Japan's CS (Sakura) Communications Satellite Experiments

The Japanese Communications Satellite (CS), called Sakura, is a "Medium Capacity Communications Satellite for Experimental Purposes" and is the first experimental communications satellite in which 30/20 GHz bands were adopted and were developed for practical domestic use. Large scale field trials have been carried out for more than three years in order to evaluate 30/20 GHz (Ka-band) and 6/4 GHz (C-band) domestic satellite communications system technologies under actual operational conditions by using the CS Sakura launched in December 1977. Through the various experiments on Kand C-band large fixed and small transportable Earth station systems, satellite control experiments, and Ka-band propagation measurements, it has been verified that the medium capacity satellite communications system meets the design objectives.     

Some Electrical/Electronic Areas Requiring Emphasis in Preparation for Future Space Programs

A panel session held at the 1965 Aerospace Conference, Houston,Tex., June 23, 1965. Panelists discussed Life-Suppport interfaces with Electric Power; Communications; Navigation; System Integration for Future Space Programs; and Reliability.     

The Digital Information Facility

The acceptance and implementation of advanced digital avionics and flight control systems is dependent on the successful integration of these systems into the current and future National Airspace System (NAS). This paper describes a digital avionics systems research facility known as the Digital Information Facility (DIF) developed to provide researchers with the ground systems and air-to-ground interfaces needed to conduct and document experiments involving a mix of new technologies within the existing NAS infrastructure. The DIF supports four NAS functions: Controller Pilot Data Link Communications (CPDLC), Flight Information Services (FIS), Differential Global Positioning System (DGPS) navigation, and Automatic Dependent Surveillance-Broadcast (ADS-B). The DIF also includes the capability to record pilot and air traffic management interactions and document research participant observations. The DIF capability includes connectivity to flight test and simulated aircraft in a fully immersive Communications, Navigation, and Surveillance (CNS) environment.     

基于TCP/IP的双机自动连接与通信

介绍了双机通信所必需的硬件连接和IP地址设置,分析了TCP服务器的注册和TCP客户端的自动连接,并以平显训练模拟系统为例,分析了双机通信和画面参数的传输。     

Insertion of controller-pilot data link communications into theNational Airspace System: is it more efficient?

This paper proposes an application of the Total Airspace and Airport Modeller (TAAM)² tool for determining the impact of new Communications, Navigation, and Surveillance (CNS) ground-based and avionics technology on the efficiency of the National Airspace System (NAS). TAAM presents an opportunity to attack this problem by simulating aircraft movements using rules that mimic actual operations. The rules can be tailored to represent local procedures, restrictions, and conflict resolution strategies, producing a realistic picture of aircraft movement. This paper describes a novel method for manipulating TAAM output to produce a measure of the voice channel occupancy (VCO) in a sector. This method can be applied for current conditions, where all communications use the voice channel, and for the future case in which Controller-Pilot Data Link Communications (CPDLC) is used to issue controller/pilot instructions. TAAM could then be used to examine the benefits of CPDLC in terms of relieving restrictions or reducing vectoring and holding. Overall system benefits such as reduction in delays or distance traveled could be estimated from the TAAM results     

高功率发射机的通用组合微波功率模块

主要介绍了用于高功率发射机的通用组合单元——微波功率模块(MPM)。MPM具有高效率、高增益、重量轻、体积小等优点。MPM已经在雷达、电子对抗和通讯等领域得到应用。随着技术的日益发展,MPM将会得到越来越广泛的应用。     

High data rate applications of ACTS technology

The NASA Advanced Communications Technology Satellite (ACTS) program will conduct high-data-rate experiments that will be applicable to the emerging broadband services of the telephony market. The existing broadband integrated services digital network (BISDN) services and delivery method as defined by the International Consultative Committee for Telephone and Telegraph (CCITT) and satellites' role in provisioning those services are discussed. The ACTS experimental efforts are summarized     

Performance Evaluation of a Satellite-Linked Experimental Network

The objectives and results of an evaluation of the performance of a U. S. Public Health Service network consisting of small earth terminals linked via the Communications Technology Satellite are documented. The main objective of the evaluation was to assess the technical performance of the network in terms of channel quality, system availability, and equipment maintainability. In addition, its capability for broad geographical coverage, channel sharing, and digital transmission was also evaluated.     

Satellite wide-area-network for telemedicine

Communications for telemedicine requires substantial bandwidths to provide timely transmission of large data sets. To provide rural America with modern Telemedicine requires very high bandwidth resources that may take decades to appear. Satellites provide the natural choice for communication between the rural primary care centers and the tertiary care hospital. However, there are problems if TCP, as required for Internet access, is to be the protocol of choice. Analysis of multi-station satellite access clearly argues for distributed non-random methods and, hence, for appropriate handling of TCP data streams.     

Report on the Geneva Space Telecommunications Conference? Broadcasting Aspects

The growth of the Intelsat Global Commercial Communications Satellite System, which provides the facilities used to exchange television programs among many countries of the world, is described. Service was initiated between North America and Western Europe in 1965. Currently, some 48 separate geographic areas throughout the world are interconnected by the Intelsat System. The unique air-transportable Earth terminal, developed by the General Electric Company, at the request of the television networks, to meet the special requirements for providing live television coverage in color of the Apollo recoveries at sea, will also be described.     

