一种新传感器组网策略在纯方位目标跟踪中的应用

纯方位目标定位精度不仅与所选择的节点数目有关，而且还与目标和节点间的相对位置有关，为了同时满足目标的定位精度尽量高和节点能量消耗尽量少这一要求，提出了一种改进的基于多目标蚁群优化算法的传感器节点组网策略。在此基础上，推导了基于当前统计模型的分散式纯方位跟踪算法并对纯方位机动目标实施跟踪。仿真结果表明：在选择相同数目节点的前提下，本文所提出的节点选择方法与传统的最近邻方法相比，跟踪精度不仅得到了提高，而且还节约了节点的能量消耗。     

基于改进蚁群算法的巡航导弹航迹规划

研究了一种基于改进蚁群算法的巡航导弹航迹规划方法，以规划出生存概率更大、飞行距离更短的攻击轨迹，有效提高巡航导弹的作战效能。提出了坐标变换的思想，通过坐标变换将蚁群算法中信息素局部更新策略和全局更新策略协同作用的机制合理地应用到了航迹规划中，通过将信息素全局更新规则中的信息素常量和挥发率进行自适应变化来对算法进行了改进，最后对算法进行了计算机编程仿真实现。仿真结果验证了改进算法能有效避免算法过早陷入局部最优，加快算法的收敛速度，能取得目标函数更优的航迹规划路径。     

A theoretical assessment of the feasibility of potential Lunar Reconnaissance Orbiter radio occultation observations of the lunar ionosphere

The existence of a “dense” lunar ionosphere has been controversial for decades. Positive ions produced from the lunar surface and exosphere are inferred to have densities that are $?$${10}^6$ – ${10}^7$ m^?3 near the surface and smaller at higher altitudes, yet electron densities derived from radio occultation measurements occasionally exceed these values by orders of magnitude. For example, about 4% of the single-spacecraft radio occultation measurements from Kaguya/SELENE were consistent with peak electron densities of $~$$3\times {10}^8$ m^?3. Space plasmas should be neutral on macroscopic scales, so this represents a substantial discrepancy. Aditional observations of electron densities in the lunar ionosphere are critical to resolving this longstanding paradox. Here we theoretically assess whether radio occultation observations using two-way coherent S-band radio signals from the Lunar Reconnaissance Orbiter (LRO) spacecraft could provide useful measurements of electron densities in the lunar ionosphere. We predict the uncertainty in a single LRO radio occultation measurement of electron density to be $~$$3\times {10}^8$ m^?3, comparable to occasional observations by Kaguya/SELENE of a dense lunar ionosphere. Thus an individual profile from LRO is unlikely to reliably detect the lunar ionosphere; however, averages of multiple ($~$10) LRO profiles acquired under similar geophysical and viewing conditions should be able to make reliable detections. An observing rate of six ingress occultations per day ($~$2000 per year) could be achieved with minimal impact on current LRO operations. This rate compares favorably with the 378 observations reported from the single-spacecraft experiment on Kaguya/SELENE between November 2007 and June 2009. The large number of observations possible for LRO would be sufficient to permit wide-ranging investigations of spatial and temporal variations in the poorly understood lunar ionosphere. These findings strengthen efforts to conduct such observations with LRO.     

改进人工蜂群算法及其轴流压气机优化应用

为了探索更优的全局优化算法并将其应用于轴流压气机气动优化上,将标准人工蜂群（ABC）算法中采蜜蜂和观察蜂探索新蜜源的方式进行改进,从而更好地利用总体蜜源的探索信息,得到改进人工蜂群（IABC）算法。经基准函数测试表明,改进算法既能提升全局寻优能力,又能加快收敛速度。采用IABC算法和经过校核的CFD数值方法搭建优化平台,对单级跨声速轴流压气机Stage35进行优化。优化变量为动叶和静叶径向6个截面的弯、掠、前缘重弯值和尾缘重弯值,以流量和压比相对变化保持在0.5%以内为约束条件,以提高绝热效率为优化目标。结果表明：在设计转速下,优化后设计点绝热效率提升0.83%,全工况范围内平均绝热效率提升2.0%,同时喘振裕度提升1.0%,验证了IABC算法在轴流压气机优化中的有效性。     

