机载惯性/天文组合导航研究

为了满足军用机载平台导航系统对自主性、抗干扰、长航时、高可靠性的要求,设计了一种机载／天文组合导航系统。该系统以激光捷联惯导系统为核心,辅以自主性高、可靠性高的天文导航系统。试验表明,采取一定的技术措施,定位精度有望达到500m,定向精度有望达到30″。     

基于天体系统粒子群算法的异步电机参数辨识

针对标准粒子群优化(PSO)算法存在易早熟收敛的缺点,提出了一种基于天体系统模型的粒子群优化算法(CSPSO).在CSPSO算法中,参照天文学中的天体系统模型,将种群划分为多个相对独立的天体系统,每个系统按照自己的运行规则在不同的空间中运行,在算法的后期引入混沌优化,最终确定出优化问题的全局最优解.将CSPSO算法应用于异步电机参数辨识问题中,仿真结果表明CSPSO算法比GA算法和PSO算法具有更精确的参数辨识能力.     

Optimal Trajectories for Earth-to-Mars Flight

This paper deals with the optimal transfer of a spacecraft from a low Earth orbit (LEO) to a low Mars orbit (LMO). The transfer problem is formulated via a restricted four-body model in that the spacecraft is considered subject to the gravitational fields of Earth, Mars, and Sun along the entire trajectory. This is done to achieve increased accuracy with respect to the method of patched conics.The optimal transfer problem is solved via the sequential gradient-restoration algorithm employed in conjunction with a variable-stepsize integration technique to overcome numerical difficulties due to large changes in the gravitational field near Earth and near Mars. The optimization criterion is the total characteristic velocity, namely, the sum of the velocity impulses at LEO and LMO. The major parameters are four: velocity impulse at launch, spacecraft vs. Earth phase angle at launch, planetary Mars/Earth phase angle difference at launch, and transfer time. These parameters must be determined so that V is minimized subject to tangential departure from circular velocity at LEO and tangential arrival to circular velocity at LMO.For given LEO and LMO radii, a departure window can be generated by changing the planetary Mars/Earth phase angle difference at launch, hence changing the departure date, and then reoptimizing the transfer. This results in a one-parameter family of suboptimal transfers, characterized by large variations of the spacecraft vs. Earth phase angle at launch, but relatively small variations in transfer time and total characteristic velocity.For given LEO radius, an arrival window can be generated by changing the LMO radius and then recomputing the optimal transfer. This leads to a one-parameter family of optimal transfers, characterized by small variations of launch conditions, transfer time, and total characteristic velocity, a result which has important guidance implications. Among the members of the above one-parameter family, there is an optimum–optimorum trajectory with the smallest characteristic velocity. This occurs when the radius of the Mars orbit is such that the associated period is slightly less than one-half Mars day.     

光子结构的猜想及其数学仿真

通过研究光的波粒二象性,对光子结构进行了研究并提出了自建光子模型.自建光子模型具有以下特性:①光子与原子核存在引力作用;②光子的电场与磁场交替变换使其具备了相位效应,且光强由光子数与光子相位和两个因素决定.在此基础上,通过借鉴天体物理中关于二体运动的三种轨迹,利用其中结论对大量原子核的引力作用进行概率分析,使用中心极限定理提出出射角度基本符合高斯分布的假设.接着对光子的相位叠加效应进行了分析.最后,对大量光子进行模拟仿真,并将仿真结果与单缝衍射、双缝干涉、多缝干涉现象等实验现象进行了对比.     

东北地区地仙信仰的人类学研究

动物信仰是中国北方地区最普遍的民间信仰。它在不同的地域反映出了不同的社会文化特征。华北地区的“四大门”和东北地区的“地仙”表面上虽具有相似的信仰形态,但在东北地区,动物信仰经过融合多种地方因素已经发展成一套具有地方特色的信仰体系。     

如何在理论力学课中加强天文教学

简要介绍了在理论力学课的教学过程中,如何适量、适度地穿插天文学内容的一些做法和体会,通过教学实践达到了较好的教学效果.     

天体系统和粒子系统的相似性归纳

归纳给出宏观天体系统和微观粒子系统在运动形式、系统结构、作用力形式和电磁特性等4个方面的相似特性.     

两组星矢量的最小均方误差匹配算法

在多星矢量定位中，由本地坐标系中的光电探测器拍摄到的多星矢量数据需要变换到赤道坐标系中，并与赤道坐标系中的多星矢量数据进行匹配，当匹配误差达到最小时，根据变换矩阵即可确定舰位和航向。由于存在测量误差，因此不可能精确匹配。通过与点模式匹配问题类比，给出了一个求取两组星矢量之间最佳变换矩阵的算法，该算法使匹配误差在均方根意义下达到最小并且其计算复杂性仅为O（n），从而提高了天文定位的精度以及天文定位系统的反应速度。     

Kinematics in Randers-Finsler geometry and secular increase of the astronomical unit

Kinematics in Finsler space is investigated. It is shown that the result based on the kinematics with a special Finsler structure is in good agreement with the reported value of the secular trend in the astronomical unit, dAU/dt=15±4[m/century]. The space deformation parameter λ in this special structure is very small, with a scale of 10^-6, and should be a constant. This is consistent with the reported value of an anomalous secular eccentricity variation of the Moon's orbit.