Mobile Earth Station Research Articles

Design of Bifurcated Beam using Convex Bent Array Feed for Satellite Mobile Earth Station Application

Design of Bifurcated Beam using Convex Bent Array Feed for Satellite Mobile Earth Station Application

The design of the C mobile earth station simulator based on C language

The communication equipment software of the Global Maritime Distress and Safety System is based on DOS platform, and the equipment operation simulator used for training and assessment is generally developed by VC, VB and FLASH technology. There are a lot of difference between the simulator and the real machine on the interface and the operating response. The operation of the simulator is done with mouse, while the operation of the real machine must be done with the keyboard only on board ships. The Inmarsat-C mobile earth station simulator has being developed by C language. The simulator terminal operating interface and response is identical with the real machine operation because the developing language of the simulator is the same as the real machine. Because the adoption of the doubly-linked list data structure, program structure is clear and code is simplified.

Adaptive Array Antennas for Mobile Earth Stations: A Review

Adaptive Array Antennas for Mobile Earth Stations: A Review

Analysis of interference and availability between satellite and ground components in an integrated mobile‐satellite service system

SummaryAn integrated mobile‐satellite service (MSS) system is one of the most promising infrastructures for the efficient use of satellite frequency, and the satellite coverage can be extended by reusing the satellite frequency in its ground components. However, the co‐channel interferences caused by the frequency reusing technique may lead to the performance degradation. This paper presents the interference analysis for an integrated MSS system that is composed of a multi‐beam satellite, complementary ground components (CGCs), and mobile earth stations, by using statistical simulations. These statistical results are then used to evaluate the availability of the system. Our simulation results reveal that the satellite frequency reuse in the CGCs of the integrated MSS system can increase efficiency of satellite spectrum utilization with a tradeoff between CGC network capacity and intra‐system interferences. Copyright © 2015 John Wiley & Sons, Ltd.

Low-cost multibeam phased array antenna for communications with GEO satellites

In this article, we have shown the development of a unique design concept in which a single planar array antenna consisting of N × M elements on a mobile earth station, such as a navy ship, will require only M phase shifters (for each beam) and one or two hard-wired squints to communicate with several GEO satellites simultaneously by generating multiple independent beams. Our simplified design enables a reduction in both the cost and the complexity of a PAA. This unique concept reduces complexity by requiring full scan capability only in the azimuth plane, thereby reducing the number of phase shifters from NM to M for each beam. At the same time, only one or two hard-wired squints are used in the elevation plane, further reducing the complexity and thus the cost of development of such a PAA.

MSS 대역 WCDMA ATC 서비스 주파수 할당을 위한 인접 채널 간섭 분석

최근 기존의 MSS(Mobile Satellite Service) 대역에 지상망과 위성망의 하이브리드 형태인 ATC(Ancillary Terrestrial Component) 서비스 도입이 추진되고 있다. 새로운 MSS/ATC 서비스 주파수 할당을 위해서는 기존의 지상망에 의한 인접 채널 간섭뿐만 아니라 시스템 자체 내의 인접 채널 간섭 분석이 중요하다. 이에 본 논문에서는 인접 채널 간섭에 의한 ACIR(Adjacent Channel Interference Ratio), 지상 이동국 및 위성 이동 지구국의 수를 파라미터로 하여 업링크에서는 지상 기지국 최소 허용 전력 및 시스템 용량(capacity) 손실, 다운링크에서는 1 빔(beam) 당 1 셀(cell)을 가정하여 MSS/ATC 시스템 용량 손실에 대한 시스템 성능을 평가하였다. MSS/ATC 서비스 주파수 배치에 따른 주파수 공유를 위해 두 가지 시나리오 즉, 5 MHz 및 10 MHz 주파수 간격에 대한 ACIR 기준값을 평가하였으며, 향후 이 기준값에 따른 ATC 서비스 커버리지 및 수신 필터 설계 등이 요구된다. A candidate hybrid satellite and terrestrial network architecture, MSS/ATC(Mobile Satellite Service/Ancillary Terrestrial Component), is proposed for utilizing efficiently the exist MSS bands. Studies on the adjacent channel interference from the existing terrestrial mobile services and MSS/ATC itself are important to allocate a new ATC service frequency in MSS band. In this paper, we have analyzed the minimum permission power of terrestrial base station and the capacity loss with parameters of ACIR, number of MS(mobile Station) and MES(Mobile Earth Station) in uplink, and also, the capacity performance based on 1 beam and 1 cell assumption for MSS/ATC in downlink. The ACIR requirements are estimated in two MSS/ATC frequency allocation scenarios for 5 MHz and 10 MHz guard band to share spectrum with adjacent systems, and according to these ACIR requirements the service coverage and the receiver filter for ATC system should be designed in near future.

