Satellite Communication Services Research Articles

Corner truncated broadband patch antenna with circular slots

ABSTRACTIn this communication, a corner truncated broadband patch antenna with circular slots is presented. The proposed antenna is fabricated on 14 * 14 * 1.57 mm3 Rogers RT5870 substrate (εr = 2.33 and loss tangent of 0.0012) and a 50‐Ω SMA connector is used for excitation. Bandwidth enhancement has been reported due to cutting of two circular slots and truncating the corners of the square patch, which gives rise to mode splitting phenomenon and better impedance matching. Simulated results show that the impedance bandwidth (S11 < 10 dB) of the proposed antenna is 19% (10.8–13.2 GHz). Measured results are in good agreement with the simulated results. The fractional bandwidth of the proposed antenna has enhanced from 8.5 to 19% as compared to the simple patch antenna, showing an enhancement of 123%. The peak gain of the proposed antenna is 7 dB. The antenna finds application in satellite communication, radar communication, and other alleged wireless communication services. Details and comparison of the proposed antenna with simple patch antenna have been described. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:845–849, 2015

Development of Satellite/3G+ Multi-Link Communication Terminal Based on Medical Rescue Information System

This paper introduces a satellite /3G+ multi-link communication terminal based on medical rescue information system, which provides 3G wireless network and satellite communication services and integrates cellular phone, maritime satellite terminal, BeiDou user device and Iridium phone [1]. The new terminal could improve the communication adaptability and transmission efficiency for the emergency medical rescue information system even in hostile environmental conditions [2] (such as earthquake, flood, and war). Tests showed that: this terminal has the advantages of simple access, rapid switch, efficient transmission, it can also guarantee timely and effective interaction of all kinds of information, so as to ensure the time-effect treatment for emergency medical rescue system [3].

Special issue on S‐band mobile satellite technologies

This special issue of the Wiley International Journal of Satellite Communications and Networking hosts a selection of papers related to S-band mobile satellite R&D activities recently completed in the frame of the European Space Agency ARTES programs. The S-band allocation to hybrid satellite and terrestrial services in Europe 2009 and in other parts of the world has attracted operator, industry, and research institution interest for its commercial exploitation. The aim is to illustrate the most recent technical achievements either to improve the S-band satellite system performance or to demonstrate with prototypes the feasibility of new technologies in the user terminal receivers. Dealing with mobile satellite communication services in S-band, the reference air interface for all these scientific papers is the Digital Video Broadcasting - Satellite services to Handhelds (DVB-SH) standard [1], designed to support high-quality broadcasting services over the harsh land mobile satellite (LMS) channel while at the same time able to exploit the presence of terrestrial gap fillers. DVB-SH represents a state-of-the-art air interface for hybrid satellite/terrestrial mobile broadcasting (interactive) networks [2]. In [3], the authors have summarized key findings of an in-depth analysis of the benefits provided by different system architectures and technologies for next generation S-band mobile satellite broadcasting network with interactivity. Along with advanced antenna and payload architectures, a promising way forward in this context is the migration from the conventional single polarization per beam to an advanced dual polarization per beam MIMO architecture for effective spectrum exploitation. In this context, system capacity simulations are showing potential improvements in a 60% to 90% range in terms of overall throughput. Two leading European antenna manufacturers present in [4] and [5] their user terminal antenna prototypes to primarily target professional automotive applications. The main aspects of antenna design are introduced, and the performance of switchable dual polarized vehicular transmit/receive antennas is validated. The form factor of the antenna design described is not only fully in line with typical automotive commercial requirements but also suitable for other markets such as the maritime or the machine-to-machine ones. The aim of [6] is to review the state-of-the-art techniques and architectures supporting beamforming in mobile satellite systems and to evaluate the potential benefits/drawbacks of on-ground beamforming compared to on-board beamforming approach. For this analysis, also some of the beamforming error sources, such as propagation effects at feeder link level, on-board degradations at payload level, differential atmospheric perturbations and Doppler shift effect have been investigated. Finally, a preliminary assessment of the potential advantages given by adopting adaptive beamforming and more advanced on-ground signal processing techniques in multi-spots mobile satellite systems is presented. Stimulated by the large capacity increase potential provided by the dual-polarized S-band satellite systems, the authors in [7] derive a comprehensive MIMO channel model. This paper describes the joint wideband and narrowband modeling approach, provides examples of the usage, and finally describes some evaluation results. This new MIMO model for a dual-polarized LMS-channel environment has been evaluated by comparing the simulated results with data gathered from an extensive field trials carried out within the duration of the project.

