小卫星磁场分布测量方法研究

文章通过分析卫星磁场与地磁场的关系,确立了磁场分布的测量方法,并对测量误差进行了分析.     

卫星系统和部件的退磁方法

1 前言自从对 IMP 和 OGO 卫星系统和部件进行磁试验以来,退磁已经做为一种把试验物体恢复到近零的原始磁状态的方法。1962年和1963年间,在部件磁试验设备(CMTF)中使用了直流退磁。近此时候完成的退磁试验是用60Hz 交流磁场退磁,代替了直流退磁。在一般的情况下,用初始磁场强度等于材料的矫顽力的磁场强度为铁磁材料退磁,肯定会退掉由材料磁性饱和引起的剩磁。     

在地磁场中做卫星磁测量的几个问题

卫星地面磁测量是卫星环境试验的一个重要组成部分,精确的磁测量必须磁场或可控磁场中做。在没有大型磁设备的情况下,提出在地磁场中做磁测量题。本文分析了在地磁场中做磁测量的特点和影响测量精度的因素,指出了在场中做磁测量的应用范围,测量方法及在测量中应注意的问题,给出了在地磁做磁矩测量的几个试验测量结果。     

中低轨道地磁动态模拟器

文章介绍了1台能为中低轨道飞行器提供动态地磁场环境的模拟器,详细论述了模拟器的系统组成、线圈结构、电源和磁强计指标参数、控制方式和调试方法,介绍了根据WMM2000地磁场模型计算出轨道上各点的磁场值,利用数值分析的方法找出输出电流与产生磁场大小的对应表达式,从而根据计算出的磁场值和输出电流,用程控电源成功实现了中低轨道地磁场的动态模拟.     

OGO和ERS卫星的磁试验

这篇文章描述了在位于 Malibu 的 TRW Malibu 磁试验设备中完成的 OGO 和 ERS 卫星磁特性的试验结果和使用的试验方法。最关心的卫星磁特性是在星载磁探测器位置处的卫星磁场,包括永磁场和感磁场。同时还关心星的"硬"磁场,即永磁场的大小和可以被一般磁化环境引起变化的"软"磁场的大小。一般磁化环境是指卫星在发射进入轨道前,会遇到的磁化环境。另外关心的磁特性是卫星磁场的分布图和位于卫星中心的偶极子矩和高阶的多极子矩,其中包括永磁矩和感磁矩。Malibu 试验室由安装在地下室6.4m 的三轴 Fanselau—Braunbeck 线圈系统和一些试验楼组成。转台位于其中的一座试验楼里,在这座试验楼里给卫星做没有线圈的磁试验。例如,OGO 卫星太大了,不能放入 Fanselau—Braunbeck 线圈系统中,因此就在此试验楼里进行试验。有线圈和没有线圈的试验方法是将卫星相对于固定的三轴磁通门探测器进行两轴旋转。旋转周期要比能觉察到的环境地磁场的变化周期短。可用一个远距离的探测器对地磁场的变化进行补偿,来满足上述的要求。磁通门探测器的输出由多通道 Sanborn 记录仪和 X—Y绘图仪记录,X—Y绘图仪可以立即按比例绘制旋转平面的磁矩大小,还可以给出在卫星座标系中的磁矩方向。卫星再绕另一相互垂直正交轴旋转,记录其数据。从这些数据中可以得到的总的磁矩矢量。ERS 卫星是一个280mm 的八面体,所以很容易将其放入 Fanselau—Braun-beck 线圈系统。在线圈系统中能够分别测量卫星场永磁分量和感磁分量。     

卫星部件用大型螺旋管式充退磁设备设计

在卫星的研制过程中,对磁性较大的部件进行充退磁处理是卫星磁试验的重要环节之一。文章简述了卫星充退磁原理、国内外卫星充退磁设备现状;提出了大型螺旋管方式充退磁设备技术方案和设计要求。设备的成功研制,填补了国内卫星磁测试领域的技术空白,已对数千个卫星部件、单机进行了充退磁试验,退磁效率达到40%～90%。     

