A Self-organizing Bearings-only Target Tracking Algorithm in Wireless Sensor Network

In the bearings-only target tracking, wireless sensor network (WSN) collects observations of the target direction at various nodes and uses an adaptive filter to combine them for target tracking. An efficient network management is necessary to gain an optimal tradeoff between locating accuracy and energy consumption. This article proposes a self-organizing target tracking algorithm to select the most beneficial subset of nodes to track the target at every snapshot. Compared with traditional methods, this scheme avoids the need for keeping global position information of the network as in greedy selection. Each node judges its future usefulness depending on the knowledge of its own position and using simple mathematics computation. Simulations indicate that this scheme has locating accuracy comparable to the global greedy algorithm. Also, it has good robustness against node failure and autonomous adaptability to the change of the network scale. Furthermore, this algorithm consumes limited energy because only a portion of nodes partakes in the selection at every snapshot.     

Local node selection for localization in a distributed sensor network

This paper discusses a new localized resource manager for a wireless sensor network of bearings-only sensors. Specifically, each node uses knowledge of the target under surveillance to determine whether it should actively collect measurements and how far to disseminate the data in order for the sensor network to maintain track of the target. At each node, the resource manager requires only knowledge of the relative location to the target for itself and the active nodes from the previous snapshot. The decentralized strategy represents a modification to the global node selection (GNS) method that exploits knowledge of the location of all nodes in the network. Simulations show that despite the lack of global network knowledge, the new localized management method is almost as effective as GNS in terms of balancing the tradeoff between energy usage and localization accuracy.     

Heuristics of node selection criteria to assess robustness of world airport network

The world airport network (WAN) is one of the networked infrastructures that shape today's economic and social activity,so its resilience against incidents affecting the WAN is an important problem.In this paper,the robustness of air route networks is extended by defining and testing several heuristics to define selection criteria to detect the critical nodes of the WAN.In addition to heuristics based on genetic algorithms and simulated annealing,custom heuristics based on node damage and node betweenness are defined.The most effective heuristic is a multiattack heuristic combining both custom heuristics.Results obtained are of importance not only for advance in the understanding of the structure of complex networks,but also for critical node detection.     

航路网络生成及优化

空中交通流运行的安全性和成本取决于航路网络结构。基于节点度实现航路网络枢纽节点和干线节点分层,利用全局耦合生成主干网络,运用距离连接概率实现干线节点社区化,采用连接概率生成社区网络;采用DBSCAN聚类算法,基于角度和距离实现航路网络优化;以中国大陆空域为例,实现了主干航路网络和局部干线航路网络的生成及优化,验证了方法的可行性。在与相关研究对比,基于节点度的枢纽节点选取更加客观合理,所构建的分层航路网络结构符合机场点的分布特性,采用DBSCAN聚类算法优化效率明显提高。     

控制器故障下的软件定义机载网络数据平面迁移策略

软件定义网络（SDN）为突破机载网络功能僵化所造成的瓶颈提供了新的契机。针对软件定义机载网络控制域内控制节点故障问题,提出一种基于时延和负载均衡的传输节点迁移策略,将故障控制节点所管控数据平面中的传输节点迁移至其他正常控制节点,恢复网络的正常管控。以迁移时延和负载均衡率为目标,建立迁移优化模型,提出基于时延和负载均衡的传输节点迁移算法,指导数据平面中的迁移动作,最终对两个性能目标进行综合权衡。实验结果表明,与距离就近迁移（DCM）策略和分布式逐跳（DHA）策略相比,所提策略在迁移时延和负载均衡率2个方面进行了合适的折中,避免出现迁移时延过大或控制节点负载失衡的情况,有效解决机载网络故障恢复问题。     

A Fast Global Node Selection Algorithm for Bearings-only Target Localization

In the target tracking, the nodes aggregate their observations of the directions of arrival of the target. The network then uses an extended Kalman filter （EKF） to combine the measurements from multiple snapshots to track the target. In order to rapidly select the best subset of nodes to localize the target with the minimum mean square position error and low power consumption, this paper proposes a simple algorithm, which uses the location information of the target and the network. The lower botmd of localization error is utilized according to the distances between the target and the selected active nodes. Furthermore, the direction likelihoods of the active nodes is predicted by way of the node/target bearing distributing relationships.     

