水下无线传感器网络的节点精确定位

以无线传感器网络(WSN)水下应用为背景,针对特定的环境要求,提出了一种可实现网络规模升级的分布式无锚点网络节点自定位机制。该定位算法通过距离误差估计和分布式坐标计算方法,有效地减少了由于测量距离误差所带来的坐标计算误差和节点坐标计算所带来的通信开销,有利于网络节点能量的合理使用和大规模的WSN布放。通过试验仿真计算,验证了该定位机制的合理性,为水下WSN应用提供了有力的技术支持。     

Alleviating time inconsistent behaviors via a competition scheme

Under quasi‐hyperbolic discounting, the valuation of a payoff falls relatively rapidly for earlier delay periods, but then falls more slowly for longer delay periods. When the salespersons with quasi‐hyperbolic discounting consider the product sale problem, they would exert less effort than their early plan, thus resulting in losses of future profit. We propose a winner‐takes‐all competition to alleviate the above time inconsistent behaviors of the salespersons, and allow the company to maximize its revenue by choosing an optimal bonus. To evaluate the effects of the competition scheme, we define the group time inconsistency degree of the salespersons, which measures the consequence of time inconsistent behaviors, and two welfare measures, the group welfare of the salespersons and the company revenue. We show that the competition always improves the group welfare and the company revenue as long as the company chooses to run the competition in the first place. However, the effect on group time inconsistency degree is mixed. When the optimal bonus is moderate (extreme high), the competition motivates (over‐motivates) the salesperson to work hard, thus alleviates (worsens) the time inconsistent behaviors. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 357–372, 2017     

双天线干涉SAR系统无控制点场景的高精度参考相位快速估计算法

为解决无控制点场景参考相位的快速估计问题,对影响参考相位的因素进行理论分析,给出参考相位与影响因素的解析关系式。结合系统参数进行仿真分析,分析参考相位对高程误差的影响。根据分析结果,结合外部粗精度高程数据、滤波后的干涉相位及相干系数,提出高精度参考相位快速估计算法,并给出算法详细实现流程。对实际机载双天线干涉合成孔径雷达系统获取的数据进行处理,结果表明:算法在文中的系统参数下可以达到优于2 m的相对高程精度,处理4096×6560像素的数据块时,参考相位估计速度至少增大20倍。     

北斗全球系统导航信号恒包络调制和复用技术

出于以导频通道为代表的北斗全球导航卫星系统现代化信号结构升级以及后向兼容的需求,北斗系统近几年提出了多种新型恒包络调制和复用技术,包括适用于北斗系统B1频点的正交复用二进制偏移载波(QMBOC)调制和非对称双正交相移键控(ADualQPSK)调制,适用于B2频点的时分复用AltBOC(TDAlt BOC)调制与非对称恒包络二进制偏移载波(ACE-BOC)调制,适用于B3频点的双正交相移键控(DualQPSK)调制,适用于双边带任意信号路数、任意功率配比的广义恒包络二进制偏移载波(GCE-BOC)调制。本文系统性地论述了北斗全球系统中提出的多种新型恒包络调制和复用技术,在此基础上基于GCEBOC调制总结出了一种恒包络调制的统一解析表示形式,对全面理解北斗全球系统信号设计思路及在此基础上发展设计新型的恒包络调制和复用技术均能提供重要的借鉴。     

北斗导航系统移动基准站差分定位算法

针对复杂测量环境无法建立固定基准站及进行精密定位的问题,提出一种基于北斗导航系统的移动基准站差分定位算法,即基准站与流动站同时运动并实现高精度差分定位的算法。基于载波相位测量值,在动态短基线条件下,对数据进行站间和星间双差处理,消除接收机钟差以及其他公共误差。对多频观测值进行线性组合,构造双差载波相位超宽巷、宽巷、中巷及窄巷观测量。对上述观测量进行窗口滑动均值滤波并采用逐级模糊度确定法固定整周模糊度,即沿着从超宽巷到窄巷的顺序依次求解整周模糊度。为验证算法有效性,设计基于北斗导航系统的轨道外部几何参数检测仪进行实验,实现毫米级静态相对定位精度和厘米级RTK相对定位精度。     

