Reception of Radio Controlled Signal Signal
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Reception of Low Frequency Time Signals
Reprinted from I-This reDort show: the Dossibilitks of clock svnchronization using time signals I 9 transmitted at low frequencies. The study was madr by obsirvins pulses Vol. 6, NO. 9, pp 13-21 emitted by HBC (75 kHr) in Switxerland and by WWVB (60 kHr) in tha United States. (September 1968), The results show that the low frequencies are preferable to the very low frequencies. Measurementi show that by carefully selecting a point on the decay curve of the pulse it is possible at distances from 100 to 1000 kilo- meters to obtain time measurements with an accuracy of +40 microseconds. A comparison of the theoretical and experimental reiulb permib the study of propagation conditions and, further, shows the drsirability of transmitting I seconds pulses with fixed envelope shape. RECEPTION OF LOW FREQUENCY TIME SIGNALS DAVID H. ANDREWS P. E., Electronics Consultant* C. CHASLAIN, J. DePRlNS University of Brussels, Brussels, Belgium 1. INTRODUCTION parisons of atomic clocks, it does not suffice for clock For several years the phases of VLF and LF carriers synchronization (epoch setting). Presently, the most of standard frequency transmitters have been monitored accurate technique requires carrying portable atomic to compare atomic clock~.~,*,3 clocks between the laboratories to be synchronized. No matter what the accuracies of the various clocks may be, The 24-hour phase stability is excellent and allows periodic synchronization must be provided. Actually frequency calibrations to be made with an accuracy ap- the observed frequency deviation of 3 x 1o-l2 between proaching 1 x 10-11. It is well known that over a 24- cesium controlled oscillators amounts to a timing error hour period diurnal effects occur due to propagation of about 100T microseconds, where T, given in years, variations. -
Five Years of VLF Worldwide Comparison of Atomic Frequency Standards
RADIO SCIENCE, Vol. 2 (New Series), No. 6, June 1967 Five Years of VLF Worldwide Comparison of Atomic Frequency Standards B. E. Blair,' E. 1. Crow,2 and A. H. Morgan (Received January 19, 1967) The VLF radio broadcasts of GBR(16.0 kHz), NBA(18.0 or 24.0 kHz), and NSS(21.4 kHz) have enabled worldwide comparisons of atomic frequency standards to parts in 1O'O when received over varied paths and at distances up to 9000 or more kilometers. This paper summarizes a statistical analysis of such comparison data from laboratories in England, France, Switzerland, Sweden, Russia, Japan, Canada, and the United States during the 5-year period 1961-1965. The basic data are dif- ferences in 24-hr average frequencies between the local atomic standard and the received VLF radio signal expressed as parts in 10"'. The analysis of the more recent data finds the receiving laboratory standard deviations, &, and the transmission standard deviation, ?, to be a few parts in 10". Averag- ing frequencies over an increasing number of days has the effect of reducing iUi and ? to some extent. The variation of the & with propagation distance is studied. The VLF-LF long-term mean differences between standards are compared with the recent portable clock tests, and they agree to parts in IO". 1. Introduction points via satellites (Steele, Markowitz, and Lidback, 1964; Markowitz, Lidback, Uyeda, and Muramatsu, Six years ago in London, the XIIIth General Assem- 1966); improvements in the transmission of VLF and bly of URSI adopted a resolution (No. 2) which strongly LF radio signals (Milton, Fey, and Morgan, 1962; recommended continuous very-low-frequency (VLF) Barnes, Andrews, and Allan, 1965; Bonanomi, 1966; and low-frequency (LF) transmission monitoring US. -
Deep Space Atomic Clock
National Aeronautics and Space Administration Deep Space Atomic Clock tion and radio science. Here are some examples of how one-way deep-space tracking with DSAC can improve navigation and radio science that is not supported by current two-way tracking. Ground-based 1. Simultaneously track two spacecraft on a atomic clocks are downlink with the Deep Space Network (DSN) the cornerstone of at destinations such as Mars, and nearly dou- spacecraft navigation ble a space mission’s tracking data because it for most deep-space missions because of their use no longer has to “time-share” an antenna. in generating precision two-way tracking measure- ments. These typically include range (the distance 2. Improve tracking data precision by an order of between two objects) and Doppler (a measure of magnitude using the DSN’s Ka-band downlink the relative speed between them). A two-way link (a tracking capability. signal that originates and ends at the ground track- ing antenna) is required because today’s spacecraft 3. Mitigate Ka-band’s weather sensitivity (as clocks introduce too much error for the equivalent compared to two-way X-band) by being able one-way measurements to be useful. Ground atom- to switch from a weather-impacted receiving ic clocks, while providing extremely stable frequen- antenna to one in a different location with no cy and time references, are too large for hosting on tracking outages. a spacecraft and cannot survive the harshness of space. New technology is on the horizon that will 4. Track longer by using a ground antenna’s en- change this paradigm. -
