Enhanced View of Time Specification
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Mike Zornek • March 2020
Working with Time Zones Inside a Phoenix App Mike Zornek • March 2020 Terminology Layers of Wall Time International Atomic Time (ITA) Layers of Wall Time Universal Coordinated Time (UTC) International Atomic Time (ITA) Layers of Wall Time Universal Coordinated Time (UTC) Leap Seconds International Atomic Time (ITA) Layers of Wall Time Standard Time Universal Coordinated Time (UTC) Leap Seconds International Atomic Time (ITA) Layers of Wall Time Standard Time Time Zone UTC Offset Universal Coordinated Time (UTC) Leap Seconds International Atomic Time (ITA) Layers of Wall Time Wall Time Standard Time Time Zone UTC Offset Universal Coordinated Time (UTC) Leap Seconds International Atomic Time (ITA) Layers of Wall Time Wall Time Standard Offset Standard Time Time Zone UTC Offset Universal Coordinated Time (UTC) Leap Seconds International Atomic Time (ITA) Things Change Wall Time Standard Offset Politics Standard Time Time Zone UTC Offset Politics Universal Coordinated Time (UTC) Leap Seconds Celestial Mechanics International Atomic Time (ITA) Things Change Wall Time Standard Offset changes ~ 2 / year Standard Time Time Zone UTC Offset changes ~ 10 / year Universal Coordinated Time (UTC) 27 changes so far Leap Seconds last was in Dec 2016 ~ 37 seconds International Atomic Time (ITA) "Time Zone" How Elixir Represents Time Date Time year hour month minute day second nanosecond NaiveDateTime Date Time year hour month minute day second nanosecond DateTime time_zone NaiveDateTime utc_offset std_offset zone_abbr Date Time year hour month minute day second -
Standard Frequencies and Time Signals from NBS Stations WWV and WWVH
UNITED STATES DEPARTMENT OF COMMERCE Frederick H. Mueller, Secretary NATIONAL BUREAU OF STANDARDS A. V. Astin, Director Standard Frequencies and Time Signals From NBS Stations WWV and WWVH National Bureau of Standards Miscellaneous Publication 236 Reprinted July 1, 1961 with corrections (First issued December 1, 1960) Detailed descriptions are given of six technical services broadcast by National Bureau of Standards radio stations WWV and WWVH. The services include 1, standard radio frequencies; 2, standard audio frequencies; 3, standard time intervals; 4, standard musical pitch; 5, time signals; and 6, radio propagation forecasts. Other domestic and foreign standard frequency and time signal broadcasts are tabulated. 1. Technical Services and Related Information The National Bureau of Standards’ radio sta- at 1900 UT (Universal Time, UT, is the same as tions WWV (in operation since 1923) and WWVH GMT and GCT). (since 1948) broadcast six widely used technical (b) Accuracy services: 1, Standard radio fiequencies; 2, stand- Since December 1, 1957, the standard radio ard audio frequencies ; 3, standard time intervals ; transmissions from stations WWV and WWVII 4, standard musical pitch; 5, time signals; 6, radio have been held as nearly constant as possible with propagation forecasts. respect to the atomic frequency standards which The radio stations are located as follows: WWV, constitute the United States Frequency Standard Beltsville, Maryland (Box 182, Route 2, Lanham, (USFS), maintained and operated by the Radio Marvland) : WWVH. Maui. Hawaii (Box 901. Standards Laboratory of the National Bureau of PunGene, Maui). Coordinatk of the stitions are.:‘ Standards. Carefully made atomic standards WWV (lat. 38’59’33’’ N, long. -
Operation Guide 3448
MO1611-EA © 2016 CASIO COMPUTER CO., LTD. Operation Guide 3448 ENGLISH Congratulations upon your selection of this CASIO watch. Warning ! • The measurement functions built into this watch are not intended for taking measurements that require professional or industrial precision. Values produced by this watch should be considered as reasonable representations only. • Note that CASIO COMPUTER CO., LTD. assumes no responsibility for any damage or loss suffered by you or any third party arising through the use of your watch or its malfunction. E-1 About This Manual • Keep the watch away from audio speakers, magnetic necklaces, cell phones, and other devices that generate strong magnetism. Exposure to strong • Depending on the model of your watch, display text magnetism can magnetize the watch and cause incorrect direction readings. If appears either as dark figures on a light background, or incorrect readings continue even after you perform bidirectional calibration, it light figures on a dark background. All sample displays could mean that your watch has been magnetized. If this happens, contact in this manual are shown using dark figures on a light your original retailer or an authorized CASIO Service Center. background. • Button operations are indicated using the letters shown in the illustration. • Note that the product illustrations in this manual are intended for reference only, and so the actual product may appear somewhat different than depicted by an illustration. E-2 E-3 Things to check before using the watch Contents 1. Check the Home City and the daylight saving time (DST) setting. About This Manual …………………………………………………………………… E-3 Use the procedure under “To configure Home City settings” (page E-16) to configure your Things to check before using the watch ………………………………………… E-4 Home City and daylight saving time settings. -