Alerting Service for GEO Satellite System

There are great differences between terrestrial cellular communication system and GEO (Geostationary Earth Orbit) mobile satellite system. In GEO mobile satellite system, subscribers could not be paged when the MES (Mobile Earth Station) is normally out of coverage area due to additional propagation path losses. To alert the subscribers in such situation, a more penetrative and computationally efficient coding modulation is needed. In this paper two kinds of orthogonal coded modulation, which are 6PSK based and BPSK based, are analyzed. Through compared with the common paging channel modulation method, and the performance analysis of them, we conclude that they can increase the SNR (Signal Noise Ratio) of actual transmitted information, which is greatly more than the SNR of data in the common paging channel. To be emphasized, we also confirm the predominance of 6PSK modulation.

Application of a new methodology for the coordination of the fixed service (FS) with mobile earth stations on board vessels in realistic interference conditions

This paper addresses an in-depth analysis of the interference produced to the fixed service (FS) by the earth stations on board vessels (ESVs) operating with geostationary satellites and proposes a new methodology for the development of coordination areas around the FS receivers, taking into account parameters such as the velocity of the ESVs and their frequency of passage from specific locations. Simulations performed in realistic interference conditions prove the validity of the new methodology, which can constitute the basis for the development of new methods for the coordination between the fixed service and the ESVs contributing, by this way, significantly to the harmonic coexistence of the two services.

Aperiodic array consisting of subarrays for use in small mobile Earth stations

A simple yet practical method of designing an aperiodic array consisting of subarrays is shown. By properly controlling the excitation phase of each subarray, the designed aperiodic array has the capability to track a geostationary satellite within some limited angles. Starting with an initial position of the subarrays, their optimum positions in terms of the side lobe performance can be obtained by a newly developed algorithm which uses the steepest descent method together with an appropriately defined cost function. An example of an aperiodic array consisting of 16 subarrays in the 14 GHz band is shown. It can track a geostationary satellite at the maximum of 2/spl deg/ off its mechanical boresight (the direction perpendicular to the surface of the array). Although it is nearly square with the maximum dimension of only 47/spl lambda/ (wavelength), its calculated side lobe patterns satisfy most of the requirements specified in the International Telecommunication Union (ITU) recommendations, which must be met by all earth stations with antennas of larger than 50/spl lambda/ in diameter.

A new methodology for the determination of the co-ordination area around stations of the fixed service (FS) with respect to mobile Earth stations on board vessels (ESVs)

The extensive use of Earth stations located on board sea going vessels (ESVs) has created the necessity for the development of a new type of co-ordination area around the fixed service receivers (FSRs) operating in frequency bands C and Ku. To date there is not a single method concerning the calculation of the co-ordination area around the FSRs, which takes into account the mobility of the interfering stations. This paper addresses an in-depth analysis of the interference produced to the FSRs by the ESVs and proposes a new method for the development of the co-ordination area around the FSRs, taking into account parameters such as the velocity of the ESVs and their frequencies of passage from specific locations. Simulations performed for three different operational scenarios prove the validity of the new methodology. Copyright © 2005 John Wiley & Sons, Ltd.

