GPS在移动监控系统中的应用

GPS（全球定位系统）作为一种先进且通用的导航定位技术,被广泛应用于军事、民用等各个方面。另一方面,在硬件开发中,嵌入式Linux系统由于其开放性、廉价性、健壮性和安全性等优点而越来越广泛地成为嵌入式系统的主要开发平台。介绍了一种专门为移动监控设备设计的GPS接收机,以及在嵌入式Linux系统下编写的定位程序。经过调试,接收机可实现定位功能;并且在使用中体现出体积小、精度高、实时性较强等优点,能够满足移动监控设备导航定位的要求。     

Network centric military communications [Special section introduction]

Communications networks continue to play an increasingly important role in global military operations. Among allied forces, improved network centric capabilities have been met with enthusiastic support as they are rolled out into the field. However, as military operations become more and more dependent on networks, it is clear that a host of difficult technical challenges remain. These challenges span all layers of the communications protocol stack and in many cases are representative of the complex nature of large-scale communications networks. This feature topic includes four articles that touch on important challenge areas ranging from network security to mobile ad hoc network design.     

Civil GPS from a future perspective

After a review of the present GPS program status and its announced schedule, a change of perspective to the future is attempted. Well before the year 2000, widespread civil use is predicted, spurred by the availability of simple and reliable $500 equipment for applications including hiking and automobile driving. The purpose is to focus on today's system issues of L2access, user charge policy, differential GPS standards, global mapping standards, and how to obtain a fair return on the American GPS investment, from the future perspective. The challenge is clear; the questions are: "Who is concerned?" and "Where does the civil planning responsibility lie?"     

美网络战略首提主动防御 我需关注网络战备升级风险

今年7月,美国国防部发布《网络空间行动战略》,首度提出主动防御理念,强调可动用军事力量打击网络攻击行为。面对不断加剧的网络空间竞争态势和严峻挑战,我国应在高度关注的同时,积极采取行动,避免我国网络空间行动能力与国际先进水平的差距进一步拉大。     

美军网络信息安全建设发展现状研究与启示

美国是互联网技术发源地,美军成为当今世界网络信息安全的领跑者,了解并研究美军网络信息安全发展,对我军如何应对当前严峻的网络信息安全挑战具有极其重大的意义。文中对美军网络信息安全的地位、管理体制、相关制度等方面进行介绍,通过了解美军网络信息安全的发展现状、研究美军主要网络信息安全计划及防范策略,结合当前我军网络信息安全发展实际,提出了建设我军网络信息安全策略的启示。     

The Military and Air Traffic Control

The Department of Defense currently operates about 30 000 aircraft, the largest most varied single fleet of aircraft of those using the National Aviation System (NAS). For this and other important reasons discussed herein, military participation in evolving an efficient and effective NAS forces consideration of a number of important issues by the developers and operators of any future Air Traffic Control (ATC) system. These issues range from those critical aspects of national security and the sovereignty of our air space, through major economic factors in equipping military aircraft and facilities for operation in the NAS, to the necessity for optimizing safety and using efficiently the air space of the world. This paper discusses the roles of the military, both as a user and operator of ATC systems and as a developer of ATC related systems and equipments. The different areas of the NAS in which interfaces exist between the civil and military are defined. These areas include operations, organizational interfaces, and equipment and facility interfaces and in many cases are covered by formal agreements. By way of illustration, two typical military flights are used to show the combined interaction of a military aircraft with both civil and military ground facilities. Communications, navigation, and surveillance requirements are discussed with respect to the various phases of the example flights. An indication of the future ground systems (military and civil) with which military aircraft might interact emphasizes the heavy burden placed on the airborne electronics systems. The paper finally suggests possible approaches that can be considered to ensure that the airborne equipment will not only be compatible with the various military, FAA, and ICAO ground environments in which the aircraft will function, but will also provide some basis for standardization and for efficient spectrum utilization.     

