GPS is not only useful for communications and navigation purposes but it has veritably become a lifeline of the world economy. We cannot conceive of modern-day trade, industry and commerce without GPS.
April 6 2019 seems to be just another date on the calendar. But it is not! On April 6 GPS will be rolled over to zero again and this process may lead to the introduction of fatal errors in GPS equipment and other machines that rely on GPS. The consequences of even a negligible error margin in GPS could lead to serious implications. For instance, the error of one nanosecond in GPS time can lead to one foot in position error.
Scientists globally are working against this tight deadline of April 6 to rectify the issue of GPS number rollover smoothly before it causes glitches in thousands of scientific equipment and leads to unimaginable loss and disruption. As a result of the week number rollover, GPS receivers could be set to the wrong time and as a result, transmit inaccurate data.
Scientists researching seismology and particles physics, along with everyone who uses GPS for scientific purposes, are checking their equipment to check whether they are vulnerable. Manufacturers are providing instructions to GPS users for fixing it.
It is an arduous task for scientists because it involves resetting equipment that might be underground or shrouded under blankets of ice. In some cases, equipment may have to be replaced entirely, in case the manufacturer isn’t providing a new upgrade.
High-precision instruments like seismometers and radio telescopes rely on GPS for fixing accurate time, staying in connect with the world and storing data. A slight malfunction could wreak havoc on millions of systems and cause unmitigated disruption.
Most consumer devices are expected to remain unexpected from the rollover because most of the new devices have been built to adjust themselves t and manufacturers are either rolling out new updates or advising people how to adjust their equipment. In case of old equipment, they won’t stop working as soon as clock strikes past midnight on April 6, but depending on their configuration and last update they will fail within weeks or months or even a year.
So users don’t need to panic and replace their old instruments beforehand or contact manufacturers for new firmware updates. Most of the companies are providing all the required information on their websites. Even the US Department of Homeland Security has issued a detailed memo for GPS users.
GPS number rollover and its need?
Anyone who gets Coordinated Universal Time (UTC) from GPS will have to be aware of the rollover and plan in advance
GPS transmits the precise date and time to a receiver by feeding the receiver with the current week and the current number of seconds into the week. Using this, the receiver is able to transmit date and time into the usual day, month, year, time format.
However, the field with the week number is a 10-bit binary, which limits the range of week number from 0 to 1024.
GPS Zero week started on January 6, 1980, when the GPS was first launched. The counter ran out and had to be reset from zero on August 21, 1999.
The WN (week number) parameter in the GPS navigation message “rolls over” to zero every 1024 weeks starting from 0000Z January 6, 1980. The next WN rollover will occur April 6, 2019.
The WN parameter is provided via a ten (10) bit parameter – or “counter.” The valid range of values for the WN parameter is 0 to 1023 (or 1024 total values). The WN parameter is incremented by one each week. At the end of the 1024th week, the counter experiences a rollover (resets) to 0. Each WN rollover event defines a new GPS Time Epoch.
Geoscience seems to be the hardest hit by the anticipation of GPS rollover. It has been months now since Geoscientists in the US, Germany and other countries are updating their receivers.
UNAVCO (University NAVSTAR Consortium), which is a consortium of more than 200 universities and organizations, has GPS instruments installed in almost every corner of the globe for research purposes and measuring Earth’s shape and crust motion. This wide network of interconnected GPS systems spread throughout the world is crucial for Earth Sciences research.
Geoscientists and other researchers have updated their instruments but there is no foolproof guarantee and based on the past record of 1999, some error margin might still be introduced which would then have to be corrected after painstaking data correction.
Scientific community world over surely will have sleepless nights on April 5 and won’t leave any lacuna for error to creep in the net day.