一种稳健的循环平稳信号时延估计算法

基于信号循环平稳特性的时延估计算法具有较强的抗干扰和抗噪声能力,但循环频率误差时性能下降严重。针对这一问题,首先分析了循环频率误差对循环时延估计算法中,循环互相关函数相关法估计性能的影响,进而提出了一种对循环频率误差稳健的改进循环时延估计算法。改进算法通过两次搜索确定循环频率的真实值。仿真实验结果表明,改进算法可以有效地校正循环频率误差,最终使时延估计误差与无循环频率误差时基本相同。     

面向联合作战行动设计的态势差分析机理研究

文章介绍了态势差的概念内涵,分析了在设计联合作战行动时为什么要分析态势差,阐述了如何分析态势差。态势差分析是工程化作战筹划的一个环节,研究态势差分析机理,能为作战行动设计提供有力支撑,提高作战筹划效率。     

飞行器试验多测控目标发射零点应急处理方法

飞行器飞行试验任务中,发射零点T0是整个测控系统启动运行的基准点,是保证测控系统有条不紊正常工作的关键因素。特别是执行多个测控目标连射飞行试验任务,多个发射零点的正确处理更是关乎试验任务的成败。在分析发射零点形成机制基础上,对发射零点在指控系统实时测控软件中的处理方法进行了研究,提出了一种实时测控软件重启后重新获得多测控目标正确发射零点的应急处理方法,解决了试验过程中一旦实时测控软件因重大软件故障导致初始发射零点丢失的问题,保障了试验任务的顺利进行。     

Single batch machine scheduling with deliveries

We consider the problem of scheduling a set of n jobs on a single batch machine, where several jobs can be processed simultaneously. Each job j has a processing time p_j and a size s_j. All jobs are available for processing at time 0. The batch machine has a capacity D. Several jobs can be batched together and processed simultaneously, provided that the total size of the jobs in the batch does not exceed D. The processing time of a batch is the largest processing time among all jobs in the batch. There is a single vehicle available for delivery of the finished products to the customer, and the vehicle has capacity K. We assume that K = rD, where and r is an integer. The travel time of the vehicle is T; that is, T is the time from the manufacturer to the customer. Our goal is to find a schedule of the jobs and a delivery plan so that the service span is minimized, where the service span is the time that the last job is delivered to the customer. We show that if the jobs have identical sizes, then we can find a schedule and delivery plan in time such that the service span is minimum. If the jobs have identical processing times, then we can find a schedule and delivery plan in time such that the service span is asymptotically at most 11/9 times the optimal service span. When the jobs have arbitrary processing times and arbitrary sizes, then we can find a schedule and delivery plan in time such that the service span is asymptotically at most twice the optimal service span. We also derive upper bounds of the absolute worst‐case ratios in both cases. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 470–482, 2015     

机翼不对称损伤飞机在大侧滑角下的操稳特性研究

对某小型电动无人机(以下简称SEPUAV)在其左翼破损40%面积矩下的操稳特性进行详细分析。首先在此损伤下典型大侧滑角定常工作点附近进行特殊的小扰动线性化,然后进行特征根和飞行运动模态的分析;其次对此特殊构型SEPUAV进行操稳特性、时频响应特性进行分析。分析结果表明:左翼破损40%面积矩SEPUAV出现特有运动模态并影响全部纵侧向运动状态的响应;部分传递函数出现较多非最小相位零点从而导致初始响应发生反向;部分通道的Bode图中出现多个波峰波谷并有相角提前等现象。分析结果对后续容损飞行控制器的设计起到铺垫的作用。