Telemedicine by Satellite Communication System and Mobile Earth Station

Telemedicine by Satellite Communication System and Mobile Earth Station

Satellite-PCS channel simulation in mobile user environments using photogrammetry and Markov chains

In this paper, we present a system that models the land-mobile satellite communication channel with a Markov chain approach supported by images of the mobile Earth station's (MES) environment. Our method employs a video camera with a fish-eye lens capturing image sequences of the user environment from the position of the moving MES, image and signal processing algorithms to recognize propagation path states and extract their duration and transition probabilities, and modeling of the communication channel characteristics using the theory of Markov stochastic processes combined with statistical fade distributions appropriate for given path states. The results demonstrate that the procedure provides a full statistical characterization of the narrow-band land-mobile satellite propagation channel in several environments.

Satellite Earth Stations Challenges Ahead

Use of satellites for telecommunications, broadcasting and remote sensing has led to new earth station technology developments. New services and applications have thrown up challenges to electronics and telecommunication engineers to develop fixed, transportable and mobile earth stations with new devices/materials/production methods. This paper takes stock of available earth stations in the country and brings out areas of new R&D and technology development to meet future challenges.

INMARSAT and the Future of Mobile Satellite Services

This paper reviews the demand for mobile satellite communications and radiodetermination services from the maritime, aviation, and land mobile communities. It briefly examines existing alternatives and the factors that are affecting the growth and development of mobile satellite communications, with particular reference to INMARSAT. Future mobile earth station standards and services are described as are the key technological developments and challenges, which need to be met before mobile satellite services-on aircraft, the smallest of vessels, and land vehicles-become widely available at significantly lower costs than today. The authors are cautiously optimistic that the 1990's will see a rapid growth of mobile satellite services, but such growth will depend in large part on the resolution of certain institutional and technical problems, particularly relating to the limited mobile satellite spectrum available at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</tex> -band.

Packet switching for mobile earth stations via low-orbit satellite network

A potentially valuable implementation of a satellite computer communication packet switched network is one which is survivable and distributed. That is, a system which dynamically adapts to changing network element connectivities, changing interconnections of users, and is not dependent on any central unit for its own internal command and control. A laboratory prototype of such a system has been constructed of a group of computers which when given communication circuits between them will, acting autonomously, create a computer communication packet switching network and which will continually adapt to changes in connectivity. In this paper, an adaptive computer communication routing algorithm is described, its application in space including a space segment design is presented, its actual implementation in real physical hardware is discussed, and system performance results as parameters are varied are presented.

Navigation Error Sensitivities for Communicating Between Fixed or Mobile Earth Stations and Satellites

The task of communicating with a satellite from a fixed or moving station on or near the earth is becoming one that must be accomplished in an increasing number of applications. It is frequently necessary in these applications to point an antenna at the satellite, and to know the range and/or range-rate along the line-of-sight connecting station and satellite, within some allowable tolerance, in order to lock on and communicate successfully. Errors in the navigation variables of the station, that is, its three-dimensional position and velocity, and in the knowledge of position and velocity of the satellite, contribute to errors in “lockon” variables, i.e., antenna-positioning, range, and range-rate. This paper summarizes the formulas that allow the errors in lockon variables to be calculated, given the errors in satellite and station navigation variables. The error sensitivities, that is, the partial derivatives of the errors in lockon variables as functions of errors in navigation variables, are presented in tabular form.

K-Band Mobile Earth Station for Domestic Satellite Communications System

Design considerations of a K -band (30/20 GHz) mobile earth station for a domestic satellite communications system are described. A Japanese Medium Capacity Communication Satellite which utilizes K and C satellite communication bands was considered for the system design. Transmitting power control method, statistical link quality estimation, and equipment description are given.