Atomic Clocks: an Application of Spectroscopy in the Last Installment of This Column (1), I Talked About Clocks As the First Scientific Instrument
14 Spectroscopy 21(1) January 2007 www.spectroscopyonline.com The Baseline Atomic Clocks: An Application of Spectroscopy In the last installment of this column (1), I talked about clocks as the first scientific instrument. What do clocks have to do with spectroscopy? Actually, the world’s most accurate clocks, atomic clocks, are based upon a spectroscopic transition of cesium or other elements, making spectroscopy a fundamental tool in our measurements of the natural universe. David W. Ball ime is one of the seven fundamental quantities in Originally, a second was defined as part of a minute, nature. I made a case in the last installment of this which was part of an hour, which was in turn defined as T column (1) that mechanical devices for measuring part of a day. Thus, 1 s was 1/(60 ϫ 60 24), or 1/86,400 time — clocks — might be considered the world’s first sci- of a day. However, even by the 17th century, defining the entific instruments. Clocks are ubiquitous because the day itself was difficult. Was the day based upon the position measurement of time is a fundamental activity that is im- of the sun (the solar day) or the position of distant stars portant to computer users, pilots, and lollygaggers alike. (the sidereal day)? At what latitude (that is, position toward the north or south) is a day measured? Over time it was rec- The Second ognized that measuring time accurately was a challenge. Quantities of time are expressed in a variety of units that In 1660, the Royal Society proposed that a second be de- we teach our grade-schoolers, but the IUPAC-approved termined by the half-period (that is, one swing) of a pendu- fundamental unit of time is the second (abbreviated “s” not lum of a given length. -
Splash Proof Atomic Clock with Outdoor Temperature/Humidity
SPLASH PROOF ATOMIC CLOCK WITH OUTDOOR TEMPERATURE/HUMIDITY MODEL: 515-1912 DC: 092419 TABLE OF CONTENTS 3. Power up 3. Buttons 3. Atomic Time 4. Settings Menu 5. Custom Display Views 6. Timer 7. Search for Outdoor Sensor 7. Low Battery 7. Specifications 8. We’re Here to Help 8. Join the Conversation 8. Warranty Info 8. Care and Maintenance 8. FCC Statement 8. Canada Statement Atomic Digital Clock Page | 2 POWER UP 1. Insert 2-AA batteries into your Outdoor Sensor. 2. Insert 2-AA batteries into your Atomic Clock. 3. Configure basic Settings. 4. Once the sensor is reading to your clock, place sensor outside in a shaded location. Watch sensor mounting video: bit.ly/TH_SensorMounting TX191TH AA Outdoor Sensor AA AA AA 515-1912 Atomic Clock BUTTONS TIMER +PLUS (+) MINUS- (-) SET Hold: Set Timer duration Hold: Search for Press: Change Hold: Set Time Press: Start, Pause or Outdoor Sensor Display Press: Search for Restart Timer Press: Adjust Values Atomic Time Signal ATOMIC TIME • The clock will only search for the WWVB Atomic Time Signal at UTC 7:00, 8:00, 9:00, 10:00, and 11:00. • The Atomic Time Indicator will flash while searching, and will remain solid on screen when connected. • From the normal time display, press the SET button to search for the WWVB Atomic Time Signal. Atomic Digital Clock Page | 3 SETTINGS MENU Daylight Saving Time Options: DST ON- Clock gains 1 hour in spring and loses 1 hour in the fall DST OFF- Clock remains in Standard Time all year long DST ALWAYS ON- Clock remains in Daylight Saving Time all year long Settings order: • Beep ON/OFF • Atomic ON/OFF • DST (Daylight Saving Time) o DST ON o DST OFF o DST ALWAYS ON • Time Zone TIME ZONES AST = Atlantic • Hour EST = Eastern • Minutes CST = Central • Year MST = Mountain PST = Pacific • Month AKT = Alaska • Date HAT = Hawaii • Fahrenheit/Celsius To begin: 1. -
Governing the Time of the World Written by Tim Stevens
Governing the Time of the World Written by Tim Stevens This PDF is auto-generated for reference only. As such, it may contain some conversion errors and/or missing information. For all formal use please refer to the official version on the website, as linked below. Governing the Time of the World https://www.e-ir.info/2016/08/07/governing-the-time-of-the-world/ TIM STEVENS, AUG 7 2016 This is an excerpt from Time, Temporality and Global Politics – an E-IR Edited Collection. Available now on Amazon (UK, USA, Ca, Ger, Fra), in all good book stores, and via a free PDF download. Find out more about E-IR’s range of open access books here Recent scholarship in International Relations (IR) is concerned with how political actors conceive of time and experience temporality and, specifically, how these ontological and epistemological considerations affect political theory and practice (Hutchings 2008; Stevens 2016). Drawing upon diverse empirical and theoretical resources, it emphasises both the political nature of ‘time’ and the temporalities of politics. This chronopolitical sensitivity augments our understanding of international relations as practices whose temporal dimensions are as fundamental to their operations as those revealed by more established critiques of spatiality, materiality and discourse (see also Klinke 2013). This transforms our understanding of time as a mere backdrop to ‘history’ and other core concerns of IR (Kütting 2001) and provides opportunities to reflect upon the constitutive role of time in IR theory itself (Berenskoetter 2011; Hom and Steele 2010; Hutchings 2007; McIntosh 2015). One strand of IR scholarship problematises the historical emergence of a hegemonic global time that subsumed within it local and indigenous times to become the time by which global trade and communications are transacted (Hom 2010, 2012). -