GLONASS Time. 2. Generation of System Timescale
GLONASS TIME SCALE DESCRIPTION Definition of System 1. System timescale: GLONASS Time. 2. Generation of system timescale: on the basis of time scales of GLONASS Central Synchronizers (CS). 3. Is the timescale steered to a reference UTC timescale: Yes. a. To which reference timescale: UTC(SU), generated by State Time and Frequency Reference (STFR). b. Whole second offset from reference timescale: 10800 s (03 hrs 00 min 00 s). tGLONASS =UTC (SU ) + 03 hrs 00 min c. Maximum offset (modulo 1s) from reference timescale: 660 ns (probability 0.95) – in 2014; 4 ns (probability 0.95) – in 2020. 4. Corrections to convert from satellite to system timescale: SVs broadcast corrections τn(tb) and γn(tb) in L1, L2 frequency bands for 30-minute segments of prediction interval. a. Type of corrections given; include statement on relativistic corrections: Linear coefficients broadcast in operative part of navigation message for each SV (in accordance with GLONASS ICD). Periodic part of relativistic corrections taking into account the deviation of individual SVs orbits from GLONASS nominal orbits is incorporated in calculation of broadcast corrections to convert from satellite timescale to GLONASS Time. b. Specified accuracy of corrections to system timescale: The accuracy of calculated offset between SV timescale and GLONASS Time – 5,6 ns (rms). c. Location of corrections in broadcast messages: L1/L2 - τn(t b) – line 4, bits 59 – 80 of navigation frame; - γn(t b) - line 3, bits 69 – 79 of navigation frame. d. Equation to correct satellite timescale to system timescale: L1/L2 tGLONASS = t +τ n (tb ) − γ n (tb )( t − tb ) where t - satellite time; τn(t b), γn(tb) - coefficients of frequency/time correction; tb - time of locking frequency/time parameters. -
GPS Operation V1 4.Fm
Operation of the Courtyard CY490 SPG While Connected to the GPS Receiver No part of this document may be transmitted or reproduced in any form or by any means, electronic or mechanical, including photocopy, recording or any information storage and retrieval system, without permission in writing from Courtyard Electronics Limited. Introduction One of the best sources of reference for both frequency and time, is the Global Positioning System. The GPS system only transmits a complete UTC-GPS time message once every 12.5 minutes. So when powering up the GPS receiver it might be best to wait 12.5 minutes before relying on the GPS time. The CY490 SPG uses a 12 channel GPS receiver. As the SPG is powered the GPS receiver begins searching for satellites from which it can get time, frequency and phase information. In a good reception area as many as 12 satellites may be visible. The SPG only requires 3 satellites to be located and fully decoded before it can start using the GPS data. The search for the first 3 satellites can take up to 3 minutes, but is often accomplished in 2. If less than 3 satellites are available, the SPG will not lock to GPS. The number of satellites can be monitored on the first menu and on the remote control program CY490MiniMessage. The CY490MiniMessage gives a graphic view of satellites and provides much information for the user. GPS and television From a GPS receiver, the Master Clock can derive UTC and also add the appropriate time offset and provide corrected local time. -
8 Alert Input Monitor
Chapter 1: Introduction OMEGAPHONE® OMA-P1108 Voice Synthesized Monitoring & Alarm System User’s Manual IMPORTANT SAFETY INSTRUCTIONS Your OMA-P1108 has been carefully designed to give you years of safe, reliable performance. As with all electrical equipment, however, there are a few basic precautions you should take to avoid hurting yourself or damaging the unit: • Read the installation and operating instructions in this manual carefully. Be sure to save it for future reference. • Read and follow all warning and instruction labels on the product itself. •To protect the OMA-P1108 from overheating, make sure all openings on the unit are not blocked. Do not place on or near a heat source, such as a radiator or heat register. • Do not use your OMA-P1108 near water, or spill liquid of any kind into it. • Be certain that your power source matches the rating listed on