SATELLITE BASED EDUCATION AND TRAINING IN REMOTE SENSING AND GEO-INFORMATION: AN E-LEARNING APPROACH TO MEET THE GROWING DEMANDS IN INDIA

Abstract. One of the prime activities of Indian Space Research Organisation's (ISRO) Space Program is providing satellite communication services, viz., television broadcasting, mobile communication, cyclone disaster warning and rescue operations etc. so as to improve their economic conditions, disseminate technical / scientific knowledge to improve the agriculture production and education for rural people of India. ISRO, along with National Aeronautical and Space Administration (NASA) conducted experimental satellite communication project i.e. Satellite Instructional Television Experiment (SITE) using NASA’s Advanced Telecommunication Satellite (i.e. ATS 6) with an objective to educate poor people of India via satellite broadcasting in 1975 and 1976, covering more than 2600 villages in six states of India and territories. Over the years India built communication satellites indigenously to meet the communication requirements of India. This has further lead to launch of an exclusive satellite from ISRO for educational purposes i.e. EDUSAT in 2004 through which rich audio-video content is transmitted / received, recreating virtual classes through interactivity. Indian Institute of Remote Sensing (IIRS) established in 1966, a premier institute in south East Asia in disseminating Remote Sensing (RS) and Geographical Information System (GIS), mainly focusing on contact based programs. But expanded the scope with satellite based Distance Learning Programs for Universities, utilizing the dedicated communication satellite i.e. EDUSAT in 2007. IIRS conducted successfully eight Distance Learning Programs in the last five years and training more than 6000 students mainly at postgraduate level from more than 60 universities /Institutions spread across India. IIRS obtained feedback and improved the programs on the continuous basis. Expanded the scope of IIRS outreach program to train user departments tailor made in any of the applications of Remote Sensing and Geoinformation, capacity building for ISRO’s operational projects / new satellite missions, developing e-learning contents and launching e-learning courses under twelfth five year (i.e. 2012–17) plan period of Government of India, in addition to continuing of existing distance learning programs for universities.

Developing ITS Services for the Open SafeTRIP Platform

The goal of the ongoing SafeTRIP project is to provide the ITS community with a bidirectional communications platform on which any organisation can develop its own ITS and multimedia entertainment applications. This platform is open to developers willing to benefit from a wide range of state-of-the-art satellite communications services (using the recently allocated S-band spectrum for Mobile Satellite Services and based on standards co-developed by several SafeTRIP partners), as well as almost ubiquitous terrestrial communications networks. It is also available to researchers who wish to exploit its flexibility and open standards, as well as its advanced communications capabilities. This paper briefly presents the platform architecture and focuses more specifically on case studies exemplifying the development process for three different applications. It also shows how to capitalise on the enabling functions of the platform to streamline development. Finally, a number of challenges specific to the automotive environment are analysed.

Antennas for multiple spot beam satellites

Ka-band payloads are becoming more and more popular for satellite communication. The wider band width in Ka-band allows a better satisfaction of the increasing demand for capacity. In addition to the use of more resources, a more efficient use of the available resources will become key for a successful development of satellite communication services. Modern antenna concepts allow a high frequency reuse scheme and, therefore, an extreme efficient use of the most rare resource in satellite communication, the frequency band width. In this paper, we describe the design and the use of different types of such antennas.

L Band Propagation Measurements for DAB Service Planning in INDIA

The nature of variations of L band satellite signal strength for direct reception -both in fixed as well as in mobile reception are important technical parameters for the planning of satellite broadcast and communication services network. These parameters have been assessed through a field experiment using simulated satellite conditions. Variation of signal strength due to vegetation; urban structures; etc. as well as the building penetration loss along with the Standard Deviation of each of these variations has been assessed based on the data collected during the fixed and mobile reception. This paper gives an insight into the propagation in ‘L’ band under the simulated satellite conditions.

