GPS Calendars

Geospatial Resources: GPS Calendars

GPS or GNSS Calendars are different then traditional calendars that most of us are used to working with, yet they are pretty common these days due to the increased use of GPS equipment. Yet there is never one around when you need one, so if you find your self doing a lot of GPS field work like myself then you may notice that you will working in Julian Days & GPS Weeks frequently so will want to print off your own copy or use an online utility to help you out.

For those new to GPS or GNSS Calendars: Julian Day is simply the numeric number of the day in that given year, example March 5th of the year 2013 would be the 64th day of the year with a julian day of 064 and a GPS week of 1730.

The GPS Week # would be 17302 (the # 2 on the end represents Monday from the formula Sunday=0, Monday=1, Tuesday=2, Wednesday=3, Thursday=4, Friday=5, Saturday=6).

Now one can easily calculate this info but I find it quicker to just resort to reference pages or use online utilities and here a few that I use:

NOAA GPS Reference Calendar or Canadian Spatial Reference System GPS Calendars provide PDF versions for printing your own reference pages

http://earth-info.nga.mil/GandG/sathtml/calendars.html

The Canadian Geodetic Service offers an online interactive GPS calendar utility that I often use (http://webapp.geod.nrcan.gc.ca/geod/tools-outils/calendr.php), simply click on a date in the calendar and the utility will show you the corresponding Julian Day, GPS Week and GPS Week Number for various years