空中力量体系对抗中目标选择方法

基于目标价值的目标选择方法,能够综合体现目标自身属性和体系网络结构对目标选择的影响。文章在分析空中力量体系网络结构的基础上,将目标价值分为属性价值和结构价值2个维度,利用模糊偏序关系建立属性价值评估模型,定义节点连通度和节点关键度,确定结构价值评估算法,实例分析结果验证了该目标选择方法的有效性。     

AeroMTP: A fountain code-based multipath transport protocol for airborne networks

Airborne networks(ANs) are special types of ad hoc networks that can be used to enhance situational awareness, flight coordination and flight efficiency in civil and military aviation.Compared to ground networks, ANs have some unique attributes including high node mobility, frequent topology changes, mechanical and aerodynamic constrains, strict safety requirements and harsh communication environment.Thus, the performance of conventional transmission control protocol(TCP) will be dramatically degraded in ANs.Aircraft commonly have two or more heterogeneous network interfaces which offer an opportunity to form multiple communication paths between any two nodes in ANs.To satisfy the communication requirements in ANs, we propose aeronautical multipath transport protocol(Aero MTP) for ANs, which effectively utilizes the available bandwidth and diversity provided by heterogeneous wireless paths.Aero MTP uses fountain codes as forward error correction(FEC) codes to recover from data loss and deploys a TCP-friendly rate-based congestion control mechanism for each path.Moreover, we design a packet allocation algorithm based on optimization to minimize the delivery time of blocks.The performance of Aero MTP is evaluated through OMNe T++ simulations under a variety of test scenarios.Simulations demonstrate that Aero MTP is of great potential to be applied to ANs.     

时变耦合复杂网络的混沌同步在保密通信中的应用

在时变耦合复杂动态网络同步的基础上研究复杂网络节点间的保密通信，并以Lorenz方程为复杂网络节点的状态方程为例，验证了复杂网络的同步在保密通信中应用的有效性。     

航空电子微距太赫兹互连DRR访问容量分析

为了减轻机载电子系统线缆和连接器的重量,减小其体积并降低维护成本,在航空电子组件的电路板或芯片之间,可以采用太赫兹通信技术实现厘米量级的微距互连。采用开关键控（OOK）调制和非相干解调实现点到点太赫兹互连,给出了数据速率、数据包长度等参数的设计方法,进而构建包含用户节点和簇头节点的半双工多路访问分簇网络架构。在簇内用户节点到簇头节点的介质访问控制协议中采用赤字轮询（DRR）机制,并采用随机网络演算（SNC）方法得到概率保证意义下多路访问的有效服务容量,分析了阻塞干扰对DRR服务曲线的影响。分析和算例表明,DRR访问在保证实时性能界限的条件下兼顾了多路访问的灵活性,满足航空电子微小型化组件之间太赫兹通信和分簇组网的需求。     

Acoustic node calibration using a moving source

Acoustic nodes, each containing an array of microphones, can track targets in x-y space from their received acoustic signals, if the node positions and orientations are known exactly. However, it is not always possible to deploy the nodes precisely, so a calibration phase is needed to estimate the position and the orientation of each node before doing any tracking or localization. An acoustic node can be calibrated from sources of opportunity such as beacons or a moving source. We derive and compare several calibration methods for the case where the node can hear a moving source whose position can be reported back to the node. Since calibration from a moving source is, in effect, the dual of a tracking problem; methods derived for acoustic target trackers are used to obtain robust and high resolution acoustic calibration processes. For example, two direction-of-arrival-based calibration methods can be formulated based on combining angle estimates, geometry, and the motion dynamics of the moving source. In addition, a maximum likelihood (ML) solution is presented using a narrowband acoustic observation model, along with a Newton-based search algorithm that speeds up the calculation the likelihood surface. The Cramer-Rao lower bound (CRLB) on the node position estimates is also derived to show that the effect of position errors for the moving source on the estimated node position is much less severe than the variance in angle estimates from the microphone array. The performance of the calibration algorithms is demonstrated on synthetic and field data.     

