EOW
What is EOW?
- End Of Week
(EOW) refers to a common GPS satellite week number rollover issue that
affects many handheld GPS receivers.
- The GPS satellites that provide your GPS receiver with date/time
information reset their internal database every 1024 weeks (19.69 years).
- Each time this week number rollover occurs, many older GPS receivers
will begin reporting an incorrect date nearly 20 years in the past.
- Most modern GPS receivers have been pre-programmed to handle these
events without user intervention.
Why does this 'Week Number Rollover' happen?
- Most legacy GPS satellites were configured to transmit the current week
number using a 10-bit message.
- This 10-bit system limits the amount of time that can be covered to 1024
weeks, or 19.7 years.
- Official GPS time started on January 6 (1980), resulting in the first
week number rollover event occurring on August 22 (1999).
- Additional week number rollover events will occur on April 7 (2019) and
again on November 21 (2038), etc.
- Future generation GPS satellites will be configured to use a 13-bit week
number, effectively resolving this ambiguity.
- Read this
gpsworld article for additional information.
Can I still use my GPS
receiver?
- The short answer is 'Yes, most GPS receivers will still be able to
determine your position accurately', however...
- Any features or functions that use the current date/time will no longer
operate properly.
- For example, marked waypoints and saved tracks will have incorrect
date/time stamps.
- Additional operations that require month/year conversions may also fail.
Can I correct the time on my Garmin GPS
receiver?