Air traffic implementation in the Asia-Pacific region

With the 21st century just around the corner, demands for air transport in the Asia and Pacific regions will increase further. Taking into account the opening of new airports and expansion of existing ones, such as Singapore, Hong Kong, Shangai and Kimpo, it is estimated that the North Pacific traffic volumes will be 1.7 times greater by the year 2000 compared to that of 1992, and 2.9 times greater by the year 2010. In dealing with such traffic in that region use of the new Communications Navigation Surveillance Air Traffic Management (CNS/ATM) through Multi-Function Transport Satellite (MTSAT) system is indispensable     

基于PowerPC8640的PCI-E总线接口设计

PCI-E总线因为其自身的特点和关键技术优势,被公认为下一代总线标准。PowerPC8640内部集成有PCI-E接口,同时本身是一款高性能的处理器。重点介绍了PowerPC8640集成的PCI-E接口的特征以及软件初始化流程,PowerPC8640的PCI-E接口作为主设备,设计了两种PCI-E从设备的实现方式：使用FPGA的PCI-E硬核和专用PCI-E转PCI的芯片PEX8112,实现PCI-E的通信。经加电试验,所有功能都已实现,表明采用PowerPC8640实现PCI-E的方法可行,而且简化了硬件设计和软件开发。     

Effect of errors on a contention-based TDMA protocol

A hybrid contention-based time-division multiple access (TDMA) protocol was previously proposed for data transmission (D. Tsai et al., IEEE Trans. on Communications, COM-36, Feb. 1988, p.225-8). It provides satisfactory performance for an error-free channel. The effect of channel errors on the performance of this protocol is studied. To remain operational the protocol must be modified, and the modified protocol is then analyzed. Results derived include the average of frame length, the number of slots wasted, the number of residual packets, and delay. Numerical examples show that channel errors can sometime be damaging but can be recovered by proper error control codes     

Satellite communication-a continuing revolution

SATCOM technology has revolutionized communications over the last 40 years. Initial SATCOM systems provided trunk telephony through large, fixed stations; current systems offer many services to smaller, fixed and mobile terminals. Personal Communications Systems, when fully implemented, will allow individuals to communicate with “anyone, anywhere, anytime,” and thus transform the world into a truly global village. New systems (currently being planned) will offer innovative services, such as computer networking and multimedia to the expanding mass market at an affordable cost. The rate of SATCOM progress shows no sign of slowing, and this revolution is expected to continue well into the future     

The FedSat Microsatellite Mission

An Australian research microsatellite, FedSat with a complement of four payloads was launched from Tanegashima, Japan on 14 December 2002 into a near-circular sun synchronous 10:30 LT polar orbit at an inclination of 98.7° and altitude 800 km. Scientific experiments include a triaxial fluxgate magnetometer with a frequency response up to 100 Hz and a GPS receiver to monitor total electron content (TEC) and provide a precise orbit determination. Communications experiments include a Ka-band transponder and a UHF packet data service. A high performance computer payload will test reconfigurable computing technology. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrodeless ultraviolet communications system

The Laser Communications Laboratory (LCL) of the Wright Laboratory Avionics Directorate is heavily involved in designing optical communications systems covering the full optical spectrum to meet our current and future military communications requirements. This paper summarizes the in-house designed and built solar blind ultraviolet communications system used in the LCL to investigate non-line-of-sight data and voice links. It also summarizes some of the previous DoD work accomplished to exploit free space communications via ultraviolet radiation. In addition, safety factors peculiar to ultraviolet radiation in a closed cockpit environment are addressed. An evaluation of the current electrodeless ultraviolet communications system and a synopsis of planned future projects to improve the system are included in the paper     

Investment Costs of Terrestrial Long-Haul Telecommunication Facilities

The investment costs of long-haul, modern, radio relay and coaxialcable systems, as determined from data submitted to the Federal Communications Commission, are presented. Formulas to determine costs per voice-circuit-mile, and per television-channel-mile, are developed. The specific facilities investigated are the TD-2, TD-3, and TH radio relay systems, and the L-3 12-tube and L-4 20-tube coaxial cable systems. The radio relay systems are significantly, with one exception, less expensive than coaxial cable systems over their design capacity ranges. The L-4 20-tube coaxial cable system (32 400 voice circuits) and the TD-3 radio relaysystem (12 000 voice circuits) have approximately equal investment costs per voice-circuit-mile ($3.40) at full capacity.     

The Space Weather Forecast Program

This paper describes the Space Weather Forecast Program managed by the Communications Research Laboratory of Japan. It is a long-range program consisting of three phases of five years each. This program emerged after an effort to investigate future needs for space environment prediction. We conclude that solar flares and magnetic storms are two main critical phenomena which will affect human's space activities in the 21st century. The core of the program is to set up a Space Weather Forecast Center which has core facilities: (1) a computer network system; (2) ground facilities for continuous observation of the Sun; and (3) a satellite-based space environment monitoring system. Emphasis is placed upon the necessity of internal cooperation for efficient operation of the Forecast Center.     

Free flight is in the future: large-scale controller pilot data link communications emulation testbed

NASA's Glenn Research Center (GRC) is responsible for the Advanced Communications for Air Traffic Management (AC/ATM) Project, a sub-element task of the Advanced Air Transportation Technologies (AATT) Project of the NASA Airspace Systems Program. The AC/ATM Project is developing new communications technologies and tools that will enable Free Flight, an operating mode in which pilots will have the freedom to select their path and speed in real-time. The goal of the AC/ATM Project is to enable a communications infrastructure providing the capacity, efficiency, and flexibility necessary to realize benefits arising from the future mature Free Flight environment. A key infrastructure element is the Aeronautical Telecommunications Network (ATN) that the Federal Aviation Administration (FAA) is in the process of fielding.