the AC power transformer. If you’re not sure of the type of power supply to your facility, consult your dealer or local power company. • Do not allow anything to rest on the power cord. Do not locate this product where the cord will be abused by persons walking on it. • Do not overload wall outlets and extension cords, as this can result in the risk of fire or electric shock. •Never push objects of any kind into this product through ventilation holes as they may touch dangerous voltage points or short out parts that could result in a risk of fire or electric shock. •To reduce the risk of electric shock, do not disassemble this product, but return it to Omega Customer Service, or other approved repair facility, when any service or repair work is required. -
15 Pecision System Clock Architecture
Pecision System Clock Architecture 15 Pecision System Clock Architecture “Time iz like money, the less we hav ov it teu spare the further we make it go.” Josh Billing Encyclopedia and Proverbial Philosophy of Wit and Humor, 1874 225 Pecision System Clock Architecture Limitations of the Art Over the almost three decades that NTP has evolved, accuracy expectations have improved from 100 ms to less than 1 ms on fast LANs with multiple segments interconnected by switches and less than a few milliseconds on most campus and corporate networks with multiple subnets interconnected by routers. Today the practical expectations with a GPS receiver, PPS signal and precision kernel support are a few microseconds. In principle the ultimate expectations are limited only by the 232-ps resolution of the NTP timestamp format or about the time light travels three inches. Improving accuracy expectations below the PPS regime is proving intricate and tricky. In this chapter we turn to the most ambitious means available to minimize errors in the face of hardware and software not designed for extraordinary timekeeping. First we examine the hardware and software components for a precision system clock and evolve an optimal design. Next we survey timestamping techniques using both hardware, driver and software methods to minimize errors due to media, device and operating system latencies. Finally, we explore the IEEE 1588 Precision Time Protocol (PTP), how it is used in a high speed LAN, and how it and NTP can sail in the same boat. The parting shots section proposes a hardware assisted design which provides performance equivalent to PTP with only minimal modifications to the Unix operating system kernel. -
Kronosync® Transmitter Operations Guide
KRONOsync Transmitter System Operations Guide 11869 Teale St. Culver City, CA 90230 Tech Support: 888-608-0125 www.InnovationWireless.com System Operations Guide Thank You for Purchasing the KRONOsync GPS/NTP Wireless Clock System from Innovation Wireless. We appreciate having you as a customer and wish you many years of satisfied use with your KRONOsync clock system. Innovation Wireless has incorporated our 40+ years of experience in clock manufacturing with the best of today’s innovative technology into the KRONOsync system. The result being an accurate, reliable, ‘Plug and Play’, wireless clock system for your facility. Please read this manual thoroughly before making any connections and powering up the transmitter. Following these instructions will enable you to obtain optimum performance from the KRONOsync Wireless Clock System. If you have any questions during set-up, please contact Technical Support at 1-888-608-0125. Thank you again for your purchase. From all of us at Innovation Wireless 2 | P a g e Innovation Wireless System Operations Guide System Operations Guide Table of Contents KRONOsync Transmitter Set-up .................................................................................................................... 4 Mounting the GPS Receiver .......................................................................................................................... 4 Connecting the NTP Receiver........................................................................................................................ 4 Power -
Date and Time Terms and Definitions