卫星载荷磁场优化计算方法研究

针对传统计算方法存在的计算复杂、计算成本高等不足,利用某处地磁场下卫星载荷的磁场测量数据,逆计算出卫星载荷的等效磁化率,再根据等效磁化率就可计算在不同磁化方向、不同地磁场大小下卫星载荷产生的感应磁场。根据均匀磁化卫星载荷的特点,将积分方程法中系数矩阵元素的体积分形式化为面积分形式,并消除积分计算的奇异性,建立基于单元表面积分的感应磁场计算模型,从而降低计算成本。最后,实验结果表明:磁场测量值和计算值吻合得较好,该算法的有效性和可行性得以验证。     

地磁环境下卫星磁试验中的外干扰磁场控制补偿方法

针对地磁环境下外干扰磁场影响卫星磁试验精度问题,综合分析外干扰源场和卫星近场特性;通过合理布局(包括位置和方式)外干扰磁场监测传感器和卫星磁场采集传感器,增设动态磁场采集的A/D取样扫描频率循环控制、信号统计、滤波、数据拟合等信号处理功能,解决了监测传感器和采集传感器所得到的干扰信号的同步性、等效性、一致性,以及采集传感器信号中卫星真实磁场与干扰磁场之间的不相干性;实现了卫星磁试验的外干扰磁场有效闭环控制、自动跟踪、补偿和修正。通过24 h实时监测,外干扰磁场波动控制在0.5~1.0 n T范围内,获得地磁环境下卫星24 h"准零磁"环境磁试验条件,满足卫星磁试验对磁环境的技术要求。     

一种组合磁钢叠加磁场洛伦兹力磁轴承设计方法

针对现有洛伦兹力磁轴承功耗较高、工作气隙磁场非均匀性问题，提出一种基于组合磁钢叠加磁场的新型洛伦兹力磁轴承设计方法。首先建立了传统洛伦兹力磁轴承电磁力矩模型，揭示了洛伦兹力磁轴承功耗和控制精度与其磁场性能之间的对应关系。在此基础上，引入了磁场强度均值和磁场均匀度的概念，并以此为依据设计出一种轴向整环充磁磁钢与径向分块充磁磁钢组合工作的新型方案。其中轴向充磁磁钢产生主磁场，保证工作气隙周向均匀性，辅助以径向充磁磁钢，使磁场主要聚集在工作气隙处。相比现有洛伦兹力磁轴承，在相同尺寸约束条件下，新型洛伦兹力磁轴承径向磁场均匀度提升了8.7%，磁场强度提升了51.8%，周向磁场连续性显著提高。仿真结果表明,新型洛伦兹力磁轴承可以有效降低功耗、提升控制精度，研究成果可为研制超高精度磁悬浮惯性机构提供一条新的技术途径。     

卫星动力学环境模拟试验技术展望

卫星对严酷的动力学环境的适应能力直接关系到卫星飞行任务的成败,试验控制技术是动力学环境试验的关键环节.文章通过对模拟试验控制技术的研讨,包括振动试验中的力限控制技术和声试验响应控制技术的探讨,以及对卫星结构在动力学试验中故障诊断方法的分析,进一步展望卫星动力学模拟试验技术的未来.     

Refinement of the Oblique Dipole Model in the Evolution of Rotary Motion of a Charged Body in the Geomagnetic Field

When solving problems related to the induction of the Earth's magnetic field, the potential of which is expressed in the form of a series of spherical harmonic functions, it is necessary to use an approximate model of the geomagnetic field that satisfies the two conflicting requirements of simplicity and accuracy. As is noted in [3, p. 10], at the stage of design of satellites, especially at the stage of preliminary analysis of their dynamics, simple models of the geomagnetic field are usually employed. This offers additional possibilities for theoretical analysis of the problem. The averaged model and the model of a right dipole are just such simple models. The quadrupole model of the geomagnetic field developed in [4] is more accurate, but also more complex. The model of an oblique or skewed dipole is intermediate. The quadrupole model generalizes the simpler models mentioned above, and its analysis allows estimation of the accuracy of each model. It turns out that the oblique dipole model, which differs from the model of a right dipole by small correcting terms, does not take into account other correcting terms caused by the quadrupole part of the geomagnetic field, which are greater in magnitude. The evolution of the rotary motion of a charged rigid body in the geomagnetic field is considered, and the incorrectness of the oblique dipole model is demonstrated. The effect of the quadrupole component of the geomagnetic field on the body dynamics is revealed.     

