A study of auroral displays photographed from the DMSP-2 satellite and from the Alaska meridian chain of stations

In the first part of the paper, a brief historical review of the progress of our knowledge on morphological aspects of the aurora is given. A particular emphasis is made in describing technical developments in auroral observations. In the second part, a large number of DMSP-2 photographs are examined in detail; in particular, substorm features, such as the initial brightening, the poleward expansion, westward traveling surges, eastward drifting patches, omega bands, torch-like structures, polar cap auroras, are illustrated. Whenever available, simultaneous photographs from the Alaska meridian chain of stations are used to describe in detail time variations of auroral displays before, during and after the passage of the satellite. In the last part, recent progress in understanding auroral phenomena is briefly reviewed from the point of view of magnetospheric physics.     

TDRSS Telecommunications Payload: An Overview

The telecommunications payload is described for the tracking and data relay satellite system (TDRSS). The salient design features of the electronic equipment, as well as the performance requirements that such equipment must satisfy to fulfill NASA and Western Union communication functions are presented. Operational characteristics associated with the single and multiple access channels used to relay information to and from users are also highlighted.     

A method for satellite time series anomaly detection based on fast-DTW and improved-KNN

In satellite anomaly detection, there are some problems such as unbalanced sample distribution, fewer fault samples, and unobvious anomaly characteristics. These problems cause the extisted anomaly detection methods are difficult to train accurate classification model, and the accuracy of anomaly detection is hard to improve. At the same time, the monitoring data of satellite has high dimension and is difficult to extract effective features. Based on the DTW over-sampling method, this paper realizes the over-sampling of fault samples in satellite time series, and constructs a distributed and balanced time series data set. The Fast-DTW method is applied to calculate the distance between different time series, which can improve the speed of similarity calculation. KNN (K-Nearest Neighbor) method is applied for classification and the best classification result is obtained by search the optimal hyper-parameters k. The results show that the proposed method has high anomaly detection accuracy and consumes short calculation time.     

On-ground vehicle navigation using satellite navigation equipment

The problems are considered of a modelling research of navigation features and improvement of the navigating filters algorithms used in the navigating devices of ground mobile vehicles (MV). It is supposed that the methods and approaches known as real time kinematic (RTK) are incorporated in a basis of researched navigating devices and algorithms. Thus, the measurements from satellite navigating systems such as GLONASS/GPS, and also the measurements from other traditional measuring means (tactile sensors, steering wheel angle and/or inertial measuring instruments) are used in the navigating device of the MV. In the present report we solve the problems and describe the methods of a modeling research of the features of functional units algorithms of the MV navigating processor with account of a satellite navigation set integration with other measuring instruments. The improvement of these devices interaction is made by means of the computer complex "AutoMobil," allowing us to simulate the certain conditions of these navigating tools operation. The imitation computer complex "AutoMobil" for researches of the MV navigation is developed within the frameworks of a programming environment "Delphi-7".     

磁强计数据辨识卫星自旋状态

针对近地低轨三轴稳定卫星在轨管理后期,除磁强计外其他姿态敏感器都无效情况下的姿态异常问题,分析了三轴稳定卫星失去姿态基准后,星体自旋状态下三轴磁强计测量数据的特点,提出了使用磁强计测量数据的矢量信息,以找到能够获取卫星状态的方法,从而建立了磁强计测量矢量与卫星自旋轴的几何关系,给出了处于自旋状态下的卫星自旋轴确定方法。通过此种辨识方法,获得了某气象卫星姿态异常翻转状态下的自旋矢量方向和自旋角速度,从而证明了该辨识方法快速、有效,可以作为姿态异常卫星自旋状态的辨识手段,为恢复卫星姿态提供了重要信息,具有一定的工程应用价值。     

航天器解体模型研究的新进展

航天器解体模型用于描述航天器因爆炸或碰撞解体所产生碎片的数量、尺寸、面质比以及速度等特性的分布规律,对于空间碎片环境建模与演化、空间碎片撞击风险评估及空间解体事件分析具有重要意义。分析了目前广泛使用的NASA标准解体模型的特点,介绍了近年来国内外在航天器解体模型方面的研究进展。国外的研究主要介绍了日本九州大学和德国EMI实验室开展的卫星撞击试验以及NASA最近启动的新一轮卫星撞击研究项目。国内的研究主要介绍中国空气动力研究与发展中心（CARDC ）开展的卫星撞击试验和仿真研究,以及在此基础上发展的CARDC-SBM航天器碰撞解体模型,并比较分析了该模型与 NASA 标准解体模型的差别。对当前航天器解体模型研究存在的不足进行了分析,提出了下一步应关注的研究方向。     

应用标校卫星鉴定测控系统精度方法探讨

根据标校卫星的用途及所需提供的高精度比较标准等技术要求,针对星载比较标准及靶场数据处理状况,提出了改进和提高测控系统精度鉴定的技术途径.探讨和提出了4种类型的数据处理技术和方法,简述了它们的思路和关键技术,分析了应用条件和特点.其中.第1种方法是目前使用的经典鉴定方法;后3种方法（自鉴定方法、精确标准鉴定方法和融合处理鉴定方法）都充分利用了星上测量资源、卫星轨道运动特性以及优良的差分、自校准等融合处理技术,它们都明显优于经典鉴定方法.可以使标校卫星提供更精确的比较标准,扩大其目前的功能和用途.特别是融合处理鉴定方法,不仅可以精确地评定定位系统测量精度,而且可以为测速系统精度评定提供一种良好的技术途径.     