Communication system architecture for planetary exploration

Future human missions to Mars will require effective communications supporting exploration activities and scientific field data collection. Constraints on cost, size, weight, and power consumption for all communications equipment make optimization of these systems very important. These information and communication systems connect people and systems together into coherent teams performing the difficult and hazardous tasks inherent in planetary exploration. The communication network supporting vehicle telemetry data, mission operations, and scientific collaboration must have excellent reliability and flexibility. We propose hybrid communication architectures consisting of space-based links, a surface-based deployable mid-range communications network and a cluster of short-range links to solve the problems of connectivity and bandwidth, while meeting the other constraints of weight and power. A network of orbiting satellites could cover much of the planet surface, but this space-based capability may not be optimal for cost or performance. Specifically, a minimal space-based capability can be augmented using mobile cellular repeaters deployable by robots and human EVA. This method results in an increase in the number of radio nodes, but the distances separating them is decreased. This results in a significant increase in bandwidth and decrease in radio power, and therefore, node size, complexity, and power consumption. This paper will discuss the results of field testing such hybrid radio systems for the support of scientific surveys. System analysis of design tradeoffs will yield insight into optimal solutions that will be compared to other approaches providing a method of effectively evaluating new candidate architectures     

基于场景识别的惯性基类脑导航方法

针对无人机导航中惯性器件产生的漂移误差不断随时间累积进而影响导航精度的问题,以仿生类脑导航为研究背景,提出了一种新的导航方法。与传统导航策略不同的是,该方法从周期性校正累积位置误差的角度出发,采用设置位置细胞节点的思路,利用训练好的卷积神经网络模型在细胞节点处进行图像匹配,从而在位置细胞节点处实现惯导位置漂移误差校正。同时,建立节点之间的漂移误差模型,调整误差方程系数,以达到修正漂移误差的目的。最后,基于无人机飞行实验结果验证了该方法对自主导航的有效性和鲁棒性,该方法能够有效提高无人机导航的精度。     

A Note on Bounds for Target Tracking with pd>1

Recently several new results for Cramer-Rao lower bounds (CRLBs) in dynamical systems have been developed. Several different approaches and approximations have been presented. For the general case of target tracking with a detection probability smaller than one and possibly in the presence of false measurements, two main approaches have been presented. The first approach is the information reduction factor (IRF) approach. The second approach is the enumeration (ENUM) approach, also referred to as the conditioning approach. It has been found that the ENUM approach leads to a strictly larger covariance matrix than the IRF approach, however, still providing a lower bound on the attainable error covariance. Thus, the ENUM approach provides a strictly tighter bound on the attainable performance. It has been conjectured that these bounds converge to one another in the limit or equivalently after an initial transition stage. We demonstrate, using some recent results from the modified Riccati equation (MRE) and by means of counter examples, that this conjecture does not hold true in general. We also demonstrate that the conjecture does hold true in the special case of deterministic target motion, or equivalently in the absence of process noise. Furthermore, we show that the detection probability has an influence on the limiting behaviors of the bounds. Moreover, we show that the MRE approximation provides a very good and computationally efficient approximation of the ENUM bound. The various results are illustrated by means of representative examples.     