Time Signal Stations 1By Michael A
122 Time Signal Stations 1By Michael A. Lombardi I occasionally talk to people who can’t believe that some radio stations exist solely to transmit accurate time. While they wouldn’t poke fun at the Weather Channel or even a radio station that plays nothing but Garth Brooks records (imagine that), people often make jokes about time signal stations. They’ll ask “Doesn’t the programming get a little boring?” or “How does the announcer stay awake?” There have even been parodies of time signal stations. A recent Internet spoof of WWV contained zingers like “we’ll be back with the time on WWV in just a minute, but first, here’s another minute”. An episode of the animated Power Puff Girls joined in the fun with a skit featuring a TV announcer named Sonny Dial who does promos for upcoming time announcements -- “Welcome to the Time Channel where we give you up-to- the-minute time, twenty-four hours a day. Up next, the current time!” Of course, after the laughter dies down, we all realize the importance of keeping accurate time. We live in the era of Internet FAQs [frequently asked questions], but the most frequently asked question in the real world is still “What time is it?” You might be surprised to learn that time signal stations have been answering this question for more than 100 years, making the transmission of time one of radio’s first applications, and still one of the most important. Today, you can buy inexpensive radio controlled clocks that never need to be set, and some of us wear them on our wrists. -
Proposal of Atomic Clock in Motion: Time in Moving Clock
Proposal of atomic clock in motion: Time in moving clock Masanori Sato Honda Electronics Co., Ltd., 20 Oyamazuka, Oiwa-cho, Toyohashi, Aichi 441-3193, Japan E-mail: [email protected] Abstract: The time in an atomic clock in motion is discussed using the analogy of a sing around sound source. Sing around frequency is modified according to the motion of the sing around sound source, using the Lorentz transformation equation. Thus, if we use the sing around frequency as a reference, we can define the reference “time”. We propose that the time delay of an atomic clock in motion be derived using the sing around method. In this letter, we show that time is defined by a combination of light speed and motion. PACS numbers: 03.30.+p Key words: Atomic clock in motion, Lorentz transformation, Michelson-Morley experiment, special relativity, sing around 1. INTRODUCTION The derivation of the Lorentz transformation equation was clearly described by Feynman et al. [1]. The Doppler shift equation was observed to be different between acoustic wave and light, thus we determined the reason for this difference [2]. We pointed out that the frequency of a sound source should be modified according to its motion. We proposed a sing around sound source whose frequency changes with its velocity, as is suggested by the Lorentz transformation equation. We discussed the reference frequency of a moving sound source with respect to the Lorentz transformation equation. The sing around sound source moving in air exhibits a decrease in frequency. If the modified frequency is used as a reference frequency, the time delay in a moving frame can be explained [2]. -
Best Practices for Leap Second Event Occurring on 30 June 2015
26 May 2015 Best Practices for Leap Second Event Occurring on 30 June 2015 Sponsored by the National Cybersecurity and Communications Integration Center in coordination with the United States Naval Observatory, National Institute of Standards and Technology, the USCG Navigation Center, and the National Coordination Office for Space-Based Positioning, Navigation and Timing. This product is intended to assist federal, state, local, and private sector organizations with preparations for the 30-June 2015 Leap Second event. Entities using precision time should be mindful that no leap second adjustment has occurred on a non- holiday weekday in the past decade. Of the three leap seconds implemented since 2000, two have been scheduled on 31 December and the most recent was on Sunday, 1 July 2012. Please report operational challenges you experience to the following organizations: GPS -- United States Coast Guard Navigation Center (NAVCEN), via the NAVCEN Website, http://www.navcen.uscg.gov/ under "Report a GPS Problem" Network Timing Protocols (NTP) -- Michael Lombardi at NIST, Boulder, Colorado at 303-497- 3212, or [email protected]. ============================================= 1. Leap Second Introduction The Coordinated Universal Time (UTC) time standard, based on atomic clocks, is widely used for international timekeeping and as the reference for time in most countries. UTC is the basis of legal time for most of the world. UTC must be adjusted at irregular intervals to maintain its correlation to mean solar time due to irregularities in the Earth’s rotation. These adjustments, called leap seconds, are pre-determined. The next leap second will occur on 30 June 2015 at 23:59:59 UTC. -
