LEADER 05051nam 2200649Ia 450 001 9910969860903321 005 20251116161113.0 010 $a0-309-16885-6 010 $a1-280-18323-3 010 $a9786610183234 010 $a0-309-50320-5 035 $a(CKB)111069351129672 035 $a(OCoLC)52815083 035 $a(CaPaEBR)ebrary10038597 035 $a(SSID)ssj0000106781 035 $a(PQKBManifestationID)11984036 035 $a(PQKBTitleCode)TC0000106781 035 $a(PQKBWorkID)10110049 035 $a(PQKB)10848059 035 $a(Au-PeEL)EBL3375326 035 $a(CaPaEBR)ebr10038597 035 $a(OCoLC)919475387 035 $a(MiAaPQ)EBC3375326 035 $a(BIP)53857737 035 $a(BIP)8001758 035 $a(EXLCZ)99111069351129672 100 $a20030714d2002 uy 0 101 0 $aeng 135 $aurcn||||||||| 181 $ctxt 182 $cc 183 $acr 200 03$aAn Assessment of precision time and time interval science and technology /$fCommittee for an Assessment of Precision Time and Interval Science and Technoloy, Naval Studies Board, Division on Engineering and Physical Sciences, National Research Council of The National Academies 205 $a1st ed. 210 $aWashington, D.C. $cNational Academy Press$dc2002 215 $a1 online resource (88 p.) 300 $aBibliographic Level Mode of Issuance: Monograph 311 08$a0-309-08522-5 320 $aIncludes bibliographical references. 327 $aFront Matter -- Preface -- Acknowledgment of Reviewers -- Contents -- Executive Summary -- 1 The Navy and PTTI -- 2 State of the Art of PTTI Physics and Devices -- 3 State of PTTI Research and Infrastructure -- 4 Research Opportunities in PTTI -- 5 Defense Needs for PTTI -- 6 Findings and Recommendations -- A Committee Biographies -- B Tutorial on PTTI Frequency Standards -- C Acronyms and Abbreviations -- D Glossary. 330 $aKnowledge of time is essential to precise knowledge of location, and for this reason the Navy, with its need to navigate on the high seas, has historically played an important role in the development and application of advanced time realization and dissemination technologies. Discoveries coming from basic research funded by the Office of Naval Research (ONR) lie at the heart of today's highest performance atomic clocks, Naval Research Laboratory (NRL) expertise played a role in developing the space-qualified atomic clocks that enable the Global Positioning System (GPS), and the U.S. Naval Observatory (USNO) maintains and disseminates the standard of time for all of the Department of Defense (DOD). The Navy has made major investments in most aspects of precision time and time interval (PTTI) science and technology, although specific PTTI-related research has also been funded by the Defense Advanced Research Projects Agency (DARPA) and non-DOD agencies such as the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the Department of Commerce. Navy funding, largely through ONR, has a history of being an early enabler of key new developments. Judicious funding decisions by the Navy-particularly by ONR program officers-have underpinned most of the major advances in PTTI science and technology (S&T) in the last 50 years. PTTI is important to modern naval needs, and indeed to all the armed Services, for use in both navigation and communications. Precise time synchronization is needed to efficiently determine the start of a code sequence in secure communications, to perform navigation, and to locate the position of signal emitters. Precise frequency control is required in communications for spectrum utilization and frequency-hopped spread-spectrum techniques. There are many examples of essential military operations that depend on PTTI and could benefit from improvements in PTTI technology. These include: -GPS clocks and autonomous operations, -Weapon system four-dimensional coordination, -GPS antijamming, -Network-centric warfare, and -Secure military communications. This report summarizes that reductions in the size, weight, and power requirements and increases in the ruggedness of PTTI devices without sacrificing performance would put more accurate and precise timekeeping in the hands of the warrior, improving capabilities in all of the above operations. 606 $aTime measurements 606 $aAtomic clocks 606 $aNaval research$zUnited States 615 0$aTime measurements. 615 0$aAtomic clocks. 615 0$aNaval research 676 $a529/.7 712 02$aNational Research Council (U.S.).$bCommittee for an Assessment of Precision Time and Time Interval Science and Technology. 712 02$aNational Research Council (U.S.).$bNaval Studies Board. 801 0$bMiAaPQ 801 1$bMiAaPQ 801 2$bMiAaPQ 906 $aBOOK 912 $a9910969860903321 996 $aAn Assessment of precision time and time interval science and technology$94474089 997 $aUNINA