基于动态变结构BP神经网络的目标威胁评估

针对传统目标威胁估计方法和BP神经网络的不足,在BP神经网络的基础上,建立了基于动态变结构BP神经网络的目标威胁估计模型.该模型通过在权值向量更新公式中引入冲量函数,加快了网络的搜索速度和精度,保证了网络获得全局最优值;通过实时调整隐含层节点数目,可以将网络结构优化,极大地提升了网络的灵活性.仿真结果表明,与传统目标威胁估计方法和BP神经网络相比,动态变结构BP神经网络具有更好的预测能力和收敛速度,可以快速、准确地完成目标威胁估计.     

数据分发服务自发现机制的研究

机载综合化电子系统中网络类型不断多样化,传统数据总线已不再满足要求,对象管理组织(OMG)提出了的一种基于发布订阅模型的数据分发服务,对实现统一通信平台,提供灵活、实时的数据分发能力具有指导意义.在使用数据分发服务时,不同节点间的相互识别,建立发布订阅关系的过程极为重要,影响分布式系统的通信性能,因此,研究数据分发服务的自发现机制具有极其重要的意义.     

Future architecture of flight control systems

The development of fault tolerant embedded control systems such as flight control systems (FCS) are currently highly specialized and time-consuming. We introduce a conceptual architecture for the next decade control system where all control and logic are distributed to a number of computer nodes locally linked to actuators and connected via a communication network. In this way, we substantially reduce the life-cycle cost of embedded systems and attain scalable fault tolerance. All fault tolerance is based on redundancy. Our philosophy is to cover permanent faults with hardware replication and handle all error processing caused by both permanent and transient faults with software techniques. With intelligent nodes and use of inherent redundancy we introduce a robust and simple fault tolerant system that utilizes minimum hardware and has bandwidth requirements of less than 300 kbits/s, which can be met with an electrical bus. The study is based on an FCS for JAS 39 Gripen, a multi-role combat aircraft that is statically unstable at subsonic speed.     

Topology tracking of dynamic UAV wireless networks

Wireless network is the communication foundation that supports the intelligentization of Unmanned Aerial Vehicle(UAV) swarm. The topology of UAV communication network is the key to understanding and analyzing the behavior of UAV swarm, thus supporting the further prediction of UAV operations. However, the UAV swarm network topology varies over time due to the high mobility and diversified mission requirements of UAVs. Therefore, it is important but challenging to research dynamic topology infere...     

一种面向航空集群的集中控制式网络部署方法

软件定义网络（SDN）的发展为机载网络构建提供了全新的设计思想。针对航空集群环境下控制平面的可扩展性问题,研究了混合层次式架构下的多控制器部署问题。首先,为实现对底层传输节点的弹性管控,通过扩展控制层级定义了本地控制器资源池。然后,为减少时间复杂度,实现本地控制器的快速部署,将传统的多控制器直接部署转化为子域划分和域内部署两个步骤,提出了基于节点密度排序的子域划分算法和基于改进多目标模拟退火的域内控制器部署算法。实验结果表明：与已有算法相比,所提算法在保证控制器的负载均衡基础上,可以有效减少网络控制链路的平均时延和平均失连率,同时时间复杂度更低,能够适用于大规模及动态网络环境下的控制器部署场景。     

一种基于多无人机的中继节点布置问题建模与优化方法

针对战场环境下急需在无法通信的节点间构建有效通信链路的情形,使用多无人机作为中继节点,建立了中继节点布置(RNP)问题模型。模型以中继链路有效和无人机安全为约束,以中继布置点位置及相应的无人机为输出,不但考虑了使用的中继无人机数量,还考虑了构建中继链路花费的时间。考虑到该问题是难以求解的混合整数多目标优化问题,同时在紧急应用情形下,要求求解算法快速有效,建立了一种多项式时间中继节点布置算法(PTRPA)。仿真实验验证了所提模型确实能够在更短的时间内完成有效中继链路构建;通过Monte-Carlo方法对比和分析不同因素对PTRPA算法、随机抽样算法、遗传算法求解该问题的结果性能和时间性能的影响,验证了PTRPA算法不但能够给出接近最优的解,且快速有效,满足战场决策需求。