论军用光缆与民用光缆的区别

目前光缆广泛应用于各个领域，军事上也大量使用，但军用光缆与民用光缆在各方面的要求上都有着较大的区别。通过比较光缆产品的国家军用标准与国家标准的区别，全面分析军用光缆和民用光缆的区别，旨在为设计、生产及使用各方提供一点参考。     

DoD revamps testing organization

As a result of a GAO (general accounting office) audit, the U.S. Department of Defense (DoD) has designated the Navy as DoD's automatic test systems (ATS) ED, and a new joint ATS memorandum of agreement among the SAEs is in process. The DoD's policy for ATS acquisitions has remained fairly constant since its inception in 1994. However, emphasis has shifted to acquiring standard DoD ATS family testers as the preferred acquisition choice. The U.S. DoD has emphasized automatic testing since the early 1990s, when the DoD inspector general (IG) conducted a series of audits on the "Development and Acquisition of DoD Maintenance and Diagnostic Systems" in each of the armed services.     

Commercial-Components Initiative: Ground Benign Systems-plasticencapsulated microcircuits

The purpose of the Commercial Components Initiative-Ground Benign Systems was to determine if commercial off-the-shelf PEM (plastic-encapsulated microcircuits) are suitable for use in ground-benign, dynamically-fixed military electronic systems. If so, they could replace the more expensive components presently specified by DoD (US Dept. of Defense), resulting in appreciable life-cycle cost savings. At issue is whether the components produced for the commercial industry are reliable and durable enough to withstand the environments and life expectancies of military systems. Reliability was not formally proven. A more practical informal reliability test for this project, which DSD dubbed Run for Reliability, was to install the PCB in the system and let the operational hours accrue beyond the subsystem and Signal Processor lifetime allocations. The Run for Reliability shows promise that commercial hardware could be proven in a formal reliability demonstration test     

高动态GPS单点定位的精度分析

在工作中,我们经常采用GPS用户台对空中高速运动目标进跟踪测量,而普通GPS算法无法给出高动态单点定位的定位精度。运用最小二乘原理解算动态GPS用户台的定位方程,并对其进行精度评定能够得到动态单点定位精度,且简单、实用,具有很高的实际应用价值。     

一种GPS定位解算算法的研究

GPS 利用卫星发射的无线电信号，通过计算卫星与 GPS 接收机之间的相对位置， 进而确定出用户接收机在地球上的位置，可以为用户接收机提供实时的定位、测速和授时等服务。 通过使用最小二乘法，对 GPS 的定位解算算法进行研究，设计了一种基于最小二乘法的 GPS 定位解算算法。通过使用模拟源对所设计的 GPS 定位算法进行了定位解算试验验证，将定位解算结果与设定的模拟接收机位置进行比较，试验结果表明，该定位解算算法具有良好的定位效果。     

GPS performance in navigation

We discuss Global Positioning System (GPS) measurements available for civil use and algorithms for processing them to obtain real-time estimates of position and velocity. The main objective is to characterize the measurements and to demonstrate the levels of performance achievable with a single GPS receiver and with system augmentations which make corrections to the measurements available to the user in real time. Representative results with positioning accuracy levels ranging from tens of meters to centimeters are given based on actual measurements     

全球定位系统及其应用

全球定位系统在军事通信中的作用功不可设，如今又全方位应用于民用市场。本文简述了全球定位系统的发展概况，系统组成，工作原理及相应的技术指标，并主要从民用方面分析了它的应用前景。     

On the evolution of Internet technologies

The Internet has been evolving from its origins in the early 1970s, based on work sponsored by the U.S. Defense Advanced Research Projects Agency. While the basic design was known in 1973 and first published in 1974 and the system essentially deployed in the academic and military communities on January 1, 1983, much has happened in the intervening 20 years. The first commercial Internet services emerged in 1989 after the interconnection of the Internet to commercial e-mail services. By 1993, commercial versions of the World Wide Web had appeared, and by 2003, voice over IP service was growing rapidly, after its first commercial introduction around 1995 (See Vocaltec: http://www.vocaltec.com/html/about/company.shtml). The Internet of the future will be shaped by the tectonic forces of regulation, commercialization, technological change, and a wide range of policy concerns expressed at local, national, regional and international levels. In this paper, the effect of these forces is considered and an attempt made to project their effects into the future.     

Silver bullets and cybersecurity

Within 24 hours in November 2002, a British hacker was indicted by the US justice Department for breaking into military and NASA computer systems and the US Congress passed a bill that funded $903 million for computer security initiatives (Wired.com, 14 Nov. 2002). Meanwhile, nearly every multimedia conference since 11 September 2001 has discussed the need for increased computer security, both in the public and private sector. Is this burgeoning field all hype? It seems that although some hype exists, the fears are warranted. On one hand, terrorists and "hacktivists" have employed various means to attack or shut down government sites since the Web's inception. On the other hand, despite grave warnings by the US government and security companies, we have not really seen great dangers of cyberterrorism in the private sector. What we have seen, however, is an increase in general hackers attacking the public and private sector either to prove they can, to cause aggravation, or for financial gain. The paper discusses basis security concerns, event management software and intrusion detection.     

