NAME Time::GPS - Global Positioning System time DESCRIPTION The Global Positioning System (GPS) includes as an integral feature the dissemination of a very precise time scale. This time scale is produced by atomic clocks on the satellites, and is steered to keep in step with International Atomic Time (TAI). The GPS time scale is thus indirectly a realisation of Terrestrial Time (TT). GPS time is one of the most accurate and the most accessible realisations of TAI. This module represents instants on the TAI time scale as a scalar number of TAI seconds since an epoch. This is an appropriate form for all manner of calculations. The epoch used is that of TAI, at UT2 instant 1958-01-01T00:00:00.0 as calculated by the United States Naval Observatory, even though GPS did not exist then. This matches the convention used by "Time::TAI" for instants on the TAI scale and by "Time::TT" for instants on the TT scale. There is also a conventional way to represent GPS time instants using day-based notations associated with planetary rotation `time' scales. The `day' of GPS is a nominal period of exactly 86400 GPS seconds, which is slightly shorter than an actual Terran day. The start of the GPS time scale, at UTC instant 1980-01-06T00:00:00.0 (TAI instant 1980-01-06T00:00:19.0) is assigned the label 1980-01-06T00:00:00.0 (MJD 44244.0). Because GPS time is not connected to Terran rotation, and so has no inherent concept of a day, it is somewhat misleading to use such day-based notations. Conversion between this notation and the linear count of seconds is supported by this module. This notation does not match the similar day-based notations used for TAI and TT. INSTALLATION perl Build.PL ./Build ./Build test ./Build install AUTHOR Andrew Main (Zefram) COPYRIGHT Copyright (C) 2006, 2009, 2010, 2012 Andrew Main (Zefram) LICENSE This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.