面向航空节点的IP/LEO卫星网络移动性管理方法(英文)

Taking into chief consideration the features of aviation nodes in satellite networks, such as high moving speed, long communication distance, and high connection frequency, this article proposes an aviation-oriented mobility management method for IP/low earth orbit （LEO） satellite networks. By introducing the concept of ground station real-time coverage area, the proposed method uses ground-station-based IP addressing method and cell paging scheme to decrease the frequency of IP binding update requests as well as the paging cost. In comparison with the paging mobile IP （P-MIP） method and the handover-independent IP mobility management method, as is verified by the mathematical analysis and simulation, the proposed method could decrease the management cost. It also possesses better ability to support the aviation nodes because it is subjected to fewer influences from increased node speeds and newly coming connection rates.     

A (design-oriented) reliability model for active phased arrays insatellite communication systems

This paper proposes a modeling approach to relate the power section reliability of satellite payloads to the on-board antenna complexity. The aim of the model is to support the development of design tools for satellite systems adopting active phased arrays. The achieved results are rendered parametric with respect to a key system requirement, the effective isotropic radiated power, due to its direct impact on transmitter configuration and technological features as well as on the critical compromise between transmitter and antenna specifications     

分布式单星转发的定位测速模型及其应用

在城市峡谷中通过接收导航卫星信号以实现连续的定位与测速一直是卫星导航应用中的一个难题。针对此问题,借鉴卫星导航对抗中转发式欺骗干扰的定位控制基本原理,提出了通过分布式单星转发来解决城市峡谷中实现连续卫星导航的新方法,并构建了分布式单星转发的定位测速模型。在此基础上详细讨论了转发器天线对被遮挡卫星的指向跟踪、转发器相关参数的获取、转发器收发之间的有效隔离、直达信号与转发信号的同时利用等应用性问题。所提出方法的可行性得到了仿真试验的有效验证,从而为城市峡谷中的卫星导航应用提供了新的参考。     

Low cost satellite ground control facility design

A design approach common to the areas of satellite operations command and control, tracking, subsystem analysis, system planning and scheduling, orbit determination and maintenance, and data routing and control is discussed. Specific satellite mission applications and operations are isolated from the remainder of the design to allow application to a broad variety of satellite systems. Discussions of specific satellite missions are limited to the context of understanding the general magnitude and scope of what a ground control facility is required to support. By isolating the common satellite operational functions, a low cost generic approach that allows for phased implementation of system changes with minimal impact to on-orbit assets and mission performance is developed. The goals of this approach are to provide the capability for growth, maintainability, and operability of the satellite system. A brief discussion of satellite systems followed by the introduction of the general function of any satellite control facility sets the stage for the overall design approach. The factors that define the design along with the key design features are presented, with a discussion of each product available in each functional area     

Attitude stabilization and control of earth satellites

In this paper a survey is made of some aspects of satellite attitude stabilization and control. After a brief discussion of the equations of motion governing the satellite's behaviour, the various disturbing torques acting on a satellite in a space environment are considered. Quantitative values for a hypothetical satellite are discussed. Next, attention is given to several methods of attitude stabilization and control. The analysis is based on the various means to exert torques on the satellite for control purposes. Passive methods, such as spin-stabilization and gravity-gradient stabilization, are discussed in some detail. Not only are the basic principles involved indicated, but also some quantitative values of the variables concerned are mentioned where possible.     

Target localization based on cross-view matching between UAV and satellite

Matching remote sensing images taken by an unmanned aerial vehicle (UAV) with satellite remote sensing images with geolocation information. Thus, the specific geographic location of the target object captured by the UAV is determined. Its main challenge is the considerable differences in the visual content of remote sensing images acquired by satellites and UAVs, such as dramatic changes in viewpoint, unknown orientations, etc. Much of the previous work has focused on image matching of homologous data. To overcome the difficulties caused by the difference between these two data modes and maintain robustness in visual positioning, a quality-aware template matching method based on scale-adaptive deep convolutional features is proposed by deeply mining their common features. The template size feature map and the reference image feature map are first obtained. The two feature maps obtained are used to measure the similarity. Finally, a heat map representing the probability of matching is generated to determine the best match in the reference image. The method is applied to the latest UAV-based geolocation dataset (University-1652 dataset) and the real-scene campus data we collected with UAVs. The experimental results demonstrate the effectiveness and superiority of the method.     

