向视域分析方法,该方法在保证空域覆盖要求的条件下得到选址范围的边界,以及不同位置设置站点所需的天线高度。然后,为避免定位点和航路受到设备顶空盲区的影响,推导出定位点的不合理选址半径和航路不合理选址宽度的计算方法,并在选址范围内剔除顶空盲区影响下不合理的选址区域。最后,对于设备选址其他影响因素造成的不合理选址区域也进行了类似分析,最终可确定一个小范围的选址区域。     

基于多目标规划的民用机场场面监视雷达选址方法

为了应对日益复杂的机场场面交通状况,许多大型民用机场开始采用场面监视雷达作为机场管制指挥的辅助技术手段。根据场面监视雷达的技术特点,采用多目标规划的方法,以雷达台址与机场跑道中心点距离达到最小和雷达塔高达到最大为目标函数,以选址用地范围、障碍物遮蔽、雷达天线下视角盲区及机场侧净空等方面的限制作为约束条件,构建出场面监视雷达选址模型,阐释了解的概念及无解情形下的解决方案。通过实例对选址模型进行了应用研究,并针对松弛变量进一步阐释了最优解对各种限制条件的权衡结果,拓展了对解空间的了解。     

监视数据在全国流量管理系统中的设计研究

监视数据是全国流量管理系统中最重要,也是最基础的数据。覆盖范围广、数据内容准确的监视数据,对流量管理的预测精准度、决策可信度至关重要。文章结合全国流量管理系统,详细论述监视数据的分级引接和处理的设计方案。同时,对不同类型监视数据的特点进行分析,对比空管自动化系统,详细论述了全国流量管理系统中的目标相关算法和航迹与计划关联算法的特点。     

基于遗传算法的组网雷达优化部署

组网雷达优化部署是发挥雷达网互补与倍增性能的前提和基础,由于雷达网部署涉及的因素很多,是一个多约束条件的多目标优化问题。采用一种基于遗传算法的组网雷达优化部署算法,采用综合性能函数作为优化目标函数,在种群产生时加入约束条件,将有约束问题转化为无约束的优化问题,克服了枚举法执行速度慢和专家推理法知识组合爆炸的问题。仿真结果表明,该方法能达到最优或准最优解,是一种有效的组网雷达优化部署方法。     

基于遗传算法的组网雷达优化部署

组网雷达优化部署是发挥雷达网互补与倍增性能的前提和基础,由于雷达网部署涉及的因素很多,是一个多约束条件的多目标优化问题。采用一种基于遗传算法的组网雷达优化部署算法,采用综合性能函数作为优化目标函数,在种群产生时加入约束条件,将有约束问题转化为无约束的优化问题,克服了枚举法执行速度慢和专家推理法知识组合爆炸的问题。仿真结果表明,该方法能达到最优或准最优解,是一种有效的组网雷达优化部署方法。     

基于免疫计算的WCDMA网络基站选址优化

为了解决WCDMA网络基站选址优化问题,该文给出了一个基于免疫计算的选址优化方案。研究了容量约束下的小区面积,给出了免疫优化算法框架,并与文献算法进行了对比实验。实验结果表明:该文算法方案能以较小的网络建设代价满足覆盖要求,具有较好的应用价值。     

基于PageRank算法的改进物流节点选址模型研究

文中针对物流网络设计中的关键物流配送节点选址问题传统算法的局限性,结合PageRank算法和贪心算法,设计了一种考虑交通拥堵情况和节点利用率的连续型多物流节点选址算法。算法将各交通小区货运需求量通过PageRank算法进行推荐排序,然后使用贪心算法和聚类算法不断迭代,获得覆盖所有需求同时满足利用率的物流节点。同时基于南京市仙林区物流数据展开实验。实验结果显示本文提出的算法相比较传统的多元节点算法,在物流节点个数方面,数量有明显减少;在服务交通小区覆盖率方面,本文提出算法覆盖率略低于多元节点法,但覆盖率均超过90%,即该算法覆盖范围利用率均能达到平均水平。综合考虑物流节点的建设及运营成本,可得出如下结论:文中提出的基于PageRank算法的连续型多物流节点覆盖算法较传统的节点选择算法高效。     

基于模拟退火算法的城市电动汽车充电站优化布局

阐述了电动汽车充电站选址模型,以充电站收益最大化为目标函数,交通流量为约束条件,并运用模拟退火算法求解该模型。结果表明,将模拟退火算法应用于电动汽车充电站选址可以为电动汽车项目管理者提供一个优化或近似最优的选址方案。     

