Kinda/sorta another Y2K problem for GPS

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DEyncourt
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Joined: Sun Jan 20, 2008 2:38 am

Kinda/sorta another Y2K problem for GPS

Post by DEyncourt »

Some older devices which use the US GPS system may stop working in April 2019.

Basically the standard GPS system has only 10 bits to count the weeks. The initial setup started on January 1, 1980, so just short of every 20 years the count will flip from 1023 to 0. The last time this happened was in 1999, so while devices using GPS were not that common to the public, it was also hidden by the more general Y2K problem.

Now without likely firmware corrections, some older devices will revert to 1999 and will be getting nonsensical data from GPS satellites starting in April.

Do note that since about 2010 newer devices that use GPS which follow the ICD-200/IS-GPS-200 specification are set to handle the April reset gracefully, so you might check for this spec with any device based on older designs.

Other newer devices use a 13-bit counter so they can continue to work for 8 times longer.
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