The Soviet Union's GLONASS Navigation Satellites

GLONASS (Global Orbiting Navigation Satellite System) is the most recent satellite navigation system developed by the Soviet Union and currently in the pre-operational stage. Obvious parallels exist between GLONASS and the NAVSTAR Global Positioning System (GPS) developed in the United States and also, at present, in a pre-operational phase. In the progress towards operational status, the launch capability for NAVSTAR satellites has been seriously affected by the recent failure of the Space Shuttle Challenger, clearly increasing the prospects of GLONASS reaching operational status first. It is therefore the main purpose of this paper to discuss certain aspects of the GLONASS satellite navigation system, in particular its orbital features and radio-frequency signal characteristics. Comparisons with NAVSTAR are inevitable and for this reason, the paper begins with a brief resume of relevant features of the NAVSTAR GPS system for later reference. The main section of the paper then deals with orbital behaviour, radio frequency signal structure and channelisation using NAVSTAR as a reference point for discussion.     

ANALYSIS OF LOCATION ACCURACY FOR AN EMITTER USING SATELLITE- MOUNTED INTERFEROMETER

ＡＮＡＬＹＳＩＳＯＦＬＯＣＡＴＩＯＮＡＣＣＵＲＡＣＹＦＯＲＡＮＥＭＩＴＴＥＲＵＳＩＮＧＳＡＴＥＬＬＩＴＥ┐ＭＯＵＮＴＥＤＩＮＴＥＲＦＥＲＯＭＥＴＥＲＺｈｏｕＹｉｙｕ（周一宇）,ＧｕｏＺｈｉｇａｎｇ（郭志刚）（ＮａｔｉｏｎａｌＵｎｉｖｅｒｓｉｔｙｏｆＤ...     

基于惯性辅助的北斗接收机完好性监测方法研究

针对传统卫星导航接收机在卫星数小于5颗及卫星星座构型不佳的情况下无法实现卫星故障识别与隔离的问题,结合卫星导航接收机在弹上的实际应用情况,利用惯导的辅助数据设计了一种基于多级Kalman滤波的北斗接收机完好性监测方案,给出了卫星导航接收机的RAIM滤波器结构与故障检测和隔离方法,并对其可用性进行了推导.该方案经过仿真分...     

Maritime Containers Tracking Trial Results

There are approximately 7 million maritime-style containers within Canada, and 70 million within the US. The interiors of such containers are rarely inspected. With market globalization, a large amount of these containers enter North America on a daily basis. Such containers may include contraband or dangerous items that present an economic or security risk. Despite significant security improvements, only 3 to 5 % of the maritime containers, that arrive in, or transition through, North America, go through physical inspection. Current container tracking technologies based on GPS consume high DC power, are costly, require line-of-sight with satellites, and are often too large to be covert. It is possible to overcome some of these limitations by basing the tracking system on the FM broadcast signal which is an alternative man-made signal that is reasonably ubiquitous, provides a geographically-unique frequency spectrum and is about 100,000 times as strong as a GPS satellite signal. This allows the development of a low-cost, low-power and miniature FM receiver that can record frequency spectrums and compare them to known data in order to trace the path that the container has taken for less than $10 per container. This presents the first results of highway trials (train and sea trials are currently being conducted) of such a low-cost, covert, non-GPS based technology (called "FM Tag") that records the worldwide displacement of containers and displays the path undertaken by the container while in transit. As an added security benefit, the tag is also capable of detecting container door openings. In addition to presenting the first trial results, this covers the innovative engineering aspects of using the metal enclosure of a maritime container as a VBF antenna, thereby eliminating the need to add an external antenna and achieving the goal of being 100% covert.     

Experiments on aeronautical satellite communications using ETS-Vsatellite

The world's first aeronautical satellite communication experiments, conducted at L-band frequencies using a commercial aircraft, are described. An airborne antenna with electronically steerable beam and communication equipment was installed in a B-747F freighter flying over transoceanic flight routes. The satellite used in these experiments is the Engineering Test Satellite-Five (ETS-V). During the test period, various experiments, such as antenna pattern measurements, transmission performances, and voice quality evaluation were conducted. As the airborne antenna is the key component for the aeronautical satellite communication system, emphasis has been placed on antenna characteristics. Its performance is found to be closely related to the fading characteristics in low-elevation areas and to transmission error performance     

A multi-index assessment method for evaluating coverage effectiveness of remote sensing satellite

This paper deals with the multi-index assessment method for evaluating coverage effectiveness of remote sensing satellite. Because a series of satellite activities such as imaging, moving target observation, and environment investigation need to know the coverage characteristics, the coverage capability of the remote sensing satellite is the most important index. Thus, it is very important to establish the method of effectiveness evaluation of coverage characteristics. This paper focuses on the assessment of coverage effectiveness of remote sensing satellite, and proposes and designs a multi-index evaluation method based on index weight using entropy weight method and analytic hierarchy process. With a simulation case, the effectiveness evaluation results of single satellite coverage and multi-satellite coverage performance are given for the proposed assessment. The experimental results show that the established coverage characteristic model and the proposed assessment method are effective and right.