基于量子遗传算法的无线视频传感网络优化覆盖算法

针对智慧城市无线视频传感网络建设需要,提出一种基于量子遗传算法的网络优化覆盖算法。算法面向复杂的监视区场景,监视区中存在形状各异的障碍物,各区域的重要程度不同。以二维离散网格模型描述监视区场景,用编码描述矩阵表示监视区域,用七元组描述有向无线视频传感器。通过严格的数学推导得出了问题的数学规划模型。优化覆盖算法由IntialDeployment算法和OptimizedDeployment算法2部分组成,以获得最大有效覆盖率的网络部署方案为求解目标。采用量子遗传算法搜索解空间,通过合理编码染色体,优化量子旋转门参数,使算法的运算速度快,收敛性好。引入理想覆盖率和理想加权覆盖率2个极限值,采用相对比较法评判算法优劣。仿真实验和数据分析表明,算法获得的方案能很好地逼近理想极限值。在传感器节点数给定的情况下,算法能获得最大的覆盖率。     

多监视区域偏好可控的MIMO 雷达优化布站算法

针对分布式多输入多输出(MIMO)雷达在同时多区域监视情况下的优化布站问题,文中提出了一种多监视区域偏好可控的MIMO 雷达优化布站算法。首先,建立评价监视性能的性能指标函数,在此基础上,分析偏好信息确定重点监视区域,并确定监视区域预期性能要求;进而,提出基于偏好信息的粒子群优化算法(PSO),对天线布站位置进行优化,获取满足偏好要求的天线布站方案,并根据偏好信息从中挑选布站方案进行布站;最后,通过对多监视区域进行布站仿真,验证了所提布站方法的有效性。     

广播式自动相关监视(ADS-B)信息在空管系统中的应用研究

广播式自动相关监视(ADS-B)具有良好的监视手段,能更准确、连续、及时地掌握飞行器的飞行动态,监视范围覆盖了从"登机门到登机门",对在低海拔、非陆地区域等无法布设传统航管雷达的区域能达到补盲作用,帮助管制人员有效地实施空中交通指挥。我国航空事业起步较晚,技术力量薄弱,论文主要对广播式自动相关监视(ADS-B)的组成、工作原理、特性做阐述,介绍利用ADS-B传感器的布设网络,进行ADS-B监视信息的处理并与原有的传统航管雷达进行融合相关,提供ADS-B监视服务。     

Distribution of Reference Stations:Initial Explore on the Optimal Selection Strategy

The Satellite-based augmentation system(SBAS) is intended to provide real-time differential global navigation satellite system corrections with the high accuracy,availability,and integrity required for aviation applications.Since the performance of Satellite clock and ephemeris (SCE) corrections and Ionospheric range delay(IRD) corrections can vary dramatically depending on satellites and Ground reference stations (GRSs) geometry,therefore,we present a GRSs distribution optimized crite-ria and process to improve SBAS corrections performance.The present step-by-step optimized scheme using the average satellite surveillance dilution of precision and relative centroid metric availability of grid points as fitness values to determine the appropriate GRSs distribution to sufficiently meet the corrections requirements.The results show that the statistical mean RCM availability can reach more than 0.5518 for all IGPs and the coverage depth of GRSs in China and its surrounding areas is more than 25,which fully satisfies the requirement for solving SCE and IRD corrections.     

多用户分集与能量受限非可信中继系统遍历安全性能分析

研究了一种能量受限的非可信中继与多用户分集技术相结合的两跳链路安全网络通信模型。为提升系统安全性能，本文采用混合时间-功率分配中继(time-power splitting-based relaying, TPSR)协议,并结合机会调度策略(opportunistic scheduling strategy, OSS)从多用户分集网络中选择一个最佳目的节点作为信息接收端。基于随机选择(random selection, RS)策略，该文中利用低复杂度的高斯Q函数分析系统的安全性能以及在协作中继上进行能量采集活动不中断的条件下推导了系统的遍历安全速率(ergodic secrecy rate, ESR)的近似闭合表达式。此外，将提出的OSS与RS通信方案下性能进行对比，证明本文所提出的OSS更适用于分布式多用户选择网络。      

Backbone Topology Synthesis for Multiradio Mesh Networks

Wireless local area network (WLAN) systems are widely implemented today to provide hot-spot coverage. Operated typically in an infrastructure mode, each WLAN is managed by an access point (AP). Wireless mesh networks (WMNs) are employed for the purpose of extending the wireless coverage scope by interconnecting the underlying AP nodes. The capability and performance behavior of the WMN can further be upgraded by using multiple communications channels and by having more capable nodes use multiple radio modules. In this paper, we present a fully distributed multiradio backbone synthesis algorithm, which serves to construct a mesh backbone network of APs. We assume more capable nodes, such as APs, to be equipped with two radio modules, while less capable nodes employ a single radio module. Multihop communications among distant client stations take place in accordance with a routing algorithm that uses the mesh backbone to establish inter-WLAN routes. The presented backbone construction algorithm and the associated on-demand backbone-based routing mechanism are shown to improve the system's delay-throughput performance, as well as its asynchronous and distributed behavior in a stable fashion     

Video Encoding Using an Adaptive Digital Delta Modulator with Overshoot Suppression

