The development of aeronautical mobile satellite services over thepast thirty years

This paper presents an overview of the development of aeronautical mobile satellite services (AMSS) over the past 30 years. The inherent shortcomings of present air-ground HF communications have hindered the development of civil aviation, but according to the Future Air Navigation Systems (FANS) concept aeronautical satellite communication-including Automatic Dependent Surveillance (ADS)-will be the key to eliminating the shortcomings of HF communication systems. Satellite-based communication and surveillance will significantly improve air traffic control (ATC) over the oceanic and remote terrestrial airspace, and it will benefit civil aviation authorities, airlines as well as passengers. This paper discusses the availability of system elements, and world wide trials, demonstrations and preoperational use of aeronautical satellite communications over past years are described. Future satellite systems possible for aeronautical communications are also discussed     

Operational Concept for Multi-Carrier Broadband VHF Communications

Operational air traffic management needs have led to the concept of the broadband VHF (B-VHF) aeronautical communications system. This explains the functional principles, architecture, and internal mechanisms of the B-YHF system, showing how it can be used to provide the existing aeronautical voice and data link communications services and a multitude of new data link services expected for the next decade or two.     

中国拟建航空卫星移动通信地面地球站（GES）的技术方案

中国民航正在计划实施航空卫星移动业务通信。ＡＭＳＳ系统有三个主要组成部分：空间段，地面地球站和机载地球站。中国国际航空公司已居其两架波音７４７型飞机上装有ＡＥＳ。不久将有更多飞国际航线的飞机安装ＡＥＳ。     

A high-capacity aeronautical mobile satellite system

A conceptual system design is described for a satellite-based aeronautical safety communications system capable of serving both general aviation (GA) aircraft and commercial aviation (CA) aircraft in the contiguous US (CONUS) in the mid-1990s. It is shown how the large system capacity that is required can be obtained using a 15-m deployable antenna onboard a high-power commercial communications satellite expected to be available in the mid-1990s     

Nonredundant error correction DQPSK for the aeronautical-satellitechannel

The performance of differentially encoded quadrature phase-shift keying (DQPSK) system employing nonredundant error correction (NEC) receivers with single- and double-error correction capability is analyzed and evaluated for the aeronautical satellite channel. The NEC is an attractive coding technique which employs differential detectors with more than one symbol delay elements and which does not introduce any redundancy as other coding schemes do. As typical for aeronautical satellite communications, a Rician fading channel with Gaussian power spectrum has been considered. Unlike the additive, uncorrelated from symbol to symbol interference such as additive white Gaussian noise (AWGN) or static cochannel interference (CCI) which has been investigated in the past, analysis of the performance in a fading channel is much more difficult. The difficulty arises from the multiplicative and correlative nature of the fading interference. Bit error rate (BER) performance evaluation results have been obtained by means of computer simulation for various channel conditions, including different values of the K-factor and the fading B_DT. These results have indicated that considerable performance gains as compared with conventional differentially detected systems are achieved for high values of K and for very fast fading. Both of these conditions are encountered in typical aeronautical communication systems. Wherever possible, heuristic explanations of the trend of the obtained BER performance evaluation results are also given     

The Tactical Communications Satellite

Early in 1969 the U. S. Air Force placed into synchronous orbit the largest communications satellite built to date. This vehicle, the tactical communications satellite (TACSAT), together with a variety of ground terminals, is designed to test experimentally and develop tactical communications concepts for all military services. This paper describes the spacecraft design focusing on the communications repeater. Measured performance characteristics affecting communications utilization of the spacecraft are presented.     

A Novel Onboard-gateway-based Mechanism to Improve TCP Performance in Aeronautical Satellite Networks

The IP-based networks on aircraft serve to support Internet services via satellites. However, in aeronautical satellite hybrid net- works,the TCP protocol performance often deteriorates due to improper decreases and slow recovery of the congestion window. This paper proposes a window size determination and notification mechanism, onboard-gateway-based mechanism (OGBM), which is based on the onboard gateway in the networks on aircraft. A cross-layer approach is adopted by the onboard gateway to obtain the satellite link bandwidth information. And then, by the gateway, through changing the receiver’s advertised window field in ACK packets, TCP sources are notified of the window size of each TCP source calculated on the ground of bandwidth delay product and flow numbers. The mechanism is able to avoid improper changes of TCP window and serve multiple users. Simulation results show that the mechanism with the fairness index close to 1 improves TCP performance in aeronautical satellite networks.     