Radio Navigational Aids
RADIO NAVIGATIONAL AIDS Publication No. 117 2014 Edition Prepared and published by the NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY Springfield, VA © COPYRIGHT 2014 BY THE UNITED STATES GOVERNMENT NO COPYRIGHT CLAIMED UNDER TITLE 17 U.S.C. WARNING ON USE OF FLOATING AIDS TO NAVIGATION TO FIX A NAVIGATIONAL POSITION The aids to navigation depicted on charts comprise a system consisting of fixed and floating aids with varying degrees of reliability. Therefore, prudent mariners will not rely solely on any single aid to navigation, particularly a floating aid. The buoy symbol is used to indicate the approximate position of the buoy body and the sinker which secures the buoy to the seabed. The approximate position is used because of practical limitations in positioning and maintaining buoys and their sinkers in precise geographical locations. These limitations include, but are not limited to, inherent imprecisions in position fixing methods, prevailing atmospheric and sea conditions, the slope of and the material making up the seabed, the fact that buoys are moored to sinkers by varying lengths of chain, and the fact that buoy and/or sinker positions are not under continuous surveillance but are normally checked only during periodic maintenance visits which often occur more than a year apart. The position of the buoy body can be expected to shift inside and outside the charting symbol due to the forces of nature. The mariner is also cautioned that buoys are liable to be carried away, shifted, capsized, sunk, etc. Lighted buoys may be extinguished or sound signals may not function as the result of ice or other natural causes, collisions, or other accidents. -
STANDARD FREQUENCIES and TIME SIGNALS (Question ITU-R 106/7) (1992-1994-1995) Rec
Rec. ITU-R TF.768-2 1 SYSTEMS FOR DISSEMINATION AND COMPARISON RECOMMENDATION ITU-R TF.768-2 STANDARD FREQUENCIES AND TIME SIGNALS (Question ITU-R 106/7) (1992-1994-1995) Rec. ITU-R TF.768-2 The ITU Radiocommunication Assembly, considering a) the continuing need in all parts of the world for readily available standard frequency and time reference signals that are internationally coordinated; b) the advantages offered by radio broadcasts of standard time and frequency signals in terms of wide coverage, ease and reliability of reception, achievable level of accuracy as received, and the wide availability of relatively inexpensive receiving equipment; c) that Article 33 of the Radio Regulations (RR) is considering the coordination of the establishment and operation of services of standard-frequency and time-signal dissemination on a worldwide basis; d) that a number of stations are now regularly emitting standard frequencies and time signals in the bands allocated by this Conference and that additional stations provide similar services using other frequency bands; e) that these services operate in accordance with Recommendation ITU-R TF.460 which establishes the internationally coordinated UTC time system; f) that other broadcasts exist which, although designed primarily for other functions such as navigation or communications, emit highly stabilized carrier frequencies and/or precise time signals that can be very useful in time and frequency applications, recommends 1 that, for applications requiring stable and accurate time and frequency reference signals that are traceable to the internationally coordinated UTC system, serious consideration be given to the use of one or more of the broadcast services listed and described in Annex 1; 2 that administrations responsible for the various broadcast services included in Annex 2 make every effort to update the information given whenever changes occur. -
What Time I T
Does Anybody Really What Time It Is? 24/7/365, Here's How Time Got On Your Best Side By Michael A. Lombardi ccasionally I'll talk to people who known to most radio buffs. He used a can't believe that some radio sta- spark-gap transmitter to successfully 0tions exist solely to transmit accu- send radio signals over a distance of more rate time. While they wouldn't poke fun than one mile in 1895. By 1899 he had at the Weather Channel or even a radio transmitted signals across the English station that plays nothing but Garth Channel, and sent signals across the Brooks records (imagine that), people Atlantic Ocean in 1901. often make jokes about time signal sta- Surprisingly, in the midst of Marconi's tions. They'll ask "Doesn't the program- early work, before any radio stations exist- ming get a little boring?'or "How does ed, or before the public even completely the announcer stay awake?'There have believed his results, a proposal was made even been parodies of time signal sta- to use the new wireless medium to broad- tions. A recent Internet spoof of WWV cast time. In November 1898. an optical containedzingers like "we'll be back with instrument maker and inventor named Sir the time on WWV in just a minute, but Howard Grubb addressed the Royal first, here's another minute." Dublin Society and proposed the concept An episode of the animated Powerpuff of a radio controlled clock. After many Girls joined in the fun with a skit featur- years of working with astronomical obser- ing a TV announcer named Sonnv Dial L, vatories.