Table Of Content

XOBrtftTCCX Hgixr-.- 58883 nHnM Mr K H q9 ^ M1S1J* 1hH HHHI39SB3e 81 xs iiA Em?K? VrffiHK39B nag?* TTL NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS INMARSAT COMMUNICATIONS SYSTEM: A SYSTEMS APPROACH by Aristides Ioannis Fasoulas June, 1991 Co-Advisor: Dan C. Boger Co-Advisor: William R. Gates Approved for public release; distribution is unlimited. T256871 UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE REPORT DOCUMENTATION PAGE FormApproved OMBNo 0704-0188 1a REPORT SECURITY CLASSIFICATION lb RESTRICTIVE MARKINGS UNCLASSIFIED 2a SECURITY CLASSIFICATION AUTHORITY 3 DISTRIBUTION/AVAILABILITY OF REPORT Approved for public release; 2b DECLASSIFICATION/DOWNGRADING SCHEDULE distribution is unlimited 4 PERFORMING ORGANIZATION REPORT NUMBER(S) 5 MONITORING ORGANIZATION REPORT NUMBER(S) 6a NAME OF PERFORMING ORGANIZATION 6b OFFICE SYMBOL 7a NAME OF MONITORING ORGANIZATION (If applicable) Naval Pstgraduate School AS Naval Postgraduate School 6c. ADDRESS (City. State, and ZIPCode) 7b ADDRESS(City. State, and ZIPCode) Monterey, CA 93943-5000 Monterey, CA 93943-5000 8a. NAME OF FUNDING/SPONSORING 8b OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable) 8c. ADDRESS(City. State, and ZIPCode) 10 SOURCE OF FUNDING NUMBERS PROGRAM PROJECT TASh WORK UNIT ELEMENT NO NO NO ACCESSION NO 11 TITLE (Include Security Classification) INMARSAT COMMUNICATIONS SYSTEM A SYSTEMS APPROACH 12 PERSONAL AUTHOR(S) FASOULAS, Aristedes 13a TYPE OF REPORT 13b TIME COVERED 14 DATE OF REPORT (Year,Month, Day) 5 PAGE COUNT Masters Thesis FROM TO 1991 June 160 16 supplementary notation The views expressed in this thesis are those of the author and do not reflect the official policy or position of the Depart- ment of Defense of the US Government. 17 COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Satellite communications; International satellite communications; INMARSAT; Satellite vulnerability 19 ABSTRACT (Continue on reverse if necessary and identify by block number) This study describes the history of satellite communications from its beginning to the current date and explains the major components of satellite communications. It describes the satellite communicat ions technology, and identifies some of its problems such as speech echo, data transmission, and digital network synchronizat ion It deals with . U.S. military and international satellite communications systerns, and especially with Inmarsat. It also presents the possible threats for a satellite communications system and discusses how to deal with them, Finally, it introduces some conditions and technical considerations of the Inmarsat system in the Hellenic environment and provides some basic information for choosing a satellite system from an economic point of view. 20 DISTRIBUTION/AVAILABILITY OF ABSTRACT 21 ABSTRACT SECURITY CLASSIFICATION El UNCLASSIFIED/UNLIMITED D SAME AS RPT D DTIC USERS UNCLASSIFIED 22a NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Include AreaCode) 22c OFFICE SYMBOL Dan C. Boger 408-646-2607 AS/Bo DD Form 1473, JUN 86 Previouseditionsareobsolete SECURITY CLASSIFICATION OF THIS PAGE S/N 0102-LF-01A-6603 UNCLASSIFIED Approved for public release; distribution is unlimited, Inmarsat Communications System: A Systems Approach by Aristides I. Fasoulas Lieutenant Commander, Hellenic Navy B.S., Hellenic Naval Academy, 1976 Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN TELECOMMUNICATIONS SYSTEMS MANAGEMENT from the NAVAL POSTGRADUATE SCHOOL /June 1991 Department of Administrative Sciences 11 ABSTRACT This study describes the history of satellite communications from its beginning to the current date and explains the major components of satellite communications. It describes the satellite communications technology, and identifies some of its problems such as speech echo, data transmission, and digital network synchronization. It deals with U.S military and international satellite communications systems, and especially with Inmarsat. It also presents the possible threats for a satellite communications system and discusses how to deal with them. Finally, it introduces some conditions and technical considerations of the Inmarsat system in the Hellenic environment and provides some basic information for choosing a satellite system from an economic point of view. in II TABLE OF CONTENTS INTRODUCTION I. 1 BACKGROUND A. 1 B. OBJECTIVES 1 ORGANIZATION C. 2 II. DEVELOPMENT OF SATELLITE COMMUNICATIONS 4 A. HISTORICAL BACKGROUND 4 B. SATELLITE COMMUNICATIONS TECHNOLOGY 6 1 Basic Concepts of Satellite Communications Systems 6 . a. Satellite RF-Link 7 b. Communications Subsystem 8 (1) Communications Repeater 9 (2) Communications Antenna 12 c. Communications Satellite (spacecraft) 14 (1) Spin Stabilization 17 (2) Three Axes Stabilization 17 d. Earth Station 18 (1) Earth station antenna 18 (2) Receivers 21 (3) High power amplifier 23 IV