Antenna with optimized pattern for simultaneous reception of terrestrial signals and signals of geostationary satellites

Abstract. The link margin for satellite communication services targeting mobile users is tight. This leads to reception problems in areas with strong fading scenarios like urban areas or forested areas with dense foliage. In order to avoid loss of service in urban areas with week coverage by satellite signals, terrestrial repeaters are used. Therefore in the design of antennas for mobile reception of satellite services, an optimized characteristics for the satellite constellation, as well as an adequate coverage of the terrestrial repeaters has to be accounted for. In this paper an antenna with optimum shaped pattern for the satellite mode and adjustable gain for vertical polarization is investigated. Beside constraints regarding the radiation pattern, measurements concerning the dependence of the antenna on noise temperature and therefore the behavior in real noisy environments are carried out. A comparison with a conventional antenna shows the high performance of the new antenna in combination with a very low volume requirement.

Lirneasia Six Country Multi-Component Study 2006-2007: Thailand Report

Until recently telecommunications services in Thailand were exclusively provided by two state-owned enterprises (SOEs): the Telephone Organization of Thailand (TOT), which held a monopoly over domestic telephony, and the Communication Authority of Thailand (CAT), which had a monopoly in international gateway services. The market division between the two SOEs saw through the development of telecommunications sector in Thailand, but in the early 1990s it was recognized that the future growth of the industry would require infusion of private capital. A unique scheme to preserve the statutory monopoly of the two SOEs, while accommodating the private sector, evolved. Beginning in 1992, TOT and CAT awarded concessions to private companies to undertake network development and to provide fixed line, mobile, satellite, paging and other communication services, under a Built-Transfer-Operate (BTO) agreement. Under such an agreement private concessionaires would invest in infrastructure and then transfer legal ownership in the installed network to the state operator upon completion. In exchange, they were granted a 25-30 years exclusive use of the network.

Multi-life cycles utilization of retired satellites

Retired geosynchronous (GEO) communication satellites affect the GEO orbit environment in outer space. According to the new concept of modern design, the authors propose creatively a method of reusing retired GEO communication satellites, through adjusting retired GEO satellites to slightly inclined orbit geosynchronous (SIGSO) satellites. After these retired satellites are applied to the navigation and communication system, integrity of navigation system and positioning accuracy of the system is improved. Meanwhile, some transponders on these retired satellites can be used to establish a new satellite communication service, and initiate the study and utilization of the multi-life cycle for retired satellites. Experimental results show that this project has significant social value and can make remarkable economic benefit.

Development of the Natural Resources of the Moon and Other Celestial Bodies: Economic and Legal Aspects

The path of gradual commercialization of current space applications, such as launch services, satellite communication services, direct broadcasting services, satellite remote sensing and navigation services, and satellite weather monitoring services, will most likely be followed by future activities of use of space resources. Ventures, like mining the natural resources of the Moon and asteroids, are likely to become technologically feasible in the near future. The question is what would be the most appropriate approach to address the future needs of exploitation of space resources: should it remain the exclusive province of state governments; should the private sector take over such space activities; or should a public-private partnership type of venture be encouraged? As state governments are becoming constrained by budget deficits, an increased reliance on private sector involvement in space activities involving the extraction and use of space resources is to be expected. When deciding whether to invest in commercial ventures of resource use exploitation, any potential private investor will be faced with the issues of economic costs, risks, and perceived regulatory barriers. This study argues that the perceived regulatory barriers, i.e., the licensing requirement, the “common heritage of mankind” principle of international space law, and protection of intellectual property rights, are not obstacles to economic development. Governments should provide both policy and regulatory incentives for private sector participation in the area of space natural resource use by funding basic research and development and by sponsoring liability insurance for private ventures among other incentives.

