Do you remember the Y2K bug scare? Here’s a quick refresher — many people believed that computer systems were going to go haywire at the start of the year 2000 due to how they handled dates.
See, in the early days of computing, software was programmed to abbreviate years in double digits, say “1984” to “84,” to save (at that time) precious memory space. Many people feared that computers may misinterpret the year “2000” as “1900,” causing systems that rely on precise date records to crash and burn.
Thankfully, the Y2K bug came and went and the whole world didn’t exactly go up in flames. Now, something similar is about to happen to GPS units worldwide and the question is this — are we prepared for it?
The 2019 GPS Week Rollover
The great big eyes in the sky known as the Global Positioning System (GPS) not only tells you how to get to the nearest Starbucks, it also supplies precise timing information — called Coordinated Universal Time (UTC) — to critical systems including communications and power grids.
Aside from that, GPS also transmits accurate dates and times to receivers by providing them with the current week and the number of seconds we are into the week. The receiver will then translate these figures into a more readable month, day, year and time of day format.
Now, here’s the problem – these timestamps are encoded in a 10-bit field and therefore, the week number can only accommodate 1,024 integer values. This means that every 1,024 weeks, or around 20 years, the week counter has to reset back to zero and work its way back to 1,023 all over again.
The very first GPS week started on Jan. 6, 1980. Then the first rollover occurred 1,024 weeks later on August 21, 1999. This means that this year, on April 6, 2019, the counter will hit its 1,024th week again and will reset back to zero.
You probably know where this is headed, huh? Yep, this could mean trouble if a GPS receiver is not programmed or patched to handle the rollover.
Since GPS requires accurate timing to determine precise locations (a nanosecond error in time equals one foot in position error), not only will your GPS receiver display the wrong date and time, it will output the wrong coordinates too.
This could cause headaches for older data and navigation systems that rely on GPS for accurate timing and location.
Are we all doomed? Not really
This all sounds scary but should you be concerned, though? Will it be a great “maps-ocalypse” or will it just fizzle out as Y2K did in 1999?
Well, if you have a GPS unit that was built after 2010 or a GPS receiver that has received firmware updates in the last 10-15 years, then you should be fine.
Thankfully, manufacturers of GPS gadgets have prepared for the 2019 GPS Week Rollover and it’s likely that most modern GPS systems conform to the compatible ICD-200/IS-GPS-200 standard.
However, there’s still a possibility that your GPS unit will misinterpret the rollover and turn back its clock to Jan. 6, 1980. So come April 6, please make sure that your GPS is displaying the correct time.
If it’s saying that you’re suddenly back in the 1980s — no, you’re not going all Marty McFly at 88 miles per hour. All it probably needs is a firmware update.
DHS guidelines for the rollover
To ensure that critical systems that rely on GPS won’t be affected by the 2019 rollover, the Department of Homeland Security has these recommendations for the operators of such equipment:
- Investigate and understand their possible dependencies on GPS for obtaining UTC
- Contact the GPS manufacturers of devices they use to obtain UTC to:
A) Understand the manufacturers’ preparedness for the April 6 2019 rollover
B) Understand the actions required by critical infrastructure and other owners and operators to ensure proper operation through the April 6, 2019 rollover
- Ensure that the firmware of such devices is up to date