基于CST方法的高空低雷诺数吸附式叶型耦合优化设计

研究了一种基于类别形状函数变换（CST）方法的吸附式叶型优化设计方法,该方法可以在高空低雷诺数条件下对叶型和抽吸方案耦合优化.结果表明:优化之后在20km高空低雷诺数条件下总压损失降低了65%,静压升提高了0.02,气动性能得到较大提升.而且由于优化过程中罚函数的引入使得优化后吸附式叶型在地面条件下性能也有所提高.对于高空低雷诺数条件下吸附式叶型在抽吸位置之前适当的增加叶型负荷,再通过抽吸来控制附面层,效果最优.并且最佳抽吸位置位于层流分离泡作用区域内.在层流分离泡作用区域内抽吸可以完全消除层流分离泡对叶型性能的影响,并且可以较好控制附面层位移厚度和动量厚度的增加,有效地减小附面层内的动量损失.      

Estimation of optical maturity parameter for lunar soil characterization using Moon Mineralogy Mapper (M3)

Prolonged exposure of the microscopic outer layer of the lunar surface to the space environment leads to the maturation of the surface. Maturation can be quantified and it may be expressed in terms of optical maturity (OMAT). Optical maturity estimations are very much helpful in the identification and mapping of the major minerals present on the lunar regolith. Estimation of the maturation and mineral mapping using remote sensing techniques are achieved, by coupling spectral reflectance of the lunar surface with an optimized origin. The present work estimates the optical maturity and Ferrous oxide content of the Goldschmidt and Schrodinger craters, through the recalibration of the classical method of Lucey et al. (2000a) with an origin of (0.08, 1.18) and Moon Mineralogy Mapper (M3) data. The overall recalibration results assure that the craters are highly matured.     

三维真实地形环境下无人机救援航路规划方法

利用无人机(UAV)的三维飞行能力,采用优化方法规划路径,能够使其在救援任务中比地面车辆以更短的时间到达救援区域,提高救援效率.针对真实的地理环境,根据无人机约束采用均匀化网格方法进行地形建模,之后根据地形数据的特点设计适合数学计算与求解的数据结构.最后设计了包含偏离代价、高度代价、地形跟随/回避代价、威胁代价和安全距离代价的综合性能指标函数,并采用航路点交叉和网格搜索代替航路点搜索的方法,对蚁群算法进行改进完成航路规划.仿真结果表明:本文方法能够直接处理三维地形数据,在保持地貌的前提下,完成了无人机的三维航路规划任务,得到满足无人机约束的三维最优航路,提高了航路规划方法的实用价值.      

基于特征模型的火箭发动机伺服控制系统设计

以新型大推力火箭发动机为研究对象,提出了基于特征模型的伺服系统控制器设计方法。首先,介绍了特征建模理论并讨论了特征模型参数范围;其次,采用人工蜂群算法实时估计火箭发动机伺服系统特征模型参数,使其满足特征模型输出与实际系统输出特性等价条件;最后,使用黄金分割自适应控制律保证系统在参数估计过程中的闭环稳定性,同时引入前馈跟踪控制律,逻辑积分控制律和逻辑微分控制律使伺服控制系统快速、精确跟踪线位移指令并改善动态性能。仿真结果表明,设计的火箭发动机伺服控制系统指令跟踪精度高,动态特性良好,鲁棒性强。     

Very low frequency interferometry for the Chang’E-2 project

Very low frequency interferometry among two astronomical experiments has been proposed and accepted for further study for the second phase of China’s lunar exploration programme (the Chang’E Programme), which is envisaged to operate a lander and a rover on the surface of the moon. This experiment is an interferometer experiment in the very low frequency (VLF, f < 15 MHz) regime of radio frequencies with at least degree-level angular resolution. The goals include observing solar storm activities, Coronal Mass Ejections, Auroral Kilometric Radiation, and planetary radiation in the solar system, studying the origin of Cosmic Rays, spectral properties of pulsars, surveying ionized hydrogen in the Galaxy, and exploring coherent radio emissions.     

面向单机相依任务调度的GPU并行蚁群算法

蚁群算法是一种具有高度并行特征的群智能算法,串行实现过程中具有收敛速度慢的特点,在将其应用到相依任务序列的单机调度问题中时,以任务在不同作业序下的完成时间为基础,建立了单机调度问题的TSP模型。以任务完成时间最优化为目的,实现了一种求解相依任务单机调度的改进蚁群算法,并基于GPU对其进行了并行化设计。实验表明该算法能够完成相依任务的调度处理,通过并行化得到了较高的加速比。