Design and Implementation of a Solution for the Provisioning of Converged Remote Tower and Facility Management Services over Satellite IP for Greek Heliports

The only way to quickly provide health and disaster recovery services to the large number of isolated islands in Greece is to fly there by helicopter. For this reason, there are 46 heliports operated 24/7 by the Hellenic Civil Aviation Authority (HCAA). Unfortunately, the Greek terrain is extremely difficult as far as provisioning of telecommunication means is concerned, so connectivity with the heliports is virtually nonexistent. This leads to reduced radio coverage, especially at low altitudes, severely impairing the heliports' operational capabilities. Moreover, heliports are unmanned and unsupervised, and there is no indication as to the weather conditions there. Thus, flight controllers authorize landings/takeoffs to/from heliports, normally a life or death decision, while remaining unaware of what pilots may run into. This article presents the design and implementation of a solution to these problems, contributing to flight safety and heliport maintenance/operation procedures as well as providing a working paradigm regarding the quality of satellite communication services for other air traffic control (ATC) applications.

Satellite Navigation and Communications: An Integrated Vision

The paper addresses advanced layered architectures for the development of integration scenarios between satellite navigation and communications systems and services. This synercic cooperation represents --- in author's vision --- the core of future global networks. The concept of integration and its translation into an integrated network is displayed, together with examples of possible architectures for navigation-communications applications. In this frame, the paper addresses also the possible exploitation of stratospheric platforms (HAP) as permanent and on-demand blocks concurring to the effective deployment of the integrated vision.

MICROWAVE PROPERTIES OF TUNABLE PHASE SHIFTER USING SUPERCONDUCTOR/FERROELECTRIC THIN FILMS

ABSTRACT High temperature superconductor, YBa2Cu3O7−δ (YBCO), and ferroelectric, Ba0.1Sr0.9TiO3 (BST), multilayer thin films were deposited on MgO (100) substrates using a pulsed laser deposition. The thin films exhibited only (00l) peaks of YBCO and BST. The HTS thin films demonstrated excellent zero resistance temperature of 92.5 K. We designed and fabricated HTS ferroelectric phase shifter using high frequency system simulator and standard photolithography method, respectively. The YBCO/BST phase shifter shows a low insertion loss (2.97 dB) and large phase change (162°) with dc bias of 40 V at operating frequency of 10 GHz. The HTS ferroelectric phase shifter shows 54 of figure of merit. These results can be applicable to phased array antenna system for satellite communication services.

Satellite Communications Services for "Remote" Mobile and Fixed Site Users in the Oil and Gas Community

What is "Remote?" The community of users referred to as "Oil and Gas," along with many other resource-based industries in North America, have urgent requirements for cost-effective, reliable, and easy-to-use telecommunications in "remote" areas. Depending on the telecommunication service being considered, "remote" can mean several hundred kilometres from an urban area in the case of analog cellphone or two-way radio services. But in the case of two-way text messaging over digital cellphone networks, "remote" can mean 30–50 kms from large urban areas. Until very recently, companies and individuals operating in remote areas seldom considered satellite telecommunications as an affordable, reliable, and easy-to-use alternative to terrestrial-based cellular and two-way radio networks. However, regional mobile satellite service operators in several countries have demonstrated over the last seven years that satellite networks are an excellent complement to the limited coverage available from terrestrial networks. Some former terrestrial users have in fact switched to satellite networks because the satellite network provides better coverage and greater availability (i.e., reliability of service) at lower operating costs. Another important reason for the increasing usage of satellite networks is that the services and applications available over satellite are comparable to those available over traditional terrestrial networks. Satellite Coverage and Services Mobile Satellite Ventures (MSV) owns and operates the MSAT geostationary satellite network which provides a comprehensive range of telecommunications services throughout Canada, U.S.A., Mexico, Central America, the Caribbean, and most of Colombia and Venezuela. The MSAT-1 and MSAT-2 satellites also provide coverage 200 nautical miles off the east and west coasts of North America and throughout the Caribbean. MSV has pioneered the development of a broad range of services including phone, fax, circuit-switched data, dispatch radio, and packet-switched services. Other services, such as asset tracking, flight following, and differential GPS are also offered over the MSV network by independent operators. MSV Satellite Applications All of the MSV network services are utilized in the oil and gas industry. Mobile and fixed-site phone service and fax services are used extensively. Circuit-switched data operating at 2,400 or 4,800 bps provides access to Internet or Intranet e-mail using POP3 connections from ISPs. MSV circuit-switched data service supports continuous data transfer at 4,800 bps for parameters such as pump pressure, rotary speed, and pump load. Dispatch Radio Service provides half-duplex push-to-talk group-oriented communications services. The service replicates many elements of terrestrial "two-way radio" service and features up to 15 talk groups per mobile, private mode for one-on-one communications, priority one interrupt, and the flexibility to assign one of three different priorities to each talk group being monitored. One application of the push-to-talk dispatch radio service is in pipeline patrol where the dispatcher communicates with a fleet of vehicles in push-to-talk operation over the entire length of the pipeline. Proprietary local area networks are interfaced with the satellite network. Two major oil field service companies in the southern U.S. use Dispatch Radio as well as a company in northern B.C. that has service trucks setting up and tearing down rigs.