Date and Time Terms and Definitions Date and Time Terms and Definitions Brooks Harris Version 35 2016-05-17 Introduction Many documents describing terms and definitions, sometimes referred to as “vocabulary” or “dictionary”, address the topics of timekeeping. This document collects terms from many sources to help unify terminology and to provide a single reference document that can be cited by documents related to date and time. The basic timekeeping definitions are drawn from ISO 8601, its underlying IEC specifications, the BIPM Brochure (The International System of Units (SI)) and BIPM International vocabulary of metrology (VIM). Especially important are the rules and formulas regarding TAI, UTC, and “civil”, or “local”, time. The international standards that describe these fundamental time scales, the rules and procedures of their maintenance, and methods of application are scattered amongst many documents from several standards bodies using various lexicon. This dispersion makes it difficult to arrive at a clear understanding of the underlying principles and application to interoperable implementations. This document collects and consolidates definitions and descriptions from BIPM, IERS, and ITU-R to clarify implementation. There remain unresolved issues in the art and science of timekeeping, especially regarding “time zones” and the politically driven topic of “local time”. This document does not attempt to resolve those dilemmas but describes the terminology and the current state of the art (at the time of publication) to help guide -
Application Note AN2015-03
Application Note AN2015-03 Solving UTC and Local Time Time-Stamp Challenges Using ACSELERATOR TEAM® SEL-5045 Software Joshua Hughes INTRODUCTION As intelligent electronic devices (IEDs) that allow historical data recording and trending (such as protective relays and revenue meters) are integrated into power systems, it becomes apparent that correlating time between devices at multiple locations can be a complex issue. It is good practice to connect high-accuracy clocks to all IEDs to allow for event analysis. When comparing events, it is usually easy to determine if one event record is applicable or not because of time zone differences or daylight-saving time (DST) discrepancies. However, when comparing continuous trending data, such as load profile data, it becomes much more important to record accurate time zone and DST information. Without this information, the data profile might not provide enough detail to determine what local time the data were recorded in. This application note describes the challenges associated with time zones and DST, and it presents two ACSELERATOR TEAM® SEL-5045 Software configurations for solving time-stamp ambiguity issues. PROBLEM The two major challenges associated with data time stamps are time zones and DST application. Most users prefer that IEDs in the field be programmed with local time to make their jobs easier, but this causes complications with older devices that do not understand time zones or DST. Time Zones Local times were first determined by apparent solar time using devices such as sundials. Because apparent solar time fluctuates based on where the measurement is taken (roughly four minutes for every degree of longitude), time zones were created to maintain a standard time between multiple regions. -
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. -
Corvil Coordinated Universal Time (UTC) Clock Synchronization Report CWP-180617 CORVIL COORDINATED UNIVERSAL TIME (UTC) CLOCK SYNCHRONIZATION REPORT
Corvil Coordinated Universal Time (UTC) Clock Synchronization Report CWP-180617 CORVIL COORDINATED UNIVERSAL TIME (UTC) CLOCK SYNCHRONIZATION REPORT Introduction In an increasingly algorithmic and machine-driven world, the integrity of time has become critical. Time precision and consistency has long been a factor in measuring and optimizing high performance environments (lest clock drift lead to negative latencies), but it has become the basis for auditability, accountability, and determining causality in digital business of all types. Market transparency and surveillance, AI oversight, and cybersecurity forensics all depend on proper sequencing of events that happen in short timescales (thousandths or millionths of a second in many cases). Regulators for the Financial Services industry have taken the first steps in requiring time precision and integrity as a critical component of transparency. These regulations begin with a requirement to establish clock synchronization with a Coordinated Universal Time (UTC) source. Compliance teams, business teams, and technical teams alike benefit from having independent and continuous assessment of their synchronization status – that is, traceability to UTC. Whether for meeting European Securities and Markets Authority (ESMA) MiFID II or Securities and Exchange Commission (SEC) Consolidated Audit Trail (CAT) requirements, or simply ensuring appropriate oversight of a foundational business technology, Corvil takes the complexity and guesswork out of obtaining that independent insight. Corvil’s clock synchronization reporting capabilities simplify daily compliance and risk assessment as well as on-demand audit reporting for any time period. The reported metrics deliver evidence of a level of granularity and an internal operational standard even tighter than regulatory requirements, providing a strategic investment to address future needs.