Showing papers on "Marine chronometer published in 1992"

From sails to satellites : the origin and development of navigational science

Abstract: Introduction. 1: Geography to Magellan. 2: Numerate navigators without science. 3: Three necessary mathematical inventions. 4: A new way of thought. 5: A political history of the longitude. 6: The great pursuit of the longitude. 7: Astronomical navigation with sextant and chronometer. 8: Victoriana. 9: Self-containment. 10: The homing quality of radio. 11: The seeing quality of radio. 12: Radio, Apollonius, and Professor Doppler. 13: The path of minimum time. 14: On the price of annuities. 15: The past and the present in perspective. References. Index

GPS satellite-synchronised chronometer with local time display - uses XTAL-controlled clock and interpolation signal processor

Abstract: The radio synchronised clock contains an antenna (10) and radio receiver (20) consisting of pre-amp (22), IF section (24) and a crystal oscillator (26). The oscillator maintains local time with error delta tB (28). GPS satellites (12,14,16,18) transmit synchronising signals and time codes. By determining the relative timing of these signals, local time and position are generated by processor (30). An error estimate for delta tB is output (32) to a time generator (34). Longitude (36) is output to time-zone store (38) which outputs the difference between the Local Mean Time and GMT to the time generator. By these means a chronometer is realised which automatically indicates local time worldwide and with satellite time synchronisation. USE - Ship navigation and chronometer.

Centralizing Navigational Technology in America: The U.S. Navy's Depot of Charts and Instruments, 1830-1842

Abstract: nations plying the high seas. Driven by diverse interests from commerce to defense, navigation was and continues to be a highly visible enterprise in which each nation also has at stake its scientific and technological pride. National observatories from Paris and Greenwich to St. Petersburg and Tokyo were founded in large part to improve navigation while hydrographic (and later oceanographic) offices played a more direct role; observational instruments including the sextant, quadrant, and repeating circle were developed and refined in the service of navigation; the cherished ideal of a perfect marine timekeeper found practical fulfillment in the chronometer of John Harrison and his successors; and modern radio and satellite navigational techniques have culminated in positional "fixes" to within a few meters for many purposes. Navigation inspired a large body of astronomical, meteorological, and magnetic observations, learned papers on its theory and practice, and nautical handbooks, almanacs, and periodicals to disseminate the latest information to navigators. Worldwide, the scientific and technological effort expended toward the end of safely voyaging the earth's seas has been impressive and sustained and forms an important chapter in the history of science and technology. One part of the history of navigation that has not received adequate attention is the rise of navigational technology in the United States, DR. DICK is an astronomer and historian of science at the U.S. Naval Observatory in Washington, D.C. He is the author of Plurality of Worlds (1982) and is currently at work on a history of the Naval Observatory and of the 20th-century extraterrestrial life debate. He wishes to express his appreciation to the many archivists and librarians consulted during this research, including those at the Navy Historical Center in Washington, D.C., the Military Records Branch of the National Archives, the National Oceanic and Atmospheric Administration, and particularly to Brenda G. Corbin and Gregory Shelton, librarians at the U.S. Naval Observatory.