Using array signal processing to improve rural area coverage for satellite communications services

AbstractWe address wide—area coverage for hand—held portables using an on—board signal processing satellite in geostationary (GEO) orbit at minimum payload cost. A GEO link, being power—limited, differs from terrestrial mobile communications systems that use direct radiating antennas by requiring a focal—fed parabolic reflector, which acts as a fixed analog beamformer. We propose to cascade a high—gain parabolic reflector and a digital maximum signal—to—interference—plus—noise ratio (SINR) multi—beamformer for spatial multi—user interference suppression to achieve coverage extension. This involves on—board antenna array signal processing of multiple feeds. It is shown that nearly uniform coverage of an area the size of Canada can be provided using only five parbolic reflector apertures. Compared to conventional focussed multibeam system, link margins are typically increased from a minimum requirement of 5. 25 dB to 7. 5 dB in border areas. The more uniform coverage reduces dynamic power control requirements.

Iridium satellites help map electrical currents in space

The satellite constellation of Iridium LLC, which filed for Chapter 11 bankruptcy in 1999 after it failed to win enough business for its commercial satellite communications services, is still orbiting at an altitude of about 780 kilometers. Now, however, the satellites are helping to write a new chapter in understanding space weather.Magnetometers onboard each of the system's 66 polar‐orbiting satellites are working in conjunction with the high‐frequency, multinational Super Dual Auroral Radar Network, or SuperDARN, to provide the first continuous measurements of electrical currents between Earth's upper atmosphere and space. These tools also are generating the first global maps of electrical power flowing into the polar upper atmosphere.

Ambiguity removal technique for user position determination in nongeostationary satellite communications systems

Presently, much research has been carried out on systems providing satellite communication service based on portable terminals using nongeostationary satellites with multispot beam configurations such as ICO and Iridium. In these systems, it is necessary to detect the user terminal position accurately so that the terminal access, hand-over between the spot beams, and hand-over between the satellites are carried out efficiently. As a user position determination method by one nongeostationary satellite, the method computing the position by using the propagation delay time between the satellite and the user and the Doppler shift is a representative one. In the conventional method, the ambiguity of the estimated position in the position detection becomes a problem. In this paper, a method is proposed to eliminate ambiguity of the estimated position that becomes a problem in the position detection with a nongeostationary satellite. In addition, the area with ambiguity problem, evaluation of the time rate, and the effect of the moving speed and direction on the ambiguity elimination success probability are evaluated by computer simulation. It is shown that the proposed method can sufficiently be used in a real system. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(9): 67–75, 2000

Iridium(R) aeronautical satellite communications

The ever-increasing demand to stay in touch, to be able to communicate anywhere and anytime, has created a market for Low Earth Orbit (LEG) satellite communications services such as the Iridium System. The Iridium satellite communications network is being developed to support the needs of the passenger, the cabin crew and the flight crew. Iridium Communications LLC owns a network of satellites that provides a connection between mobile subscribers and gateway earth stations. The gateways provide connections to the public switched telephone network (PSTN), as well as to Aeronautical Gateway Subsystems (AGS). AGSs provide connections to packet data networks, and are used to initiate, ground to air safety voice calls.

Competition to international satellite communications services

Rapid construction of transoceanic fiber optic cables and the successful establishment of private satellite companies with inter-regional or global coverage have fundamentally altered the environment in which international telecommunications capacity is provided. This article presents industry data and discusses market developments which document substantial competition that has emerged in international facilities-based telecommunications. Intelsat, historically the largest provider of international telecommunications capacity, has seen its market position decline rapidly for all services and all major geographic market areas worldwide.