An overshoot suppression scheme to improve the performance of the digital Song adaptive delta modulator (DM) for picture transmission is described. This scheme allows for a faster increase in the step sizes than permitted by overshoot and settling time considerations, thus improving rise-time performance. The overshoot suppression (OSS) algorithm used has been verified using computer simulation on a PDP-8. Furthermore, experimental results using computer generated test pictures as well as pictures from a flying-spot scanner show the improvements due to the overshoot suppression scheme. It is also shown that the additional hardware required for the actual implementation of the algorithm is simpler than those encountered in the literature, and gives better signal-tracking accuracy. Upper bounds for the settling time, with and without OSS, are derived showing an improvement with the suppression scheme. Stability conditions are also derived permitting the proper selection of DM parameters.     

航管一次雷达接收/信号产生子系统

航空管制一次雷达主要用于航路空域监视,要求威力大、盲区小、可靠性高,同时探测空中降水分布,引导飞机避开气象危险区。文中介绍了一种航空管制一次雷达接收/信号产生子系统设计,采用了宽、窄双模式波形,单通道频率分集,独立气象通道,双套热冗余及在线定量监测等技术,重点解决宽空间探测范围覆盖、高目标检测概率、兼容气象探测和雷达的高可靠等问题。文中最后给出了研制结果,并进入试值勤应用阶段,取得较满意的效果。     

CDMA无线定位系统的基站选择算法

在基于CDMA网络的无线定位系统中,当移动终端处于多个基站的侦收范围时会面临定位基站的选择问题,基站选择的优化可以减少系统资源的占用,并且直接影响系统定位性能。文中提出采用精度因子的基站选择算法,通过实测验证具有较高的稳定性,并可提高系统的定位精度和实时性,对定位系统的基站架设和系统设计有实际的指导意义。     

基于理想解排序的BDSBAS监测站选址综合评价法

北斗星基增强系统(BDSBAS)作为北斗卫星导航系统的重要组成部分，不仅是解决关键行业高完好性需求的重要手段，也是应对国际激烈竞争的重要举措，还是北斗应用走向国际的重要助力。BDSBAS 地面监测站负责卫星信号的采集、分析、预处理工作，作为提供关键数据的基础设施，合理的选址在北斗星基增强系统建设过程中尤为重要，直接影响着 BDSBAS 系统的性能。主要研究分析电磁干扰、GNSS 天线遮蔽角、多路径干扰、收星数、精度因子(DOP)、 观测值精度等因素对监测站站址选择的影响，结合理论基础与真实数据，提出了一种基于理想解排序算法的综合评价办法，来解决在有限方案中监测站最佳位置的选择问题，为后续的站点布设提供参考数据与依据。     

Greedy Algorithm Applied to Relay Selection for Cooperative Communication Systems in Amplify-and-Forward Mode

Using a relaying system to provide spatial diversity and improve the system performance is a tendency in the wireless cooperative communications. Amplify-and-forward (AF) mode with a low complexity is easy to be implemented. Under the consideration of cooperative communication systems, the scenario includes one information source, M relay stations and N destinations. This work proposes a relay selection algorithm in the Raleigh fading channel. Based on the exhaustive search method, easily to realize, the optimal selection scheme can be found with a highly complicated calculation. In order to reduce the computational complexity, an approximate optimal solution with a greedy algorithm applied for the relay station selection is proposed. With different situations of the communication systems, the performance evaluation obtained by both the proposed algorithm and the exhaustive search algorithm are given for comparison. It shows the proposed algorithm could provide a solution approach to the optimal one.     

Matching and Fairness in Threat-Based Mobile Sensor Coverage

Mobile sensors can be used to effect complete coverage of a surveillance area for a given threat over time, thereby reducing the number of sensors necessary. The surveillance area may have a given threat profile as determined by the kind of threat, and accompanying meteorological, environmental, and human factors. In planning the movement of sensors, areas that are deemed higher threat should receive proportionately higher coverage. We propose a coverage algorithm for mobile sensors to achieve a coverage that will match—over the long term and as quantified by an RMSE metric—a given threat profile. Moreover, the algorithm has the following desirable properties: 1) stochastic, so that it is robust to contingencies and makes it hard for an adversary to anticipate the sensor's movement, 2) efficient, and 3) practical, by avoiding movement over inaccessible areas. Further to matching, we argue that a fairness measure of performance over the shorter time scale is also important. We show that the RMSE and fairness are, in general, antagonistic, and argue for the need of a combined measure of performance, which we call efficacy. We show how a pause time parameter of the coverage algorithm can be used to control the trade-off between the RMSE and fairness, and present an efficient offline algorithm to determine the optimal pause time maximizing the efficacy. Finally, we discuss the effects of multiple sensors, under both independent and coordinated operation. Extensive simulation results—under realistic coverage scenarios—are presented for performance evaluation.