Aeronautical information and meteorological data-link services

Aeronautical Information and Meteorological Management is a key component of the International Civil Aviation Organization's (ICAO) global Air Traffic Management (ATM) operational concept. This global ATM concept is central to the Joint Planning and Development Office's (JPDO) Next Generation Air Transportation System (NGATS), and underlies Europe's Single European Sky ATM Research (SESAR) initiative. The availability of timely, accurate, and relevant aeronautical and meteorological information in the cockpit is critical for safe conduct of flight and forms the basis for Air Traffic Management (ATM) decision-making. The data-link of aeronautical and meteorological information will facilitate the creation of a common picture of the airspace situation for all flight crews, air traffic controllers, and airline operations personnel. Change notifications, timely warnings and alerts of threats to safe and efficient flight conduct will be enabled by these services. The ultimate goal is to provide access to on-line, real-time, quality information, and weather services to any aviation user, anytime, anywhere. In this framework, we present operational services and environment of the Aeronautical Information Management (AIM) and Meteorological (MET) data-link services envisaged to be implemented over the next decade in both Europe and the USA. It reflects concepts and system performance requirements currently developed by a joint EUROCAE (WG-76) / RTCA (SC-206) Committee. The envisaged AIM data-link services are presented: aeronautical updates both in textual and graphical fore, synchronization of aeronautical data between on-board and ground systems (exchange of permanent aeronautical data regardless of AIRAC cycles). The MET data-link services are also developed: weather planning, near-term, and reactive decision services.     

NEWSKY - Concept for NEtWorking the SKY for Civil Aeronautical Communications

In this paper, an overview of the NEWSKY project is given. This project is funded by the European Commission within the 6^th framework program and is scheduled to start in early 2007. The NEWSKY project is a feasibility study to clarify if it is possible to establish a heterogeneous network for aeronautical communications which is capable of integrating different communications systems as well as different applications into a single global aeronautical network. The envisaged applications comprise not only air traffic control and management but also airline and passenger communications     

我院建成航空卫星通信实验地球站

在世界范围内实现新的通信、导航和监视／空中交通管理，能改善空中交通服务，减少运营费用和提高飞行安全等。中国民航学院建成航空卫星移动通信实验地球站，为研究新航行系统、试验自动相关监视等，创造了良好条件     

A Domestic Satellite Design

This paper deals with the design parameters of a communications satellite which would be capable of providing domestic telephony, data, and television distribution services. Certain important aspects of the design are discussed, including satellite antenna beam coverage, transponder bandwidth, and transponder radiated power for a given weight range. A baseline satellite design is then presented which has 24 transponders (with 4000 watts radiated power on-axis and 34-MHz radio-frequency bandwidth) fully accessible from the 48 contiguous United States. The design uses crossed linear polarization to reuse the satellite transmit and receive frequency spectrum.     

ATS-6 Significance

The Applications Technology Satellite (ATS-6), the most powerful, most sophisticated, most versatile communications satellite flown to date, is the last of NASA's experimental satellites intended to demonstrate major advances in communications and spacecraft technology. It is a multipurpose, multidisciplinary spacecraft whose principal objectives were to demonstrate a large, unfurlable antenna structure and precise pointing and attitude control in the synchronous orbit The spacecraft carries 27 different experiments, 3 of which demonstrate users' applications of satellite communications. Significant advances in antenna technology, precise attitude control, materials technology, spacecraft structures, and thermal control have been successfully demonstrated. The most significant accomplishments of the ATS-6 mission are the demonstration of the practicality of satellite broadcasting to small, simple, inexpensive ground stations and the uses of this potential service in the solution of social problems involving education and health care. The success of these initial demonstrations has led ATS-6 experimenters and potential users to incorporate a Public Service Satellite Consortium dedicated to the provision of satellite broadcasting services for educational and health-care applications.     