高精度地磁场模拟系统的设计与研究

根据地磁导航半实物仿真中磁场环境仿真需求,建立了高精度地磁场模拟系统,通过试验说明了系统中建立零磁空间的必要性并验证了磁屏蔽筒的屏蔽效果,同时对系统的准确性和实时性进行了试验研究。仿真结果表明,在考虑响应时间的前提下,系统能够准确实时地模拟飞行航迹上的地磁总场值,能够为地磁匹配导航半实物仿真提供真实可信的磁场仿真环境。     

Identification of sources of Pc1 geomagnetic pulsations on the basis of proton aurora observations

The relationship between proton aurora and geomagnetic pulsations Pc1, which are an indicator of development of ion-cyclotron instability in the equatorial magnetosphere, are studied on the basis of the observations of proton aurora from the IMAGE satellite, observations of particle fluxes onboard the low-orbiting NOAA satellites, and geomagnetic pulsation observations at the Lovozero observatory. A conclusion is drawn that the subauroral spots in the proton emission projected into the magnetosphere near the plasmapause are two-dimensional images at the ionospheric “screen” of the region of intense scattering of energetic protons into the loss cone at the development of an ion-cyclotron instability.     

Magnetic Storms in October 2003

Preliminary results of an analysis of satellite and ground-based measurements during extremely strong magnetic storms at the end of October 2003 are presented, including some numerical modeling. The geosynchronous satellites Ekspress-A2and Ekspress-A3, and the low-altitude polar satellites Coronas-F and Meteor-3M carried out measurements of charged particles (electrons, protons, and ions) of solar and magnetospheric origin in a wide energy range. Disturbances of the geomagnetic field caused by extremely high activity on the Sun were studied at more than twenty magnetic stations from Lovozero (Murmansk region) to Tixie (Sakha-Yakutia). Unique data on the dynamics of the ionosphere, riometric absorption, geomagnetic pulsations, and aurora observations at mid-latitudes are obtained.     

月球重力场环境对月球卫星轨道影响分析

文章分析了月球复杂的重力场环境对月球卫星轨道运行的影响。通过月球卫星冻结轨道与地球卫星冻结轨道的对比分析,结果表明月球重力场存在较大异常,并由此引起月球卫星轨道发生较大漂移。另外,月球冻结轨道在带谐项影响下还存在中等周期的漂移,仅简单考虑带谐项系数无法求得完美的月球冻结系数。由于月球重力场异常对绕月卫星的影响与地球轨道卫星情况相比存在很大差异,因此月球轨道卫星的长期运行与控制策略的设计必须充分考虑此影响。     

A new approach to the analysis and design of magnetic stabilization of satellites

The stabilization of a magnetically oriented satellite is treated from a new standpoint. Under the assumption of a uniform magnetic field, the system stability is discussed. By imposing a performance criterion, a damping control law is derived. Stabilization characteristics are analyzed using a more realistic geomagnetic field model. The practical approximate methods of the damping control are sought, and their characteristics are analyzed. Finally the flight results of the recent satellites using an approximate method are presented.     

Large and sharp changes of solar wind dynamic pressure and disturbances of the magnetospheric magnetic field at geosynchronous orbit caused by these variations

The large and sharp changes of solar wind dynamic pressure, found from the INTERBALL-1 satellite and WIND spacecraft data, are compared with simultaneous magnetic field disturbances in the magnetosphere measured by geosynchronous GOES-8, GOES-9, and GOES-10 satellites. For this purpose, about 200 events in the solar wind, associated with sharp changes of the dynamic pressure, were selected from the INTERBALL-1 satellite data obtained during 1996–1999. The large and sharp changes of the solar wind dynamic pressure were shown to result in rapid variations of the magnetic field strength in the outer magnetosphere, the increase (drop) of the solar wind dynamic pressure always lead to an increase (drop) of the geosynchronous magnetic field magnitude. The value of the geomagnetic field variation strongly depends on the local time of the observation point, reaching a maximum value near the noon meridian. It is shown that the direction of the B _z component of the interplanetary magnetic field has virtually no effect on the geomagnetic field variation because of a sharp jump of pressure. The time shift between an event in the solar wind and its response in the magnetosphere at a geosynchronous orbit essentially depends on the inclination of the front of a solar wind disturbance to the Sun-Earth line.