Impact of Galileo commercial service on location-based service providers: business model analysis and policy implications

Today's mobile location-based services (LBSs) largely depend on a free-of-charge, best-effort positioning technology, called global positioning system, which is controlled by the US military. The European alternative Galileo will not only offer a similar best-effort system by 2020, but also a premium-rate service known as Galileo commercial service (CS). Galileo CS is planned to provide higher positioning accuracy, improved security due to signal authentication and service guarantee. While the technology behind Galileo is often studied, the impact of Galileo CS on the LBS marketplace is rarely discussed. In this article, we fill this gap by analysing how improved accuracy, authentication and service guarantee may impact the business models of LBS providers. We do so by interviewing service providers, policy makers and industry experts on what new services would be enabled; technological alternatives that may emerge in the coming years; and organisational and financial issues that service providers face when adopting such a premium-priced positioning signal. We find that a more accurate, secure and reliable global navigation satellite system signal enables a range of new LBSs, although several alternative technologies are emerging that may make Galileo CS obsolete before it is even launched. To convince the LBS providers to adopt Galileo CS, the institution operating Galileo should get governments on board early on for building trust and should consider progressive pricing schemes. Still, service providers are sceptical about adopting Galileo CS, and the hope to recoup any investments in Galileo may thus be in vain.     

数据链安全保密技术现状及发展

论述了安全保密技术在数据链中的重要地位和数据链安全保密体制的主要特点。对美军数据链的安全保密技术的概况进行了分析和说明,指出解决数据链安全保密问题,将进一步推进我军数据链建设。     

一种基于卡尔曼滤波定位解算方法的研究

GPS 利用卫星发射的无线电信号，通过计算卫星与GPS 接收机之间的相对位置，进而确定出用户接收机在地球上的位置，可以为用户接收机提供实时的定位、测速和授时等服务。传统接收机通过最小二乘法进行定位解算，接收机坐标容易发生较大的跳动。通过利用卡尔曼滤波原理，根据接收机的运动特点建立模型，利用每次导航解算结果之间的联系，对定位结果进行平滑，消除由于最小二乘算法结果相对独立而产生的定位抖动误差。通过定位试验结果表明，所设计的定位解算算法具有良好的定位效果。     

WAW Location-based Service Positioning

Coordinated positioning operations require the user to be aware, not only, of his own position but also of the positions of the other elements on his team. Its deployment can be supported in WAW (??Where Are We???) location-based services, where the position of each user is made available to the rest of the group. This paper presents a method for the estimation of a user??s position based on measurements from a group of Global Positioning System (GPS) receivers. None of the GPS receiver positions, used in the estimation process, is considered to be known. The proposed approach leads to an improvement on the accuracy of the position estimates, when compared with those computed on an autonomous way, and has a direct application in the development of enhanced services in WAW location-based services. The positioning estimator takes advantage from the fact that, in this type of location-based service, GPS measurements are available from several receivers. Instead of estimating the user??s position based only on the measurements of his own GPS receiver, the proposed approach uses the measurements from all the GPS receivers in the group. The paper presents details of the positioning model and estimator used to achieve the accuracy improvements. Simulation results are presented based on real GPS satellite ephemeris, collected at the University campus.     

Information for the warrior

The Air Force has been rapidly implementing new structures to provide lightweight communications systems between a theater of operations and rear bases, within the theater of operations, and to other joint Service components. The author describes the effect that the commercial sector is having on several research and development programs being pursued in support of this mission. The Department of Defence (DoD) must be prepared for conflicts that can occur anywhere in the world. As such, the commercial infrastructure must be considered as one of many building blocks for a global system capable of reaching any theater of interest. Thus, the DoD must not only develop the technologies required to extend command and control (C²) into highly hostile environments, but must integrate these technologies with a commercial infrastructure that was designed to meet civilian market demands. This integration is discussed from three perspectives: the integration of the associated transmission fabric; the integration of military and commercial network management functions; and the seamless access to information across this global environment in a location-transparent manner