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     

Mobile Satellite Plans and Status

A variety of new communication functions will become available near the end of the decade when mobile satellite services (MSS) are introduced commercially in the United States and Canada. Mobile radios, hand carried radios and small fixed transponders will communicate directly through satellites into the telephone network or to private base stations. Voice, data, and position fixing services will be distance insensitive with good performance in difficult terrain and remote locations. Experiments with NASA satellites and studies in the U.S. and Canada demonstrated the technical feasibility and practical applications of mobile satellites. In 1983 Mobile Satellite Corporation, followed by Skylink Corporation, applied to the FCC for authorization to build and operate a land and aeronautical mobile satellite system for the United States. Canada had advanced its plans for an MSAT system. In response to these initiatives, the FCC issued a ``Notice of Proposed Rulemaking' that proposed the allocation of radio spectrum for the new service and asked for applications from prospective providers. Twelve applications were received. The shortage of radio spectrum in the U.S. has resulted in much contention over the proposed allocations, and the numerous applications have introduced competing systems concepts. The paper describes a likely system implementation, its services and markets, and the current regulatory status.     

Interfering cell identification in satellite cellular system

Global satellite cellular system architecture utilizes a constellation of satellites, each with multiple spot beams/cells to provide coverage, and employs frequency reuse techniques to efficiently reuse the allocated spectrum. Identification of interfering cells of any satellite in the constellation is critical for cell management in order to provide interference-free communications services. The principles and techniques to identify the interfering cells are developed     

30/20 GHz Band Small Earth Station for ISSDN Experiment

The system design and operational results of a 30/20 GHz band small Earth station for integrated services satellite digital network (ISSDN) experiments are presented. The Earth station has a high efficiency offset Cassegrain antenna with elliptical beam, a high power klystron amplifier with 1 kW output power and an uncooled parametric low noise amplifier with 200 K noise temperature. Experiments were performed using the medium capacity communications satellite for experimental purposes (CS). Performance on the Earth station was high. Effective radiation power (ERP) was greater than 88.1 dBW, and the receiving figure of merit (G/T) was larger than 30.6 dB/K. Good transmission characteristics were obtained through the satellite link for demand assigned time-division multiple access (DA-TDMA) with 20 Mbit/s bit rate.     

Communications satellite technology and services for the 90's

The history of satellite communications is reviewed, and its future is addressed from the viewpoint of both commercial and military users. Technological advances and new services are discussed. User's requirements are assessed     

基于铱星/INS组合定位技术在船舶中的应用研究

GNSS拒止环境下惯性/GNSS组合导航系统的性能会严重恶化,通过利用并提取机会信号中的有用观测量,可以实现机会信号和惯性系统的联合动态定位。提出了利用铱星/INS组合定位技术实现船舶的动态定位。首先深入研究了铱星的信号体制,建立了利用铱星瞬时多普勒频移进行定位的算法模型;然后,提出了利用基于扩展卡尔曼滤波(EKF)技术的铱星机会信号与INS组合定位算法;最后,通过船舶航行实测数据对所提算法进行了试验验证。结果表明,提出的利用铱星机会信号和INS组合定位方法可以有效改善无GNSS信号条件下的INS定位精度,在GNSS信号拒止环境下解决了船舶定位问题,具有重要的研究意义和实用价值。     

飞机通信寻址与报告系统消息安全研究及仿真

ACARS消息安全( AMS)以一种独立于底层通信机制的应用方式,通过安全机制及支持该机制的加密算法,提供数据机密性、消息认证和完整性的安全服务。介绍了AMS消息结构和处理过程,建议采用一种综合对称和非对称加密系统优势的航空通信方案,分析了安全会话过程,仿真试验证明, AMS在面对安全威胁时能保证ACARS消息的安全传输。     

Overview of Commercial Satellite Communications

The period from Arthur Clarke's 1945 prediction of geosynchronous satellite communications covering the entire planet until satellites were stationed over the Atlantic, Pacific, and Indian Oceans was less than 25 years. In the following 15 year period, satellite communications has affected all of us. Most international calls are carried by satellite. Much of the television that we watch has been relayed, processed, or distributed by satellite. In fact, many of us who live in cabled cities can choose among 50 channels or more for viewing on a particular night, largely brought to us by satellite. Some morning papers, radio programs, and basic weather data appear coast to coast rapidly because of the satellite. Even while we sleep, computers in an increasing number of business offices are talking to each other by satellite. Virtually the whole world, from the busiest urban center to the most remote island, can be interconnected by satellite communications networks capable of providing economical and reliable transmission of communications signals, including voice, data, electronic mail, and video. The satellite's advantages of distance insensitivity, point-to-multipoint capability, and improved quality over long distances are unique. These facts have led Clarke to speculate on the future impact of satellite communications in The View from Serendip (1977): I submit . . . that the eventual impact of the communications satellite upon the whole human race will be at least as great as that of the telephone upon the so-called developed societies.