pyacs.lib.gpstime module

Note: Leap seconds still needs to be checked an improve A Python implementation of GPS related time conversions.

Copyright 2002 by Bud P. Bruegger, Sistema, Italy

Modifications for GPS seconds by Duncan Brown

PyUTCFromGpsSeconds added by Ben Johnson

This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

GPS Time Utility functions

This file contains a Python implementation of GPS related time conversions.

The two main functions convert between UTC and GPS time (GPS-week, time of week in seconds, GPS-day, time of day in seconds). The other functions are convenience wrappers around these base functions.

A good reference for GPS time issues is:

Note that python time types are represented in seconds since (a platform dependent Python) Epoch. This makes implementation quite straight forward as compared to some algorigthms found in the literature and on the web.

pyacs.lib.gpstime.dayOfWeek(year, month, day)[source]

returns day of week: 0=Sun, 1=Mon, .., 6=Sat

pyacs.lib.gpstime.gpsWeek(year, month, day)[source]

returns (full) gpsWeek for given date (in UTC)

pyacs.lib.gpstime.julianDay(year, month, day)[source]

returns julian day=day since Jan 1 of year

pyacs.lib.gpstime.mkUTC(year, month, day, hour, minute, sec)[source]

similar to python’s mktime but for utc


returns tuple from a python time value in UTC

pyacs.lib.gpstime.wtFromUTCpy(pyUTC, leapSecs=14)[source]

convenience function: allows to use python UTC times and returns only week and tow

pyacs.lib.gpstime.gpsFromUTC(year, month, day, hour, minute, ssec, leapSecs=30)[source]

converts UTC to: gpsWeek, secsOfWeek, gpsDay, secsOfDay

a good reference is:

This is based on the following facts (see reference above):

GPS time is basically measured in (atomic) seconds since January 6, 1980, 00:00:00.0 (the GPS Epoch)

The GPS week starts on Saturday midnight (Sunday morning), and runs for 604800 seconds.

Currently, GPS time is 13 seconds ahead of UTC (see above reference). While GPS SVs transmit this difference and the date when another leap second takes effect, the use of leap seconds cannot be predicted. This routine is precise until the next leap second is introduced and has to be updated after that.

SOW = Seconds of Week SOD = Seconds of Day

Note: Python represents time in integer seconds, fractions are lost!!!

pyacs.lib.gpstime.UTCFromGps(gpsWeek, SOW, leapSecs=14)[source]

converts gps week and seconds to UTC

see comments of inverse function!

SOW = seconds of week gpsWeek is the full number (not modulo 1024)

pyacs.lib.gpstime.GpsSecondsFromPyUTC(pyUTC, _leapSecs=14)[source]

converts the python epoch to gps seconds

pyEpoch = the python epoch from time.time()