Author Topic: Global Positioning System (GPS) Rollover  (Read 558 times)

0 Members and 1 Guest are viewing this topic.

Offline WeatherHost

  • Forecaster
  • *****
  • Posts: 3550
Global Positioning System (GPS) Rollover
« on: April 18, 2019, 07:28:06 AM »
Odd statement on some of the pages showing River Gauges and Flood information:

"NOTICE:There is a service interruption for a number of stream gauges nationwide due to the Global Positioning System (GPS) Rollover that occurred on April 6 at 23:59 GMT. The National Weather Service is working with federal, state, and local partners to ensure those affected gauges obtain the necessary updates to resume data transmission. We apologize for the service interruption and hope to have the data restored as soon as possible."

Some followup searching finds:

"SUMMARY: Critical Infrastructure (CI) owners and operators and other users who obtain Coordinated Universal Time (UTC) from Global Positioning System (GPS) devices should be aware of the GPS Week Number (WN) rollover events and the possible effect a GPS WN rollover event may have on the reliability of the reported UTC. The legacy GPS navigation message has a ten (10) bit parameter that represents WN. Thus, the WN 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."

ICDHost, Webhosting:

Offline Mattk

  • Forecaster
  • *****
  • Posts: 1421
Re: Global Positioning System (GPS) Rollover
« Reply #1 on: April 18, 2019, 04:59:42 PM »
Some of NOAA's oceanic buoys may not be fixed until November due to location and access. Like it's not as if this issue just suddenly appeared one morning, it's been coming around (again) for nearly the past 20 years. Similar with BOM in Australia who had to cancel their weather balloon launches following the April 6 rollover due to affected equipment. Some marine navigation systems failed in a big way. Hard to understand really how some organisations and manufacturers got this so wrong?